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HomeMy WebLinkAbout029 Stormwater ManagementGallatin Center Subdivision Preliminary Plat Application 29 - Stormwater Management Please see the responses below to the items requested in Section 38.220.060.A.10 in the Bozeman Municipal Code. Stormwater management. A stormwater management plan meeting the requirements of section 40.04.700 and the city's adopted stormwater master plan. To control the quality, volume and rate of stormwater runoff to storm drains and prevent the deterioration of water quality, all new developments and redevelopment projects will be required to submit a stormwater management plan or a comprehensive drainage plan to the city engineering department for approval. The stormwater master plan and city Design Standards establish standards and guidelines for implementing BMPs and stormwater management is incorporated by reference and made part of this article. 1. A comprehensive drainage plan is required for all developments larger than five acres. 2. A stormwater management plan is required for all developments equal to or less than five acres and are designated as a sketch plan or larger in accordance to chapter 38, article 19, or are within 50 feet of a watercourse. 3. Redevelopment projects will be required to submit stormwater management plans or operation and maintenance plans if they meet the criteria found in the stormwater master plan, Design Standards, chapter 38, article 19, or this article. 4. Stormwater management plans and comprehensive drainage plans shall: a. Prevent any off-site direct discharge of untreated stormwater and non- stormwater from development or redevelopment improvements. b. Minimize increased post-development discharge rates or volumes. c. Provide for the removal of total suspended solids or other constituents so as to meet the median concentration of the state general permit for MS4s generated from development or redevelopment runoff prior to any off-site discharge. d. Continue BMPs for appropriate periods of time. e. Protect groundwater from development runoff infiltration. f. Implement accepted BMPs to minimize impact of a development on existing offsite infrastructure and stormwater facilities. g. Address other stormwater issues identified by the city. h. Comply with section II of the city Design Standards, and chapter 38, article 23. 5. All drainage system reports, peak flow rates and runoff volume calculations, safety requirements, and grading plans shall be certified by a licensed professional authorized by the state to perform such functions. 6. The city reserves the right to amend, modify and/or add requirements to the stormwater master plan. Please see the stormwater report included in this section, which addresses the above requirements. Page 1 of 15 STORMWATER DESIGN REPORT FOR: GALLATIN CENTER SUBDIVISION (COB Planning Application #25217) BOZEMAN, MT Prepared By: WWC Engineering/Madison 895 Technology Drive, Suite 203 Bozeman, MT 59718 (406) 586-0262 April 2026 Page 3 of 15 Table of Contents 1. Introduction ................................................................................................................. 4 2. Hydrology and Hydrogeology .................................................................................... 5 3. Existing Stormwater and Drainage Conditions ....................................................... 6 3.1 Pre-Development Runoff Calculations ............................................................... 6 Table 1 – Pre-Development Runoff Conditions .................................................... 7 4. Culvert Analysis .......................................................................................................... 7 5. Proposed Stormwater Drainage System ................................................................... 9 5.1 Post-Development Runoff Calculations ............................................................. 9 5.2 Storage Volumes ............................................................................................... 10 Table 2 – Stormwater Basin Storage Summary .................................................. 10 5.3 Conveyance Calculations....................................................................................11 5.4 Groundwater Separation ................................................................................... 11 Table 3 – Groundwater Separation Compliance ................................................ 11 5.5 Water Quality and Treatment ............................................................................ 12 5.6 Pre-Development vs. Post-Development Comparison ...................................... 12 Table 4 – Minor Storm (10-Yr, 24-Hr) Pre- vs. Post-Development Runoff ........ 12 Table 5 – Major Storm (100-Yr, 24-Hr) Pre- vs. Post-Development Runoff ...... 13 6. Evaluation of Major Storm Flood Risks ................................................................. 13 7. Operation, Inspection, and Maintenance Considerations ..................................... 14 8. References .................................................................................................................. 14 9. Conclusion .................................................................................................................. 14 10. Appendices ................................................................................................................. 15 A. Subdivision Layout and Phasing Exhibit B. Stormwater Runoff Exhibits C. Hydraulic Soil Groups Map and Summary D. Culvert Modeling Inputs and Results E. Hydraulic Modeling Inputs and Results F. Retention/Infiltration Pond Details G. Operation, Inspection, and Maintenance Plan H. Groundwater Monitoring Well Map and Data I. Geotechnical Reports J. Infrastructure Design Sheets (Preliminary) K. Groundwater Mounding Calculations L. Conveyance Calculations Page 4 of 15 895 Technology Boulevard, Suite 203, Bozeman, MT 59718 | 406.586.0262 Gallatin Center Subdivision Stormwater Design Report 1. Introduction This design report provides an overview of the proposed stormwater system for the Gallatin Center Subdivision Phase 5, located south of Cattail Street, west of North 19th Avenue, and north of Baxter Lane. The current legal description of the property is Minor Sub 210, S35, T01 S, R05 E, Lot 3. The subdivision property consists of 68.33 acres of undeveloped land, which is hayed to maintain weed control. Future development of the property is anticipated to include a residential development on proposed Lot A. Lot B will be a remainder lot subject to separate subdivision reviews in the future. The property within Lot B (future phases) will be further subdivided with subsequent applications. The future phases within Lot B are anticipated to be used for commercial developments based on the location and zoning. The exhibit included in Appendix A of this report shows the overall layout of the subdivision. Please note that while this exhibits show roadways within the remainder lot (Lot B), those roadway locations are preliminary at this time, and will be installed with subsequent subdivisions. The future phase roadways are not included in this analysis, as they will not be installed with this subdivision. The property naturally drains from south to north and has two creeks running south to north through the property: East Catron Creek and West Catron Creek. A flood study report has been conducted, which analyzed the capacity of the creeks during the 1-percent annual chance (100-year) flood event. Please see the flood study is included in section 021 Floodplains of this submittal for additional information. The subject property will be developed in phases. This subdivision application encompasses the initial phase, proposed Lot A, and will include the extension of Rawhide Ridge Road, construction of a stormwater storage basin on the southeast portion of Lot A, and installation of a temporary storage facility on the south side of the proposed Rawhide Ridge Road extension. Following this subdivision, subsequent subdivisions will be pursued for the remainder of the property (proposed Lot B). This stormwater management analysis considers the proposed improvements associated with this subdivision. Additional improvements to be installed with future subdivision(s) of proposed Lot B will be analyzed with future applications. Drainage exhibits provided in Appendix B illustrate existing (pre-development) drainage conditions, and proposed (post-development) drainage conditions. Page 5 of 15 2. Hydrology and Hydrogeology The hydrologic design for this subdivision is based on the requirements outlined in Section 6.5 of the City of Bozeman Design and Construction Standards. Runoff calculations were performed using the NRCS (SCS) Curve Number method, selected due to the large property area of the proposed subdivision. The Bozeman Design Standards, Section 6.6.3, state that the NRCS Method is accepted as an appropriate method for runoff calculations for developments and basins larger than 5 acres. Other runoff calculation methods, such as the Rational Method, were considered but were deemed inappropriate for the scale of this project. The stormwater analysis considers the major storm event (100-year, 24-hour), the minor storm event (10-year, 24-hour), and the water quality design event (0.5-inch rainfall depth). The applicable 24-hour rainfall depths defined in Table 6.5.2 of the City of Bozeman Design and Construction Standards were used in the analysis. Geotechnical investigations were conducted for the subdivision to characterize soil and groundwater conditions. Subsurface soils at the site consist primarily of Silty Clay Organic Soil of Low Plasticity (OL), Lean Clay (CL), and Poorly Graded Gravel with Sand and Cobbles (GP). Two geotechnical reports are included in Appendix I of this report. The first report includes the northern portion of the subdivision, within proposed Lot A, while the second report includes the southern remainder of the subdivision property (Lot B). The second report refers to “Gallatin Center Subdivision Phase 6” as the report will be used for future subdivisions of Lot B. However, the report analyzes the same property and is therefore applicable to this analysis. Infiltration rates for the subject property, as well as information on potential impacts to adjacent structures can be found in the geotechnical report. Groundwater monitoring wells were installed on-site in May 2025. Weekly monitoring continued through August 2025, after which the schedule transitioned to monthly readings which terminated in October 2025. Groundwater elevations vary across the site, with seasonal high groundwater observed at depths ranging from 1.4 feet to 5.7 feet below ground surface. A summary of groundwater data, including monitoring data and a well map, is provided in Appendix H. Groundwater mounding effects were considered for the proposed retention/infiltration facilities and were analyzed for the major storm event (100-year, 24-hour). The Hantush Method was used to analyze groundwater mounding, using a spreadsheet provided on the USGS website, with the methods further specified in the USGS Scientific Investigations Report 2010-5102. The soil parameters were estimated based on the soil classifications and layer depths from the geotechnical report. Both proposed retention/infiltration facilities were found to have maximum groundwater mounding of less than two feet at the location of the facilities for the 100-yr, 24-hr storm event. Since the maximum mounding is less than two feet, and the basin designs account for two feet of groundwater separation, groundwater mounding will not interfere with storage capacities. Groundwater mounding is not anticipated to have any adverse impacts on adjacent structures or other facilities. Groundwater mounding calculations are included in Appendix K of this report. Page 6 of 15 3. Existing Stormwater and Drainage Conditions The property is currently undeveloped and does not contain any existing stormwater infrastructure within its boundaries. The property naturally drains from south to north, and contains two creeks running south to north through the property: East Catron Creek and West Catron Creek. The southern edge of the property is bordered by a public street (Baxter Lane); as a result, stormwater runoff from adjacent off-site properties does not naturally flow onto the subject property, except through the watercourses. Off-site runoff that is routed to the watercourses is evaluated in the flood study report included in this submittal. Existing pre-development runoff across the site generally sheet flows northward into the drainageways or toward an existing off-site stormwater detention basin located near the northern portion of the property. Exhibit B.1 which can be found in Appendix B, illustrates the existing drainage basins within the subdivision property and their respective outfall locations. Runoff from Drainage Basins A1 and A2 discharges to West Catron Creek. Runoff from Basins B1 and B2 ultimately drains into the detention pond located at the northeast corner of the subdivision. Some of this runoff flows directly into the pond, while the remainder flows into the roadside ditch along Cattail Street, which conveys runoff to the pond. Runoff from Basin C1 drains to a culvert under the existing Rawhide Ridge Road and into a ditch that ties into East Catron Creek. Runoff from Basin D1 drains directly into East Catron Creek. 3.1 Pre-Development Runoff Calculations HydroCAD was utilized to create a hydraulic model of the pre-development conditions. The model utilizes the NRCS (SCS) hydrograph method to conduct runoff calculations. This method was selected because of the large drainage basins on the property. Soil types within each drainage area were identified using the NRCS Soil Survey of Gallatin County. A map showing the hydraulic soils groups within the property, as well as a summary of hydraulic soil group areas within each basin, are included in Appendix C of this report. These soil types and associated hydraulic soil groups within each drainage basin were used to calculate a weighted curve number (CN) for each basin area. Curve numbers from Table 6.6.2 of the Bozeman Design and Construction standards were used in determining the weighted curve numbers for each basin. The times of concentration were then determined using methods outlined in the NRCS TR-55 Manual, and assuming sheet flow lengths no more than 150 feet. These values were then used in the hydraulic model to generate hydrographs and identify peak flows and runoff volumes. Detailed methodology, including model input values, supporting calculations, and hydrographs for the pre-development conditions can be found in Appendix E.1 of this report. A summary of pre-development peak flows and runoff volumes is presented in Table 1 below. Page 7 of 15 Table 1: Pre-development Runoff Conditions Basin Name Total Area (Acres) 10-yr Pre- Development Peak Runoff Rate &Volume 100-yr Pre- Development Peak Runoff Rate &Volume Outfall (Destination) A1 2.66 0.23 cfs 0.035 acre-ft 1.00 cfs 0.092 acre-ft Outfall A (West Catron Creek) A2 19.75 2.38 cfs 0.445 acre-ft 6.60 cfs 0.987 acre-ft Outfall A (West Catron Creek) B1 14.30 0.66 cfs 0.187 acre-ft 2.61 cfs 0.493 acre-ft Outfall B (Existing Detention Basin Offsite) B2 5.76 0.21 cfs 0.075 acre-ft 0.77 cfs 0.199 acre-ft Outfall B (Existing Detention Basin Offsite) C1 4.15 0.21 cfs 0.054 acre-ft 0.84 cfs 0.143 acre-ft Outfall C (Tributary to East Catron Creek) D1 16.88 0.92 cfs 0.249 acre-ft 3.35 cfs 0.630 acre-ft Outfall D (East Catron Creek) 4. Culvert Analysis The culvert crossing for the extension of Rawhide Ridge Road over West Catron Creek, was analyzed to determine its adequacy and compliance with standards. The elevation of the proposed Rawhide Ridge Road over the culvert caused headwater effects to control the culvert analysis, requiring the pipe to be resized to comply with City of Bozeman Design Standards. The existing culvert is approximately 95 feet long and a 26-inch by 44-inch reinforced concrete arch pipe with flared end sections at both its inlet and outlet. The proposed pipe will be a 3-foot-tall, 6-foot-wide reinforced concrete box culvert, with wing walls, and a headwall structure to contain roadway grading extents at the crossing. To analyze the capacity of this culvert crossing, FHWA’s HY-8 program was used to evaluate performance during both major and minor storm events. Output parameters were compared to the criteria in City of Bozeman Design Standards Section 6.7.5. A description of how the culvert meets requirements A through G of this section is provided below: A. The proposed 3-foot by 6-foot box culvert exceeds the minimum required equivalent diameter of 24 inches. B. The analysis shows no overtopping during the minor (10-year) or major (100- year) storm events with the proposed culvert. Page 8 of 15 C. The headwater depth during the major design storm event is shown in the model to be 4.4 feet (measured from pipe invert to water surface elevation), corresponding to a HW/D (headwater-to-diameter) ratio of 0.92. This is less than the maximum allowable ratio of 1.5 (for cross-sectional areas less than 30 square feet). The equivalent diameter of the proposed pipe, which was calculated to be 4.78 feet, was used to calculate this ratio, since the pipe has a rectangular cross section. D. The culvert analysis shows a minimum velocity during the minor storm event of 2.77 ft/s, which exceeds the 2.5 ft/s minimum set forth in the standards. The culvert has a slope of approximately 1.42%, which exceeds the minimum 0.5% slope requirement. The maximum tailwater velocity during the major storm event, will be 4.09 ft/s, well under the maximum allowable velocity of 10 ft/s. E. The culvert will be reinforced concrete wing walls at the inlet and outlet, in compliance with the City of Bozeman Modifications to MPWSS Section 02725, Part 2.2. The culvert crossing will be designed and constructed to handle the HS-20 live load. This is determined based on the culvert reinforcement design and bury depth. Minimum bury depths for the specified culvert product will be adhered to ensure HS-20 live load capacity. This will be determined upon selection of a specific product and adhering to the manufacturer’s recommendations with the material submittal review. The geotechnical report included in Appendix I.2, includes information on soil corrosivity. Several corrosivity tests which were performed on the site soil, the corrosivity analysis concluded that the DIRPA DDM indicates lean clay with minimal to mildly corrosive properties. To limit effects of corrosion, 3/4-inch minus gravel will be used as the bedding material (per the geotechnical recommendation). Culvert materials with low potential for corrosion were selected. The culvert will be reinforced concrete, with tongue and groove through joints. The bedding material inside of the culvert, which is a typical requirement from the conservation district, will be non-transportable cobbles, to ensure the material does not wash out of the culvert. Details of the culvert crossing are included in the design sheets shown in Appendix J of this report. F. Wing walls will be provided at both the inlet and outlet, consistent with the preferred end treatment. G. Both ends of the culvert are accessible for inspection and debris removal from the areas around the open channel on either side. The culvert outlets into a shallow, open channel with undeveloped fields on both sides, providing clear access for inspection and debris removal. Page 9 of 15 Based on this analysis, the proposed culvert design is adequate for the Rawhide Ridge Road crossing. A summary of the culvert modeling, calculations, and results is included in Appendix D of this report. 5. Proposed Stormwater Drainage System The proposed stormwater management system for the Gallatin Center Subdivision has been designed in accordance with the City of Bozeman Design and Construction Standards. The system is intended to manage runoff generated from subdivision improvements, and control peak runoff rates and volumes so that post-development conditions do not exceed pre- development conditions at each outfall location. The subdivision improvements associated with this application include the extension of Rawhide Ridge Road, construction of a permanent stormwater storage basin on Lot A, installation of a temporary storage facility on the south side of Rawhide Ridge Road, and installation of inlets and piping to convey runoff from Rawhide Ridge Road to the basin. The basin located on the southeast corner of Lot A will function as a permanent component of the overall stormwater management system. The temporary basin south of the proposed Rawhide Ridge Road extension is intended to intercept runoff and prevent discharge to Rawhide Ridge Road during interim conditions, prior to development to the south. The temporary basin will be decommissioned once adjacent development takes place south of the roadway with independent stormwater management techniques in place. Minor improvements to Cattail Street are proposed. The proposed improvements include curb, gutter, boulevard and sidewalk installation along the portion of Cattail Street fronting the property (south side), from the planned North 27th Avenue capitol improvements to the roundabout (Cattail St. and Max Ave.), where curb and gutter is already installed. The proposed improvements will mimic the existing drainage conditions by conveying runoff via curb and gutter rather than the existing roadside ditch, allowing runoff to reach the same ultimate destination, the existing detention pond. The proposed stormwater management system will consist of sheet flow, curb and gutter, curb inlets, and storm drain piping to efficiently convey runoff to the permanent basin. Runoff from undeveloped property south of Rawhide Ridge Road will sheet flow to the temporary retention/infiltration basin. These basins are designed to provide both water quality treatment (capturing the first 0.5 inches of runoff per City standards) and quantity control (storing the 100-year, 24-hour design event). Exhibit B.2 included in Appendix B illustrates the drainage basins, storm drain network, and ultimate outfall locations for the post-development conditions. 5.1 Post-Development Runoff Calculations HydroCAD was utilized to model the proposed subdivision conditions. As with the existing conditions analysis, the model applies the NRCS (SCS) hydrograph method to conduct runoff calculations. Anticipated impervious areas and landscaped areas for the roadway improvements were used to determine curve numbers for the proposed right-of-way improvements. Curve numbers were selected from Table 6.6.2 of the City of Bozeman Design and Construction Standards. Page 10 of 15 Post-development drainage patterns remain consistent with existing conditions with the exception of Basin B2 and the addition of Basin E1. Runoff from Basin B2 will be conveyed to the proposed temporary stormwater retention and infiltration pond located south of Rawhide Ridge Road. Basin E1 runoff will be conveyed to the stormwater pond on the southeast corner of Lot A. Please refer to Exhibit B.2 in Appendix B, which shows the locations of the post-development basins and outfalls for the post-development scenario. Detailed methodology, including model input values, supporting calculations, and hydrographs for post-development conditions is provided in Appendix E.2. A summary of peak flows and runoff volumes is presented in Tables 4 and 5, shown in section 5.6 of this report. 5.2 Storage Volumes The permanent stormwater basin on Lot A provides storage and treatment for runoff from the proposed public right-of-way, including the proposed street, landscaped boulevards, and sidewalks. Although sidewalks will be installed by others with site plans, their runoff contribution has been included in the basin sizing to ensure long-term capacity. The basin on the southeast corner Lot A will be constructed with the subdivision improvements and is sized for the major storm event (100-year, 24-hour) to accommodate runoff for the proposed improvements, with additional capacity to aid in managing runoff from anticipated future improvements with subsequent subdivisions of the remainder lot (Lot B). This storage basin is designed with a washed rock area at the bottom extending to native gravels, which will ensure proper infiltration. Please see the exhibit included in Appendix F for further details on the design of this basin. Based on the runoff calculations, the Lot A basin is required to store 4,879 cubic feet of runoff. The facility has been designed to provide 7,623 cubic feet of storage. Please note that this storage facility actually has additional storage capacity, however the storage within the area closer than 2 feet to the seasonal high groundwater was negated from the storage capacity to be conservative. The pond is extended deeper to accommodate the pipe elevations draining into the facility. While the bottom of the pond is not low enough for the seasonal high groundwater to exceed the bottom of pond, the facility is designed as a wet detention pond since it does not have 2 feet of separation from the seasonal high groundwater. The facility is designed with a forebay to facilitate sediment accumulation and removal. Appendix F includes design details for the proposed stormwater storage facilities. In addition to these permanent facilities, a temporary retention/infiltration pond will be constructed with this subdivision on the south side of Rawhide Ridge Road. This pond will manage interim runoff, from Basin B2, until future phases are completed (with subsequent subdivisions) and runoff from Basin B2 is otherwise managed. Sized for the 100-year, 24- hour storm, the temporary basin is required to store 8,189 cubic feet of runoff. The facility has been sized to store 10,028 cubic feet of runoff. Once a permanent system is fully constructed with future developments south of Rawhide Ridge Road, the temporary facility will be decommissioned. Page 11 of 15 Required storage calculations as well as provided storages are included in the Hydraulic modeling information included in Appendix E of this report. Stormwater storage pond design details are provided in Appendix F. A summary of required and provided storage volumes is included in Table 2 below. Table 2: Stormwater Basin Storage Summary Storage Basin Required Storage Volume Provided Storage Volume Lot A Pond (SE Corner) 4,879 ft3 7,623 ft3 Lot B Temporary Pond 8,189 ft3 10,028 ft3 5.3 Conveyance Calculations The capacity of all conveyance facilities were analyzed to ensure proper conveyance of all runoff for the proposed improvements and compliance with City of Bozeman Design Standards. The capacities were analyzed using FlowMaster, a program which utilizes methods outlined in the FHWA’s HEC-22 Urban Drainage Design Manual. The proposed 12” PVC storm drain piping will maintain non-pressurized flow for both the major and minor storm events, while meeting diameter, slope, and velocity requirements. During the minor storm event, the proposed 12” PVC piping at a 0.5% slope will flow at depth of 5.6 inches (non-pressurized flow), with a corresponding velocity of 3.66 ft/s. During the major storm event the flow depth in the pipe will be 7.8 inches (non-pressurized flow), with a velocity of 4.17ft/s. The calculations are included in Appendix L for reference. The capacity of the inlets was analyzed for the major storm event. Based on the analysis, the depth of water accumulating at the inlet during the major storm event would be 1.9 inches. Because the sag curve is about 7.7 inches deep, no bypass occurs, and the inlets capture all runoff from the major storm event. The calculations are included in Appendix L for reference. The gutter capacity was analyzed using the parameters of a typical curb and gutter at a 0.6% slope. The flow spread was input per Bozeman Design Standards Table 6.7.1, allowing the flow to spread to the street crown with no curb overtopping. With these parameters, the gutter/street conveyance capacity is 10.26 cfs, which is well beyond the peak flow for the major storm event of 2.26 cfs. 5.4 Groundwater Separation Groundwater conditions were a key factor in the design of the proposed stormwater storage basins. Each basin has been designed with the consideration of the seasonal high groundwater elevation’s proximity to the bottom of the calculated basin storage. Although the proposed pond on Lot A does not have two feet of separation from seasonal high groundwater, the storage capacity for region within two feet of the seasonal high groundwater is negated from the storage capacity calculations. Seasonal high groundwater elevations were established using data from site monitoring wells. For each basin, the monitoring wells located closest to the proposed facility were used to determine groundwater conditions at the location of the proposed facilities. Seasonal high Page 12 of 15 groundwater levels were interpolated from nearby wells, considering both groundwater elevations and depths below ground surface. The interpolation based on groundwater elevations produced more conservative results, and these values were used for the design. Table 3 below summarizes compliance with high groundwater separation for each of the proposed retention/infiltration ponds. Table 3: Groundwater Separation Compliance Stormwater Storage Basin High Groundwater Elevation Bottom of Calculated Storage Elevation Bottom of Storage Separation from High Groundwater Lot A Pond (SE Corner) 4699.51 ft 4701.60 ft 2.09 ft Lot B Temporary Pond 4701.64 ft 4703.80 ft 2.16 ft Stormwater storage pond details provided in Appendix F demonstrate compliance with the required groundwater separation. 5.5 Water Quality and Treatment The proposed water quality treatment is implemented into the stormwater design. Runoff stored in the proposed storage basins is designed to infiltrate through native gravels for both major and minor storm events. Because the retention/infiltration basins are designed to capture and allow infiltration of runoff for storm events up to the 100-year, 24-hour event (2.34 inches of runoff), the retention infiltration basins also ensure the first 0.5 inches of rainfall (water quality event) will be properly treated through infiltration. Additionally, because the proposed pond on Lot A is treated as a wet detention facility, it includes a forebay cell for the accumulation and removal of sediments. The volume of the proposed forebay is 121 cubic feet below the weir and 369 cubic feet in total. The water quality volume for the associated drainage area is just 87 cubic feet, making the forebay more than adequate to treat the water quality volume. Additionally, the forebay was designed to be shallow with a larger footprint, rather than deep with a smaller footprint, to facilitate a longer flow length in the forebay. Please see the design details of the storage basins provided in Appendix F, which includes additional details of the pond and forebay design. 5.6 Pre-Development vs Post-Development Comparison Post-development runoff is designed to be less than or equal to pre-developed conditions, at each outfall location. This is verified in the calculated post-development hydraulic modeling results. The proposed subdivision improvements are designed such that no runoff from the improvements will discharge to the outfalls, and will instead be captured within the proposed storage facilities. The pre-development and post-development runoff conditions for each outfall are summarized in Table 4 and Table 5 below, for minor and major storm events, respectively. Page 13 of 15 Table 4: Minor Storm (10-Yr, 24-Hr) Pre-Development vs. Post-Development Runoff Outfall Pre-Development (Existing) Peak Runoff Rate & Volume Post-Development: Peak Runoff Rate & Volume A 2.49 cfs 0.479 acre-ft 2.47 cfs 0.474 acre-ft B 0.81 cfs 0.262 acre-ft 0.63 cfs 0.180 acre-ft C 0.21 cfs 0.054 acre-ft 0.21 cfs 0.054 acre-ft D 0.92 cfs 0.249 acre-ft 0.92 cfs 0.249 acre-ft Table 5: Major Storm (100-Yr, 24-Hr) Pre-Development vs. Post-Development Runoff Outfall Pre-Development (Existing) Peak Runoff Rate & Volume Post-Development: Phase 1 Peak Runoff Rate & Volume A 6.95 cfs 1.079 acre-ft 6.88 cfs 1.065 acre-ft B 3.21 cfs 0.692 acre-ft 2.52 cfs 0.475 acre-ft C 0.84 cfs 0.143 acre-ft 0.84 cfs 0.143 acre-ft D 3.35 cfs 0.630 acre-ft 3.35 cfs 0.630 acre-ft 6. Evaluation of Major Storm Flood Risks Major storm flood risks were accounted for in the design of the stormwater drainage systems. All storage facilities are designed to store runoff from major storm events (100 year, 24 hour). These facilities are designed with washed rock sections on the bottom, extending the native gravels to ensure proper infiltration. The retention/infiltration ponds are sized conservatively, to accommodate flood events beyond the 100-year, 24-hour event. Additionally, the ponds are designed such that if they were to overflow the additional runoff will not flow to any adjacent structures. A flood study report was conducted, analyzing the capacity of the creeks during the 1-percent annual chance (100-year) flood event. The flood study is included in section 021 Floodplains of this submittal. Drain-down time was evaluated for the proposed retention/infiltration areas in the storage basins to ensure that post-storm water levels return to pre-storm conditions within 72 hours, in compliance with City of Bozeman Design Standards Section 6.8.2.C. An infiltration rate of 4.0 inches per hour was assigned to the native gravels, as documented in the future phase Page 14 of 15 geotechnical report memorandum included in Appendix I.2. This infiltration rate was multiplied by the area of gravel to be installed at the bottom of each proposed pond (400 square feet per pond) to determine the infiltration capacity in cubic feet per hour. This capacity was then compared to the required storage volume for the 100-year, 24-hour storm event to determine the maximum drain-down time for each basin. The drain-down calculations, provided below, demonstrate that the drain-down time for the major storm event for each proposed pond is less than the maximum allowable 72-hour requirement. Drain-Down Time = 4.0 in/hr * (1ft/12in) * 400ft2 = 133.33 ft3/hr Lot A Pond: 4,879 ft3/133.33 ft3/hr = 36.59 hours (less than required 72 hours) Lot B Temporary Pond: 8,189 ft3/133.33 ft3/hr = 61.42 hours (less than required 72 hours) 7. Operation, Inspection, and Maintenance Considerations City maintenance of stormwater facilities will include curb inlets and storm drain pipes within public right-of-way. Curb inlets have vehicular access directly from the streets. City access to piping coming into the proposed pond on Lot A will be provided by incorporating laydown curb and an asphalt boulevard adjacent to the stormwater storage facility. Please see the Rawhide Ridge Road design sheet included in Appendix J of this report, which shows this maintenance access feature. The infrastructure design sheets included in Appendix J are preliminary at this time, since they may be updated with the infrastructure submittal associated with the subdivision. The property owner will be responsible for the maintenance of the proposed stormwater storage basins on proposed Lot B and Lot A. Stormwater Drainage and Maintenance Access easements are also provided, should the City need to access the proposed basins. These easements are shown in the exhibit included in Appendix A. A full Operation, Inspection, and Maintenance plan is included in Appendix G of this report. 8. References The following references were used in the preparation of this report: a. City of Bozeman Modifications to Montana Public Works Standard Specifications, Seventh Edition, Addendum No. 3 b. City of Bozeman Design Standards and Specifications Policy, October 2024 c. Circular DEQ 8, Montana Standards for Subdivision Storm Drainage, 2002 Edition d. HEC-22 – Urban Drainage Design Manual, Fourth Edition (February 2024) e. NRCS Technical Release-55 – Urban Hydrology for Small Watersheds (June 1986) f. FHWA – Hydraulic Design of Highway Culverts 9. Conclusion The proposed stormwater drainage facilities for the Gallatin Center Subdivision have adequate capacity to accommodate both major and minor storm events in compliance with City of Bozeman Design Standards. The design ensures that post-development runoff rates Page 15 of 15 and volumes discharged to each outfall will be equal to or less than pre-development conditions. The permanent basin on Lot A is conservatively sized to manage the 100-year, 24-hour storm event, while temporary facilities provide protection during interim phases. Groundwater separation and water quality treatment have been incorporated into the design, resulting in a system that meets regulatory requirements for the proposed subdivision improvements. 10. Appendices A. Subdivision Layout B. Stormwater Runoff Exhibits B.1 Pre-Development (Existing) Runoff Conditions B.2 Post-Development (Proposed) Runoff Conditions C. Hydraulic Soil Groups Map and Summary D. Culvert Modeling Inputs and Results E. Hydraulic Modeling Inputs and Results E.1 Pre-Development Conditions E.2 Post-Development Conditions F. Retention/Infiltration Pond Details G. Operation, Inspection, and Maintenance Plan H. Groundwater Monitoring Well Map and Data I. Geotechnical Reports I.1 North Geotechnical Report I.2 South Geotechnical Report J. Infrastructure Design Sheets (Preliminary) K. Groundwater Mounding Calculations L. Conveyance Calculations Stormwater Design Report Appendix A – Subdivision Layout WWWWWWWWWWNGNGNGNGNGNGNGFOSTSTUGPUGPUGPUGPUGPUGPFOFOFOXX X X XUGPXXXXNG NG NG NG NG NG NG NGFOFOFOFOFOFOFOFOOHPOHPOHPOHPOHPOHPOHPOHPOHPSSSSSSSSSSSSSSSSSSSSSSSSWWWWWWWSSWWUGTVUGTVUGTVUGTVW W W W W WSSSSSSSS SSUGPUGPUGPNGNGNGPROPOSED 60' PUBLIC R.O.W. CATTAIL STREET (EXISTING) KIMBERWICKE STREET (EXISTING) RAWHIDE RIDGE ROAD (EXISTING)MAX AVENUE (EXISTING)NORTH 27TH AVENUE (COB 2025 CAPITOL IMPROVEMENT)NORTH 19TH AVENUE (EXISTING)BAXTER LANE (EXISTING) SARTAIN STREET (FUTURE PHASES)MAX AVENUE (FUTURE PHASES)NORTH 25TH AVENUE (FUTURE PHASES)RAWHIDE RIDGE ROAD (PHASE 1) EDGE OF DELINEATED WETLAND (TYP.) CATTAIL STREET (EXISTING) KIMBERWICKE STREET (EXISTING) RAWHIDE RIDGE ROAD (EXISTING)MAX AVENUE (EXISTING)NORTH 27TH AVENUE (COB 2025 CAPITOL IMPROVEMENT)NORTH 19TH AVENUE (EXISTING)BAXTER LANE (EXISTING) RAWHIDE RIDGE ROAD (PHASE 1)THOMAS DRIVE (EXISTING)LOT A 16.49± ACRES 718,288± SF (PHASE 1) USPS LOT PROPOSED 25' PUBLIC TRAIL EASEMENT (TRAIL TO BE CONSTRUCTED WITH FUTURE SITE PLAN APPLICATION) SARTAIN STREET (FUTURE PHASES)MAX AVENUE (FUTURE PHASES)NORTH 25TH AVENUE (FUTURE PHASES)STORMWATER RETENTION/INFILTRATION POND (PHASE 1) LOT B (REMAINDER LOT/ FUTURE PHASES) 46.15± ACRES 2,010,168± SF TEMPORARY STORMWATER RETENTION/INFILTRATION POND (PHASE 1) STORMWATER DRAINAGE AND MAINTENANCE ACCESS EASEMENT STORMWATER DRAINAGE AND MAINTENANCE ACCESS EASEMENT LEGEND: PHASE 1 = FUTURE PHASES = PHASE LINE = K:\Bozeman\Gallatin Center LP\2024381 Gallatin Center\05CAD\Sheets\Preliminary Plat\24381-ROAD-PHASING-EXHB.dwg PHASING PLAN 12/17/2025 7:09:02 AM DESIGNED BY:DRAWN BY:CHECKED BY:DATE:JRHJRHEWRDEC. 2025SHEET---NO.DATEREVISIONPREPARED BY BY PHASING PLAN GALLATIN CENTER LIMITED PARTNERSHIP BOZEMAN, MT GALLATIN CENTER SUBDIVISION ENGI NEERING PROJECT NO. 2024381 895 TECHNOLOGY BLVD., SUITE 203 BOZEMAN, MT 59718 (406) 586-0262 www.wwcengineering.com 0 SCALE: 1" = 100' 100'50' Stormwater Design Report Appendix B – Stormwater Runoff Exhibits Stormwater Design Report Appendix C – Hydraulic Soil Groups Map and Summary Stormwater Design Report Appendix D – Culvert Modeling Input and Results HY-8 Culvert Analysis Report Rawhide Ridge Road – West Catron Creek Crossing Crossing Discharge Data Discharge Selection Method: Specify Minimum, Design, and Maximum Flow Minimum Flow: 24.60 cfs (10-Year Storm Event) Design Flow: 51.20 cfs (25-Year Storm Event) Maximum Flow: 117.00 cfs (100-Year Storm Event) Table 1 - Summary of Culvert Flows at Crossing: Crossing 1 Headwater Elevation (ft) Total Discharge (cfs) Rawhide Ridge Discharge (cfs) Roadway Discharge (cfs) Iterations 4701.72 24.60 24.60 0.00 1 4702.06 33.84 33.84 0.00 1 4702.36 43.08 43.08 0.00 1 4702.61 51.20 51.20 0.00 1 4702.92 61.56 61.56 0.00 1 4703.17 70.80 70.80 0.00 1 4703.42 80.04 80.04 0.00 1 4703.66 89.28 89.28 0.00 1 4703.88 98.52 98.52 0.00 1 4704.17 107.76 107.76 0.00 1 4704.48 117.00 117.00 0.00 1 4706.57 163.13 163.13 0.00 Overtopping Rating Curve Plot for Crossing: Crossing 1 Culvert Data: Rawhide Ridge Table 1 - Culvert Summary Table: Rawhide Ridge Total Discharge (cfs) Culvert Discharge (cfs) Headwat er Elevation (ft) Inlet Control Depth (ft) Outlet Control Depth (ft) Flo w Typ e Norm al Depth (ft) Critic al Depth (ft) Outl et Dept h (ft) Tailwat er Depth (ft) Outlet Velocity (ft/s) Tailwat er Velocity (ft/s) 24.60 cfs 24.60 cfs 4701.72 1.36 1.391 3- M1t 0.86 0.81 1.24 1.49 3.31 2.77 33.84 cfs 33.84 cfs 4702.06 1.68 1.725 3- M1t 1.04 1.00 1.43 1.68 3.95 3.00 43.08 cfs 43.08 cfs 4702.36 1.97 2.031 3- M1t 1.21 1.17 1.59 1.84 4.52 3.19 51.20 cfs 51.20 cfs 4702.61 2.20 2.283 3- M1t 1.35 1.31 1.71 1.96 4.99 3.33 61.56 cfs 61.56 cfs 4702.92 2.49 2.586 3- M1t 1.51 1.48 1.85 2.10 5.54 3.49 70.80 cfs 70.80 cfs 4703.17 2.75 2.843 7- M1t 1.65 1.63 1.96 2.21 6.01 3.61 80.04 cfs 80.04 cfs 4703.42 3.00 3.088 7- M1t 1.78 1.77 2.07 2.32 6.45 3.72 89.28 cfs 89.28 cfs 4703.66 3.27 3.325 7- M1t 1.91 1.90 2.16 2.41 6.87 3.83 98.52 cfs 98.52 cfs 4703.88 3.54 3.554 7- M1t 2.03 2.03 2.26 2.51 7.28 3.92 107.76 cfs 107.76 cfs 4704.17 3.84 3.197 5- S2n 2.15 2.16 2.15 2.59 8.35 4.01 117.00 cfs 117.00 cfs 4704.48 4.15 3.639 5- S2n 2.27 2.28 2.27 2.67 8.60 4.09 Culvert Barrel Data Culvert Barrel Type Straight Culvert Inlet Elevation (invert): 4700.33 ft, Outlet Elevation (invert): 4698.98 ft Culvert Length: 95.01 ft, Culvert Slope: 0.0142 Culvert Performance Curve Plot: Rawhide Ridge Water Surface Profile Plot for Culvert: Rawhide Ridge Site Data - Rawhide Ridge Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft Inlet Elevation: 4700.08 ft Outlet Station: 95.00 ft Outlet Elevation: 4698.73 ft Number of Barrels: 1 Culvert Data Summary - Rawhide Ridge Barrel Shape: Concrete Box Barrel Span: 6.00 ft Barrel Rise: 3.00 ft Barrel Material: Concrete Embedment: 3.00 in Barrel Manning's n: 0.0120 (top and sides) Manning's n: 0.0320 (bottom) Culvert Type: Straight Inlet Configuration: Square Edge (90º) Headwall (Ke=0.5) Inlet Depression: None Tailwater Data for Crossing: Crossing 1 Table 2 - Downstream Channel Rating Curve (Crossing: Crossing 1) Flow (cfs) Water Surface Elev (ft) Velocity (ft/s) Depth (ft) Shear (psf) Froude Number 24.60 4700.22 1.49 2.77 0.51 0.57 33.84 4700.41 1.68 3.00 0.58 0.58 43.08 4700.57 1.84 3.19 0.63 0.59 51.20 4700.69 1.96 3.33 0.67 0.59 61.56 4700.83 2.10 3.49 0.72 0.60 70.80 4700.94 2.21 3.61 0.76 0.60 80.04 4701.05 2.32 3.72 0.80 0.61 89.28 4701.14 2.41 3.83 0.83 0.61 98.52 4701.24 2.51 3.92 0.86 0.62 107.76 4701.32 2.59 4.01 0.89 0.62 117.00 4701.40 2.67 4.09 0.92 0.62 Tailwater Channel Data - Crossing 1 Tailwater Channel Option: Triangular Channel Side Slope (H:V): 4.00 (_:1) Channel Slope: 0.0055 Channel Manning's n: 0.0320 Channel Invert Elevation: 4698.73 ft Roadway Data for Crossing: Crossing 1 Roadway Profile Shape: Irregular Roadway Shape (coordinates) Irregular Roadway Cross-Section Coord No. Station (ft) Elevation (ft) 0 0.00 4706.87 1 25.00 4706.71 2 50.00 4706.57 Roadway Surface: Paved Roadway Top Width: 36.00 ft Stormwater Design Report Appendix E – Hydraulic Modeling Inputs and Results E.1 - Pre-Development (Existing) Conditions A1 Basin A1 A2 Basin A2 B1 Basin B1 B2 Basin B2 C1 Basin C1 D1 Basin D1 1R Outfall C 2R Outfall D A0 Outfall A (West Catron Creek) B0 Outfall B (Offsite Detention Facility) C0 East Catron Creek Routing Diagram for 2024525-Pre-Development ScenarioPrepared by WWC Engineering, Printed 10/1/2025 HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Subcat Reach Pond Link 2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 2HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Rainfall Events Listing (selected events) Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 10-Yr 24-Hr Type II 24-hr Default 24.00 1 1.70 2 2 100-Yr 24-Hr Type II 24-hr Default 24.00 1 2.34 2 2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 3HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 56.410 71 Herbaceous range, Fair, HSG B (A1, A2, B1, B2, C1, D1) 1.990 81 Herbaceous range, Fair, HSG C (A2, D1) 5.100 89 Herbaceous range, Fair, HSG D (A1, A2) 63.500 73 TOTAL AREA 2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 4HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.000 HSG A 56.410 HSG B A1, A2, B1, B2, C1, D1 1.990 HSG C A2, D1 5.100 HSG D A1, A2 0.000 Other 63.500 TOTAL AREA 2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 5HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.000 56.410 1.990 5.100 0.000 63.500 Herbaceous range, Fair A1, A2, B1, B2, C1, D1 0.000 56.410 1.990 5.100 0.000 63.500 TOTAL AREA Type II 24-hr 10-Yr 24-Hr Rainfall=1.70"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 6HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Time span=5.00-30.00 hrs, dt=0.05 hrs, 501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=2.660 ac 0.00% Impervious Runoff Depth=0.16"Subcatchment A1: Basin A1 Flow Length=1,131' Tc=17.9 min CN=71 Runoff=0.23 cfs 0.035 af Runoff Area=19.750 ac 0.00% Impervious Runoff Depth=0.27"Subcatchment A2: Basin A2 Flow Length=2,780' Tc=45.5 min CN=76 Runoff=2.38 cfs 0.445 af Runoff Area=14.300 ac 0.00% Impervious Runoff Depth=0.16"Subcatchment B1: Basin B1 Flow Length=1,195' Slope=0.0120 '/' Tc=50.1 min CN=71 Runoff=0.66 cfs 0.187 af Runoff Area=5.760 ac 0.00% Impervious Runoff Depth=0.16"Subcatchment B2: Basin B2 Flow Length=2,325' Tc=76.8 min CN=71 Runoff=0.21 cfs 0.075 af Runoff Area=4.150 ac 0.00% Impervious Runoff Depth=0.16"Subcatchment C1: Basin C1 Flow Length=875' Slope=0.0120 '/' Tc=43.2 min CN=71 Runoff=0.21 cfs 0.054 af Runoff Area=16.880 ac 0.00% Impervious Runoff Depth=0.18"Subcatchment D1: Basin D1 Flow Length=1,314' Slope=0.0120 '/' Tc=52.7 min CN=72 Runoff=0.92 cfs 0.249 af Inflow=0.21 cfs 0.054 afReach 1R: Outfall C Outflow=0.21 cfs 0.054 af Inflow=0.92 cfs 0.249 afReach 2R: Outfall D Outflow=0.92 cfs 0.249 af Inflow=2.49 cfs 0.479 afPond A0: Outfall A (West Catron Creek) Primary=2.49 cfs 0.479 af Inflow=0.81 cfs 0.262 afPond B0: Outfall B (Offsite Detention Facility) Primary=0.81 cfs 0.262 af Inflow=1.12 cfs 0.303 afPond C0: East Catron Creek Primary=1.12 cfs 0.303 af Total Runoff Area = 63.500 ac Runoff Volume = 1.045 af Average Runoff Depth = 0.20" 100.00% Pervious = 63.500 ac 0.00% Impervious = 0.000 ac Type II 24-hr 10-Yr 24-Hr Rainfall=1.70"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 7HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment A1: Basin A1 Runoff = 0.23 cfs @ 12.18 hrs, Volume= 0.035 af, Depth= 0.16" Routed to Pond A0 : Outfall A (West Catron Creek) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70" Area (ac) CN Description 2.610 71 Herbaceous range, Fair, HSG B 0.050 89 Herbaceous range, Fair, HSG D 2.660 71 Weighted Average 2.660 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.5 984 0.0090 4.72 88.05 Parabolic Channel, Flow through West Catron Creek W=14.00' D=2.00' Area=18.7 sf Perim=14.7' n= 0.035 Earth, dense weeds 14.4 147 0.0570 0.17 Sheet Flow, Sheet Flow (Southern Portion of A1) n= 0.150 P2= 1.18" 17.9 1,131 Total Subcatchment A1: Basin A1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.25 0.24 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type II 24-hr 10-Yr 24-Hr Rainfall=1.70" Runoff Area=2.660 ac Runoff Volume=0.035 af Runoff Depth=0.16" Flow Length=1,131' Tc=17.9 min CN=71 0.23 cfs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 8HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment A2: Basin A2 Runoff = 2.38 cfs @ 12.54 hrs, Volume= 0.445 af, Depth= 0.27" Routed to Pond A0 : Outfall A (West Catron Creek) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70" Area (ac) CN Description 0.600 81 Herbaceous range, Fair, HSG C 0.600 71 Herbaceous range, Fair, HSG B 8.500 71 Herbaceous range, Fair, HSG B 5.000 71 Herbaceous range, Fair, HSG B 5.050 89 Herbaceous range, Fair, HSG D 19.750 76 Weighted Average 19.750 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 24.4 150 0.0160 0.10 Sheet Flow, Sheet Flow (150') n= 0.150 P2= 1.18" 12.6 672 0.0160 0.89 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 4.5 881 0.0120 3.28 98.45 Channel Flow, Flow Though West Catron Creek Area= 30.0 sf Perim= 20.0' r= 1.50' n= 0.065 4.0 1,077 0.0081 4.48 83.53 Parabolic Channel, A2 Flow through A1 W=14.00' D=2.00' Area=18.7 sf Perim=14.7' n= 0.035 Earth, dense weeds 45.5 2,780 Total Type II 24-hr 10-Yr 24-Hr Rainfall=1.70"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 9HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Subcatchment A2: Basin A2 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)2 1 0 Type II 24-hr 10-Yr 24-Hr Rainfall=1.70" Runoff Area=19.750 ac Runoff Volume=0.445 af Runoff Depth=0.27" Flow Length=2,780' Tc=45.5 min CN=76 2.38 cfs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 10HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment B1: Basin B1 Runoff = 0.66 cfs @ 12.72 hrs, Volume= 0.187 af, Depth= 0.16" Routed to Pond B0 : Outfall B (Offsite Detention Facility) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70" Area (ac) CN Description 9.700 71 Herbaceous range, Fair, HSG B 4.600 71 Herbaceous range, Fair, HSG B 14.300 71 Weighted Average 14.300 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') n= 0.150 P2= 1.18" 22.7 1,045 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 50.1 1,195 Total Subcatchment B1: Basin B1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type II 24-hr 10-Yr 24-Hr Rainfall=1.70" Runoff Area=14.300 ac Runoff Volume=0.187 af Runoff Depth=0.16" Flow Length=1,195' Slope=0.0120 '/' Tc=50.1 min CN=71 0.66 cfs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 11HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment B2: Basin B2 Runoff = 0.21 cfs @ 13.16 hrs, Volume= 0.075 af, Depth= 0.16" Routed to Pond B0 : Outfall B (Offsite Detention Facility) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70" Area (ac) CN Description 4.480 71 Herbaceous range, Fair, HSG B 1.280 71 Herbaceous range, Fair, HSG B 5.760 71 Weighted Average 5.760 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.8 150 0.0116 0.09 Sheet Flow, Sheet flow (150') n= 0.150 P2= 1.18" 21.7 980 0.0116 0.75 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 27.3 1,195 0.0109 0.73 Shallow Concentrated Flow, B2 Flow Through B1 Short Grass Pasture Kv= 7.0 fps 76.8 2,325 Total Subcatchment B2: Basin B2 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type II 24-hr 10-Yr 24-Hr Rainfall=1.70" Runoff Area=5.760 ac Runoff Volume=0.075 af Runoff Depth=0.16" Flow Length=2,325' Tc=76.8 min CN=71 0.21 cfs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 12HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment C1: Basin C1 Runoff = 0.21 cfs @ 12.60 hrs, Volume= 0.054 af, Depth= 0.16" Routed to Reach 1R : Outfall C Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70" Area (ac) CN Description 1.500 71 Herbaceous range, Fair, HSG B 2.650 71 Herbaceous range, Fair, HSG B 4.150 71 Weighted Average 4.150 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') Grass: Short n= 0.150 P2= 1.18" 15.8 725 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 43.2 875 Total Subcatchment C1: Basin C1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type II 24-hr 10-Yr 24-Hr Rainfall=1.70" Runoff Area=4.150 ac Runoff Volume=0.054 af Runoff Depth=0.16" Flow Length=875' Slope=0.0120 '/' Tc=43.2 min CN=71 0.21 cfs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 13HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment D1: Basin D1 Runoff = 0.92 cfs @ 12.73 hrs, Volume= 0.249 af, Depth= 0.18" Routed to Reach 2R : Outfall D Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70" Area (ac) CN Description 15.490 71 Herbaceous range, Fair, HSG B 1.390 81 Herbaceous range, Fair, HSG C 16.880 72 Weighted Average 16.880 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') n= 0.150 P2= 1.18" 25.3 1,164 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 52.7 1,314 Total Subcatchment D1: Basin D1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Type II 24-hr 10-Yr 24-Hr Rainfall=1.70" Runoff Area=16.880 ac Runoff Volume=0.249 af Runoff Depth=0.18" Flow Length=1,314' Slope=0.0120 '/' Tc=52.7 min CN=72 0.92 cfs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 14HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Reach 1R: Outfall C [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 4.150 ac, 0.00% Impervious, Inflow Depth = 0.16" for 10-Yr 24-Hr event Inflow = 0.21 cfs @ 12.60 hrs, Volume= 0.054 af Outflow = 0.21 cfs @ 12.60 hrs, Volume= 0.054 af, Atten= 0%, Lag= 0.0 min Routed to Pond C0 : East Catron Creek Routing by Stor-Ind+Trans method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Reach 1R: Outfall C InflowOutflow Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=4.150 ac0.21 cfs 0.21 cfs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 15HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Reach 2R: Outfall D [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 16.880 ac, 0.00% Impervious, Inflow Depth = 0.18" for 10-Yr 24-Hr event Inflow = 0.92 cfs @ 12.73 hrs, Volume= 0.249 af Outflow = 0.92 cfs @ 12.73 hrs, Volume= 0.249 af, Atten= 0%, Lag= 0.0 min Routed to Pond C0 : East Catron Creek Routing by Stor-Ind+Trans method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Reach 2R: Outfall D InflowOutflow Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Inflow Area=16.880 ac0.92 cfs 0.92 cfs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 16HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond A0: Outfall A (West Catron Creek) [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 22.410 ac, 0.00% Impervious, Inflow Depth = 0.26" for 10-Yr 24-Hr event Inflow = 2.49 cfs @ 12.53 hrs, Volume= 0.479 af Primary = 2.49 cfs @ 12.53 hrs, Volume= 0.479 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond A0: Outfall A (West Catron Creek) Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)2 1 0 Inflow Area=22.410 ac2.49 cfs 2.49 cfs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 17HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond B0: Outfall B (Offsite Detention Facility) [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 20.060 ac, 0.00% Impervious, Inflow Depth = 0.16" for 10-Yr 24-Hr event Inflow = 0.81 cfs @ 12.77 hrs, Volume= 0.262 af Primary = 0.81 cfs @ 12.77 hrs, Volume= 0.262 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond B0: Outfall B (Offsite Detention Facility) Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=20.060 ac0.81 cfs 0.81 cfs Type II 24-hr 10-Yr 24-Hr Rainfall=1.70"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 18HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond C0: East Catron Creek [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 21.030 ac, 0.00% Impervious, Inflow Depth = 0.17" for 10-Yr 24-Hr event Inflow = 1.12 cfs @ 12.70 hrs, Volume= 0.303 af Primary = 1.12 cfs @ 12.70 hrs, Volume= 0.303 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond C0: East Catron Creek Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Inflow Area=21.030 ac1.12 cfs 1.12 cfs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 19HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Time span=5.00-30.00 hrs, dt=0.05 hrs, 501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=2.660 ac 0.00% Impervious Runoff Depth=0.41"Subcatchment A1: Basin A1 Flow Length=1,131' Tc=17.9 min CN=71 Runoff=1.00 cfs 0.092 af Runoff Area=19.750 ac 0.00% Impervious Runoff Depth=0.60"Subcatchment A2: Basin A2 Flow Length=2,780' Tc=45.5 min CN=76 Runoff=6.60 cfs 0.987 af Runoff Area=14.300 ac 0.00% Impervious Runoff Depth=0.41"Subcatchment B1: Basin B1 Flow Length=1,195' Slope=0.0120 '/' Tc=50.1 min CN=71 Runoff=2.61 cfs 0.493 af Runoff Area=5.760 ac 0.00% Impervious Runoff Depth=0.41"Subcatchment B2: Basin B2 Flow Length=2,325' Tc=76.8 min CN=71 Runoff=0.77 cfs 0.199 af Runoff Area=4.150 ac 0.00% Impervious Runoff Depth=0.41"Subcatchment C1: Basin C1 Flow Length=875' Slope=0.0120 '/' Tc=43.2 min CN=71 Runoff=0.84 cfs 0.143 af Runoff Area=16.880 ac 0.00% Impervious Runoff Depth=0.45"Subcatchment D1: Basin D1 Flow Length=1,314' Slope=0.0120 '/' Tc=52.7 min CN=72 Runoff=3.35 cfs 0.630 af Inflow=0.84 cfs 0.143 afReach 1R: Outfall C Outflow=0.84 cfs 0.143 af Inflow=3.35 cfs 0.630 afReach 2R: Outfall D Outflow=3.35 cfs 0.630 af Inflow=6.95 cfs 1.079 afPond A0: Outfall A (West Catron Creek) Primary=6.95 cfs 1.079 af Inflow=3.21 cfs 0.692 afPond B0: Outfall B (Offsite Detention Facility) Primary=3.21 cfs 0.692 af Inflow=4.15 cfs 0.773 afPond C0: East Catron Creek Primary=4.15 cfs 0.773 af Total Runoff Area = 63.500 ac Runoff Volume = 2.543 af Average Runoff Depth = 0.48" 100.00% Pervious = 63.500 ac 0.00% Impervious = 0.000 ac Type II 24-hr 100-Yr 24-Hr Rainfall=2.34"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 20HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment A1: Basin A1 Runoff = 1.00 cfs @ 12.14 hrs, Volume= 0.092 af, Depth= 0.41" Routed to Pond A0 : Outfall A (West Catron Creek) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34" Area (ac) CN Description 2.610 71 Herbaceous range, Fair, HSG B 0.050 89 Herbaceous range, Fair, HSG D 2.660 71 Weighted Average 2.660 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.5 984 0.0090 4.72 88.05 Parabolic Channel, Flow through West Catron Creek W=14.00' D=2.00' Area=18.7 sf Perim=14.7' n= 0.035 Earth, dense weeds 14.4 147 0.0570 0.17 Sheet Flow, Sheet Flow (Southern Portion of A1) n= 0.150 P2= 1.18" 17.9 1,131 Total Subcatchment A1: Basin A1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Type II 24-hr 100-Yr 24-Hr Rainfall=2.34" Runoff Area=2.660 ac Runoff Volume=0.092 af Runoff Depth=0.41" Flow Length=1,131' Tc=17.9 min CN=71 1.00 cfs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 21HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment A2: Basin A2 Runoff = 6.60 cfs @ 12.49 hrs, Volume= 0.987 af, Depth= 0.60" Routed to Pond A0 : Outfall A (West Catron Creek) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34" Area (ac) CN Description 0.600 81 Herbaceous range, Fair, HSG C 0.600 71 Herbaceous range, Fair, HSG B 8.500 71 Herbaceous range, Fair, HSG B 5.000 71 Herbaceous range, Fair, HSG B 5.050 89 Herbaceous range, Fair, HSG D 19.750 76 Weighted Average 19.750 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 24.4 150 0.0160 0.10 Sheet Flow, Sheet Flow (150') n= 0.150 P2= 1.18" 12.6 672 0.0160 0.89 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 4.5 881 0.0120 3.28 98.45 Channel Flow, Flow Though West Catron Creek Area= 30.0 sf Perim= 20.0' r= 1.50' n= 0.065 4.0 1,077 0.0081 4.48 83.53 Parabolic Channel, A2 Flow through A1 W=14.00' D=2.00' Area=18.7 sf Perim=14.7' n= 0.035 Earth, dense weeds 45.5 2,780 Total Type II 24-hr 100-Yr 24-Hr Rainfall=2.34"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 22HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Subcatchment A2: Basin A2 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)7 6 5 4 3 2 1 0 Type II 24-hr 100-Yr 24-Hr Rainfall=2.34" Runoff Area=19.750 ac Runoff Volume=0.987 af Runoff Depth=0.60" Flow Length=2,780' Tc=45.5 min CN=76 6.60 cfs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 23HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment B1: Basin B1 Runoff = 2.61 cfs @ 12.60 hrs, Volume= 0.493 af, Depth= 0.41" Routed to Pond B0 : Outfall B (Offsite Detention Facility) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34" Area (ac) CN Description 9.700 71 Herbaceous range, Fair, HSG B 4.600 71 Herbaceous range, Fair, HSG B 14.300 71 Weighted Average 14.300 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') n= 0.150 P2= 1.18" 22.7 1,045 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 50.1 1,195 Total Subcatchment B1: Basin B1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)2 1 0 Type II 24-hr 100-Yr 24-Hr Rainfall=2.34" Runoff Area=14.300 ac Runoff Volume=0.493 af Runoff Depth=0.41" Flow Length=1,195' Slope=0.0120 '/' Tc=50.1 min CN=71 2.61 cfs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 24HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment B2: Basin B2 Runoff = 0.77 cfs @ 13.00 hrs, Volume= 0.199 af, Depth= 0.41" Routed to Pond B0 : Outfall B (Offsite Detention Facility) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34" Area (ac) CN Description 4.480 71 Herbaceous range, Fair, HSG B 1.280 71 Herbaceous range, Fair, HSG B 5.760 71 Weighted Average 5.760 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.8 150 0.0116 0.09 Sheet Flow, Sheet flow (150') n= 0.150 P2= 1.18" 21.7 980 0.0116 0.75 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 27.3 1,195 0.0109 0.73 Shallow Concentrated Flow, B2 Flow Through B1 Short Grass Pasture Kv= 7.0 fps 76.8 2,325 Total Subcatchment B2: Basin B2 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type II 24-hr 100-Yr 24-Hr Rainfall=2.34" Runoff Area=5.760 ac Runoff Volume=0.199 af Runoff Depth=0.41" Flow Length=2,325' Tc=76.8 min CN=71 0.77 cfs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 25HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment C1: Basin C1 Runoff = 0.84 cfs @ 12.50 hrs, Volume= 0.143 af, Depth= 0.41" Routed to Reach 1R : Outfall C Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34" Area (ac) CN Description 1.500 71 Herbaceous range, Fair, HSG B 2.650 71 Herbaceous range, Fair, HSG B 4.150 71 Weighted Average 4.150 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') Grass: Short n= 0.150 P2= 1.18" 15.8 725 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 43.2 875 Total Subcatchment C1: Basin C1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type II 24-hr 100-Yr 24-Hr Rainfall=2.34" Runoff Area=4.150 ac Runoff Volume=0.143 af Runoff Depth=0.41" Flow Length=875' Slope=0.0120 '/' Tc=43.2 min CN=71 0.84 cfs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 26HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment D1: Basin D1 Runoff = 3.35 cfs @ 12.62 hrs, Volume= 0.630 af, Depth= 0.45" Routed to Reach 2R : Outfall D Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34" Area (ac) CN Description 15.490 71 Herbaceous range, Fair, HSG B 1.390 81 Herbaceous range, Fair, HSG C 16.880 72 Weighted Average 16.880 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') n= 0.150 P2= 1.18" 25.3 1,164 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 52.7 1,314 Total Subcatchment D1: Basin D1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)3 2 1 0 Type II 24-hr 100-Yr 24-Hr Rainfall=2.34" Runoff Area=16.880 ac Runoff Volume=0.630 af Runoff Depth=0.45" Flow Length=1,314' Slope=0.0120 '/' Tc=52.7 min CN=72 3.35 cfs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 27HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Reach 1R: Outfall C [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 4.150 ac, 0.00% Impervious, Inflow Depth = 0.41" for 100-Yr 24-Hr event Inflow = 0.84 cfs @ 12.50 hrs, Volume= 0.143 af Outflow = 0.84 cfs @ 12.50 hrs, Volume= 0.143 af, Atten= 0%, Lag= 0.0 min Routed to Pond C0 : East Catron Creek Routing by Stor-Ind+Trans method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Reach 1R: Outfall C InflowOutflow Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=4.150 ac0.84 cfs 0.84 cfs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 28HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Reach 2R: Outfall D [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 16.880 ac, 0.00% Impervious, Inflow Depth = 0.45" for 100-Yr 24-Hr event Inflow = 3.35 cfs @ 12.62 hrs, Volume= 0.630 af Outflow = 3.35 cfs @ 12.62 hrs, Volume= 0.630 af, Atten= 0%, Lag= 0.0 min Routed to Pond C0 : East Catron Creek Routing by Stor-Ind+Trans method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Reach 2R: Outfall D InflowOutflow Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)3 2 1 0 Inflow Area=16.880 ac3.35 cfs 3.35 cfs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 29HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond A0: Outfall A (West Catron Creek) [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 22.410 ac, 0.00% Impervious, Inflow Depth = 0.58" for 100-Yr 24-Hr event Inflow = 6.95 cfs @ 12.48 hrs, Volume= 1.079 af Primary = 6.95 cfs @ 12.48 hrs, Volume= 1.079 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond A0: Outfall A (West Catron Creek) Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)7 6 5 4 3 2 1 0 Inflow Area=22.410 ac6.95 cfs 6.95 cfs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 30HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond B0: Outfall B (Offsite Detention Facility) [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 20.060 ac, 0.00% Impervious, Inflow Depth = 0.41" for 100-Yr 24-Hr event Inflow = 3.21 cfs @ 12.66 hrs, Volume= 0.692 af Primary = 3.21 cfs @ 12.66 hrs, Volume= 0.692 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond B0: Outfall B (Offsite Detention Facility) Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)3 2 1 0 Inflow Area=20.060 ac3.21 cfs 3.21 cfs Type II 24-hr 100-Yr 24-Hr Rainfall=2.34"2024525-Pre-Development Scenario Printed 10/1/2025Prepared by WWC Engineering Page 31HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond C0: East Catron Creek [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 21.030 ac, 0.00% Impervious, Inflow Depth = 0.44" for 100-Yr 24-Hr event Inflow = 4.15 cfs @ 12.60 hrs, Volume= 0.773 af Primary = 4.15 cfs @ 12.60 hrs, Volume= 0.773 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond C0: East Catron Creek Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)4 3 2 1 0 Inflow Area=21.030 ac4.15 cfs 4.15 cfs E.2 - Post-Development (Proposed) Conditions A1 Basin A1 A2 Basin A2 B1 Basin B1 B2 Basin B2 C1 Basin C1 D1 Basin D1 E1 Basin E1 1R Outfall C 2R Outfall D A0 Outfall A (West Catron Creek) B0 Outfall B (Offsite Detention Facility) C0 East Catron Creek E0 Retention/Infiltration Pond (SE Portion of Lot A) T0 Temp. Pond (Lot B) Routing Diagram for 2024525-Post-Development - Phase 1 Scenario Prepared by WWC Engineering, Printed 12/15/2025 HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Subcat Reach Pond Link 2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 2HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Rainfall Events Listing (selected events) Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 10-Yr 24 Hr Type II 24-hr Default 24.00 1 1.70 2 2 100-Yr 24 Hr Type II 24-hr Default 24.00 1 2.34 2 2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 3HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 55.270 71 Herbaceous range, Fair, HSG B (A1, A2, B1, B2, C1, D1) 2.000 81 Herbaceous range, Fair, HSG C (A2, D1) 5.100 89 Herbaceous range, Fair, HSG D (A1, A2) 0.750 98 Impervious (Roadway and Sidewalks) (E1) 0.190 61 Pervious (Landscaped Boulevards) (E1) 0.200 69 SE Lot A/Pond Area (E1) 63.510 73 TOTAL AREA 2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 4HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.000 HSG A 55.270 HSG B A1, A2, B1, B2, C1, D1 2.000 HSG C A2, D1 5.100 HSG D A1, A2 1.140 Other E1 63.510 TOTAL AREA 2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 5HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.000 55.270 2.000 5.100 0.000 62.370 Herbaceous range, Fair 0.000 0.000 0.000 0.000 0.750 0.750 Impervious (Roadway and Sidewalks) 0.000 0.000 0.000 0.000 0.190 0.190 Pervious (Landscaped Boulevards) 0.000 0.000 0.000 0.000 0.200 0.200 SE Lot A/Pond Area 0.000 55.270 2.000 5.100 1.140 63.510 TOTAL AREA 2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 6HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Pipe Listing (all nodes) Line# Node Number In-Invert (feet) Out-Invert (feet) Length (feet) Slope (ft/ft) n Width (inches) Diam/Height (inches) Inside-Fill (inches) Node Name 1 E1 0.00 0.00 71.0 0.0050 0.010 0.0 12.0 0.0 Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 7HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Time span=5.00-30.00 hrs, dt=0.05 hrs, 501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=2.500 ac 0.00% Impervious Runoff Depth=0.16"Subcatchment A1: Basin A1 Flow Length=1,131' Tc=17.9 min CN=71 Runoff=0.21 cfs 0.033 af Runoff Area=19.590 ac 0.00% Impervious Runoff Depth=0.27"Subcatchment A2: Basin A2 Flow Length=2,780' Tc=45.5 min CN=76 Runoff=2.36 cfs 0.441 af Runoff Area=13.790 ac 0.00% Impervious Runoff Depth=0.16"Subcatchment B1: Basin B1 Flow Length=1,195' Slope=0.0120 '/' Tc=50.1 min CN=71 Runoff=0.63 cfs 0.180 af Runoff Area=5.460 ac 0.00% Impervious Runoff Depth=0.16"Subcatchment B2: Basin B2 Flow Length=2,325' Tc=76.8 min CN=71 Runoff=0.20 cfs 0.071 af Runoff Area=4.150 ac 0.00% Impervious Runoff Depth=0.16"Subcatchment C1: Basin C1 Flow Length=875' Slope=0.0120 '/' Tc=43.2 min CN=71 Runoff=0.21 cfs 0.054 af Runoff Area=16.880 ac 0.00% Impervious Runoff Depth=0.18"Subcatchment D1: Basin D1 Flow Length=1,314' Slope=0.0120 '/' Tc=52.7 min CN=72 Runoff=0.92 cfs 0.249 af Runoff Area=1.140 ac 65.79% Impervious Runoff Depth=0.68"Subcatchment E1: Basin E1 Flow Length=729' Tc=7.1 min CN=87 Runoff=1.30 cfs 0.064 af Inflow=0.21 cfs 0.054 afReach 1R: Outfall C Outflow=0.21 cfs 0.054 af Inflow=0.92 cfs 0.249 afReach 2R: Outfall D Outflow=0.92 cfs 0.249 af Inflow=2.47 cfs 0.474 afPond A0: Outfall A (West Catron Creek) Primary=2.47 cfs 0.474 af Inflow=0.63 cfs 0.180 afPond B0: Outfall B (Offsite Detention Facility) Primary=0.63 cfs 0.180 af Inflow=1.12 cfs 0.303 afPond C0: East Catron Creek Primary=1.12 cfs 0.303 af Peak Elev=4,702.36' Storage=0.064 af Inflow=1.30 cfs 0.064 afPond E0: Retention/Infiltration Pond (SE Outflow=0.00 cfs 0.000 af Peak Elev=4,703.99' Storage=0.071 af Inflow=0.20 cfs 0.071 afPond T0: Temp. Pond (Lot B) Outflow=0.00 cfs 0.000 af Total Runoff Area = 63.510 ac Runoff Volume = 1.093 af Average Runoff Depth = 0.21" 98.82% Pervious = 62.760 ac 1.18% Impervious = 0.750 ac Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 8HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment A1: Basin A1 Runoff = 0.21 cfs @ 12.18 hrs, Volume= 0.033 af, Depth= 0.16" Routed to Pond A0 : Outfall A (West Catron Creek) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Area (ac) CN Description 2.400 71 Herbaceous range, Fair, HSG B 0.050 71 Herbaceous range, Fair, HSG B 0.050 89 Herbaceous range, Fair, HSG D 2.500 71 Weighted Average 2.500 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.5 984 0.0090 4.72 88.05 Parabolic Channel, West Catron Creek W=14.00' D=2.00' Area=18.7 sf Perim=14.7' n= 0.035 Earth, dense weeds 14.4 147 0.0570 0.17 Sheet Flow, Sheet Flow (Southern Portion of A1) n= 0.150 P2= 1.18" 17.9 1,131 Total Subcatchment A1: Basin A1 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Runoff Area=2.500 ac Runoff Volume=0.033 af Runoff Depth=0.16" Flow Length=1,131' Tc=17.9 min CN=71 0.21 cfs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 9HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment A2: Basin A2 Runoff = 2.36 cfs @ 12.54 hrs, Volume= 0.441 af, Depth= 0.27" Routed to Pond A0 : Outfall A (West Catron Creek) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Area (ac) CN Description 0.600 81 Herbaceous range, Fair, HSG C 0.390 71 Herbaceous range, Fair, HSG B 8.500 71 Herbaceous range, Fair, HSG B 5.050 71 Herbaceous range, Fair, HSG B 5.050 89 Herbaceous range, Fair, HSG D 19.590 76 Weighted Average 19.590 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 24.4 150 0.0160 0.10 Sheet Flow, Sheet Flow n= 0.150 P2= 1.18" 12.6 672 0.0160 0.89 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 4.5 881 0.0120 3.28 98.45 Channel Flow, Channel Flow Area= 30.0 sf Perim= 20.0' r= 1.50' n= 0.065 4.0 1,077 0.0081 4.48 83.53 Parabolic Channel, A2 Flow through A1 W=14.00' D=2.00' Area=18.7 sf Perim=14.7' n= 0.035 Earth, dense weeds 45.5 2,780 Total Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 10HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Subcatchment A2: Basin A2 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)2 1 0 Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Runoff Area=19.590 ac Runoff Volume=0.441 af Runoff Depth=0.27" Flow Length=2,780' Tc=45.5 min CN=76 2.36 cfs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 11HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment B1: Basin B1 Runoff = 0.63 cfs @ 12.72 hrs, Volume= 0.180 af, Depth= 0.16" Routed to Pond B0 : Outfall B (Offsite Detention Facility) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Area (ac) CN Description 9.190 71 Herbaceous range, Fair, HSG B 4.600 71 Herbaceous range, Fair, HSG B 13.790 71 Weighted Average 13.790 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') n= 0.150 P2= 1.18" 22.7 1,045 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 50.1 1,195 Total Subcatchment B1: Basin B1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Runoff Area=13.790 ac Runoff Volume=0.180 af Runoff Depth=0.16" Flow Length=1,195' Slope=0.0120 '/' Tc=50.1 min CN=71 0.63 cfs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 12HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment B2: Basin B2 Runoff = 0.20 cfs @ 13.16 hrs, Volume= 0.071 af, Depth= 0.16" Routed to Pond T0 : Temp. Pond (Lot B) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Area (ac) CN Description 4.160 71 Herbaceous range, Fair, HSG B 1.300 71 Herbaceous range, Fair, HSG B 5.460 71 Weighted Average 5.460 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.8 150 0.0116 0.09 Sheet Flow, B1 Sheet flow n= 0.150 P2= 1.18" 21.7 980 0.0116 0.75 Shallow Concentrated Flow, B1 Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 27.3 1,195 0.0109 0.73 Shallow Concentrated Flow, B1 Flow Through B2 Short Grass Pasture Kv= 7.0 fps 76.8 2,325 Total Subcatchment B2: Basin B2 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Runoff Area=5.460 ac Runoff Volume=0.071 af Runoff Depth=0.16" Flow Length=2,325' Tc=76.8 min CN=71 0.20 cfs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 13HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment C1: Basin C1 Runoff = 0.21 cfs @ 12.60 hrs, Volume= 0.054 af, Depth= 0.16" Routed to Reach 1R : Outfall C Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Area (ac) CN Description 1.550 71 Herbaceous range, Fair, HSG B 2.600 71 Herbaceous range, Fair, HSG B 4.150 71 Weighted Average 4.150 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') Grass: Short n= 0.150 P2= 1.18" 15.8 725 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 43.2 875 Total Subcatchment C1: Basin C1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Runoff Area=4.150 ac Runoff Volume=0.054 af Runoff Depth=0.16" Flow Length=875' Slope=0.0120 '/' Tc=43.2 min CN=71 0.21 cfs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 14HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment D1: Basin D1 Runoff = 0.92 cfs @ 12.73 hrs, Volume= 0.249 af, Depth= 0.18" Routed to Reach 2R : Outfall D Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Area (ac) CN Description 15.480 71 Herbaceous range, Fair, HSG B 1.400 81 Herbaceous range, Fair, HSG C 16.880 72 Weighted Average 16.880 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') n= 0.150 P2= 1.18" 25.3 1,164 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 52.7 1,314 Total Subcatchment D1: Basin D1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Runoff Area=16.880 ac Runoff Volume=0.249 af Runoff Depth=0.18" Flow Length=1,314' Slope=0.0120 '/' Tc=52.7 min CN=72 0.92 cfs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 15HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment E1: Basin E1 [47] Hint: Peak is 772% of capacity of segment #2 Runoff = 1.30 cfs @ 11.99 hrs, Volume= 0.064 af, Depth= 0.68" Routed to Pond E0 : Retention/Infiltration Pond (SE Portion of Lot A) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Area (ac) CN Description * 0.750 98 Impervious (Roadway and Sidewalks) * 0.190 61 Pervious (Landscaped Boulevards) * 0.200 69 SE Lot A/Pond Area 1.140 87 Weighted Average 0.390 34.21% Pervious Area 0.750 65.79% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.5 18 0.0200 0.59 Sheet Flow, Asphalt sheet flow Smooth surfaces n= 0.011 P2= 1.18" 6.3 640 0.0060 1.69 0.17 Channel Flow, Gutter flow Area= 0.1 sf Perim= 1.2' r= 0.08' n= 0.013 Concrete, trowel finish 0.3 71 0.0050 4.17 3.28 Pipe Channel, Pipe Flow 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.010 PVC, smooth interior 7.1 729 Total Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 16HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Subcatchment E1: Basin E1 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)1 0 Type II 24-hr 10-Yr 24 Hr Rainfall=1.70" Runoff Area=1.140 ac Runoff Volume=0.064 af Runoff Depth=0.68" Flow Length=729' Tc=7.1 min CN=87 1.30 cfs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 17HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Reach 1R: Outfall C [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 4.150 ac, 0.00% Impervious, Inflow Depth = 0.16" for 10-Yr 24 Hr event Inflow = 0.21 cfs @ 12.60 hrs, Volume= 0.054 af Outflow = 0.21 cfs @ 12.60 hrs, Volume= 0.054 af, Atten= 0%, Lag= 0.0 min Routed to Pond C0 : East Catron Creek Routing by Stor-Ind+Trans method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Reach 1R: Outfall C InflowOutflow Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=4.150 ac0.21 cfs 0.21 cfs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 18HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Reach 2R: Outfall D [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 16.880 ac, 0.00% Impervious, Inflow Depth = 0.18" for 10-Yr 24 Hr event Inflow = 0.92 cfs @ 12.73 hrs, Volume= 0.249 af Outflow = 0.92 cfs @ 12.73 hrs, Volume= 0.249 af, Atten= 0%, Lag= 0.0 min Routed to Pond C0 : East Catron Creek Routing by Stor-Ind+Trans method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Reach 2R: Outfall D InflowOutflow Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Inflow Area=16.880 ac0.92 cfs 0.92 cfs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 19HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond A0: Outfall A (West Catron Creek) [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 22.090 ac, 0.00% Impervious, Inflow Depth = 0.26" for 10-Yr 24 Hr event Inflow = 2.47 cfs @ 12.53 hrs, Volume= 0.474 af Primary = 2.47 cfs @ 12.53 hrs, Volume= 0.474 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond A0: Outfall A (West Catron Creek) Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)2 1 0 Inflow Area=22.090 ac2.47 cfs 2.47 cfs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 20HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond B0: Outfall B (Offsite Detention Facility) [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 13.790 ac, 0.00% Impervious, Inflow Depth = 0.16" for 10-Yr 24 Hr event Inflow = 0.63 cfs @ 12.72 hrs, Volume= 0.180 af Primary = 0.63 cfs @ 12.72 hrs, Volume= 0.180 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond B0: Outfall B (Offsite Detention Facility) Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=13.790 ac0.63 cfs 0.63 cfs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 21HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond C0: East Catron Creek [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 21.030 ac, 0.00% Impervious, Inflow Depth = 0.17" for 10-Yr 24 Hr event Inflow = 1.12 cfs @ 12.70 hrs, Volume= 0.303 af Primary = 1.12 cfs @ 12.70 hrs, Volume= 0.303 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond C0: East Catron Creek Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Inflow Area=21.030 ac1.12 cfs 1.12 cfs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 22HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond E0: Retention/Infiltration Pond (SE Portion of Lot A) Inflow Area = 1.140 ac, 65.79% Impervious, Inflow Depth = 0.68" for 10-Yr 24 Hr event Inflow = 1.30 cfs @ 11.99 hrs, Volume= 0.064 af Outflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 4,702.36' @ 24.45 hrs Surf.Area= 0.094 ac Storage= 0.064 af Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no outflow) Volume Invert Avail.Storage Storage Description #1 4,701.60' 0.177 af Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet) 4,701.60 0.075 0.000 0.000 4,701.80 0.080 0.015 0.015 4,702.00 0.085 0.016 0.032 4,702.20 0.090 0.017 0.049 4,702.40 0.095 0.018 0.068 4,702.60 0.101 0.020 0.088 4,702.80 0.106 0.021 0.108 4,703.00 0.112 0.022 0.130 4,703.20 0.117 0.023 0.153 4,703.40 0.123 0.024 0.177 Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 23HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Pond E0: Retention/Infiltration Pond (SE Portion of Lot A) Inflow Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)1 0 Inflow Area=1.140 ac Peak Elev=4,702.36' Storage=0.064 af 1.30 cfs Type II 24-hr 10-Yr 24 Hr Rainfall=1.70"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 24HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond T0: Temp. Pond (Lot B) Inflow Area = 5.460 ac, 0.00% Impervious, Inflow Depth = 0.16" for 10-Yr 24 Hr event Inflow = 0.20 cfs @ 13.16 hrs, Volume= 0.071 af Outflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 4,703.99' @ 28.40 hrs Surf.Area= 0.387 ac Storage= 0.071 af Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no outflow) Volume Invert Avail.Storage Storage Description #1 4,703.80' 0.237 af Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet) 4,703.80 0.372 0.000 0.000 4,704.00 0.388 0.076 0.076 4,704.20 0.403 0.079 0.155 4,704.40 0.419 0.082 0.237 Pond T0: Temp. Pond (Lot B) Inflow Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=5.460 ac Peak Elev=4,703.99' Storage=0.071 af 0.20 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 25HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Time span=5.00-30.00 hrs, dt=0.05 hrs, 501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=2.500 ac 0.00% Impervious Runoff Depth=0.41"Subcatchment A1: Basin A1 Flow Length=1,131' Tc=17.9 min CN=71 Runoff=0.94 cfs 0.086 af Runoff Area=19.590 ac 0.00% Impervious Runoff Depth=0.60"Subcatchment A2: Basin A2 Flow Length=2,780' Tc=45.5 min CN=76 Runoff=6.55 cfs 0.979 af Runoff Area=13.790 ac 0.00% Impervious Runoff Depth=0.41"Subcatchment B1: Basin B1 Flow Length=1,195' Slope=0.0120 '/' Tc=50.1 min CN=71 Runoff=2.52 cfs 0.475 af Runoff Area=5.460 ac 0.00% Impervious Runoff Depth=0.41"Subcatchment B2: Basin B2 Flow Length=2,325' Tc=76.8 min CN=71 Runoff=0.73 cfs 0.188 af Runoff Area=4.150 ac 0.00% Impervious Runoff Depth=0.41"Subcatchment C1: Basin C1 Flow Length=875' Slope=0.0120 '/' Tc=43.2 min CN=71 Runoff=0.84 cfs 0.143 af Runoff Area=16.880 ac 0.00% Impervious Runoff Depth=0.45"Subcatchment D1: Basin D1 Flow Length=1,314' Slope=0.0120 '/' Tc=52.7 min CN=72 Runoff=3.35 cfs 0.630 af Runoff Area=1.140 ac 65.79% Impervious Runoff Depth=1.18"Subcatchment E1: Basin E1 Flow Length=729' Tc=7.1 min CN=87 Runoff=2.26 cfs 0.112 af Inflow=0.84 cfs 0.143 afReach 1R: Outfall C Outflow=0.84 cfs 0.143 af Inflow=3.35 cfs 0.630 afReach 2R: Outfall D Outflow=3.35 cfs 0.630 af Inflow=6.88 cfs 1.065 afPond A0: Outfall A (West Catron Creek) Primary=6.88 cfs 1.065 af Inflow=2.52 cfs 0.475 afPond B0: Outfall B (Offsite Detention Facility) Primary=2.52 cfs 0.475 af Inflow=4.15 cfs 0.773 afPond C0: East Catron Creek Primary=4.15 cfs 0.773 af Peak Elev=4,702.83' Storage=0.112 af Inflow=2.26 cfs 0.112 afPond E0: Retention/Infiltration Pond (SE Outflow=0.00 cfs 0.000 af Peak Elev=4,704.28' Storage=0.188 af Inflow=0.73 cfs 0.188 afPond T0: Temp. Pond (Lot B) Outflow=0.00 cfs 0.000 af Total Runoff Area = 63.510 ac Runoff Volume = 2.614 af Average Runoff Depth = 0.49" 98.82% Pervious = 62.760 ac 1.18% Impervious = 0.750 ac Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 26HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment A1: Basin A1 Runoff = 0.94 cfs @ 12.14 hrs, Volume= 0.086 af, Depth= 0.41" Routed to Pond A0 : Outfall A (West Catron Creek) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Area (ac) CN Description 2.400 71 Herbaceous range, Fair, HSG B 0.050 71 Herbaceous range, Fair, HSG B 0.050 89 Herbaceous range, Fair, HSG D 2.500 71 Weighted Average 2.500 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.5 984 0.0090 4.72 88.05 Parabolic Channel, West Catron Creek W=14.00' D=2.00' Area=18.7 sf Perim=14.7' n= 0.035 Earth, dense weeds 14.4 147 0.0570 0.17 Sheet Flow, Sheet Flow (Southern Portion of A1) n= 0.150 P2= 1.18" 17.9 1,131 Total Subcatchment A1: Basin A1 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)1 0 Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Runoff Area=2.500 ac Runoff Volume=0.086 af Runoff Depth=0.41" Flow Length=1,131' Tc=17.9 min CN=71 0.94 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 27HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment A2: Basin A2 Runoff = 6.55 cfs @ 12.49 hrs, Volume= 0.979 af, Depth= 0.60" Routed to Pond A0 : Outfall A (West Catron Creek) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Area (ac) CN Description 0.600 81 Herbaceous range, Fair, HSG C 0.390 71 Herbaceous range, Fair, HSG B 8.500 71 Herbaceous range, Fair, HSG B 5.050 71 Herbaceous range, Fair, HSG B 5.050 89 Herbaceous range, Fair, HSG D 19.590 76 Weighted Average 19.590 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 24.4 150 0.0160 0.10 Sheet Flow, Sheet Flow n= 0.150 P2= 1.18" 12.6 672 0.0160 0.89 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 4.5 881 0.0120 3.28 98.45 Channel Flow, Channel Flow Area= 30.0 sf Perim= 20.0' r= 1.50' n= 0.065 4.0 1,077 0.0081 4.48 83.53 Parabolic Channel, A2 Flow through A1 W=14.00' D=2.00' Area=18.7 sf Perim=14.7' n= 0.035 Earth, dense weeds 45.5 2,780 Total Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 28HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Subcatchment A2: Basin A2 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)7 6 5 4 3 2 1 0 Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Runoff Area=19.590 ac Runoff Volume=0.979 af Runoff Depth=0.60" Flow Length=2,780' Tc=45.5 min CN=76 6.55 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 29HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment B1: Basin B1 Runoff = 2.52 cfs @ 12.60 hrs, Volume= 0.475 af, Depth= 0.41" Routed to Pond B0 : Outfall B (Offsite Detention Facility) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Area (ac) CN Description 9.190 71 Herbaceous range, Fair, HSG B 4.600 71 Herbaceous range, Fair, HSG B 13.790 71 Weighted Average 13.790 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') n= 0.150 P2= 1.18" 22.7 1,045 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 50.1 1,195 Total Subcatchment B1: Basin B1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)2 1 0 Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Runoff Area=13.790 ac Runoff Volume=0.475 af Runoff Depth=0.41" Flow Length=1,195' Slope=0.0120 '/' Tc=50.1 min CN=71 2.52 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 30HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment B2: Basin B2 Runoff = 0.73 cfs @ 13.00 hrs, Volume= 0.188 af, Depth= 0.41" Routed to Pond T0 : Temp. Pond (Lot B) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Area (ac) CN Description 4.160 71 Herbaceous range, Fair, HSG B 1.300 71 Herbaceous range, Fair, HSG B 5.460 71 Weighted Average 5.460 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.8 150 0.0116 0.09 Sheet Flow, B1 Sheet flow n= 0.150 P2= 1.18" 21.7 980 0.0116 0.75 Shallow Concentrated Flow, B1 Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 27.3 1,195 0.0109 0.73 Shallow Concentrated Flow, B1 Flow Through B2 Short Grass Pasture Kv= 7.0 fps 76.8 2,325 Total Subcatchment B2: Basin B2 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Runoff Area=5.460 ac Runoff Volume=0.188 af Runoff Depth=0.41" Flow Length=2,325' Tc=76.8 min CN=71 0.73 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 31HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment C1: Basin C1 Runoff = 0.84 cfs @ 12.50 hrs, Volume= 0.143 af, Depth= 0.41" Routed to Reach 1R : Outfall C Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Area (ac) CN Description 1.550 71 Herbaceous range, Fair, HSG B 2.600 71 Herbaceous range, Fair, HSG B 4.150 71 Weighted Average 4.150 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') Grass: Short n= 0.150 P2= 1.18" 15.8 725 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 43.2 875 Total Subcatchment C1: Basin C1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Runoff Area=4.150 ac Runoff Volume=0.143 af Runoff Depth=0.41" Flow Length=875' Slope=0.0120 '/' Tc=43.2 min CN=71 0.84 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 32HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment D1: Basin D1 Runoff = 3.35 cfs @ 12.62 hrs, Volume= 0.630 af, Depth= 0.45" Routed to Reach 2R : Outfall D Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Area (ac) CN Description 15.480 71 Herbaceous range, Fair, HSG B 1.400 81 Herbaceous range, Fair, HSG C 16.880 72 Weighted Average 16.880 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') n= 0.150 P2= 1.18" 25.3 1,164 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 52.7 1,314 Total Subcatchment D1: Basin D1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)3 2 1 0 Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Runoff Area=16.880 ac Runoff Volume=0.630 af Runoff Depth=0.45" Flow Length=1,314' Slope=0.0120 '/' Tc=52.7 min CN=72 3.35 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 33HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment E1: Basin E1 [47] Hint: Peak is 1340% of capacity of segment #2 Runoff = 2.26 cfs @ 11.99 hrs, Volume= 0.112 af, Depth= 1.18" Routed to Pond E0 : Retention/Infiltration Pond (SE Portion of Lot A) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Area (ac) CN Description * 0.750 98 Impervious (Roadway and Sidewalks) * 0.190 61 Pervious (Landscaped Boulevards) * 0.200 69 SE Lot A/Pond Area 1.140 87 Weighted Average 0.390 34.21% Pervious Area 0.750 65.79% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.5 18 0.0200 0.59 Sheet Flow, Asphalt sheet flow Smooth surfaces n= 0.011 P2= 1.18" 6.3 640 0.0060 1.69 0.17 Channel Flow, Gutter flow Area= 0.1 sf Perim= 1.2' r= 0.08' n= 0.013 Concrete, trowel finish 0.3 71 0.0050 4.17 3.28 Pipe Channel, Pipe Flow 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.010 PVC, smooth interior 7.1 729 Total Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 34HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Subcatchment E1: Basin E1 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)2 1 0 Type II 24-hr 100-Yr 24 Hr Rainfall=2.34" Runoff Area=1.140 ac Runoff Volume=0.112 af Runoff Depth=1.18" Flow Length=729' Tc=7.1 min CN=87 2.26 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 35HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Reach 1R: Outfall C [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 4.150 ac, 0.00% Impervious, Inflow Depth = 0.41" for 100-Yr 24 Hr event Inflow = 0.84 cfs @ 12.50 hrs, Volume= 0.143 af Outflow = 0.84 cfs @ 12.50 hrs, Volume= 0.143 af, Atten= 0%, Lag= 0.0 min Routed to Pond C0 : East Catron Creek Routing by Stor-Ind+Trans method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Reach 1R: Outfall C InflowOutflow Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=4.150 ac0.84 cfs 0.84 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 36HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Reach 2R: Outfall D [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 16.880 ac, 0.00% Impervious, Inflow Depth = 0.45" for 100-Yr 24 Hr event Inflow = 3.35 cfs @ 12.62 hrs, Volume= 0.630 af Outflow = 3.35 cfs @ 12.62 hrs, Volume= 0.630 af, Atten= 0%, Lag= 0.0 min Routed to Pond C0 : East Catron Creek Routing by Stor-Ind+Trans method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Reach 2R: Outfall D InflowOutflow Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)3 2 1 0 Inflow Area=16.880 ac3.35 cfs 3.35 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 37HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond A0: Outfall A (West Catron Creek) [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 22.090 ac, 0.00% Impervious, Inflow Depth = 0.58" for 100-Yr 24 Hr event Inflow = 6.88 cfs @ 12.48 hrs, Volume= 1.065 af Primary = 6.88 cfs @ 12.48 hrs, Volume= 1.065 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond A0: Outfall A (West Catron Creek) Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)7 6 5 4 3 2 1 0 Inflow Area=22.090 ac6.88 cfs 6.88 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 38HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond B0: Outfall B (Offsite Detention Facility) [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 13.790 ac, 0.00% Impervious, Inflow Depth = 0.41" for 100-Yr 24 Hr event Inflow = 2.52 cfs @ 12.60 hrs, Volume= 0.475 af Primary = 2.52 cfs @ 12.60 hrs, Volume= 0.475 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond B0: Outfall B (Offsite Detention Facility) Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)2 1 0 Inflow Area=13.790 ac2.52 cfs 2.52 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 39HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond C0: East Catron Creek [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 21.030 ac, 0.00% Impervious, Inflow Depth = 0.44" for 100-Yr 24 Hr event Inflow = 4.15 cfs @ 12.60 hrs, Volume= 0.773 af Primary = 4.15 cfs @ 12.60 hrs, Volume= 0.773 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond C0: East Catron Creek Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)4 3 2 1 0 Inflow Area=21.030 ac4.15 cfs 4.15 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 40HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond E0: Retention/Infiltration Pond (SE Portion of Lot A) Inflow Area = 1.140 ac, 65.79% Impervious, Inflow Depth = 1.18" for 100-Yr 24 Hr event Inflow = 2.26 cfs @ 11.99 hrs, Volume= 0.112 af Outflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 4,702.83' @ 24.45 hrs Surf.Area= 0.107 ac Storage= 0.112 af Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no outflow) Volume Invert Avail.Storage Storage Description #1 4,701.60' 0.177 af Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet) 4,701.60 0.075 0.000 0.000 4,701.80 0.080 0.015 0.015 4,702.00 0.085 0.016 0.032 4,702.20 0.090 0.017 0.049 4,702.40 0.095 0.018 0.068 4,702.60 0.101 0.020 0.088 4,702.80 0.106 0.021 0.108 4,703.00 0.112 0.022 0.130 4,703.20 0.117 0.023 0.153 4,703.40 0.123 0.024 0.177 Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 41HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Pond E0: Retention/Infiltration Pond (SE Portion of Lot A) Inflow Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)2 1 0 Inflow Area=1.140 ac Peak Elev=4,702.83' Storage=0.112 af 2.26 cfs Type II 24-hr 100-Yr 24 Hr Rainfall=2.34"2024525-Post-Development - Phase 1 Scenario Printed 12/15/2025Prepared by WWC Engineering Page 42HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond T0: Temp. Pond (Lot B) Inflow Area = 5.460 ac, 0.00% Impervious, Inflow Depth = 0.41" for 100-Yr 24 Hr event Inflow = 0.73 cfs @ 13.00 hrs, Volume= 0.188 af Outflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 4,704.28' @ 28.40 hrs Surf.Area= 0.410 ac Storage= 0.188 af Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no outflow) Volume Invert Avail.Storage Storage Description #1 4,703.80' 0.237 af Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet) 4,703.80 0.372 0.000 0.000 4,704.00 0.388 0.076 0.076 4,704.20 0.403 0.079 0.155 4,704.40 0.419 0.082 0.237 Pond T0: Temp. Pond (Lot B) Inflow Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=5.460 ac Peak Elev=4,704.28' Storage=0.188 af 0.73 cfs A1 Basin A1 A2 Basin A2 B1 Basin B1 B2 Basin B2 C1 Basin C1 D1 Basin D1 E1 Basin E1 1R Outfall C 2R Outfall D A0 Outfall A (West Catron Creek) B0 Outfall B (Offsite Detention Facility) C0 East Catron Creek E0 Retention/Infiltration Pond (SE Portion of Lot A) T0 Temp. Pond (Lot B) Routing Diagram for 2024525-Post-Development - Phase 1 Scenario Prepared by WWC Engineering, Printed 4/3/2026 HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Subcat Reach Pond Link 2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 2HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Rainfall Events Listing (selected events) Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 Water Quality Type II 24-hr Default 24.00 1 0.50 2 2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 3HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 55.270 71 Herbaceous range, Fair, HSG B (A1, A2, B1, B2, C1, D1) 2.000 81 Herbaceous range, Fair, HSG C (A2, D1) 5.100 89 Herbaceous range, Fair, HSG D (A1, A2) 0.750 98 Impervious (Roadway and Sidewalks) (E1) 0.190 61 Pervious (Landscaped Boulevards) (E1) 0.200 69 SE Lot A/Pond Area (E1) 63.510 73 TOTAL AREA 2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 4HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.000 HSG A 55.270 HSG B A1, A2, B1, B2, C1, D1 2.000 HSG C A2, D1 5.100 HSG D A1, A2 1.140 Other E1 63.510 TOTAL AREA 2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 5HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.000 55.270 2.000 5.100 0.000 62.370 Herbaceous range, Fair 0.000 0.000 0.000 0.000 0.750 0.750 Impervious (Roadway and Sidewalks) 0.000 0.000 0.000 0.000 0.190 0.190 Pervious (Landscaped Boulevards) 0.000 0.000 0.000 0.000 0.200 0.200 SE Lot A/Pond Area 0.000 55.270 2.000 5.100 1.140 63.510 TOTAL AREA 2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 6HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Pipe Listing (all nodes) Line# Node Number In-Invert (feet) Out-Invert (feet) Length (feet) Slope (ft/ft) n Width (inches) Diam/Height (inches) Inside-Fill (inches) Node Name 1 E1 0.00 0.00 71.0 0.0050 0.010 0.0 12.0 0.0 Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 7HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Time span=5.00-30.00 hrs, dt=0.05 hrs, 501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=2.500 ac 0.00% Impervious Runoff Depth=0.00"Subcatchment A1: Basin A1 Flow Length=1,131' Tc=17.9 min CN=71 Runoff=0.00 cfs 0.000 af Runoff Area=19.590 ac 0.00% Impervious Runoff Depth=0.00"Subcatchment A2: Basin A2 Flow Length=2,780' Tc=45.5 min CN=76 Runoff=0.00 cfs 0.000 af Runoff Area=13.790 ac 0.00% Impervious Runoff Depth=0.00"Subcatchment B1: Basin B1 Flow Length=1,195' Slope=0.0120 '/' Tc=50.1 min CN=71 Runoff=0.00 cfs 0.000 af Runoff Area=5.460 ac 0.00% Impervious Runoff Depth=0.00"Subcatchment B2: Basin B2 Flow Length=2,325' Tc=76.8 min CN=71 Runoff=0.00 cfs 0.000 af Runoff Area=4.150 ac 0.00% Impervious Runoff Depth=0.00"Subcatchment C1: Basin C1 Flow Length=875' Slope=0.0120 '/' Tc=43.2 min CN=71 Runoff=0.00 cfs 0.000 af Runoff Area=16.880 ac 0.00% Impervious Runoff Depth=0.00"Subcatchment D1: Basin D1 Flow Length=1,314' Slope=0.0120 '/' Tc=52.7 min CN=72 Runoff=0.00 cfs 0.000 af Runoff Area=1.140 ac 65.79% Impervious Runoff Depth=0.02"Subcatchment E1: Basin E1 Flow Length=729' Tc=7.1 min CN=87 Runoff=0.01 cfs 0.002 af Inflow=0.00 cfs 0.000 afReach 1R: Outfall C Outflow=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afReach 2R: Outfall D Outflow=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afPond A0: Outfall A (West Catron Creek) Primary=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afPond B0: Outfall B (Offsite Detention Facility) Primary=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afPond C0: East Catron Creek Primary=0.00 cfs 0.000 af Peak Elev=4,701.63' Storage=0.002 af Inflow=0.01 cfs 0.002 afPond E0: Retention/Infiltration Pond (SE Outflow=0.00 cfs 0.000 af Peak Elev=4,703.80' Storage=0.000 af Inflow=0.00 cfs 0.000 afPond T0: Temp. Pond (Lot B) Outflow=0.00 cfs 0.000 af Total Runoff Area = 63.510 ac Runoff Volume = 0.002 af Average Runoff Depth = 0.00" 98.82% Pervious = 62.760 ac 1.18% Impervious = 0.750 ac Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 8HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment A1: Basin A1 [45] Hint: Runoff=Zero Runoff = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Depth= 0.00" Routed to Pond A0 : Outfall A (West Catron Creek) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr Water Quality Rainfall=0.50" Area (ac) CN Description 2.400 71 Herbaceous range, Fair, HSG B 0.050 71 Herbaceous range, Fair, HSG B 0.050 89 Herbaceous range, Fair, HSG D 2.500 71 Weighted Average 2.500 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.5 984 0.0090 4.72 88.05 Parabolic Channel, West Catron Creek W=14.00' D=2.00' Area=18.7 sf Perim=14.7' n= 0.035 Earth, dense weeds 14.4 147 0.0570 0.17 Sheet Flow, Sheet Flow (Southern Portion of A1) n= 0.150 P2= 1.18" 17.9 1,131 Total Subcatchment A1: Basin A1 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Type II 24-hr Water Quality Rainfall=0.50" Runoff Area=2.500 ac Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=1,131' Tc=17.9 min CN=71 0.00 cfs Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 9HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment A2: Basin A2 [45] Hint: Runoff=Zero Runoff = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Depth= 0.00" Routed to Pond A0 : Outfall A (West Catron Creek) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr Water Quality Rainfall=0.50" Area (ac) CN Description 0.600 81 Herbaceous range, Fair, HSG C 0.390 71 Herbaceous range, Fair, HSG B 8.500 71 Herbaceous range, Fair, HSG B 5.050 71 Herbaceous range, Fair, HSG B 5.050 89 Herbaceous range, Fair, HSG D 19.590 76 Weighted Average 19.590 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 24.4 150 0.0160 0.10 Sheet Flow, Sheet Flow n= 0.150 P2= 1.18" 12.6 672 0.0160 0.89 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 4.5 881 0.0120 3.28 98.45 Channel Flow, Channel Flow Area= 30.0 sf Perim= 20.0' r= 1.50' n= 0.065 4.0 1,077 0.0081 4.48 83.53 Parabolic Channel, A2 Flow through A1 W=14.00' D=2.00' Area=18.7 sf Perim=14.7' n= 0.035 Earth, dense weeds 45.5 2,780 Total Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 10HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Subcatchment A2: Basin A2 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)1 0 Type II 24-hr Water Quality Rainfall=0.50" Runoff Area=19.590 ac Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=2,780' Tc=45.5 min CN=76 0.00 cfs Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 11HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment B1: Basin B1 [45] Hint: Runoff=Zero Runoff = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Depth= 0.00" Routed to Pond B0 : Outfall B (Offsite Detention Facility) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr Water Quality Rainfall=0.50" Area (ac) CN Description 9.190 71 Herbaceous range, Fair, HSG B 4.600 71 Herbaceous range, Fair, HSG B 13.790 71 Weighted Average 13.790 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') n= 0.150 P2= 1.18" 22.7 1,045 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 50.1 1,195 Total Subcatchment B1: Basin B1 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)1 0 Type II 24-hr Water Quality Rainfall=0.50" Runoff Area=13.790 ac Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=1,195' Slope=0.0120 '/' Tc=50.1 min CN=71 0.00 cfs Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 12HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment B2: Basin B2 [45] Hint: Runoff=Zero Runoff = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Depth= 0.00" Routed to Pond T0 : Temp. Pond (Lot B) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr Water Quality Rainfall=0.50" Area (ac) CN Description 4.160 71 Herbaceous range, Fair, HSG B 1.300 71 Herbaceous range, Fair, HSG B 5.460 71 Weighted Average 5.460 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.8 150 0.0116 0.09 Sheet Flow, B1 Sheet flow n= 0.150 P2= 1.18" 21.7 980 0.0116 0.75 Shallow Concentrated Flow, B1 Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 27.3 1,195 0.0109 0.73 Shallow Concentrated Flow, B1 Flow Through B2 Short Grass Pasture Kv= 7.0 fps 76.8 2,325 Total Subcatchment B2: Basin B2 Runoff Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Type II 24-hr Water Quality Rainfall=0.50" Runoff Area=5.460 ac Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=2,325' Tc=76.8 min CN=71 0.00 cfs Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 13HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment C1: Basin C1 [45] Hint: Runoff=Zero Runoff = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Depth= 0.00" Routed to Reach 1R : Outfall C Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr Water Quality Rainfall=0.50" Area (ac) CN Description 1.550 71 Herbaceous range, Fair, HSG B 2.600 71 Herbaceous range, Fair, HSG B 4.150 71 Weighted Average 4.150 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') Grass: Short n= 0.150 P2= 1.18" 15.8 725 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 43.2 875 Total Subcatchment C1: Basin C1 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)1 0 Type II 24-hr Water Quality Rainfall=0.50" Runoff Area=4.150 ac Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=875' Slope=0.0120 '/' Tc=43.2 min CN=71 0.00 cfs Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 14HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment D1: Basin D1 [45] Hint: Runoff=Zero Runoff = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Depth= 0.00" Routed to Reach 2R : Outfall D Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr Water Quality Rainfall=0.50" Area (ac) CN Description 15.480 71 Herbaceous range, Fair, HSG B 1.400 81 Herbaceous range, Fair, HSG C 16.880 72 Weighted Average 16.880 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 27.4 150 0.0120 0.09 Sheet Flow, Sheet Flow (150') n= 0.150 P2= 1.18" 25.3 1,164 0.0120 0.77 Shallow Concentrated Flow, Shallow Concentrated Flow Short Grass Pasture Kv= 7.0 fps 52.7 1,314 Total Subcatchment D1: Basin D1 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)1 0 Type II 24-hr Water Quality Rainfall=0.50" Runoff Area=16.880 ac Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=1,314' Slope=0.0120 '/' Tc=52.7 min CN=72 0.00 cfs Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 15HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment E1: Basin E1 Runoff = 0.01 cfs @ 12.07 hrs, Volume= 0.002 af, Depth= 0.02" Routed to Pond E0 : Retention/Infiltration Pond (SE Portion of Lot A) Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Type II 24-hr Water Quality Rainfall=0.50" Area (ac) CN Description * 0.750 98 Impervious (Roadway and Sidewalks) * 0.190 61 Pervious (Landscaped Boulevards) * 0.200 69 SE Lot A/Pond Area 1.140 87 Weighted Average 0.390 34.21% Pervious Area 0.750 65.79% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.5 18 0.0200 0.59 Sheet Flow, Asphalt sheet flow Smooth surfaces n= 0.011 P2= 1.18" 6.3 640 0.0060 1.69 0.17 Channel Flow, Gutter flow Area= 0.1 sf Perim= 1.2' r= 0.08' n= 0.013 Concrete, trowel finish 0.3 71 0.0050 4.17 3.28 Pipe Channel, Pipe Flow 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.010 PVC, smooth interior 7.1 729 Total Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 16HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Subcatchment E1: Basin E1 Runoff Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)0.008 0.007 0.007 0.006 0.006 0.005 0.005 0.004 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0.000 0 Type II 24-hr Water Quality Rainfall=0.50" Runoff Area=1.140 ac Runoff Volume=0.002 af Runoff Depth=0.02" Flow Length=729' Tc=7.1 min CN=87 0.01 cfs Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 17HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Reach 1R: Outfall C [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 4.150 ac, 0.00% Impervious, Inflow Depth = 0.00" for Water Quality event Inflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Outflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routed to Pond C0 : East Catron Creek Routing by Stor-Ind+Trans method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Reach 1R: Outfall C InflowOutflow Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Inflow Area=4.150 ac 0.00 cfs 0.00 cfs Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 18HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Reach 2R: Outfall D [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 16.880 ac, 0.00% Impervious, Inflow Depth = 0.00" for Water Quality event Inflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Outflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routed to Pond C0 : East Catron Creek Routing by Stor-Ind+Trans method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Reach 2R: Outfall D InflowOutflow Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Inflow Area=16.880 ac 0.00 cfs 0.00 cfs Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 19HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond A0: Outfall A (West Catron Creek) [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 22.090 ac, 0.00% Impervious, Inflow Depth = 0.00" for Water Quality event Inflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Primary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond A0: Outfall A (West Catron Creek) Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Inflow Area=22.090 ac 0.00 cfs 0.00 cfs Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 20HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond B0: Outfall B (Offsite Detention Facility) [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 13.790 ac, 0.00% Impervious, Inflow Depth = 0.00" for Water Quality event Inflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Primary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond B0: Outfall B (Offsite Detention Facility) Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Inflow Area=13.790 ac 0.00 cfs 0.00 cfs Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 21HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond C0: East Catron Creek [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 21.030 ac, 0.00% Impervious, Inflow Depth = 0.00" for Water Quality event Inflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Primary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Pond C0: East Catron Creek Inflow Primary Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Inflow Area=21.030 ac 0.00 cfs 0.00 cfs Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 22HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond E0: Retention/Infiltration Pond (SE Portion of Lot A) Inflow Area = 1.140 ac, 65.79% Impervious, Inflow Depth = 0.02" for Water Quality event Inflow = 0.01 cfs @ 12.07 hrs, Volume= 0.002 af Outflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 4,701.63' @ 24.45 hrs Surf.Area= 0.076 ac Storage= 0.002 af Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no outflow) Volume Invert Avail.Storage Storage Description #1 4,701.60' 0.177 af Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet) 4,701.60 0.075 0.000 0.000 4,701.80 0.080 0.015 0.015 4,702.00 0.085 0.016 0.032 4,702.20 0.090 0.017 0.049 4,702.40 0.095 0.018 0.068 4,702.60 0.101 0.020 0.088 4,702.80 0.106 0.021 0.108 4,703.00 0.112 0.022 0.130 4,703.20 0.117 0.023 0.153 4,703.40 0.123 0.024 0.177 Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 23HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Pond E0: Retention/Infiltration Pond (SE Portion of Lot A) Inflow Hydrograph Time (hours)30292827262524232221201918171615141312111098765Flow (cfs)0.008 0.007 0.007 0.006 0.006 0.005 0.005 0.004 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0.000 0 Inflow Area=1.140 ac Peak Elev=4,701.63' Storage=0.002 af 0.01 cfs Type II 24-hr Water Quality Rainfall=0.50"2024525-Post-Development - Phase 1 Scenario Printed 4/3/2026Prepared by WWC Engineering Page 24HydroCAD® 10.20-5c s/n 04342 © 2023 HydroCAD Software Solutions LLC Summary for Pond T0: Temp. Pond (Lot B) Inflow Area = 5.460 ac, 0.00% Impervious, Inflow Depth = 0.00" for Water Quality event Inflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Outflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 4,703.80' @ 5.00 hrs Surf.Area= 0.372 ac Storage= 0.000 af Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no inflow) Volume Invert Avail.Storage Storage Description #1 4,703.80' 0.237 af Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet) 4,703.80 0.372 0.000 0.000 4,704.00 0.388 0.076 0.076 4,704.20 0.403 0.079 0.155 4,704.40 0.419 0.082 0.237 Pond T0: Temp. Pond (Lot B) Inflow Hydrograph Time (hours) 30292827262524232221201918171615141312111098765Flow (cfs)1 0 Inflow Area=5.460 ac Peak Elev=4,703.80' Storage=0.000 af 0.00 cfs Stormwater Design Report Appendix F – Retention/Infiltration Pond Details W W W W W W WWWWWSTSTRAWHIDE RIDGE ROAD (PROPOSED)MAX AVENUE (EXISTING)TOP OF POND EL. 4703.40' RAWHIDE RIDGE ROAD (PROPOSED) 4:1 SIDE SLOPES (TYPICAL) 20' X 10' WASHED ROCK TO BE EXCAVATED DOWN TO NATIVE GRAVELS. ENSURE PROPER DRAINAGE 4703.0 4702. 0 4700. 0 4703. 0 4701.0 BOTTOM OF POND EL. 4699.51' STAGE STORAGE: LOT A RETENTION/INFILTRATION POND ELEV AREA (sq. ft.) DEPTH (ft) AVG END INC. VOL. (cu. ft.) AVG END TOTAL VOL. (cu. ft.) 4,701.6000 3,260.0554 N/A N/A 0.0000 4,701.8000 3,480.0819 0.2000 674.0137 674.0137 4,702.0000 3,703.3076 0.2000 718.3390 1392.3527 4,702.2000 3,929.7707 0.2000 763.3078 2155.6605 4,702.4000 4,159.4740 0.2000 808.9245 2964.5850 4,702.6000 4,392.3771 0.2000 855.1851 3819.7701 4,702.8000 4,628.1286 0.2000 902.0506 4721.8207 4,703.0000 4,867.0797 0.2000 949.5208 5671.3415 4,703.2000 5,109.3205 0.2000 997.6400 6668.9815 4,703.4000 5,364.9218 0.2000 1047.4242 7716.4057 4,699.6000 1,352.0429 N/A N/A 0.0000 WSSS 47044704 TOP OF POND EL. 4704.40' RAWHIDE RIDGE ROAD (PROPOSED) 4:1 SIDE SLOPES (TYPICAL) 40' X 10' WASHED ROCK TO BE EXCAVATED DOWN TO NATIVE GRAVELS. ENSURE PROPER DRAINAGE. STAGE STORAGE TABLE: TEMPORARY POND ELEV AREA (sq. ft.) DEPTH (ft) AVG END INC. VOL. (cu. ft.) AVG END TOTAL VOL. (cu. ft.) 4,703.8000 15,710.8456 N/A N/A 0.0000 4,704.0000 16,377.9756 0.2000 3208.8821 3208.8821 4,704.2000 17,048.6485 0.2000 3342.6624 6551.5445 4,704.4000 17,723.5499 0.2000 3477.2198 10028.7644 BOTTOM OF POND/ TOP OF ROCK 3"± DIA. FREE DRAINING ROUND ROCK FROM FINISH GRADE TO 12" BELOW NATIVE GRAVEL LAYER. 4H:1V 6" TOPSOIL TOP OF POND ELEV. 4703.40' BOTTOM OF CALCULATED STORAGE 4701.60' ELEV. 4699.51' (SEASONAL HIGH GW) 0' - 1.0' BGS SILTY CLAY ORGANIC SOIL (OL) 1.0' - 3.0' BGS LEAN CLAY (CL) 3.0' - 22.0' BGS POORLY GRADED GRAVEL (GP) BOTTOM OF POND/ TOP OF ROCK 3"± DIA. FREE DRAINING ROUND ROCK FROM FINISH GRADE TO 12" BELOW NATIVE GRAVEL LAYER. 4H:1V 6" TOPSOILTOP OF POND ELEV. 4704.40' ELEV. 4701.64' (SEASONAL HIGH GW) C2.3 4 SECTION VIEW DETAIL: LOT A RETENTION/INFILTRATION POND SCALE: 1" = 3' ELEV. 4703.80'0' - 1.3' BGS SILTY CLAY ORGANIC SOIL (OL) 1.3' - 4.0' BGS LEAN CLAY (CL) 4.0' - 7.0' BGS POORLY GRADED GRAVEL (GP)STST17.0' 14.6' 14.6' 10.0' WEIR CONCRETE BOTTOM FOR SEDIMENT ACCUMULATION AND REMOVAL FREE DRAINING ROCK UP SIDESLOPE CONNECT TO NATIVE GRAVELS 12" RCP PIPE INLET INV. ELEV. = 4700.30 REINFORCED CONCRETE FOREBAY CELL WALL 4.0'1.0' 1.0' 1.5' (TYP.) 3.5' TOP OF WALL ELEV. = 4701.51 WEIR CREST ELEV. = 4700.51 BOTTOM OF POND ELEV. = 4699.51 BOTTOM OF FOOTING ELEV. = 4697.01 REINFORCEMENT #4 AT 12" O.C. 1.5' 10.0' WEIR 17.0' COMPACTED GRAVEL BASE C2.3 1 SECTION VIEW DETAIL: LOT A WET DETENTION POND SCALE: 1" = 3' 1 C2.3 4C2.3PLAN VIEW OF LOT A WET DETENTION POND SCALE: 1" = 30' PLAN VIEW OF TEMPORARY RETENTION/INFILTRATION POND SCALE: 1" = 50'K:\Bozeman\Gallatin Center LP\2024381 Gallatin Center\05CAD\Sheets\Preliminary Plat\24381-STORM-POND_EXHB.dwg DETAILS (4) 4/3/2026 4:06:38 PMDESIGNED BY: DRAWN BY: CHECKED BY: DATE: JRH JRH EWR/STH MARCH 2026 SHEET C2.3NO.DATEREVISIONPREPARED BYBYDETAILSGALLATIN CENTER LPBOZEMAN, MTGALLATIN CENTER SUBDIVISION, PHASE 5ENGINEERINGPROJECT NO. 2024381 895 TECHNOLOGY BLVD., SUITE 203BOZEMAN, MT 59718(406) 586-0262www.wwcengineering.com2 C2.3 LOT A WET DETENTION POND DETAIL FOREBAY DETAIL SCALE: 1" = 10' C2.3 2 SECTION VIEW DETAIL: FOREBAY CELL WALL SCALE: 1" = 3' TEMPORARY RETENTION/INFILTRATION POND DETAILS C2.3 3 SECTION VIEW DETAIL: FOREBAY CELL WALL SCALE: 1" = 3' 3 C2.3 Stormwater Design Report Appendix G – Operation, Inspection, and Maintenance Plan Page 1 of 4 GALLATIN CENTER SUBDIVISION STORMWATER FACILITY OPERATION, INSPECTION, AND MAINTENANCE PLAN Please see the responses to the requirements outlined in the City of Bozeman Design Standards and Specifications Sec. 6.2.3. a) A description of the responsible party or entity for operation, inspection, and maintenance as well as replacement of storm drainage facilities and the legal mechanism for succession/assignment. Response: The party responsible for operation, inspection, and maintenance as well as replacement of storm drainage facilities located outside of public right-of-way will be the property owner. b) A list of contact names and contact information (phone number, e-mail address, mailing address). Response: Gallatin Center Limited Partnership Phone: (406) 579-8248 Email: eugene@eg-construction.com Mailing Address: Gallatin Center LP P.O. Box 906 Bozeman, MT 59771-0906 c) Site plan illustrating the storm drainage facility and system components. Response: The stormwater report included in this subdivision application includes several exhibits which show the drainage facilities and system components. d) A detailed list of required maintenance and inspection activities, schedule, and frequency for the various system components. Response: A detailed summary of required maintenance and inspection activities, schedule, and frequency for the stormwater collection system and retention/infiltration facilities is outlined below:  Curb Inlets & Pipes: o Keep the curb inlets of the facility free of leaves, rocks, and other debris. Inspect the curb inlets every 3 months and after heavy rains that deliver 0.5 inches of rainfall. Clean sediment from curb inlets with a Vac Truck when sediment at the bottom of basin exceeds 6”. Operators need to be properly trained in catch basin maintenance. Maintain a log of the amount of sediment collected and the date of cleaning. Page 2 of 4 o Keep the stormwater drainage piping free of leaves, rocks, and other debris. Inspect the piping bi-annually. Clean sediment from stormwater drainage piping with a Jet/Vac Truck when sediment at the bottom of stormwater drainage piping exceeds 3”. Operators must be properly trained in catch basin maintenance. Maintain a log of the amount of sediment collected and the date of cleaning.  Stormwater Storage Basins: o The storm water basins are to be mowed regularly. During the summer months, mow approximately every two weeks. Unless visibly tainted, dispose of lawn clippings in the same manner as yard waste. Otherwise, bag and dispose of at sanitary landfill. o Remove sediment by hand with a flat bottom shovel during the summer months whenever sediment covers vegetation. Have the grass cut short in that particular location so that the bed can be made as level as possible. o Re-sod damaged or disturbed areas immediately, or use grass plugs from the adjacent up-slope area. o Inspect the facilities periodically, especially after heavy rains (preferably monthly and after each storm that delivers 0.5 inches of rainfall). o Inspect flow control outlet semi-annually and clean it when soil and vegetation buildup interfere with flow introduction. o See that litter and other debris are removed from retention basins and swales. o Owner to maintain and fund Operation and Maintenance of stormwater storage facilities. o Remove sediment in the concrete forebay with a flat bottom shovel periodically when sediment accumulation occurs. e) Stormwater Facility Inspection Form with exhibit illustrating maintenance inspection requirements (see Attachment E). Response: The Stormwater Facility Inspection Form is included at the end of this narrative. The stormwater report included in this subdivision application includes several exhibits which show the drainage facilities and system components. f) Expected design life and replacement schedule for each component of the facility. Response: The proposed stormwater system will include curb inlets, manholes, PVC storm drain piping, and surface retention/infiltration basins. Assuming proper maintenance and installation, all facilities are anticipated to last more than 75 years, unless maintenance inspections indicate a need for replacement sooner. Page 3 of 4 g) Itemized cost estimates for recurring operation, inspection, and maintenance activities and planned facility replacement. Response:  Recurring Operation: The surface retention/infiltration basins and stormwater collection systems are passive systems that require minimal maintenance to ensure ongoing operation.  Inspection: o Curb Inlet and Storm Piping Inspection – This inspection is a visual inspection that will require very little time by the facility maintenance person. It is anticipated no cost will be incurred for this inspection. o Retention/Infiltration Basins – Inspection of surface ponds does not require any equipment and requires very little time. The visual inspection is not anticipated to incur any cost.  Maintenance Activities: o Curb Inlet and Storm Piping Maintenance – The required maintenance is completely dependent on the accumulation of sediment in the basin and piping. It is anticipated that Jat-Vac cleaning will be required once every 5 years to remove the sediment at an estimated cost of $750.00. o Retention/Infiltration Basins – Maintenance for the surface retention/infiltration basins will require regular mowing, removing debris, lawn clippings, and sediment, re-sodding damaged areas. h) A financial plan and funding mechanism for funding the recurring operation, inspection, and maintenance activities and planned facility replacement. The plan shall include sinking fund calculations considering estimated inflation over the life of the system components and a determination of the annual funding to be set-aside for operation, inspection, maintenance, and replacement needs. Response: As mentioned above, it is estimated that the cost for maintaining the curb inlets and piping will occur every 5 years, and will cost $750.00. It is estimated that the retention/infiltration basins will be mowed approximately 15 times per year. Each time the basin is mowed, it will cost approximately $120 per visit, totaling $1800.00 per year for mowing services. The basin may need to be re-sodded in damaged areas approximately every 10 years, which is estimated to cost about $5000.00. Overall, the total average maintenance costs are estimated to be about Page 4 of 4 $150.00 per year for the inlets and piping, and about $2300.00 per year for the retention/infiltration basin, totaling $2450.00 per year for all stormwater facilities. Estimated Maintenance Cost Summary Facility Interval Cost per Occurrence Estimated Cost per Year Curb Inlet and Storm Piping (Jet Vac) 5 years $750.00 $150.00 Retention/Infiltration Basins (Mowing) Bi-weekly (Summer Only) $120.00 $1800.00 Retention/Infiltration Basins (Re-Sod) 10 years $5000.00 $500.00 Yearly Estimated Maintenance Cost $2,450.00 The costs described above do not account for inflation, and are values based on anticipated costs at the time of installation in 2026. Inflation is considered using an assumed 3% inflation rate, which is the annual average inflation rate over the past 10 years. The estimated inflation calculations for the next 75 years are shown on the following page. The funding mechanism for the curb inlets and piping maintenance is to be determined by the City of Bozeman, as the City is responsible for the maintenance of the curb inlets and piping within public right-of-way. Maintenance for the stormwater facilities outside of public right-of-way, including the proposed retention/infiltration basins, is the property owner’s responsibility. The maintenance for these facilities will be privately funded by the property owner. Inflation Calculations for Stormwater Maintenance Costs (Assumes 3% Inflation Rate) Year Curb Inlet and Storm Piping Retention/Infiltration Basins (Mowing) Retention/Infiltration Basins (Re-Sod) Total Estimated Yearly Cost 2026 $150.00 $1,800.00 $500.00 $2,450.00 2027 $154.50 $1,854.00 $515.00 $2,523.50 2028 $159.14 $1,909.62 $530.45 $2,599.21 2029 $163.91 $1,966.91 $546.36 $2,677.18 2030 $168.83 $2,025.92 $562.75 $2,757.50 2031 $173.89 $2,086.69 $579.64 $2,840.22 2032 $179.11 $2,149.29 $597.03 $2,925.43 2033 $184.48 $2,213.77 $614.94 $3,013.19 2034 $190.02 $2,280.19 $633.39 $3,103.59 2035 $195.72 $2,348.59 $652.39 $3,196.69 2036 $201.59 $2,419.05 $671.96 $3,292.60 2037 $207.64 $2,491.62 $692.12 $3,391.37 2038 $213.86 $2,566.37 $712.88 $3,493.11 2039 $220.28 $2,643.36 $734.27 $3,597.91 2040 $226.89 $2,722.66 $756.29 $3,705.84 2041 $233.70 $2,804.34 $778.98 $3,817.02 2042 $240.71 $2,888.47 $802.35 $3,931.53 2043 $247.93 $2,975.13 $826.42 $4,049.48 2044 $255.36 $3,064.38 $851.22 $4,170.96 2045 $263.03 $3,156.31 $876.75 $4,296.09 2046 $270.92 $3,251.00 $903.06 $4,424.97 2047 $279.04 $3,348.53 $930.15 $4,557.72 2048 $287.42 $3,448.99 $958.05 $4,694.45 2049 $296.04 $3,552.46 $986.79 $4,835.29 2050 $304.92 $3,659.03 $1,016.40 $4,980.35 2051 $314.07 $3,768.80 $1,046.89 $5,129.76 2052 $323.49 $3,881.86 $1,078.30 $5,283.65 2053 $333.19 $3,998.32 $1,110.64 $5,442.16 2054 $343.19 $4,118.27 $1,143.96 $5,605.42 2055 $353.48 $4,241.82 $1,178.28 $5,773.59 2056 $364.09 $4,369.07 $1,213.63 $5,946.79 2057 $375.01 $4,500.14 $1,250.04 $6,125.20 2058 $386.26 $4,635.15 $1,287.54 $6,308.95 2059 $397.85 $4,774.20 $1,326.17 $6,498.22 2060 $409.79 $4,917.43 $1,365.95 $6,693.17 2061 $422.08 $5,064.95 $1,406.93 $6,893.96 2062 $434.74 $5,216.90 $1,449.14 $7,100.78 2063 $447.78 $5,373.41 $1,492.61 $7,313.81 2064 $461.22 $5,534.61 $1,537.39 $7,533.22 2065 $475.05 $5,700.65 $1,583.51 $7,759.22 2066 $489.31 $5,871.67 $1,631.02 $7,991.99 2067 $503.98 $6,047.82 $1,679.95 $8,231.75 Inflation Calculations for Stormwater Maintenance Costs (Assumes 3% Inflation Rate) 2068 $519.10 $6,229.25 $1,730.35 $8,478.70 2069 $534.68 $6,416.13 $1,782.26 $8,733.07 2070 $550.72 $6,608.61 $1,835.73 $8,995.06 2071 $567.24 $6,806.87 $1,890.80 $9,264.91 2072 $584.26 $7,011.08 $1,947.52 $9,542.86 2073 $601.78 $7,221.41 $2,005.95 $9,829.14 2074 $619.84 $7,438.05 $2,066.13 $10,124.02 2075 $638.43 $7,661.19 $2,128.11 $10,427.74 2076 $657.59 $7,891.03 $2,191.95 $10,740.57 2077 $677.31 $8,127.76 $2,257.71 $11,062.79 2078 $697.63 $8,371.59 $2,325.44 $11,394.67 2079 $718.56 $8,622.74 $2,395.21 $11,736.51 2080 $740.12 $8,881.42 $2,467.06 $12,088.61 2081 $762.32 $9,147.87 $2,541.07 $12,451.26 2082 $785.19 $9,422.30 $2,617.31 $12,824.80 2083 $808.75 $9,704.97 $2,695.83 $13,209.55 2084 $833.01 $9,996.12 $2,776.70 $13,605.83 2085 $858.00 $10,296.01 $2,860.00 $14,014.01 2086 $883.74 $10,604.89 $2,945.80 $14,434.43 2087 $910.25 $10,923.03 $3,034.18 $14,867.46 2088 $937.56 $11,250.72 $3,125.20 $15,313.48 2089 $965.69 $11,588.24 $3,218.96 $15,772.89 2090 $994.66 $11,935.89 $3,315.53 $16,246.08 2091 $1,024.50 $12,293.97 $3,414.99 $16,733.46 2092 $1,055.23 $12,662.79 $3,517.44 $17,235.46 2093 $1,086.89 $13,042.67 $3,622.96 $17,752.53 2094 $1,119.50 $13,433.95 $3,731.65 $18,285.10 2095 $1,153.08 $13,836.97 $3,843.60 $18,833.65 2096 $1,187.67 $14,252.08 $3,958.91 $19,398.66 2097 $1,223.30 $14,679.64 $4,077.68 $19,980.62 2098 $1,260.00 $15,120.03 $4,200.01 $20,580.04 2099 $1,297.80 $15,573.63 $4,326.01 $21,197.44 2100 $1,336.74 $16,040.84 $4,455.79 $21,833.37 2101 $1,376.84 $16,522.07 $4,589.46 $22,488.37 Stormwater Design Report Appendix H – Groundwater Monitoring Well Map and Data 1000 ft N➤➤N Image © 2025 Airbus Image © 2025 Airbus Image © 2025 Airbus Project Name: Gallatin Center Subdivision Project Number: 24-381 1 3.45 4.83 1.38 4.97 1.52 5.12 1.67 5.39 1.94 5.47 2.02 5.51 2.06 2 2.39 6.94 4.55 7.28 4.89 7.40 5.01 7.75 5.36 7.79 5.40 7.76 5.37 3 1.25 5.88 4.63 6.15 4.90 6.21 4.96 6.53 5.28 6.62 5.37 6.72 5.47 4 0.92 5.60 4.68 5.89 4.97 6.00 5.08 6.26 5.34 6.38 5.46 6.47 5.55 5 0.90 6.59 5.69 6.90 6.00 7.03 6.13 7.30 6.40 7.38 6.48 7.46 6.56 6 3.44 6.25 2.81 6.45 3.01 6.62 3.18 6.89 3.45 6.94 3.50 7.05 3.61 7 2.20 5.05 2.85 5.18 2.98 5.35 3.15 5.67 3.47 5.75 3.55 5.78 3.58 8 3.20 6.19 2.99 6.46 3.26 6.75 3.55 6.63 3.43 7.11 3.91 7.28 4.08 9 1.74 5.76 4.02 6.08 4.34 6.23 4.49 6.44 4.70 6.55 4.81 6.67 4.93 10 3.11 6.46 3.35 6.68 3.57 6.83 3.72 7.07 3.96 7.23 4.12 7.35 4.24 11 3.48 6.30 2.82 6.71 3.23 6.92 3.44 7.39 3.91 7.43 3.95 7.61 4.13 12 3.63 7.38 3.75 7.59 3.96 7.77 4.14 8.04 4.41 8.16 4.53 8.28 4.65 13 4.49 6.47 1.98 6.55 2.06 6.73 2.24 6.95 2.46 7.13 2.64 7.24 2.75 14 1.41 4.25 2.84 4.41 3.00 4.65 3.24 4.91 3.50 4.96 3.55 5.10 3.69 15 2.02 5.53 3.51 5.80 3.78 5.89 3.87 6.18 4.16 6.26 4.24 6.42 4.40 16 2.21 5.62 3.41 5.89 3.68 6.02 3.81 6.27 4.06 6.39 4.18 6.58 4.37 17 2.43 5.68 3.25 5.84 3.41 5.96 3.53 5.97 3.54 6.21 3.78 6.31 3.88 18 3.16 6.95 3.79 7.33 4.17 7.56 4.40 7.89 4.73 7.94 4.78 8.04 4.88 19 2.71 7.89 5.18 8.54 5.83 8.75 6.04 9.17 6.46 9.32 6.61 9.48 6.77 20 2.32 7.22 4.90 7.40 5.08 7.67 5.35 7.95 5.63 8.00 5.68 8.15 5.83 1 3.45 5.51 2.06 5.50 2.05 5.56 2.11 5.50 2.05 5.57 2.12 5.57 2.12 5.72 2.27 2 2.39 8.02 5.63 7.78 5.39 7.82 5.43 7.78 5.39 7.89 5.50 7.95 5.56 8.19 5.80 3 1.25 7.06 5.81 6.74 5.49 6.79 5.54 6.78 5.53 6.87 5.62 6.90 5.65 7.04 5.79 4 0.92 6.52 5.60 6.50 5.58 6.55 5.63 6.49 5.57 6.59 5.67 6.61 5.69 6.75 5.83 5 0.90 7.53 6.63 7.57 6.67 7.53 6.63 7.53 6.63 7.61 6.71 7.61 6.71 7.75 6.85 6 3.44 7.04 3.60 7.14 3.70 7.06 3.62 7.04 3.60 7.17 3.73 7.12 3.68 7.13 3.69 7 2.20 5.85 3.65 5.97 3.77 5.81 3.61 5.80 3.60 5.95 3.75 5.98 3.78 5.94 3.74 8 3.20 7.14 3.94 7.27 4.07 7.22 4.02 7.30 4.10 7.37 4.17 7.42 4.22 7.26 4.06 9 1.74 6.65 4.91 6.73 4.99 6.71 4.97 6.67 4.93 6.75 5.01 6.74 5.00 6.76 5.02 10 3.11 7.30 4.19 7.40 4.29 7.37 4.26 7.32 4.21 7.35 4.24 7.39 4.28 7.39 4.28 11 3.48 7.68 4.20 7.66 4.18 7.65 4.17 7.49 4.01 7.60 4.12 7.76 4.28 7.71 4.23 12 3.63 8.21 4.58 8.08 4.45 8.20 4.57 8.13 4.50 8.16 4.53 8.15 4.52 8.11 4.48 13 4.49 7.32 2.83 7.15 2.66 7.20 2.71 7.21 2.72 7.16 2.67 7.18 2.69 7.20 2.71 14 1.41 5.14 3.73 5.18 3.77 5.07 3.66 4.93 3.52 5.06 3.65 5.10 3.69 5.05 3.64 15 2.02 6.42 4.40 6.38 4.36 6.39 4.37 6.35 4.33 6.40 4.38 6.43 4.41 6.44 4.42 16 2.21 6.51 4.30 6.63 4.42 6.63 4.42 6.61 4.40 6.73 4.52 6.65 4.44 6.71 4.50 17 2.43 6.35 3.92 6.40 3.97 6.39 3.96 6.37 3.94 6.46 4.03 6.42 3.99 6.40 3.97 18 3.16 8.17 5.01 8.21 5.05 8.17 5.01 8.20 5.04 8.27 5.11 8.25 5.09 8.28 5.12 19 2.71 9.59 6.88 9.67 6.96 9.70 6.99 9.71 7.00 9.78 7.07 DRY - DRY - 20 2.32 8.26 5.94 8.31 5.99 8.36 6.04 8.35 6.03 8.40 6.08 8.39 6.07 8.44 6.12 Piezometer Well Measured Depth (ft) Groundwater Depth (ft) Groundwater Depth (ft) 6/4/2025 Measured Depth (ft) Groundwater Depth (ft) Measured Depth (ft) Groundwater Depth (ft) 5/30/2025 Measured Depth (ft) Casing Height (ft) 5/9/2025 5/16/2025 5/23/2025 Groundwater Depth (ft) 5/2/2025 Measured Depth (ft) IMEG Test Pit Groundwater Depth (ft) 6.50 (seepage at 2.30) 8.00 (seepage at 5.00) 9.00 (Seepage at 7.00) 9.00 (Seepage at 6.00) 9.00 (Seepage at 7.50) 6.00 6.00 (seepage at 5.00) 5.00 6.00 (seepage at 5.40) 6.00 (seepage at 5.80) 5.00 (seepage at 3.00) 5.00 4.50 6.00 (seepage at 4.00) 7.00 (seepage at 4.00) Piezometer Well Casing Height (ft) - - - 6/20/2025 Measured Depth (ft) Groundwater Depth (ft) 7.00 (seepage at 4.00) - Measured Depth (ft) Groundwater Depth (ft) 6/27/2025 7/2/2025 7/11/2025 7/18/2025 Groundwater Depth (ft) Measured Depth (ft) Groundwater Depth (ft) Measured Depth (ft) Groundwater Depth (ft) 6/11/2025 Measured Depth (ft) Groundwater Depth (ft) 8/1/2025 Measured Depth (ft) Groundwater Depth (ft) 7/25/2025 Measured Depth (ft) Groundwater Depth (ft) Measured Depth (ft) 1 3.45 5.69 2.24 5.83 2.38 5.91 2.46 5.78 2.33 5.67 2.22 5.34 1.89 2 2.39 8.25 5.86 8.34 5.95 8.45 6.06 8.37 5.98 8.22 5.83 7.75 5.36 3 1.25 7.13 5.88 7.21 5.96 7.33 6.08 7.22 5.97 7.05 5.80 6.59 5.34 4 0.92 6.77 5.85 6.89 5.97 6.98 6.06 6.82 5.90 6.63 5.71 6.22 5.30 5 0.90 7.77 6.87 7.91 7.01 7.99 7.09 7.85 6.95 7.61 6.71 7.19 6.29 6 3.44 7.10 3.66 7.34 3.90 7.27 3.83 7.12 3.68 6.95 3.51 6.67 3.23 7 2.20 5.91 3.71 6.21 4.01 6.10 3.90 5.95 3.75 5.82 3.62 5.44 3.24 8 3.20 7.35 4.15 7.64 4.44 7.55 4.35 7.37 4.17 7.20 4.00 6.90 3.70 9 1.74 6.72 4.98 6.88 5.14 6.85 5.11 6.71 4.97 6.60 4.86 6.42 4.68 10 3.11 7.33 4.22 7.47 4.36 7.50 4.39 7.40 4.29 7.22 4.11 7.10 3.99 11 3.48 7.68 4.20 7.80 4.32 7.84 4.36 7.63 4.15 7.31 3.83 6.91 3.43 12 3.63 8.08 4.45 8.21 4.58 8.26 4.63 8.12 4.49 7.84 4.21 7.94 4.31 13 4.49 7.11 2.62 7.25 2.76 7.28 2.79 7.03 2.54 6.82 2.33 6.68 2.19 14 1.41 5.08 3.67 5.18 3.77 5.22 3.81 4.99 3.58 4.67 3.26 4.51 3.10 15 2.02 6.42 4.40 6.48 4.46 6.53 4.51 6.38 4.36 6.13 4.11 5.85 3.83 16 2.21 6.61 4.40 6.78 4.57 6.87 4.66 6.47 4.26 6.61 4.40 6.40 4.19 17 2.43 6.36 3.93 6.65 4.22 6.55 4.12 6.40 3.97 6.39 3.96 6.04 3.61 18 3.16 8.14 4.98 8.37 5.21 8.24 5.08 8.14 4.98 7.93 4.77 7.70 4.54 19 2.71 DRY - DRY - DRY - 9.68 6.97 9.34 6.63 9.05 6.34 20 2.32 8.38 6.06 8.47 6.15 8.55 6.23 8.38 6.06 8.08 5.76 7.70 5.38 Measured Depth (ft) Groundwater Depth (ft) 8/29/2025 9/29/2025 10/24/2025 Measured Depth (ft) Groundwater Depth (ft) Piezometer Well Casing Height (ft) 8/8/2025 8/14/2025 8/22/2025 Groundwater Depth (ft) Measured Depth (ft) Groundwater Depth (ft) Measured Depth (ft) Groundwater Depth (ft) Measured Depth (ft) Groundwater Depth (ft) Measured Depth (ft) Stormwater Design Report Appendix I – Geotechnical Reports I.1 – Phase 1/Lot A Geotechnical Report MONTANA | WASHINGTON | IDAHO | NORTH DAKOTA | PENNSYLVANIA 406.761.3010 tdhengineering.com 1800 River Drive North Great Falls, MT 59401 June 10, 2025 Thompson Thrift Development, Inc. Attn: Ms. Jessica Tuttle 901 Wabash Avenue Terre Haute, IN 47807 RE: CORROSIVITY ADDENDUM #1 RAWHIDE RIDGE PRELIMINARY GEOTECHNICAL ASSESSMENT TD&H ENGINEERING JOB NO. 25-009-001 Dear Ms. Tuttle, In May 2025, TD&H completed and distributed a preliminary report of geotechnical investigation for the Rawhide Ridge project summarizing the results of the field and laboratory studies performed for this project along with preliminary design recommendations to be considered during project planning. At the time of this report, complete corrosivity test results were not available due to mechanical issues with the testing apparatus at our subcontract laboratory performing these tests. The following addendum is intended to summarize recently received corrosivity test results to consideration during project planning. CORROSIVITY TEST RESULTS Two samples of the lean clay and a single composite gravel sample were sent to Alpine Analytical Laboratories to be analyzed to evaluate the corrosion potential of the soils. Testing was to include pH, marble pH, resistivity, and sulfate content; however, the laboratories testing equipment for sulfate analysis was inoperable and results were not available at the time of original report. Results of the remaining tests were summarized in the original report and are also duplicated below along with the new sulfate test results for clarity. Material Type Sample Location pH Marble pH Resistivity (ohm- cm) Sulfate Content (%) Lean CLAY B-04 (0.5 – 2.0 ft) 8.3 8.0 9,860 < 0.04% B-04 (2.5 – 4.0 ft) 8.4 8.1 10,200 < 0.04% GRAVEL COMPOSITE 8.0 8.0 18,200 < 0.04% Based on the testing results summarized above, the soils encountered on this site pose little corrosive risk to steel structures placed in direct contact with the soil. Additionally, the sulfate contents measured in the samples tested were below the quantifiable threshold for JUNE 10, 2025 ii tdhengineering.com the test method utilized. At these levels, the risk of sulfate attack on buried concrete elements is considered low with all samples being Class 0 per the standard American Concrete Institute (ACI) classification system and considered negligible per the U.S. Bureau of Reclamation Classification system. The samples selected for testing were intended to represent the primary soil types encountered during our field investigation. Based on these results we anticipate no need for specialized coatings or other protective measures for steel elements, and the use of conventional Type I or II cement for concrete structures is considered adequate with no need for the use of a sulfate resistant cement products. These results are also consistent with our experience with similar soils in the Bozeman area. We trust this information is sufficient for the project team to proceed with project planning and feasibility evaluation at this time. Please let us know if there are any questions or concerns regarding the results of the corrosivity testing as summarized above and documented on the attached laboratory reports. Sincerely, Craig Nadeau PE & Principal Peter Klevberg PE Geotechnical Manager Geotechnical Engineer TD&H ENGINEERING TD&H ENGINEERING ATTACHMENTS: UPDATED ALPINE ANALYTICAL TEST REPORTS (3 PAGES) 1315 Cherry, Helena, MT 59601 (406)449-6282 SOIL ANALYSIS Client:TD&H Engineering Date Reported:09-Jun-25 Sample ID:25-009 B-04 (0.5-2.0ft) Project ID:25-009-001 Chain of Custody #:88 Site ID:Rawhide Ridge Laboratory ID:07F205 Date / Time Sampled:25-Apr-25 Sample Matrix:Soil Date / Time Received:09-May-25 @ 16:15 Analytical Method Parameter Result Date/Time By Reference pH, s.u.8.3 12-May-25 @ 15:00 CE MT 232-04 Marble pH, s.u.8.0 13-May-25 @ 17:00 CE MT 232-04 Resistivity, kohm/cm 9.86 12-May-25 @ 16:15 CE MT 232-16 Sulfates, mg/Kg <400 09-Jun-25 @ 10:25 CE MT 532-16 Comments: Results are As Delivered References: Methods for Chemical Analysis of Water and Wastes, US EPA, 600/4-79-020, March 1983. USDA Handbook 60 Method of Sampling and Testing MT232-04, Soil Corrosion Test (Montana Method). Method 43 - 4 : ASA Monograph 9 Part1 Reviewed by: Analyzed Page 2 of 5 1315 Cherry, Helena, MT 59601 (406)449-6282 SOIL ANALYSIS Client:TD&H Engineering Date Reported:09-Jun-25 Sample ID:25-009 B-04 (2.5-4.5ft) Project ID:25-009-001 Chain of Custody #:88 Site ID:Rawhide Ridge Laboratory ID:07F206 Date / Time Sampled:25-Apr-25 Sample Matrix:Soil Date / Time Received:09-May-25 @ 16:15 Analytical Method Parameter Result Date/Time By Reference pH, s.u.8.4 12-May-25 @ 15:00 CE MT 232-04 Marble pH, s.u.8.1 13-May-25 @ 17:00 CE MT 232-04 Resistivity, kohm/cm 10.2 12-May-25 @ 16:15 CE MT 232-16 Sulfates, mg/Kg <400 09-Jun-25 @ 10:25 CE MT 532-16 Comments: Results are As Delivered References: Methods for Chemical Analysis of Water and Wastes, US EPA, 600/4-79-020, March 1983. USDA Handbook 60 Method of Sampling and Testing MT232-04, Soil Corrosion Test (Montana Method). Method 43 - 4 : ASA Monograph 9 Part1 Reviewed by: Analyzed Page 3 of 5 1315 Cherry, Helena, MT 59601 (406)449-6282 SOIL ANALYSIS Client:TD&H Engineering Date Reported:09-Jun-25 Sample ID:25-009 Composite Gravel Project ID:25-009-001 Chain of Custody #:88 Site ID:Rawhide Ridge Laboratory ID:07F207 Date / Time Sampled:25-Apr-25 Sample Matrix:Soil Date / Time Received:09-May-25 @ 16:15 Analytical Method Parameter Result Date/Time By Reference pH, s.u.8.0 12-May-25 @ 15:00 CE MT 232-04 Marble pH, s.u.8.0 13-May-25 @ 17:00 CE MT 232-04 Resistivity, kohm/cm 18.2 12-May-25 @ 16:15 CE MT 232-16 Sulfates, mg/Kg <400 09-Jun-25 @ 10:25 CE MT 532-16 Comments: Results are As Delivered References: Methods for Chemical Analysis of Water and Wastes, US EPA, 600/4-79-020, March 1983. USDA Handbook 60 Method of Sampling and Testing MT232-04, Soil Corrosion Test (Montana Method). Method 43 - 4 : ASA Monograph 9 Part1 Reviewed by: Analyzed Page 4 of 5 MONTANA | WASHINGTON | IDAHO | NORTH DAKOTA | PENNSYLVANIA JOB NO. 25-009-001 May 2025 PRELIMINARY REPORT OF GEOTECHNICAL INVESTIGATION CLIENT ENGINEER Thompson Thrift Development, Inc. 901 Wabash Avenue Terre Haute, IN Craig Nadeau, PE Craig.nadeau@tdhengineering.com REPORT OF GEOTECHNICAL INVESTIGATION PROJECT NAME PROJECT LOCATION 406.761.3010 tdhengineering.com 1800 River Drive North Great Falls, MT 59401 RAWHIDE RIDGE HOUSING DEVELOPMENT BOZEMAN, MONTANA Rawhide Ridge Housing Development Table of Contents Bozeman, Montana i Table of Contents 1.0 EXECUTIVE SUMMARY ......................................................................................................... 1 2.0 INTRODUCTION ..................................................................................................................... 2 2.1 Purpose and Scope .......................................................................................................... 2 2.2 Project Description ........................................................................................................... 2 3.0 SITE CONDITIONS ................................................................................................................. 4 3.1 Geology and Physiography .............................................................................................. 4 3.2 Surface Conditions ........................................................................................................... 5 3.3 Subsurface Conditions ..................................................................................................... 5 3.3.1 Soils ......................................................................................................................... 5 3.3.2 Ground Water ......................................................................................................... 7 4.0 PRELIMINARY ENGINEERING ANALYSIS .......................................................................... 9 4.1 Introduction ....................................................................................................................... 9 4.2 Site Grading and Excavations.......................................................................................... 9 4.3 Monolithic Turndown Slabs ............................................................................................ 11 4.4 Retaining Walls .............................................................................................................. 13 4.5 Exterior Flatwork ............................................................................................................ 14 4.6 Pavements ..................................................................................................................... 14 4.7 Soil Corrosivity ............................................................................................................... 15 5.0 PRELIMINARY RECOMMENDATIONS ............................................................................... 17 5.1 Site Grading and Excavations........................................................................................ 17 5.2 Monolithic Turndown Slabs ............................................................................................ 18 5.3 Retaining Wall ................................................................................................................ 20 5.4 Exterior Flatwork ............................................................................................................ 21 5.5 Pavements ..................................................................................................................... 21 6.0 SUMMARY OF PRELIMINARY FIELD AND LABORATORY STUDIES ............................. 25 6.1 Field Explorations ........................................................................................................... 25 6.2 Laboratory Testing ......................................................................................................... 26 7.0 LIMITATIONS ........................................................................................................................ 27 Rawhide Ridge Housing Development Appendix Bozeman, Montana ii APPENDIX ♦ Boring Location Map (Figure 1) ♦ Logs of Exploratory Borings (Figures 2 through 10) ♦ Laboratory Test Data (Figures 11 through 26) ♦ Alpine Analytical Corrosivity Test Reports (Figures 27 through 29) ♦ MPWSS Section 02234 & 02235 ♦ Soil Classification and Sampling Terminology for Engineering Purposes ♦ Classification of Soils for Engineering Purposes Rawhide Ridge Housing Development Executive Summary Bozeman, Montana Page 1 PRELIMINARY GEOTECHNICAL REPORT RAWHIDE RIDGE HOUSING DEVELOPMENT BOZEMAN, MONTANA 1.0 EXECUTIVE SUMMARY A preliminary geotechnical investigation was performed for the proposed Rawhide Ridge Housing Development to be located on the west side of Max Avenue between Rawhide Ridge and Cattail Streets in Bozeman, Montana. The borings performed as part of this preliminary site investigation encountered varying topsoil and surficial clay overlying native gravels. The topsoil depth ranged from approximately 0.5 to 2.5 feet across the site with the underlying clay extending to total depths ranging from 2.5 to 7.0 feet. All borings encountered native gravels generally comprised of clayey sand with gravel or poorly-graded gravel with clay and sand extending to depths of more than 22.0 feet, the maximum depth investigated. Ground water was shallow in all borings, varying from 2.5 to 6.5 feet across the property. Based on the preliminary boring information and our experience in the Bozeman area, the seismic site class appears to be Site Class D, and the risk of seismically-induced liquefaction or soil settlement is considered low. In our experience, many sites of similar composition may facilitate an upgrade to Site Class C using more accurate methods, such as a Multi-Channel Analysis of Surface Waves (MASW) to measure the shear wave velocity of the soils. TD&H has the ability to perform this test internally and would advise a MASW survey be included in the scope of work for the final site investigation if the project moves forward to optimize the site class utilized in design of the structures. The primary geotechnical concerns regarding this potential project are the shallow ground water and the highly compressible topsoil and lean clay soils present on site. While the thicknesses of the surface clay and topsoil strata are relatively thin and thus could be removed and replaced, this process will be complicated on many portions of the site due to the very shallow ground water. Current ground water elevations are generally near the bottom of the existing clay and have the potential to rise above this elevation during periods of high seasonal ground water. Based on our experience and the preliminary site investigation results, the site is considered suitable for the use of conventional shallow foundations including thickened-edge monolithic slab systems but should anticipate the need to perform ground improvements. Ground improvements are likely to consist of either the removal and replacement of the native clays with compacted engineered gravel fill or the installation of engineered aggregate piers (EAPs) beneath foundations to improve bearing conditions. Site development upon the existing clay soils should anticipate the need for greater thicknesses of base course and subbase materials beneath exterior flatwork, roadways, parking lots, etc. to address the native clays which exhibit high to moderate compressibility and in-situ moistures which greatly exceed the typical range required for proper compaction. Thus, subgrade soils are expected to be weak and unstable during construction. Rawhide Ridge Housing Development Introduction Bozeman, Montana Page 2 2.0 INTRODUCTION 2.1 Purpose and Scope This report presents the results of our preliminary geotechnical study for the planned Rawhide Ridge Housing Development to be located west of Max Avenue between Rawhide Ridge and Cattail Streets in Bozeman, Montana. The purpose of the geotechnical study is to determine the general surface and subsurface conditions at the proposed site and to develop geotechnical engineering recommendations for support of the proposed structures and design of related facilities. This report describes the field work and laboratory analyses conducted for this project, the surface and subsurface conditions encountered, and presents our recommendations for the proposed foundations and related site development. Our preliminary field investigation included drilling nine soil borings across the proposed site. Samples were obtained from the borings and returned to our Great Falls laboratory for testing. Laboratory testing was performed on selected soil samples to determine engineering properties of the subsurface materials. The information obtained during our field investigations and laboratory analyses was used to develop recommendations for the design of the proposed foundation systems. 2.2 Project Description The proposed project is in preliminary planning stages; thus, limited information is available at this time. However, the project site covers approximately 18.95 acres located on the west side of Max Avenue between Rawhide Ridge and Cattail Streets and centered at approximate 45°42’20.8”N latitude and 111°04’14.3”W longitude. The following outlines the preferred design and construction practices for this project when possible: • Building design supported on Type II unstiffened monolithic slabs or conventional trench- poured footings supported on a turndown slab. Interior walls supported on shallower, thickened slab profiles. Standard footing width for conventional spread footings is 12 inches. Footing drains are not included in typical design details. • Foundation walls or monolithic turndowns would be bank-poured without wooden formwork. Interior partition walls utilize 12-inch wide thickened slabs with 8-inch embedment. • Conventional slab-on-grade details include 4 inches of clean aggregate as an under-slab drainage material with 6-mil vapor barrier directly under the slab. Preliminary structural load information was provided as follows: Rawhide Ridge Housing Development Introduction Bozeman, Montana Page 3 Product Description Load Type Maximum Load Value Classic 3-story, walk-up apartment homes Wall 3,000 plf Column 75 kips Select 2-story, direct access apartment homes Wall 2,000 plf Column 50 kips Amenities 1 and/or 2-story Clubhouse/Leasing; 1-story garages Wall 1,500 plf Column 15 kips Site improvements will include the following: • Pavements: Heavy and Light-Duty Flexible Pavements • Equipment Support Pads (Reinforced Concrete) • Retaining Walls: Assume ≤ 5 feet • Storm Water Detention Features (possible subsurface structures) • Swimming Pool (average 5-foot depth) Rawhide Ridge Housing Development Site Conditions Bozeman, Montana Page 4 3.0 SITE CONDITIONS 3.1 Geology and Physiography The site is geologically characterized as Braid plain alluvium (Qabo) overlying bedrock formations of the Madison Valley member (Tscmv). The Braid plain alluvium are generally comprised of rounded to well-rounded cobble gravels, with clasts as large as boulders mixed with sand, silt and clay. Clasts are mostly comprised of Archean metamorphic rock and dark colored volcanic rock with subordinate limestone. Wells in the area generally indicate alluvial thicknesses of approximately 30 feet overlying Tertiary deposits. The Madison Valley member in the project area generally consists of grayish orange, cross-bedded sandstone with pebble conglomerate interbedded with brownish orange tuffaceous siltstone and marl. Conglomerate zones vary from matrix supported to clast supported. GEOLOGIC MAP OF THE BOZEMAN 30’ X 60’ QUADRANGLE SOUTHWESTERN MONTANA (VUKE, Lonn, Berg, & Schmidt, 2014) Based on the preliminary boring information and our experience in the Bozeman area, the seismic site class appears to be Site Class D, and the risk of seismically-induced liquefaction or soil settlement is considered low. In our experience, many sites of similar composition may facilitate an upgrade to Site Class C using more accurate methods, such as a Multi-Channel Analysis of Surface Waves (MASW) to measure the shear wave velocity of the soils. TD&H has the ability to perform APPROXIMATE SITE LOCATION Rawhide Ridge Housing Development Site Conditions Bozeman, Montana Page 5 this test internally and would advise a MASW survey be included in the scope of work for the final site investigation if the project moves forward to optimize the site class utilized in design of the structures. 3.2 Surface Conditions The proposed project site is located on the west side of Max Avenue between Rawhide Ridge and Cattail Streets and centered at approximate 45°42’20.8”N latitude and 111°04’14.3”W longitude. The property includes approximately 18.95 acres of relatively undeveloped land. The property appears to be split diagonally from the southwest to northeast corner, with the southeast portion being some form of agricultural use based on the straw bales evident in aerial photography and present on site at the time of our investigation. The northwest portion of the property appears to be vegetated with native grasses. The west side of the property contains an existing drainage running from north to south parallel to Thomas Drive which appears to consist of abundant wetland zones along this side of the property. Finally, a small pond structure is located in the northeast corner near the existing round-about at Max Avenue and Cattail Street. Based on measured elevations at the boring locations and site observations, the site generally appears to slope downward toward the northeast corner of the property at slopes ranging from 1 to 3 percent. The topography is best described as nearly level to gently sloping. A low lying drainage exists from the approximate southwest corner of the property extending diagonally towards the center of the property and roughly lying at the edge of the existing agricultural portion of the property. This area exhibited very soft surface soils and standing water at the time of our investigation which may have been due to recent snow melt. 3.3 Subsurface Conditions 3.3.1 Soils The subsurface soil conditions appear to be relatively consistent based on our exploratory drilling and soil sampling. In general, the subsurface soil conditions encountered within the borings consist of topsoil ranging in thickness from 0.5 to 2.5 feet at one location. The topsoil is underlain by native lean clay soils extending to depths of 2.5 to 7.0 feet below existing site grades. All borings encountered native gravels at below the surficial clays and extending to depths of more than 22.0 feet, the maximum depth investigated for this project. The subsurface soils are described in detail on the enclosed boring logs and are summarized below. The stratification lines shown on the logs represent approximate boundaries between soil types, and the actual in situ transition may be gradual vertically or discontinuous laterally. TOPSOIL The topsoil exhibits some variability in thickness across the property. The topsoil is easily identified by the dark brown to black color, slight organic odor, and visual organic material it Rawhide Ridge Housing Development Site Conditions Bozeman, Montana Page 6 contains. Topsoil thicknesses ranged from 0.5 to 2.5 feet at the nine borings locations with an average thickness of approximately 1.2 feet. Two boring locations (B-01 and B-06), both located on the west side of the property along the existing drainage, exhibited topsoil thicknesses of approximately 2.0 and 2.5 feet, respectively. The topsoil appears to be either lean clay or elastic silt and is considered soft or very loose, respectively, as indicated by penetration resistance values which ranged from 3 to 4 blows per foot (bpf). This material is highly compressible but non-expansive based on the consolidation-swell test result shown on Figures 20 and 22. A single sample of the topsoil contained 0.2 percent gravel, 13.2 percent sand, and 86.6 percent fines. The fines of this sample were determined to be elastic silt with a liquid limit of 57 percent and a plasticity index of 26 percent. The natural moisture contents varied from 30.0 to 59.7 percent and averaged 42.7 percent. A single composite sample of the topsoil from depths of 0.0 to 1.2 feet from various borings was combined for use in a loss on ignition (LOI) test to determine the organic content. The results of this test are shown on Figure 24 and indicated an organic content of 12.4 percent within the topsoil. LEAN CLAY Lean clay was encountered beneath the topsoil in all nine borings at depths ranging from 0.5 to 2.5 feet and extends to depths of 2.5 to 7.0 feet with an average clay depth of approximately four feet across the property. The transition from lean clay topsoil to lean clay is easily identified by the sharp color transition from the nearly black topsoil to the light tan lean clay. The lean clay is very soft to firm as indicated by penetration resistance values which ranged from 2 to 7 bpf. This material is moderately compressible and slightly expansive based on the consolidation-swell results shown on Figures 21 and 23. Two samples of the lean clay contained 0.0 and 0.1 percent gravel, 3.6 and 3.7 percent sand, and 96.4 and 96.2 percent fines, respectively. The same samples exhibited liquid limits of 41 and 38 percent and plasticity indices of 22 and 16 percent. The natural moisture contents varied from 19.7 to 30.9 percent and averaged 26.0 percent. Two samples of the lean clay obtained from B-02 (0.6 – 2.0 ft) and B-09 (2.5 – 3.6 ft) were analyzed using a loss on ignition (LOI) test to determine their organic content. The results of these tests are shown on Figures 25 and 26 and indicated an organic content of 2.7 and 6.3 percent, respectively. NATIVE GRAVELS Native gravel deposits were encountered in all nine borings beneath the surficial lean clay and topsoil at depths of 2.5 to 7.0 feet. All borings with depths to gravel exceeding four feet are located along the west side of the property near the existing drainage and suspected wetland areas. The gravels are generally considered to be either clayey gravel with sand or poorly-graded gravel with clay and sand. These deposits are considered medium dense to very dense as indicated by penetration resistance values which ranged from 13 to 88 bpf and averaged 38 bpf. Individual SPT samples were combined throughout the gravel depth Rawhide Ridge Housing Development Site Conditions Bozeman, Montana Page 7 in two individual borings for gradation testing which resulted in samples containing 51.7 and 47.0 percent gravel, 37.4 and 37.8 percent sand, and 10.9 and 15.2 percent fines. However, due to the destructive nature of the SPT test, these samples do not provide an accurate depiction of the native material composition, which we anticipate containing more gravels up to 6-inch diameter or larger and less fines than indicated by these tests. The natural moisture contents varied from 4.5 to 36.7 percent and averaged 13.1 percent due to variations in clay content and proximity to ground water. CLAYEY SAND WITH GRAVEL Layers of clayey sand with gravel were observed in borings B-06 and B-07 at depths of 9.5 to 14.0 feet and 8.0 to 12.5 feet, respectively. Thinner zones of sandy materials are also anticipated elsewhere on site. Where observed, the clayey sand with gravel is medium dense based on penetration resistance values of 12 and 18 bpf. A single sample of this material contained 38.7 percent gravel, 46.6 percent sand, and 14.7 percent fines (silt and clay). The natural moisture contents were measured as 16.0 and 16.3 percent for these samples. 3.3.2 Ground Water Ground water was encountered within each of the borings performed for this preliminary investigation and as summarized in the table below. Water levels were measured at the time of drilling based on the first observation of free water on soil samples or drilling equipment as well as immediately after the removal of augers from the borehole with similar depths noted in each instance. Boring Ground Elevation (ft) Water Depth (ft) Water Elevation (ft) B-01 4,693.52 5.0 4,688.52 B-02 4,691.92 6.0 4,685.92 B-03 4,693.44 3.0 4,690.44 B-04 4,698.03 6.5 4,691.53 B-05 4,697.47 4.0 4,693.47 B-06 4,700.26 2.5 4,697.76 B-07 4,699.15 3.5 4,695.65 B-08 4,702.45 3.5 4,698.95 B-09 4,700.67 3.5 4,697.17 Rawhide Ridge Housing Development Site Conditions Bozeman, Montana Page 8 The presence or absence of observed ground water may be directly related to the time of the subsurface investigation. Numerous factors contribute to seasonal ground water occurrences and fluctuations, and the evaluation of such factors is beyond the scope of this report. Rawhide Ridge Housing Development Preliminary Engineering Analysis Bozeman, Montana Page 9 4.0 PRELIMINARY ENGINEERING ANALYSIS 4.1 Introduction The primary geotechnical concerns anticipated for the proposed development of this project are the shallow ground water, areas of soft compressible clay soils beneath the typical depth for foundations in the Bozeman area, and areas of thick topsoil which will require greater stripping depths. The shallow ground water is expected to have impacts on both design and construction depending on the final site grading. The shallow ground water, in some areas, will complicate the mitigation of the settlement risk posed by the soft surficial soil. Similar soft soils are generally dealt with through the removal and replacement of this zone since it is relatively thin; however, this process is much more difficult when trying to place fill beneath the ground water elevation and dewatering of a site of this scale is difficult and costly. Thus, in some areas of this site, use of engineered aggregate piers may be better suited to the site conditions to improve the bearing properties of the clay soils and control settlements. While most of the site exhibits typical topsoil depths of one foot or less, two borings along the west side of the project near the existing drainages encountered dark black organic topsoil extending to depths of 2.0 to 2.5 feet. Thus, areas of this site should anticipate the need for greater stripping depths to remove organics soils unsuitable for construction. 4.2 Site Grading and Excavations The ground surface at the proposed site is best described as nearly level to gently sloping and based on the measured elevations at boring locations appears to slope between 1 and 3 percent down toward the northeast corner. A low lying drainage exists from the approximate southwest corner of the property extending diagonally towards the center of the property and roughly lying at the edge of the existing agricultural portion. This area exhibited very soft surface soils and standing water at the time of our investigation which may have been due to recent snow melt. This portion of the project is anticipated to prove difficult for access for construction equipment due to the increasing thickness of saturated surface topsoil and clay soils in this region. All topsoil and surficial clay soils encountered are considered moisture sensitive and should be expected to exhibit moisture contents significantly higher than those typically required for compaction. Thus, abundant precipitation and construction traffic are likely to adversely impact these soils, especially once the existing vegetation has been removed. This should be anticipated by the contractor, and traffic directly on exposed fine-grained soils should be limited to the extent possible. When construction traffic is required on the stripped clay soils, the use of low contact pressure equipment and avoidance of sharp turning or maneuvering of equipment is advised. Based on our preliminary field work, topsoil and lean clay soils are anticipated to range from depths of 2.5 to 7.0 feet across the project site. The thickest deposits of these materials are anticipated on the west side of the project near the existing drainage channel. Beneath the surface clays, water bearing native gravels should be anticipated extending to depths of more than 22.0 feet, the Rawhide Ridge Housing Development Preliminary Engineering Analysis Bozeman, Montana Page 10 maximum depth investigated. The soils encountered during our investigation are not anticipated to pose any difficulty with excavation to conventional construction equipment; thus, blasting or other specialized excavation methods are not required for this site. Ground water and potentially unstable soils will be the biggest challenge posed to excavations for this project. The clay soils present on site are generally soft to firm and are expected to hold a vertical cut for short term construction; however, the underlying gravels are expected to be prone to sloughing, especially at or below the water table, leading to unstable excavations where encountered. Based on the borings, ground water should be anticipated within most excavations for this project depending on the final site grading. Ground water at the time of our investigation ranged from 2.5 to 6.5 feet below existing site grades and is likely to be encountered in many foundation excavations as well as most conventional utility excavations, such as water and sewer, which commonly utilize minimum bury depths of 6.0 to 8.0 feet locally. Based on the ground water elevations measured, the probable flow path for ground water matches the existing topography, with ground water flow toward the northeast corner anticipated for this project. Gallatin County maintains a publicly available GIS database which includes potentiometric contours for the region. The image from this map is shown below, which generally confirms a ground water flow direction from south to north through the Bozeman area. Gallatin County Interactive Mapper – Maddison Potentiometric Contours Rawhide Ridge Housing Development Preliminary Engineering Analysis Bozeman, Montana Page 11 At this time, no ground water monitoring wells were available to aid in evaluating potential seasonal fluctuations in ground water levels. The field investigation for this project, performed in early April, is not anticipated to be the shallowest level at which ground water could be seen. In our experience, seasonal high ground water elevations are not observed until late May or early June of each year. We are not aware of any long-term ground water monitoring data available in the valley, as most projects monitor for only a single season or less. Thus, an accurate idea of seasonal fluctuations is difficult to ascertain and can vary by location; however, the majority of projects with which we have been involved in performing ground water monitoring observed an annual fluctuation of only one to three feet between the seasonal high and low elevations. We understand that wells are being installed by others on site for this purpose. Future data from these wells will be critical to understanding the risk the shallow ground water poses to this project. 4.3 Monolithic Turndown Slabs It is our understanding the use of monolithic turndown slabs is the preferred construction for the proposed housing development. The soils encountered on site pose no substantial expansive risk that will impact such construction; however, the native clay soils are considered moderate to highly compressible, and the settlement risk of the various structures will be significantly controlled by the final site grading, the type of materials used for site grading, and the resulting thickness of compressible clay beneath foundation elements. In our experience, allowable bearing pressures for similar clay soils are low ranging from approximately 1,000 to 1,500 pounds per square foot (psf), and these soils commonly exhibit in-situ moisture contents which greatly exceed the optimum for compaction. This is expected to be the case for this project site where the average moisture content of the clay was 26 percent and typical optimum moisture content for such materials would range from 16 to 20 percent using the preferred standard proctor method (ASTM D698). The high moisture of these soils makes them difficult to work with and less than ideal for a foundation bearing stratum. Furthermore, the intended use of turndown slabs at the perimeter for frost depth and shallow thickened footings on the interior for support would lead to a greater risk of differential settlements due to the variations in clay soils which would remain beneath foundations. The frost depth requirement for the City of Bozeman is 36 inches for single-story construction and 48 inches for two-story or larger. However, TD&H commonly recommends a minimum of 48 inches for all structures regardless of size. Depending on final site grading, the frost depth requirement would place many exterior foundations on or near the underlying gravel while interior footings would remain on compressible clay, creating an increased risk of differential movements. To help ensure adequate foundation performance, it would be advised that all interior and exterior foundations be supported on the underlying gravels in lieu of the compressible near surface clays. The common approach is to remove and replace the limited depth of clay with properly compacted imported structural gravel to transfer all foundation loads to the underlying gravels, which are a far superior bearing stratum able to support bearing pressures of 3,000 to 5,000 psf with less overall settlement risk. Similar improvements would be advised beneath all interior bearing locations to provide uniform performance and avoid differential movements within the structure related to interior footings bearing on compressible clay soils. This will not preclude the use of thickened slab Rawhide Ridge Housing Development Preliminary Engineering Analysis Bozeman, Montana Page 12 sections to support interior walls but will increase the amount of excavation and replacement required at interior bearing locations. Conventional over-excavation and replacement methods based on current site grades would warrant excavation depths of 2.5 to 7.0 feet; however, the depth of imported fill required could increase depending on final site grading. The figure below compares the depth to gravel, shown in red, to the ground water depth at the time of drilling, shown in blue, for each of the boring locations. Comparing these values provides insight into the difficulties with ground water that may be encountered during the over-excavation process. Based on these data, the clouded area along the west side of the property is expected to be the zone in which excavations to remove the surface clays are likely to encounter ground water. Alternative ground improvement options in this area may be better suited to the site due to the ground water issues. Rawhide Ridge Housing Development Preliminary Engineering Analysis Bozeman, Montana Page 13 On the clouded region shown in the figure above, ground water is expected to be encountered in excavations required to remove the highly compressible clay soils. Thus, in this region the use of engineered aggregate piers (EAP) may be a more economical option to improve the existing clays in place without the need to excavate down and deal with the abundant ground water issues. Similar foundation improvements have been utilized widely in the Bozeman area for sites encountering similar compressible clay soils which cannot be economically removed due to their depth or other concerns such as ground water. EAPs can be installed using either a drill and fill method or a displacement method. For this site, given the soft condition of the clay soils and they shallow ground water, the use of a displacement method using a downhole mandrel may be a preferred option. The construction of the EAP system significantly increases stresses in the soil causing densification and a significant reduction in overall compressibility. Such improvements would be required beneath all interior and exterior foundations, but the depth of improvements would vary across the area shown depending on final site grading and design by the EAP installer. EAPs generally allow for a design bearing pressure on the order of 4,000 psf which is comparable to the remove and replacement option discussed above. Both the over-excavation and replacement options, when utilized uniformly beneath a structure at all interior and exterior locations, are anticipated to be suitable to limit total settlements to ¾-inch or less with differential settlements being ⅜-inch or less. The non-load bearing slab portions of the proposed monolithic slab foundation would benefit from the complete removal of the clay or the use of EAPs beneath these areas; however, we do not believe that the cost associated with these improvements is required to achieve suitable slab performance. A common approach, preferred in the Bozeman area, includes the use of a section of compacted structural gravel beneath the slab separated from the native soils using a heavy woven reinforcing geotextile such as a Mirafi RS380i. Alternatively, the use of a combination of a non- woven geotextile and a reinforcing geogrid can also be considered. Typical gravel thicknesses with this approach range from 12 to 24 inches, depending on thickness of clay soil which will remain beneath the structure’s slab and its overall compressibility. Depending on the final site grading for the project, we anticipate 12 inches of structural gravel being adequate for this project. The preferred 4-inch drainage course of clean rock can still be installed between the structural fill and the concrete construction as a leveling course. Additionally, using the proposed thickened-slab sections to support interior bearing locations, it would be advised that the geotextile(s) and structural fill be placed uniformly across the building footing and would lie above all interior ground improvements (over-excavation or EAPs) discussed previously. 4.4 Retaining Walls Retaining walls, when required in the final site grading, will be subjected to horizontal loading due to lateral earth pressures. The lateral earth pressures are a function of the natural and backfill soil types and acceptable wall movements, which affect soil strain to mobilize the shear strength of the Rawhide Ridge Housing Development Preliminary Engineering Analysis Bozeman, Montana Page 14 soil. More soil movement is required to develop greater internal shear strength and lower the lateral pressure on the wall. To fully mobilize strength and reduce lateral pressures, soil strain and allowable wall rotation must be greater for clay soils than for cohesionless, granular soils. The lowest lateral earth pressure against walls for a given soil type is the active condition and develops when wall movements occur. Passive earth pressures are developed when the wall is forced into the soil, such as at the base of a wall on the side opposite the retained earth side. When no soil strain is allowed by the wall, this is the "at-rest" condition, which creates pressures having magnitudes between the passive and active conditions. The distribution of the lateral earth pressures on the structure depends on soil type and wall movements or deflections. In most cases, a triangular pressure distribution is satisfactory for design and is usually represented as an equivalent fluid unit weight. Preliminary design parameters for your consideration are given in the recommendations section of this report. 4.5 Exterior Flatwork The natural on-site soils, exclusive of topsoil, are generally suitable to support lightly to moderately loaded, exterior concrete flatwork. At a minimum, a leveling course of granular fill directly beneath the slab is recommended to provide a structural cushion, a capillary-break from the subgrade, and a drainage medium. Conventional construction typically utilizes four to six inches of granular material beneath exterior flatwork; however, the requirements may vary locally. While the anticipated lean clay subgrade across the project site is not considered expansive, it is considered moisture sensitive and is likely to exhibit highly elevated moisture contents at the time of construction and throughout the life of the project based on the relatively shallow ground water in the area. Currently, these clay soils are estimated to be approximately four to eight percent above the optimum water content for compaction of similar materials, which will make subgrade preparation, compaction, and grading more challenging. Assuming difficulties with subgrade compaction may be realized during construction, exterior concrete flatwork incorporating only a basic drainage layer can experience greater movement and cracking, especially when they experience heavier load conditions or vehicle traffic. Similar flatwork structures which are anticipated to be utilized by vehicles or see heavier loads should anticipate the need for more subsurface improvements to help improve performance on the subgrade soils present on this site. Construction in these areas would be advised to incorporate a minimum 12-inch compacted structural gravel beneath the concrete with reinforcing geotextiles at the subgrade surface, similar to those discussed for the interior of the planned structures. 4.6 Pavements A pavement section is a layered system designed to distribute concentrated traffic loads to the subgrade. Performance of the pavement structure is directly related to the physical properties of the Rawhide Ridge Housing Development Preliminary Engineering Analysis Bozeman, Montana Page 15 subgrade soils and the magnitude and frequency of traffic loadings. Pavement design procedures are based on strength properties of the subgrade and pavement materials, along with the design traffic conditions. Little is known about the traffic conditions for the development at this time; however, we have assumed that given its use as primarily housing that traffic would generally be limited to passenger car vehicles and light truck traffic associated with deliveries or weekly services such as garbage collection. The preliminary pavement sections outlined in this report have been based on assumed equivalent single axle loads (ESALs) of 50,000 and 100,000 for light and heavy- duty pavements, respectively. The anticipated subgrade material is the in-situ lean clay which is expected to be classified as either an A-6 or A-7 soil in accordance with the American Association of State Highway and Transportation Officials (AASHTO) classification. AASHTO considers this soil type to be a relatively poor subgrade due to its moisture sensitivity, reduced strength at high moisture, and poor drainage properties. Typical California Bearing Ratio (CBR) values for this type of soil can range from 3 to 5 percent when properly moisture conditioned and compacted; however, the elevated moistures of the clay indicated by laboratory testing are expected to result in the inability to achieve preferred levels of compaction during construction and a reduced CBR value. The incorporation of a heavy woven reinforcing geotextile or inclusion of a geogrid in addition to a separation geotextile is advised for this project due to the anticipated over-optimum moisture content of the clay subgrade, which will limit the ability to compact it prior to construction. This will help improve performance by helping reinforce the weak clay subgrade while providing the necessary separation between the clay subgrade and the pavement gravels to prevent the migration of fines or loss of aggregate into the subgrade. The preliminary pavement sections presented in this report are based on an assumed CBR value of two percent, assumed traffic loadings, recommended pavement section design information presented in the Asphalt Institute and AASHTO Design Manuals, and our past pavement design experience in Bozeman. 4.7 Soil Corrosivity Two samples of the lean clay and a single composite gravel sample were sent to Alpine Analytical Laboratories to be analyzed to evaluate the corrosion potential of the soils. Testing was to include pH, marble pH, resistivity, and sulfate content; however, the laboratories testing equipment for sulfate analysis is currently down and those results are pending. The following table provides a summary of the results received and a follow-up addendum will be issued summarizing the results of the sulfate testing when available. Rawhide Ridge Housing Development Preliminary Engineering Analysis Bozeman, Montana Page 16 Material Type Sample Location pH Marble pH Resistivity (ohm-cm) Lean CLAY B-04 (0.5 – 2.0 ft) 8.3 8.0 9,860 B-04 (2.5 – 4.0 ft) 8.4 8.1 10,200 GRAVEL COMPOSITE 8.0 8.0 18,200 Based on the testing results summarized above, the soils encountered on this site pose little corrosive risk to steel structures placed in direct contact with the soil and we anticipate no need to specialized coatings or other protective measures. This is also consistent with our experience with similar soils in the Bozeman area. While results of sulfate testing have yet to be received, to be reportedly separately, our experience in the region has been that sulfate levels are generally low. Thus, we do not anticipate buried soils to be corrosive to concrete elements that would warrant specialized sulfate resistant cement to be utilized in construction. Rawhide Ridge Housing Development Preliminary Recommendations Bozeman, Montana Page 17 5.0 PRELIMINARY RECOMMENDATIONS The following recommendations are intended to provide preliminary information for use in the design team during project planning and budgeting. These recommendations are not suitable for use in any final design application or construction without prior supplemental geotechnical investigation to confirm their suitability to be performed after development of a final site layout and grading plan for the project. 5.1 Site Grading and Excavations 1. All topsoil and organic material should be removed from the proposed building and pavement areas and any areas to receive site grading fill. For preliminary planning purposes, an average stripping thickness of approximately 12 inches is expected for the property; however, greater stripping depths should be anticipated in localized areas within the clouded region shown in Section 4.3 above. Stripping should remove all dark brown to black topsoil down to the transition to the underlying tan colored lean clay. 2. All fill and backfill should be non-expansive, free of organics and debris and should be approved by the project geotechnical engineer. The on-site soils, exclusive of topsoil, are suitable for use as backfill and general site grading fill on this project; however, it should be anticipated that moisture conditioning of the native clay soils will be required prior to use in any fill or backfill application. The average moisture content of the soil is currently four to eight percent above the typical optimum for this soil making achieving compaction difficult without prior moisture conditioning. 3. All fill should be placed in uniform lifts not exceeding 8 inches in thickness for fine- grained soils and not exceeding 12 inches for granular soils. All materials compacted using hand compaction methods or small walk-behind units should utilize a maximum lift thickness of 6 inches to ensure adequate compaction throughout the lift. All fill and backfill shall be moisture conditioned to near the optimum moisture content and compacted to the following percentages of the maximum dry density determined by a standard proctor test which is outlined by ASTM D698 or equivalent (e.g. ASTM D4253-D4254). a) Below Foundations or Spread Footings ...................................... 98% b) Below Interior Slabs-on-Grade .................................................... 98% c) Exterior Foundation & Retaining Wall Backfill ............................. 95% d) Below Pavements & Exterior Flatwork ........................................ 95% e) General Landscaping or Nonstructural Areas ............................. 92% f) Utility Trench Backfill, To Within 2 Feet of Surface ...................... 95% Rawhide Ridge Housing Development Preliminary Recommendations Bozeman, Montana Page 18 4. Imported structural fill, when required, should be non-expansive, free of organics and debris, and conform to the material requirements outlined in Section 02234 or 02235 of the Montana Public Works Standard Specifications (MPWSS). All gradations outlined in these standards are acceptable and copies of these have been included in the appendix for reference. 5. Develop and maintain site grades which will rapidly drain surface and roof runoff away from foundation and subgrade soils; both during and after construction. Site grading shall be prepared by others to satisfy the minimum requirements of the applicable building codes. 6. For preliminary earthwork calculations, a composite volumetric shrinkage factor of 10 to 15 percent is appropriate for excavated, moisture conditioned, and recompacted lean clay soils. A shrinkage factor of approximately five percent is anticipated for native gravels. 7. Site utilities should be installed with proper bedding in accordance with pipe manufacturer’s requirements. Utility trenches should anticipate the need for shoring systems (trench boxes or other) during installation as well as dewatering to facilitate construction. Trench backfills using native soils should also anticipate the need for moisture conditioning of the native clays prior to use as backfill as discussed in Item 2 above. 8. It will be the ultimate responsibility of the Contractor to provide safe working conditions in connection with underground excavations. Temporary construction excavations greater than four feet in depth, which workers will enter, will be governed by OSHA guidelines given in 29 CFR, Part 1926. For preliminary planning purposes, subsoils encountered in the borings are considered Type B for the surface lean clays and Type C for the underlying native gravels. The soil conditions can change over time and must be re-evaluated by the contractor prior to any construction activities. 5.2 Monolithic Turndown Slabs 9. While not recommended due to the settlement risk, if exterior or interior footings bearing directly on native clay soils are considered, bearing pressures are anticipated to range from 1,000 to 1,500 psf. Performance of these foundations will be a function of the clay thickness and final site grading, which will vary and have not yet been determined. We anticipate total settlements of up to one inch with differential movements of ½- to ¾- inch could be possible with this option. 10. For structures on the east side of the property (outside the clouded region shown on the figure in Section 4.3), conventional over-excavation and replacement of the clay Rawhide Ridge Housing Development Preliminary Recommendations Bozeman, Montana Page 19 soils with compacted structural fill may be possible depending on future ground water fluctuation information. In these areas it is advised that clay soils be excavated down to the native gravel surface and structural fill recompacted back up to the design footing elevation. The structural fill should extend at least two feet beyond the limits of the load bearing footing at all locations with this option. Footings bearing on properly compacted structural fill extending to native gravels can generally utilize an allowable soil bearing pressure ranging from 4,000 to 5,000 psf. Settlements for similar construction are not anticipated to exceed ¾-inch with differential movements generally being less than ½-inch. 11. For structures on the west side of the property (inside the clouded region shown on the figure in Section 4.3), conventional over-excavation and replacement of the clays soils is not expected to be practical due to the need to excavate below the ground water level. In these areas, structures should anticipate the need to utilize alternative ground improvements such as engineered aggregate piers (EAPs) to improve subsurface conditions. EAPs should consider the use of a displacement installation method using a driven mandrel. The design should be performed by the EAP designer/contractor to provide a bearing pressure of at least 4,000 psf while limiting total settlements to less than ¾-inch with differential settlements being less than ½-inch. 12. Exterior footings and footings beneath unheated areas should be placed at least 48 inches below finished exterior grade for frost protection. While this depth is generally advised by TD&H for all structures, the City of Bozeman will allow for a frost depth of 36 inches to be utilized for single-story structures only. Interior footings beneath heated areas should be placed at least 12 to 24 inches below finished floor elevation. Footings in this depth range supported on either structural fill or EAP improved soils may be designed using the full bearing pressures listed in Items 10 or 11 above; however, deeper interior footings would help to reduce the amount of structural fill or the length of EAP elements required depending on final site grading. If footings supported on native soils, discussed in Item 9 are considered, interior footings in this range should anticipate a 10 to 25 percent reduction in the allowable bearing capacity for interior footings at depths of 24-inch and 12-inch respectively. 13. Lateral loads are resisted by sliding friction between the footing base and the supporting soil and by lateral pressure against the footings opposing movement. For preliminary design purposes, a friction coefficient of 0.25 is typical if footings supported on native soils are anticipated. Footings supported on either compacted structural fill or EAP improved soils often realize a friction value ranging from 0.4 to 0.5. A lateral resistance pressure of 150 to 250 psf per foot of depth are appropriate for backfill consisting of properly moisture conditioned and compacted native clays. Rawhide Ridge Housing Development Preliminary Recommendations Bozeman, Montana Page 20 14. At a minimum, interior slab portions of the structures should incorporate at least 12 inches of compacted structural fill separated from the underlying native soils by a woven reinforcing geotextile. The use of a Mirafi RS380i is generally recommended; however, if the combination of a geogrid and separation geotextile is preferred, we would advise the use of a Mirafi 180N separation geotextile with a Tensar TX160 triaxial geogrid. The structural fill and geosynthetic reinforcement should be continuous within the building footprint and constructed over top of EAP elements, when utilized. An addition cushion course of clean rock may be incorporated between the concrete and the structural fill if preferred but shall not be considered part of the recommended structural fill thickness. 15. If no acceptable risk of slab movements on the interior of the building can be accepted for this project, we do not advise that unimproved native clay soils remain within the building footprint and that either the excavation and replacement or EAP improvements extend throughout the slabs per Items 10 and 11 above. 5.3 Retaining Wall 16. Retaining walls anticipated for potential site grading applications on this project should consider the following preliminary design values depending on wall type. All walls which are laterally braced should utilize at-rest design properties. Active design values are only appropriate for wall structures which are able to rotate or deflect laterally at least four percent of the exposed wall height. The provided values do not include any safety factors, and appropriate safety factors need to be included in the design of the wall structure by others. Design Parameters Soil Type Native Clay Native / Imported Gravel Active Pressure Coefficient 0.50 0.26 Active Equivalent Fluid Pressure 60 psf per foot 35 psf per foot At-Rest Pressure Coefficient 0.67 0.41 At-Rest Equivalent Fluid Pressure 80 psf per foot 55 psf per foot Passive Pressure Coefficient 2.00 3.85 Passive Equivalent Fluid Pressure 240 psf per foot 520 psf per foot 17. Backfill placed against the sides of the footings and the base of the walls to resist lateral loads should be placed and compacted per the requirements of Item 3c above. 18. Backfill should be selected, placed, and compacted per Items 2 and 3 above. Care should be taken not to over-compact the backfill since this could cause excessive Rawhide Ridge Housing Development Preliminary Recommendations Bozeman, Montana Page 21 lateral pressure on the walls. Only hand-operated compaction equipment should be used within 5 feet of retaining walls. 19. Retaining walls over 4 feet in height should incorporate backfill drainage systems and/or weep holes to prevent the accumulation of hydrostatic pore pressures. Design of drain system is the responsibility of the wall designer. 5.4 Exterior Flatwork 18. For normally loaded, exterior concrete flatwork, at a minimum a typical cushion course consisting of free-draining, crushed gravel should be placed beneath the concrete and compacted to the requirements of Item 2 above. Cushion course thicknesses generally range from four to six inches but may vary based on local requirements. Conventional construction, as has been described, is not intended to mitigate expansion or settlement concerns associated with the subsurface conditions encountered and may not be suitable for especially sensitive or expense flatwork or those which will realize heavy loads or vehicle traffic. In most cases, the cost to repair and/or replace exterior flatwork when excessive movements occur is far more economical than efforts to mitigate these movements. 19. Heavily loaded or sensitive exterior flatwork which would be especially costly to replace or for which cracking or vertical movements is not desired (i.e colored, textured, or other specialty concrete) should consider additional subsurface improvements as outlined in Items 14 and 15 above as recommended for interior building slabs. 20. It is our understanding that the inclusion of a vapor barrier directly beneath the concrete is part of the preferred construction. Geotechnically, this is also advised pending information regarding final site grading due to the shallow ground water observed during the preliminary site investigation. 5.5 Pavements 21. The following preliminary asphalt pavement sections are advised for consideration during preliminary project planned and must be verified during final investigation. Rawhide Ridge Housing Development Preliminary Recommendations Bozeman, Montana Page 22 FLEXIBLE ASPHALT PAVEMENT SECTIONS Pavement Component Light-Duty Section Heavy-Duty Section Component Thickness Asphaltic Concrete Pavement 3” 4” Crushed Base Course 6” 6” Crushed Subbase Course 12” 12” Total 21” 22” The asphalt pavement sections provided above have not considered construction phase traffic in their development. Traffic during the construction phase of large housing development projects, such as that proposed, has encountered issues with pavement performance by the end of construction, especially in high traffic areas for large vehicles or where construction equipment perform tight radius turns on the pavement. Any areas which will be utilized for construction traffic following pavement installation should consider increasing the asphalt thickness in those areas to a minimum of five inches to account for the larger vehicles, increased travel volumes, and tight radius turns typical during the construction phase. 21. The following preliminary rigid concrete pavement sections are advised for consideration during preliminary project planning and must be verified during final investigation. RIGID PORTLAND CEMENT CONCRETE SECTIONS Pavement Component Light-Duty Section Heavy-Duty Section Component Thickness Portland Cement Concrete Pavement 6” 8” Crushed Base Course 12” 12” Crushed Subbase Course ----- ----- Total 18” 20” We do not advise the light-duty section be utilized in any areas which may be used for construction phase traffic for this project. The increased concrete strength is warranted in these areas. Rawhide Ridge Housing Development Preliminary Recommendations Bozeman, Montana Page 23 22. Final asphalt pavement thicknesses exceeding 3 inches shall be constructed in two uniform lifts. 23. Crushed base courses shall conform to the material properties outlined in Section 02235 of the Montana Public Works Standard Specifications (MPWSS). All gradations outlined in this specification are acceptable for this application based on the local availability and contractor preference. Crushed subbase courses shall conform to material properties outlined in Section 02234 of the MPWSS. All gradations outlined in this specification are acceptable for this application based on local availability and contractor preference. 24. Where the existing grades will be raised more than the thickness of the pavement section, all fill should be placed, compacted and meet the general requirements given in Items 2 and 3d above. 25. All pavement sections outlined in the tables above should incorporate reinforcing geosynthetics between the prepared clay subgrade and the gravel pavement materials. Either a woven geotextile consisting of a Mirafi RS380i, or equivalent, or the combination of a non-woven separation geotextile beneath a reinforcing geogrid is advised. When a geotextile and grid combination is preferred a Mirafi 180N, or equal, and a Tensar TX160 triaxial geogrid are recommended. Prior to the installation of the geosynthetics, the subgrade should be cleared of all loose soil and statically compacted to the extent possible without excessive pumping of the clay subgrade. 26. Ideally, the asphaltic cement should be a Performance Graded (PG) binder having the following minimum high and low temperature values based on the desired pavement reliability. Reliability Min. High Temp Rating Min. Low Temp Rating 50% 35.8 -23.8 98% 39.8 -32.6 Of the locally available asphalt suppliers, the use of PG 58-28 grade oil, standard in the MPWSS specifications, is recommended for this site as this will provide the best low temperature performance. Rawhide Ridge Housing Development Preliminary Recommendations Bozeman, Montana Page 24 27. The concrete utilized for rigid pavement sections has been assumed to be able to provide a minimum compressive strength of 4,000 psi and a minimum modulus of rupture of 570 psi for the section thicknesses outlined above. If the concrete materials available cannot meet these minimum requirements, the concrete pavement section warrants modification based on the concrete properties available for this project. Rawhide Ridge Housing Development Summary of Field & Laboratory Studies Bozeman, Montana Page 25 6.0 SUMMARY OF PRELIMINARY FIELD AND LABORATORY STUDIES 6.1 Field Explorations The preliminary field exploration program was conducted between April 2nd and 4th, 2025. A total of nine borings were drilled to depths ranging from 21.5 to 22.0 feet at the locations shown on Figure 1 to observe subsurface soil and ground water conditions. The borings were advanced through the subsurface soils using a track-mounted Mobile B-57 drill rig equipped with 3.25-inch I.D. hollowstem augers. The subsurface exploration and sampling methods used are indicated on the attached boring logs. The borings were logged by Mr. Craig Nadeau, PE of TD&H Engineering. The location and elevation of the borings were recorded by TD&H survey personnel using a Trimble GPS unit. The following table summarized the latitude, longitude, and ground surface elevation for each boring performed. Boring Latitude Longitude Elevation (ft) B-01 45° 42' 25.62304" -111° 04' 17.61191" 4,693.52 B-02 45° 42' 26.20011" -111° 04' 11.77163" 4,691.92 B-03 45° 42' 23.61006" -111° 04' 13.92607" 4,693.44 B-04 45° 42' 22.58656" -111° 04' 17.34034" 4,698.03 B-05 45° 42' 21.27598" -111° 04' 11.44030" 4,697.47 B-06 45° 42' 19.72563" -111° 04' 17.49355" 4,700.26 B-07 45° 42' 19.05105" -111° 04' 14.06893" 4,699.15 B-08 45° 42' 16.79146" -111° 04' 11.36283" 4,702.45 B-09 45° 42' 16.95051" -111° 04' 16.64019" 4,700.67 Samples of the subsurface materials were taken using 1⅜-inch I.D. split spoon samplers. The samplers were driven 18 inches, when possible, into the various strata using a 140-pound drop hammer falling 30 inches onto the drill rods. For each sample, the number of blows required to advance the sampler each successive six-inch increment was recorded, and the total number of blows required to advance the sampler the final 12 inches is termed the penetration resistance (“N- value”). This test is known as the Standard Penetration Test (SPT) described by ASTM D1586. When the sampler is driven more than 18 inches, the number of blows required to advance the sampler the second and third six-inch increments are used to determine the N-value. Penetration resistance values indicate the relative density of granular soils and the relative consistency of fine- grained soils. Samples were also obtained by hydraulically pushing a 3-inch I.D., thin-walled Shelby tube sampler into the subsoils. Logs of all soil borings, which include soil descriptions, sample depths, and penetration resistance values, are presented on the Figures 2 through 10. Measurements to determine the presence and depth of ground water were made in the borings by lowering an electronic water sounder or steel tape through the open boring after the completion of drilling. Water levels at completion of drilling were generally consistent with when free water was Rawhide Ridge Housing Development Summary of Field & Laboratory Studies Bozeman, Montana Page 26 first observed on drilling equipment and soil cuttings during drilling. The depths or elevations of the water levels measured, if encountered, and the date of measurement are shown on the boring logs. 6.2 Laboratory Testing Samples obtained during the field exploration were returned to our materials laboratory where they were observed and visually classified in general accordance with ASTM D2487, which is based on the Unified Soil Classification System. Representative samples were selected for testing to determine the engineering and physical properties of the soils in general accordance with ASTM or other approved procedures. Tests Conducted: To determine: Natural Moisture Content Representative moisture content of soil at the time of sampling. Grain-Size Distribution Particle size distribution of soil constituents describing the percentages of clay/silt, sand and gravel. Atterberg Limits A method of describing the effect of varying water content on the consistency and behavior of fine-grained soils. Consolidation Measurements of the percent compression experienced under various loading conditions. For use in settlement analysis and foundation design. Constant Volume Swell Determination of the maximum uplift force exerted by a soil specimen during inundation by gradual increases in the applied resisting force to maintain a fixed samples height. Loss on Ignition (LOI) Determination of organic matter content of samples through the ignition of previously oven-dried soil to constant mass and measuring the percent of mass lost during ignition. The laboratory testing program for this project consisted of 63 moisture-visual analyses, six sieve (grain-size distribution) analyses, and 3 Atterberg Limits analyses. The results of the water content analyses are presented on the boring logs, Figures 2 through 10. The grain-size distribution curves and Atterberg limits are presented on Figures 11 through 19. In addition, two consolidation tests, two constant volume swell tests, and three losses on ignition tests were performed. The consolidation-swell tests are shown on Figures 20 through 23 and the results of the loss on ignition testing is shown on Figure 24 through 26. Rawhide Ridge Housing Development Limitations Bozeman, Montana Page 27 7.0 LIMITATIONS This preliminary report has been prepared in accordance with generally accepted geotechnical engineering practices in this area for use by the client for preliminary planning and budgetary purposes. The findings, analyses, and preliminary recommendations contained in this report reflect our professional opinion regarding potential impacts the subsurface conditions may have on the proposed infrastructure and are based on site conditions encountered during the preliminary site investigation. Our preliminary analysis assumes that the results of the exploratory borings are representative of the subsurface conditions throughout the site, that is, that the subsurface conditions everywhere are not significantly different from those disclosed by the subsurface study and that the planned construction will not deviate from the typical project parameters outlined in the project Request for Proposal (RFP). Unanticipated soil conditions are commonly encountered and cannot be fully determined by a limited number of soil borings and laboratory analyses. Thus, additional investigation is recommended once a final site development plan and specifics regarding the planned construction are confirmed for the project. The preliminary recommendations contained within this report are based on the limited subsurface conditions observed in the borings at this stage of the project and are subject to change pending additional investigation developed after reviewing a site development and grading plan. This report was prepared for the exclusive use of the owner and architect and/or engineer in the preliminary schematic design, project planning, and budgeting for the proposed development. It is not intended to be utilized in any final design applications or for construction without additional investigation following our review of a site development and grading plan of the planned construction. The intent of this preliminary assessment was to provide factual data regarding subsurface conditions and a preliminary engineering assessment of the impacts of those conditions on the anticipated construction. Prepared by: Reviewed by: Craig Nadeau PE & Principal Peter Klevberg PE Geotechnical Manager Geotechnical Engineer TD&H ENGINEERING TD&H ENGINEERING 0 4 8 12 16 20 24 28 TOPSOIL: Lean CLAY (CL), relatively soft, black to dark brown, moist, high plasticity, abundant organics to approximately 12 to 18 inches - See Figures 20 and 22 for consolidation-swell test reports Lean CLAY (CL), soft to very soft, light brown, moist Clayey GRAVEL with Sand (GC), medium dense to dense, wet, brown to dark gray Bottom of Boring 2.0 5.6 22.0 PUSH 1-1-1-1 0-4-10- 11 2-4-11- 15 5-15-19 11-21- 20-21 T LEGEND LOG OF SOIL BORING B-01SPT blows per foot Atterberg Limits Field Moisture content Rawhide Ridge Development Reconnaissance Bozeman, MontanaGroundwater Level Grab/composite sample 1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE 2-1/2-inch I.D. split spoon Drilled by:Wiley Drilling Track-Mounted Mobile B-57 with 4.25-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic 3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. 4-2-2025 25-009-001 No sample recovery Figure No.2 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Snow Covered Native Grasses SURFACE ELEVATION:4,693.52 ft DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT 0 10 20 30 40 50 = BLOWS PER FOOT = MOISTURE CONTENT 1 of 1 0 4 8 12 16 20 24 28 TOPSOIL: Lean CLAY (CL), soft, black, moist, high plasticity Lean CLAY (CL), soft, light brown, moist Poorly-Graded GRAVEL with Clay and Sand (GP- GC), medium dense to very dense, reddish gray, slightly moist to wet - Rock lodged in tip of spoon. Bottom of Boring 0.6 3.2 21.5 1-2-2-3 1-3-10- 22 18-29- 21-22 8-15- 42-16 9-18-23 23-38- 50 57 88 LEGEND LOG OF SOIL BORING B-02SPT blows per foot Atterberg Limits Field Moisture content Rawhide Ridge Development Reconnaissance Bozeman, MontanaGroundwater Level Grab/composite sample 1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE 2-1/2-inch I.D. split spoon Drilled by:Wiley Drilling Track-Mounted Mobile B-57 with 4.25-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic 3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. 4-2-2025 25-009-001 No sample recovery Figure No.3 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Snow Covered Native Grasses SURFACE ELEVATION:4,691.92 ft DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT 0 10 20 30 40 50 = BLOWS PER FOOT = MOISTURE CONTENT 1 of 1 0 4 8 12 16 20 24 28 TOPSOIL: Lean CLAY (CL), relatively soft, black, moist, high plasticity Lean CLAY (CL), relatively soft, light brown, moist Clayey GRAVEL with Sand (GC), medium dense to very dense, brown and gray, wet - 9" of heave in augers prior to sampling Bottom of Boring 0.5 2.8 21.5 1-5-13- 25 2-26- 37-39 4-13-13 10-21- 21 9-29- 35-35 63 64 LEGEND LOG OF SOIL BORING B-03SPT blows per foot Atterberg Limits Field Moisture content Rawhide Ridge Development Reconnaissance Bozeman, MontanaGroundwater Level Grab/composite sample 1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE 2-1/2-inch I.D. split spoon Drilled by:Wiley Drilling Track-Mounted Mobile B-57 with 4.25-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic 3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. 4-2-2025 25-009-001 No sample recovery Figure No.4 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Snow Covered Native Grasses SURFACE ELEVATION:4,693.44 ft DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT 0 10 20 30 40 50 = BLOWS PER FOOT = MOISTURE CONTENT 1 of 1 0 4 8 12 16 20 24 28 TOPSOIL: Lean CLAY (CL), appears very soft, black, moist, high plasticity Lean CLAY (CL), firm to soft, light brown, moist Clayey GRAVEL with Sand (GC), medium dense to very dense, brown and gray, wet Bottom of Boring 0.5 7.0 22.0 1-3-3-3 1-1-2-1 3-2-4 6-8-11- 11 7-12- 19-13 17-16- 20-16 6-18- 43-16 61 LEGEND LOG OF SOIL BORING B-04SPT blows per foot Atterberg Limits Field Moisture content Rawhide Ridge Development Reconnaissance Bozeman, MontanaGroundwater Level Grab/composite sample 1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE 2-1/2-inch I.D. split spoon Drilled by:Wiley Drilling Track-Mounted Mobile B-57 with 4.25-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic 3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. 4-2-2025 25-009-001 No sample recovery Figure No.5 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Snow Covered Native Grasses SURFACE ELEVATION:4,698.03 ft DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT 0 10 20 30 40 50 = BLOWS PER FOOT = MOISTURE CONTENT 1 of 1 0 4 8 12 16 20 24 28 TOPSOIL: Lean CLAY (CL), very soft, black, moist, high plasticity Lean CLAY (CL), soft, light brown, moist Clayey GRAVEL with Sand (GC), medium dense to dense, brown and gray, moist to wet Bottom of Boring 1.0 2.5 22.0 1-1-2-1 3-15- 14-18 4-17- 15-14 7-13- 15-16 5-20- 20-29 13-24- 14-19 LEGEND LOG OF SOIL BORING B-05SPT blows per foot Atterberg Limits Field Moisture content Rawhide Ridge Development Reconnaissance Bozeman, MontanaGroundwater Level Grab/composite sample 1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE 2-1/2-inch I.D. split spoon Drilled by:Wiley Drilling Track-Mounted Mobile B-57 with 4.25-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic 3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. 4-3-2024 25-009-001 No sample recovery Figure No.6 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Snow Covered Native Grasses SURFACE ELEVATION:4,697.47 ft DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT 0 10 20 30 40 50 = BLOWS PER FOOT = MOISTURE CONTENT 1 of 1 0 4 8 12 16 20 24 28 TOPSOIL: Elastic SILT (MH), very loose, black, moist, abundant organics to about 12 to 18 inches Lean CLAY (CL), relatively soft, light brown, moist - See Figures 21 and 23 for consolidation-swell reports Clayey GRAVEL with Sand (GC), medium dense, brown and gray, moist to wet Clayey SAND with Gravel (SC), medium dense, brown, wet Clayey GRAVEL with Sand (GC), medium dense, brown and gray, wet - Heaving sands locked inner bit in augers at 15.0 feet. Forced to remove augers and redrill to depth once water available on site. Bottom of Boring 2.5 5.3 9.5 14.0 22.0 1-1-2-2 PUSH 1-12- 13-19 3-6-6-8 6-16-16 12-27- 9-50/4" T 57 LEGEND LOG OF SOIL BORING B-06SPT blows per foot Atterberg Limits Field Moisture content Rawhide Ridge Development Reconnaissance Bozeman, MontanaGroundwater Level Grab/composite sample 1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE 2-1/2-inch I.D. split spoon Drilled by:Wiley Drilling Track-Mounted Mobile B-57 with 4.25-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic 3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. 4/2/25 - 4/3/2025 25-009-001 No sample recovery Figure No.7 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Snow Covered Native Grasses SURFACE ELEVATION:4,700.26 ft DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT 0 10 20 30 40 50 = BLOWS PER FOOT = MOISTURE CONTENT 1 of 1 0 4 8 12 16 20 24 28 TOPSOIL: Elastic SILT (MH), very loose, black, moist Lean CLAY (CL), relatively firm, light brown, moist Clayey GRAVEL with Sand (GC), dense, brown to gray, moist to wet Clayey SAND with Gravel (SC), medium dense, brown, wet Clayey GRAVEL with Sand (GC), very dense to medium dense, brown and gray, wet Bottom of Boring 1.0 2.5 8.0 12.5 22.0 0-1-2-2 3-20- 22-25 5-23- 20-10 3-9-9-6 20-27- 23-39 7-12- 12-23 59.7 LEGEND LOG OF SOIL BORING B-07SPT blows per foot Atterberg Limits Field Moisture content Rawhide Ridge Development Reconnaissance Bozeman, MontanaGroundwater Level Grab/composite sample 1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE 2-1/2-inch I.D. split spoon Drilled by:Wiley Drilling Track-Mounted Mobile B-57 with 4.25-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic 3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. 4/3/2025 25-009-001 No sample recovery Figure No.8 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Snow Covered Native Grasses SURFACE ELEVATION:4,699.15 ft DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT 0 10 20 30 40 50 = BLOWS PER FOOT = MOISTURE CONTENT 1 of 1 0 4 8 12 16 20 24 28 TOPSOIL: Elastic SILT (MH), very loose, black, moist Lean CLAY (CL), relatively firm, light brown, moist Clayey GRAVEL with Sand (GC), dense to very dense, brown to gray, moist to wet Bottom of Boring 1.0 3.0 22.0 1-2-2-3 3-18- 18-23 6-18- 20-16 5-27-30 13-22- 19-13 57 LEGEND LOG OF SOIL BORING B-08SPT blows per foot Atterberg Limits Field Moisture content Rawhide Ridge Development Reconnaissance Bozeman, MontanaGroundwater Level Grab/composite sample 1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE 2-1/2-inch I.D. split spoon Drilled by:Wiley Drilling Track-Mounted Mobile B-57 with 4.25-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic 3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. 4/4/2025 25-009-001 No sample recovery Figure No.9 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Snow Covered Native Grasses SURFACE ELEVATION:4,702.45 ft DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT 0 10 20 30 40 50 = BLOWS PER FOOT = MOISTURE CONTENT 1 of 1 0 4 8 12 16 20 24 28 TOPSOIL: Elastic SILT (MH), very loose, black, moist Lean CLAY (CL), firm to soft, light brown, moist Clayey GRAVEL with Sand (GC), medium dense to dense, brown to gray, moist to wet Bottom of Boring 1.2 3.6 22.0 0-1-2-2 1-2-5- 22 19-21- 25-27 6-16- 11-10 7-17- 23-25 11-11- 17-13 LEGEND LOG OF SOIL BORING B-09SPT blows per foot Atterberg Limits Field Moisture content Rawhide Ridge Development Reconnaissance Bozeman, MontanaGroundwater Level Grab/composite sample 1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE 2-1/2-inch I.D. split spoon Drilled by:Wiley Drilling Track-Mounted Mobile B-57 with 4.25-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic 3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate boundaries between soil types. Actual boundaries may be gradual or transitional. 4/3/2025 - 4/4/2025 25-009-001 No sample recovery Figure No. 10 SheetGRAPHICLOGSOIL DESCRIPTION SURFACE:Snow Covered Native Grasses SURFACE ELEVATION:4,700.67 ft DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT 0 10 20 30 40 50 = BLOWS PER FOOT = MOISTURE CONTENT 1 of 1 Tested By: BS Checked By: Particle Size Distribution Report ASTM C117 & C136 PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.00010.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 0.0 0.1 0.2 0.6 2.9 96.26 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM C117 & C136)Material Description Atterberg Limits Coefficients Classification Test Remarks Sample Date:Location: B-01 Sample Number: A-31528 Depth: 2.5 - 4.5 ft Client: Project: Project No:Figure Sieve Size or Diam. (mm.) Finer (%) Spec.* (%) Out of Spec. (%) Pct. of Fines Lean CLAY 3/8" #4 #10 #20 #40 #60 #80 #100 #200 100.0 99.9 99.7 99.4 99.1 98.7 98.4 98.1 96.2 22 38 16 CL A-6(16) Report No. A-31528-206 Report Date: 4-23-2025 F.M.=0.05 4-2-2025 Thompson Thrift Development Rawhide Ridge Development Reconnaissance Bozeman, Montana 25-009-001 PL= LL=PI= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= USCS=AASHTO= *(no specification provided) 11 Tested By: IR Checked By: Particle Size Distribution Report ASTM C117 & C136 PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.00010.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 29.1 22.6 13.6 12.9 10.9 10.96 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM C117 & C136)Material Description Atterberg Limits Coefficients Classification Test Remarks Sample Date:Location: B-02 Sample Number: A-31536COMP Depth: 3.2 - 21.5 ft Client: Project: Project No:Figure Sieve Size or Diam. (mm.) Finer (%) Spec.* (%) Out of Spec. (%) Pct. of Fines Poorly-Graded GRAVEL with Clay and Sand 1.5 1 3/4" 1/2" 3/8" #4 #10 #20 #40 #60 #80 #100 #200 100.0 84.2 70.9 62.1 56.9 48.3 34.7 27.6 21.8 18.0 15.9 14.6 10.9 Not Tested Not Tested Not Tested 29.2998 25.8710 11.4016 5.3896 1.1774 0.1590 GP-GC Report No. A-31536COMP-206 Report Date: 4-23-2025 F.M.=4.98 4-2-2025 Thompson Thrift Development Rawhide Ridge Development Reconnaissance Bozeman, Montana 25-009-001 PL=LL=PI= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= USCS=AASHTO= *(no specification provided) 12 Tested By: BS Checked By: Particle Size Distribution Report ASTM C117 & C136 PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.00010.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 0.0 0.2 0.1 1.0 12.1 86.66 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM C117 & C136)Material Description Atterberg Limits Coefficients Classification Test Remarks Sample Date:Location: B-06 Sample Number: A-31560 Depth: 0.0 - 2.0 ft Client: Project: Project No:Figure Sieve Size or Diam. (mm.) Finer (%) Spec.* (%) Out of Spec. (%) Pct. of Fines TOPSOIL: Elastic SILT 3/8" #4 #10 #20 #40 #60 #80 #100 #200 100.0 99.8 99.7 99.3 98.7 97.7 95.3 93.1 86.6 31 57 26 0.1097 MH A-7-5(26) Report No. A-31560-206 Report Date: 4-23-2025 F.M.=0.10 4/2-3/2025 Thompson Thrift Development Rawhide Ridge Development Reconnaissance Bozeman, Montana 25-009-001 PL= LL=PI= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= USCS=AASHTO= *(no specification provided) 13 Tested By: BC Checked By: Particle Size Distribution Report ASTM C117 & C136 PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.00010.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 0.0 0.0 0.4 0.8 2.4 96.46 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM C117 & C136)Material Description Atterberg Limits Coefficients Classification Test Remarks Sample Date:Location: B-06 Sample Number: A-31561 Depth: 2.5 - 4.5 ft Client: Project: Project No:Figure Sieve Size or Diam. (mm.) Finer (%) Spec.* (%) Out of Spec. (%) Pct. of Fines Lean CLAY 3/8" #4 #10 #20 #40 #60 #80 #100 #200 100.0 100.0 99.6 99.2 98.8 98.6 98.4 98.2 96.4 19 41 22 CL A-7-6(22) Report No. A-31561-206 Report Date: 4-23-2025 F.M.=0.05 4/2-3/2025 Thompson Thrift Development Rawhide Ridge Development Reconnaissance Bozeman, Montana 25-009-001 PL= LL=PI= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= USCS=AASHTO= *(no specification provided) 14 Tested By: BC Checked By: Particle Size Distribution Report ASTM C117 & C136 PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.00010.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 10.4 28.3 11.6 19.0 16.0 14.76 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM C117 & C136)Material Description Atterberg Limits Coefficients Classification Test Remarks Sample Date:Location: B-07 Sample Number: A-31571 Depth: 10.0 - 12.0 ft Client: Project: Project No:Figure Sieve Size or Diam. (mm.) Finer (%) Spec.* (%) Out of Spec. (%) Pct. of Fines Clayey SAND with Gravel 1 3/4" 1/2" 3/8" #4 #10 #20 #40 #60 #80 #100 #200 100.0 89.6 82.0 75.2 61.3 49.7 40.6 30.7 24.3 21.1 19.2 14.7 Not Tested Not Tested Not Tested 19.3434 15.1112 4.3973 2.0456 0.4014 0.0792 SC Report No. A-31571-206 Report Date: 4-23-2025 F.M.=3.97 4-3-2025 Thompson Thrift Development Rawhide Ridge Development Reconnaissance Bozeman, Montana 25-009-001 PL=LL=PI= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= USCS=AASHTO= *(no specification provided) 15 Tested By: IR Checked By: Particle Size Distribution Report ASTM C117 & C136 PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.00010.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 17.1 29.9 10.0 14.3 13.5 15.26 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM C117 & C136)Material Description Atterberg Limits Coefficients Classification Test Remarks Sample Date:Location: B-09 Sample Number: A-31583COMP Depth: 3.6 - 22.0 ft Client: Project: Project No:Figure Sieve Size or Diam. (mm.) Finer (%) Spec.* (%) Out of Spec. (%) Pct. of Fines Clayey GRAVEL with Sand 1.5 1 3/4" 1/2" 3/8" #4 #10 #20 #40 #60 #80 #100 #200 100.0 91.3 82.9 69.1 64.4 53.0 43.0 35.0 28.7 24.5 21.9 20.3 15.2 Not Tested Not Tested Not Tested 24.1460 20.3932 7.3375 3.7650 0.4942 GC Report No. A-31583COMP-206 Report Date: 4-23-2025 F.M.=4.39 4/3-4/2025 Thompson Thrift Development Rawhide Ridge Development Reconnaissance Bozeman, Montana 25-009-001 PL=LL=PI= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= USCS=AASHTO= *(no specification provided) 16 Tested By: BC Checked By: LIQUID AND PLASTIC LIMITS TEST REPORT PLASTICITY INDEX0 10 20 30 40 50 60 LIQUID LIMIT 0 10 20 30 40 50 60 70 80 90 100 110 CL-ML C L o r O L C H o r O H ML or OL MH or OH Dashed line indicates the approximate upper limit boundary for natural soils 47 WATER CONTENT36.4 36.8 37.2 37.6 38 38.4 38.8 39.2 39.6 40 40.4 NUMBER OF BLOWS 5 6 7 8 9 10 20 25 30 40 MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS Project No.Client:Remarks: Project: Location: B-01 Sample Number: A-31528 Depth: 2.5 - 4.5 ft Figure Lean CLAY 38 22 16 99.1 96.2 CL 25-009-001 Thompson Thrift Development 17 Report No. A-31528-207 Report Date: 4-23-2025Rawhide Ridge Development Reconnaissance Bozeman, Montana Tested By: BC Checked By: LIQUID AND PLASTIC LIMITS TEST REPORT PLASTICITY INDEX0 10 20 30 40 50 60 LIQUID LIMIT 0 10 20 30 40 50 60 70 80 90 100 110 CL-ML C L o r O L C H o r O H ML or OL MH or OH Dashed line indicates the approximate upper limit boundary for natural soils 47 WATER CONTENT55.2 55.6 56 56.4 56.8 57.2 57.6 58 58.4 58.8 59.2 NUMBER OF BLOWS 5 6 7 8 9 10 20 25 30 40 MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS Project No.Client:Remarks: Project: Location: B-06 Sample Number: A-31560 Depth: 0.0 - 2.0 ft Figure TOPSOIL: Elastic SILT 57 31 26 98.7 86.6 MH 25-009-001 Thompson Thrift Development 18 Report No. A-31560-207 Report Date: 4-23-2025Rawhide Ridge Development Reconnaissance Bozeman, Montana Tested By: BS Checked By: LIQUID AND PLASTIC LIMITS TEST REPORT PLASTICITY INDEX0 10 20 30 40 50 60 LIQUID LIMIT 0 10 20 30 40 50 60 70 80 90 100 110 CL-ML C L o r O L C H o r O H ML or OL MH or OH Dashed line indicates the approximate upper limit boundary for natural soils 47 WATER CONTENT39.2 39.6 40 40.4 40.8 41.2 41.6 42 42.4 42.8 43.2 NUMBER OF BLOWS 5 6 7 8 9 10 20 25 30 40 MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS Project No.Client:Remarks: Project: Location: B-06 Sample Number: A-31561 Depth: 2.5 - 4.5 ft Figure Lean CLAY 41 19 22 98.8 96.4 CL 25-009-001 Thompson Thrift Development 19 Report No. A-31561-207 Report Date: 4-12-2025Rawhide Ridge Development Reconnaissance Bozeman, Montana Tested By: CRN Checked By: CONSOLIDATION TEST REPORT Percent Strain13.5 12.0 10.5 9.0 7.5 6.0 4.5 3.0 1.5 0.0 -1.5 Applied Pressure - psf 100 1000 10000 Natural Dry Dens.LL PI Sp. Gr. Overburden Pc Cc Cr Initial Void Saturation Moisture (pcf) (psf) (psf)Ratio 69.8 % 43.5 % 62.8 Not Not 2.7 180 2859 0.39 0.03 1.682 Lean CLAY CL 25-009-001 Thompson Thrift Development Rawhide Ridge Development Reconnaissance Bozeman, Montana Report No. A-31527-219 Report Date: 4-23-2025 20 MATERIAL DESCRIPTION USCS AASHTO Project No.Client:Remarks: Project: Location: B-01 Depth: 0.5 - 2.5 ft Sample Number: A-31527 Figure Tested By: CRN Checked By: CONSOLIDATION TEST REPORT Percent Strain5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 Applied Pressure - psf 100 1000 10000 Natural Dry Dens.LL PI Sp. Gr. Overburden Pc Cc Cr Initial Void Saturation Moisture (pcf) (psf) (psf)Ratio 93.2 % 22.8 % 101.5 41 22 2.7 500 2512 0.12 0.01 0.661 Lean CLAY CL A-7-6(22) 25-009-001 Thompson Thrift Development Rawhide Ridge Development Reconnaissance Bozeman, Montana Report No. A-31561-219 Report Date: 4-23-2025 21 MATERIAL DESCRIPTION USCS AASHTO Project No.Client:Remarks: Project: Location: B-06 Depth: 2.5 - 4.5 ft Sample Number: A-31561 Figure Sat. Moist Project No.25-009-001 Thompson Thrift Development Remarks: Project:Rawhide Ridge Report No. A-31527-216 Bozeman, Montana Location:B-01 Sample Depth (ft):0.5 - 2.5 22 Technician:CRN Reviewed By: Client: Figure CONSTANT VOLUME SWELL TEST REPORT AASHTOUSCS CL MATERIAL DESCRIPTION Lean CLAY Natural Dry Density (pcf)LL PI Swell (%)eo Sp. Gr. Cs Swell Pressure (psf) ~ 130 Overburden (psf) Pc (psf)Cc N/A 1.39583.0 42.9 70.2 N/A N/A 2.7 200 N/A N/A N/A 0 20 40 60 80 100 120 140 0.00 200.00 400.00 600.00 800.00 1000.00 1200.00 1400.00 1600.00 Swell Pressure (psf)Time (min) Sat. Moist Project No.25-009-001 Thompson Thrift Development Remarks: Project:Rawhide Ridge Report No. A-31561-216 Bozeman, Montana Location:B-06 Sample Depth (ft):2.5 - 4.5 23 Technician:CRN Reviewed By: Client: Figure CONSTANT VOLUME SWELL TEST REPORT AASHTO A-7-6 USCS CL MATERIAL DESCRIPTION Lean CLAY Natural Dry Density (pcf)LL PI Swell (%)eo Sp. Gr. Cs Swell Pressure (psf) ~ 260 Overburden (psf) Pc (psf)Cc N/A 0.68796.5 24.6 99.6 41 19 2.7 490 N/A N/A N/A 0 50 100 150 200 250 300 0.00 200.00 400.00 600.00 800.00 1000.00 1200.00 1400.00 1600.00 Swell Pressure (psf)Time (min) Date Sample Received: Sample Source: Technician: CRN Mass of Oven Tray Apparatus(g) Initial Mass of Tray & Soil Sample(g) Initial Mass of Dry Soil Sample(g) Percent Lost on Ignition (Percent Organic Carbon) FIGURE 24 Deviations From Standard (SOP - 237): 12.38% Final Mass of Tray & Soil Sample(g) Final Mass of Soil Sample(g) Test Data - After Burning Mass Loss on Ignition(g) 3994.3 791.9 111.9 REPORT OF LOSS ON IGNITION - SOIL Thomas, Dean & Hoskins, Inc. 1800 River Drive North Great Falls, Montana 59401 Project Number:25-009-001 Terre Haute, IN Project:Rawhide Ridge 5/6/2025 Sample Number:A-31534COMP Peter Klevberg, P.E. Laboratory Manager 4106.2 3202.4 Test Data - Before Burning Date of Test: Attn:----- Composite (0.0 - 1.2 ft) 5/5/2025 903.8 Client:Thompson Thrift Devel. Report Number:A-31534COMP-237 Address: 901 Wabash Ave Report Date: Date Sample Received: Sample Source: Technician: CRN Mass of Oven Tray Apparatus(g) Initial Mass of Tray & Soil Sample(g) Initial Mass of Dry Soil Sample(g) Percent Lost on Ignition (Percent Organic Carbon) FIGURE 25 Deviations From Standard (SOP - 237): 2.72% Final Mass of Tray & Soil Sample(g) Final Mass of Soil Sample(g) Test Data - After Burning Mass Loss on Ignition(g) 3612.7 411.1 11.5 REPORT OF LOSS ON IGNITION - SOIL Thomas, Dean & Hoskins, Inc. 1800 River Drive North Great Falls, Montana 59401 Project Number:25-009-001 Terre Haute, IN Project:Rawhide Ridge 5/6/2025 Sample Number:A-31534 Peter Klevberg, P.E. Laboratory Manager 3624.2 3201.6 Test Data - Before Burning Date of Test: Attn:----- B-02 (0.6 - 2.0 ft) 5/5/2025 422.6 Client:Thompson Thrift Devel. Report Number:A-31534-237 Address: 901 Wabash Ave Report Date: Date Sample Received: Sample Source: Technician: CRN Mass of Oven Tray Apparatus(g) Initial Mass of Tray & Soil Sample(g) Initial Mass of Dry Soil Sample(g) Percent Lost on Ignition (Percent Organic Carbon) FIGURE 26 Deviations From Standard (SOP - 237): 6.28% Final Mass of Tray & Soil Sample(g) Final Mass of Soil Sample(g) Test Data - After Burning Mass Loss on Ignition(g) 3590.7 280.6 18.8 REPORT OF LOSS ON IGNITION - SOIL Thomas, Dean & Hoskins, Inc. 1800 River Drive North Great Falls, Montana 59401 Project Number:25-009-001 Terre Haute, IN Project:Rawhide Ridge 5/6/2025 Sample Number:A-31582 Peter Klevberg, P.E. Laboratory Manager 3609.5 3310.1 Test Data - Before Burning Date of Test: Attn:----- B-09 (2.5 - 3.6 ft) 5/5/2025 299.4 Client:Thompson Thrift Devel. Report Number:A-31582-237 Address: 901 Wabash Ave Report Date: 1315 Cherry, Helena, MT 59601 (406)449-6282 SOIL ANALYSIS Client:TD&H Engineering Date Reported:5/ Sample ID:25-009 B-04 (0.5-2.0ft) Project ID:25-009-001 Chain of Custody #:88 Site ID:Rawhide Ridge Laboratory ID:07F205 Date / Time Sampled:25-Apr-25 Sample Matrix:Soil Date / Time Received:09-May-25 @ 16:15 Analytical Method Parameter Result Date/Time By Reference pH, s.u.8.3 12-May-25 @ 15:00 CE MT 232-04 Marble pH, s.u.8.0 13-May-25 @ 17:00 CE MT 232-04 Resistivity, kohm/cm 9.86 12-May-25 @ 16:15 CE MT 232-16 Comments: Results are As Delivered References: Methods for Chemical Analysis of Water and Wastes, US EPA, 600/4-79-020, March 1983. USDA Handbook 60 Method of Sampling and Testing MT232-04, Soil Corrosion Test (Montana Method). Method 43 - 4 : ASA Monograph 9 Part1 Reviewed by: Analyzed Page 2 of 5FIGURE 27 1315 Cherry, Helena, MT 59601 (406)449-6282 SOIL ANALYSIS Client:TD&H Engineering Date Reported:5/ Sample ID:25-009 B-04 (2.5-4.5ft) Project ID:25-009-001 Chain of Custody #:88 Site ID:Rawhide Ridge Laboratory ID:07F206 Date / Time Sampled:25-Apr-25 Sample Matrix:Soil Date / Time Received:09-May-25 @ 16:15 Analytical Method Parameter Result Date/Time By Reference pH, s.u.8.4 12-May-25 @ 15:00 CE MT 232-04 Marble pH, s.u.8.1 13-May-25 @ 17:00 CE MT 232-04 Resistivity, kohm/cm 10.2 12-May-25 @ 16:15 CE MT 232-16 Comments: Results are As Delivered References: Methods for Chemical Analysis of Water and Wastes, US EPA, 600/4-79-020, March 1983. USDA Handbook 60 Method of Sampling and Testing MT232-04, Soil Corrosion Test (Montana Method). Method 43 - 4 : ASA Monograph 9 Part1 Reviewed by: Analyzed Page 3 of 5FIGURE 28 1315 Cherry, Helena, MT 59601 (406)449-6282 SOIL ANALYSIS Client:TD&H Engineering Date Reported:5/ Sample ID:25-009 Composite Gravel Project ID:25-009-001 Chain of Custody #:88 Site ID:Rawhide Ridge Laboratory ID:07F207 Date / Time Sampled:25-Apr-25 Sample Matrix:Soil Date / Time Received:09-May-25 @ 16:15 Analytical Method Parameter Result Date/Time By Reference pH, s.u.8.0 12-May-25 @ 15:00 CE MT 232-04 Marble pH, s.u.8.0 13-May-25 @ 17:00 CE MT 232-04 Resistivity, kohm/cm 18.2 12-May-25 @ 16:15 CE MT 232-16 Comments: Results are As Delivered References: Methods for Chemical Analysis of Water and Wastes, US EPA, 600/4-79-020, March 1983. USDA Handbook 60 Method of Sampling and Testing MT232-04, Soil Corrosion Test (Montana Method). Method 43 - 4 : ASA Monograph 9 Part1 Reviewed by: Analyzed Page 4 of 5FIGURE 29 TD&H Engineering Consultants Great Falls, Kalispell, Bozeman, MT Spokane, WA; Lewiston, ID, Watford City, ND TD&H Engineering Consultants Great Falls, Kalispell, Bozeman, MT Spokane, WA; Lewiston, ID, Watford City, ND I.2 – Future Phases/Lot B Geotechnical Report & Memorandum Update 1143 Stoneridge Drive Suite 1, Bozeman, MT 59718 (406) 587-1115 Imegcorp.com July 30, 2025 Gallatin Center LP PO Box 906 Bozeman, MT 59771-0906 RE: Geotechnical Investigation Report Gallatin Center Subdivision Phase 6 Bozeman, Montana IMEG# 25002287.00 Per your request, IMEG has conducted a subsurface soils investigation for the above referenced property located in the Southeast Quarter of Section 35, Township 1 South, Range 5 East in Bozeman, Montana. The scope of services was to conduct a subsurface soils investigation and provide a soils investigation report for the proposed subdivision Lots B-G of the Gallatin Center Subdivision Phase 6. The report documents the subsurface conditions, soil properties, and provides foundation design and general earthwork recommendations. Proposed Construction A total of six subdivision lots are proposed for Phase 6 of the Gallatin Center Subdivision, and at this time the proposed lots do not have any associated development plans but are anticipated to consist of commercial development. It has been assumed that each structure will utilize a slab-on-grade with stem wall foundation. In determining the allowable bearing capacity and settlement estimates, it has been assumed that the foundation footings will not be subjected to unusual loading conditions such as eccentric loads. A footing is eccentrically loaded if the load transferred to the footing is not directed through the center of the footing. This creates a bending moment in the footing and results in a non-uniform load transfer to the underlying soil. If any of the foundation footings will be eccentrically loaded, please contact this office so we can appropriately revise our allowable bearing capacity and settlement estimates. Site Description The portion of the subject property covered in this report has an approximate area of 49.131 acres and is currently accessed from Baxter Lane, North 19th Ave., Rawhide Ridge, Max Ave., Cattail Street, and Thomas Drive. The subject property is currently undeveloped and relatively flat with a couple areas of Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 2 of 20 wetlands and streams. No other significant geological or topographical features were observed across the subject property. Subsurface Soil and Conditions On May 1, 2025 a member of the staff of IMEG visited the site to conduct a subsurface soils investigation. The subsurface soils investigation consisted of examining seventeen exploratory test pit excavations. The exploratory test pits were excavated with a Bobcat E88 tracked excavator provided and operated by Elevation Excavating. The test hole locations were chosen based on the location of the desired building sites, as depicted on the site plans sent to our office via email. The soil profiles revealed by the exploratory excavations were logged and visually classified according to ASTM D 2488, which utilizes the nomenclature of the Unified Soil Classification System (USCS). The relative density of each soil layer was estimated based on penetration tests performed with a static cone penetrometer, probing of the excavation sidewalls with a rock hammer and the overall stability of the excavation. Any evidence of seepage or other groundwater conditions were also noted. The locations of the exploratory test pits are shown on the included Test Pit Location Map. The subsurface soil conditions encountered in the test pits are described below and in more detail on the included Test Pit Logs. The following paragraphs briefly summarize the subsurface soils and conditions observed in the exploratory test pits excavated for the field investigation. The soil horizons are described as they were encountered in the test pit excavations, starting with the horizon nearest the surface and proceeding with each additional horizon encountered with depth. Please refer to the attached test pit logs for more detailed information. The first soil horizon encountered in each of the exploratory excavations was a Silty Clay Organic Soil of Low plasticity (OL). This material was dark brown to black in color, moist and very soft. This material was encountered to depths varying from 1.0 feet below grounds surface (bgs) to 3.0 feet bgs. Organic soils are highly compressible and are not suitable for foundation support. This material must be removed from beneath all foundation elements and in any area that will receive asphalt or concrete pavements. Underlying the Organic Soil in each of the excavations was a Lean Clay (CL). This material was grayish brown to gray in color and was moist to saturated. This material was encountered to depths varying from approximately 4.0 feet bgs to 14.5 feet bgs. This material was present at the end of excavation in test pits 2 through 5. Penetration tests performed on this material indicated that it was very soft to soft in consistency and not suitable for foundation support. This material must be removed from beneath all foundation elements (footings and Slabs). Underlying the Lean Clay in each of the remaining excavations was a Poorly Graded Gravel with Sand and Cobbles (GP). This material was grayish brown in color, moist, and medium dense to dense in consistency. This material was encountered to the end of each excavation at depths varying from approximately 6.5 feet bgs to 15.0 feet bgs. Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 3 of 20 Based on the subsurface investigation, it is recommended that the loads from the proposed structures be transmitted to the Poorly Graded Gravel with Sand and Cobbles or to a structural fill pad overlying this material. It is required that the excavation for any structure be observed by a licensed geotechnical engineer to verify that the proper foundation subgrade material has been reached prior to the forming or casting of any foundation elements or the placement and compaction of any required structural fill. Groundwater Groundwater and/or seepage were encountered within each exploratory excavation and the groundwater elevation has been routinely monitored by WWC Engineering. As of the writing of this report, the peak groundwater elevations in the monitoring wells have varied from 1.38 feet bgs (MW-1) to 5.69 feet bgs (MW-5) based on monitoring data received from WWC Engineering. Given the shallow depth of groundwater across the site, basement and crawl space foundations are not feasible. It is recommended that slab-on-grade with stem wall foundations be utilized for any foundation constructed on this site. Natural Resources Conservation Service Soil Survey The Natural Resources Conservation Service (NRCS) Web Soil Survey (WSS) provides soil data and information produced by the National Cooperative Soil Survey. The NRCS has determined the physical characteristics and engineering properties, among other data, of near surface soils across the United States. These data are reviewed against our observations and analysis of the subsurface soils encountered during the field investigation to determine if a correlation is present. If a strong correlation is determined, it is likely that other engineering properties or characteristics described by the NRCS regarding the soils present on the subject property are accurate as well. It should be noted that the NRCS typically only describes the soils located within 5 feet of the surface. Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 4 of 20 Figure 1. NRCS Soils Map NRCS Soil Survey information of the area was taken from the NRCS WSS, Version 2.0. For more information, please visit the NRCS Web Soil Survey on the World Wide Web, at http://websoilsurvey.nrcs.usda.gov/app/. The subject property location is shown as a black triangle on Figure 1 above. The NRCS Soils Survey identifies three soil types across the desired building areas. The soil types are 64B – Straw Loam, 57B – Turner Loam, and 537A – Lamoose Silt Loam. The NRCS describes these soil types as alluvium and loamy alluvium. The soils encountered in the exploratory excavations correlate well with the NRCS mapping. Alluvial soils were encountered in each of the exploratory excavations. Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 5 of 20 Geologic Setting The following paragraphs discuss the geologic setting in the direct vicinity of the subject property. The geologic setting is determined from a review of surface geology maps and reports published by the United States Geological Survey and others that contain the subject property. This information is especially helpful in determining any geologic hazards that may be present in the immediate area (such as landslide deposits) and what types of soil and rock may be present in the area. Additional information regarding the parent material and depositional environment of a given soil type can also sometimes be obtained or inferred from these maps and reports. Figure 2. Geologic Map The local surface geology in the direct vicinity of the subject property was determined from the USGS Geologic Map of the Bozeman 30’ x 60’ Quadrangle, Southwestern Montana. The subject property location Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 6 of 20 is shown as a black triangle on Figure 2 above. The USGS Geological Map identifies one surface geology formation across the desired building site. This formation is Qabo – Braid Plain Alluvium. Qabo “Braid plain alluvium, older than Qab (Pleistocene)—Rounded to well-rounded, dominantly cobble gravel with clasts as large as boulders, and sand, silt, and clay; mostly composed of clasts of Archean metamorphic rock, and dark-colored volcanic rock, with subordinate Paleozoic limestone and Proterozoic Belt rocks. Clast lithologies in general order of decreasing abundance include Precambrian metamorphic rocks, mafic volcanic rocks, dacite(?) porphyry, quartzite, sandstone, limestone, and chert. A well in this unit indicates a thickness of 9 m (30 ft) of alluvium overlying Tertiary deposits.” Seismicity The USGS provides seismic design parameters for the design of buildings and bridges across the United States. These parameters are based on the 2015 National Earthquake Hazards Reduction Program (NEHRP) Recommended Seismic Provisions. The primary intent of the NEHRP Recommended Seismic Provisions is to prevent, for typical buildings and structures, serious injury and life loss caused by damage from earthquake ground shaking. The following seismic design parameters were determined for the subject property using the USGS Seismic Design Application: Approximate site Location: Latitude = 45.702° N Longitude = 111.068° W Maximum Considered Earthquake (MCE) Spectral Response Acceleration Parameters: Short Period (SS) = 0.706g 1-Second Period (S1) = 0.219g Site Coefficients and Adjusted MCE Spectral Response Acceleration Parameters: SMS = 0.872g SM1 = 0.474g Design Spectral Response Acceleration Parameters: SDS = 0.581g SD1 = 0.316g The seismic site class for this project is D. Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 7 of 20 Regional Faults The USGS and Montana Bureau of Mines and Geology (MBMG) have compiled a map of Quaternary Class A faults and earthquake epicenters in western Montana; a Class A fault is one that is associated with at least one large magnitude earthquake within the last 1.6 million years. A review of this map indicated that there are four Class A faults in the general Bozeman area and numerous earthquake epicenters. The faults mapped near the subject property are the Bridger Fault (691), the Gallatin Range Fault (692), the Central Park Fault (670) and the Elk Creek Fault (694). The subject property location is shown as a black triangle on Figure 3 Below. Figure 3. Quaternary Class A Fault Map Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 8 of 20 Liquefaction In general terms, liquefaction is defined as the condition when saturated, loose, fine sand-type soils lose their support capabilities due to the development of excessive pore water pressure, which can develop during a seismic event. Loose silty sandy soils, if located below the groundwater table, have the potential to liquefy during a major seismic event. Our subsurface investigation did not encounter any loose sand or silt horizons within the depth of excavation that will be located within the water table, and, it is our opinion that the potential for differential settlement resulting from liquefaction during a moderate seismic event is low. Foundation Recommendations Based on the subsurface soils encountered in the exploratory excavations, it will be acceptable to utilize slab-on-grade with stem wall foundations, provided the recommendations made in this report are properly implemented. Please find the following as general recommendations for all foundation elements: • In order to keep the footing out of the active frost zone it is recommended that the bottom of all footing elevations be a minimum of 48 inches below finished grade. • All foundation footings are to bear on the Poorly Graded Gravel with Sand and Cobbles or on a structural fill pad overlying this material. All foundation footings shall be dimensioned for an allowable bearing capacity of 2,500 pounds per square foot (psf). • Due to the very soft consistency and saturation of the Lean Clay soils during seasonal ground water peaks, it is recommended the entire foundation footprint continue down to native gravel and imported structural fill be utilized to achieve desired foundation elevations. • It would also be acceptable to utilize a deep foundation such as rammed aggregated piers that are bearing on and/or within the Poorly Graded Gravel with Sand and Cobbles. • All site grading and drainage recommendations must be properly implemented. • The exposed subgrade must remain in a dry condition throughout construction of the foundation elements. • If construction takes place during the colder months of the year, the subgrade must be protected from freezing throughout construction. This may require the use of insulating blankets and/or ground heaters. Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 9 of 20 Allowable Bearing Capacity The bearing capacity of a soil is defined as the ultimate pressure per unit area by the foundation that can be supported by the soil in excess of the pressure caused by the surrounding soil at the footing level. Bearing capacity is determined by the physical and chemical properties of the soil located beneath the proposed structures footings. It is recommended that the loads from the proposed structure be transmitted to the Poorly Graded Gravel with Sand and Cobbles or on to a structural fill pad overlying this material. For this scenario it is recommended that an allowable bearing capacity of 2,500 pounds per square foot be used to dimension all foundation footings, if conventional over excavation methods are utilized. These allowable bearing capacities may be increased by one third for short term loading conditions such as those from wind or seismic forces. Settlement While the soil at the site may be able to physically support the footings, it is also important to analyze the possible settlement of the structure. In many cases, settlement determines the allowable bearing capacity. When a soil deposit is loaded by a structure, deformations within the soil deposit will occur. The total vertical deformation of the soil at the surface is called total settlement. Total settlement is made up of two components: elastic settlement and consolidation settlement. Elastic settlement is the result of soil particles rearranging themselves into a denser configuration due to a load being imposed on them and usually occurs during the construction process and shortly after. Consolidation settlement occurs more slowly and over time as water within the pore spaces of a soil are forced out and the soil compresses as the stress from the load is transferred from the water molecules to the soil particles. Consolidation settlement is more of a concern with fine-grained soils with low permeability and high in-situ moisture contents. The degree of settlement is a function of the type of bearing material, the bearing pressure of the foundation elements, local groundwater conditions, and in some cases determines the allowable bearing capacity for a structures’ footings. In addition to analyzing total settlement, the potential for differential settlement must also be considered. Differential settlement occurs in soils that are not homogeneous over the length of the foundation or in situations where the foundation rests on cut and fill surfaces. If the foundation rests on structural fill overlaying properly prepared soils with rock, differential settlement is expected to be well within tolerable limits. Areas that have significantly more fill under the foundation footings (four feet of more) create greater potential for differential settlement. In these cases the structural fill must be installed properly and tested frequently. Compaction efforts and structural fill consistence are vital in minimizing differential settlement. For this project it is not anticipated that significant quantities of structural fill will be required. For this project, total settlement is expected to consist of elastic settlement. Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 10 of 20 A settlement analysis based on conservative soil parameter estimates, the recommended allowable bearing capacity, and the assumption that all recommendations made in this report are properly adhered to, indicates the total and differential settlement are expected to be ¾-inch or less. Structures of the type assumed can generally tolerate this amount of movement, however, these values should be checked by a structural engineer to verify that they are acceptable. Please note that the settlement estimates are based on loads originating from the proposed structure. If additional loads are introduced, such as the placement of large quantities of fill, our office should be contacted to re-evaluate the settlement estimates. Lateral Pressures Lateral pressures imposed upon foundation and retaining walls due to wind, seismic forces, and earth pressures may be resisted by the development of passive earth pressures and/or frictional resistance between the base of the footings and the supporting soils. If a foundation or retaining wall is restrained from moving, the lateral earth pressure exerted on the wall is called the at-rest earth pressure. If a foundation or retaining wall is allowed to tilt away from the retained soil, the lateral earth pressure exerted on the wall is called the active earth pressure. Passive earth pressure is the resistance pressure the foundation or retaining wall develops due to the wall being pushed laterally into the earth on the opposite side of the retained soil. Each of these pressures is proportional to the distance below the earth surface, the unit weight of the soil, and the shear strength properties of the soil. It is recommended that all foundation and retaining walls be backfilled with well-draining granular material. Well-draining granular backfill has a more predictable behavior in terms of the lateral earth pressure exerted on the foundation or retaining wall and will not generate expansive related forces. If backfill containing significant quantities of clayey material is used, the seepage of water into the backfill could potentially generate horizontal swelling pressures well above at-rest values. Additionally, seepage into a clayey backfill material will also cause significant hydrostatic pressures to build up against the foundation wall due to the low permeability of clay soils and will make the backfill susceptible to frost action. Subsurface walls that are restrained from moving at the top are recommended to be designed for an equivalent fluid pressure of 70 pounds per cubic foot (pcf) (at-rest pressure); the equivalent fluid pressure is the product of the retained soils unit weight and its coefficient of active or at-rest earth pressure. Any subsurface walls that are allowed to move away from the restrained soil, such as cantilevered retaining walls, are recommended to be designed for an equivalent fluid pressure of 50 pcf (active pressure). For passive pressures, an equivalent fluid pressure of 250 pcf is recommended, and the coefficient of friction between the cast-in-place concrete and the Poorly Graded Gravel with Sand and Cobbles and/or structural fill is 0.5. These recommended values were calculated assuming a near horizontal backfill and that the onsite soils will be used as foundation wall backfill provided, they are not to moist and are able to be properly compacted. It is also assumed that the backfill will be compacted as recommended in this report. Also, Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 11 of 20 please note that these design pressures do not include a factor of safety and are for static conditions, they do not account for additional forces that may be induced by seismic loading. Subgrade Preparation and Structural Fill In general, the excavation for each structure must be level and uniform and continue down through any organics and lean clay to the Poorly Graded Gravel with Sand and Cobbles; please note that it is recommended the entire building footprint continue down to native gravel. If any soft spots or boulders are encountered, they will need to be removed and backfilled with structural fill. The excavation width must extend a minimum of one footing width from the outside edges of the footings or to a distance equal to ½ the height of the required structural fill. For example, if 4 feet of structural fill is required under the foundation footings, the excavation width must extend out a minimum distance of 2 feet from the outside edges of the foundation footings. Once the excavation is complete, the native subgrade shall be compacted to an unyielding condition with a large smooth drum roller. Any areas of the excavation that are observed to be rutting or pumping shall be sub excavated and replaced with structural fill. Following compaction of the native subgrade, any required structural fill can be placed and compacted or the foundation footings may be formed and cast. Structural fill is defined as all fill that will ultimately be subjected to structural loadings, such as those imposed by footings, floor slabs, pavements, etc. None of the soils encountered in the exploratory excavations are suitable for reuse as structural fill, and structural fill will need to be imported for this project. Imported structural fill is recommended to be a well graded gravel with sand that contains less than 15 percent of material that will pass a No. 200 sieve and that has a maximum particle size of 3.0 inches. Also, the fraction of material passing the No. 40 sieve shall have a liquid limit not exceeding 25 and a plasticity index not exceeding 6. The gravel and sand particles also need to be made up of durable rock materials that will not degrade due to moisture or the compaction effort; i.e. no shale or mudstone fragments should be present. It would also be acceptable to utilize a ¾-inch crushed washed rock as structural fill in areas of standing water to provide a capillary break. Structural fill must be placed in lifts no greater than 12-inches (uncompacted thickness) and be uniformly compacted to a minimum of 97 percent of its maximum dry density, as determined by ASTM D698. If ¾- inch crushed washed rock is utilized it is recommended to be compacted to an unyielding condition. Typically, the structural fill must be moisture conditioned to within + 2 percent of the materials optimum moisture content to achieve the required density. It is recommended that the structural fill be compacted with a large vibrating smooth drum roller. Please note that if a moisture-density relationship test (commonly referred to as a proctor) needs to be performed for a proposed structural fill material to determine its maximum dry density in accordance with ASTM D698, a sample of the material must be delivered to this office a minimum of three full working days prior to density testing being needed. Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 12 of 20 At no time should surface water runoff be allowed to flow into and accumulate within the excavation for the foundation elements. If necessary, a swale or berm should be temporarily constructed to reroute all surface water runoff away from the excavation. Excavation should not proceed during large precipitation events. If any of the foundation footings are found to be located on a test pit, the area will need to be excavated down to the full depth of the test pit and structural fill be placed and compacted in controlled lifts as described in this report to bring the area back up to the desired grade. It would also be acceptable to utilize Rammed Aggregate piers (RAP) bearing on and/or within the poorly graded gravel with sand and cobbles as an alternative to the complete removal and replacement of the soils above the poorly graded gravel with sand and cobbles. This system is a specialized design that is proprietary to the drilling and installation method, and it is recommended that a licensed RAP contractor be contacted for the design and installation of this service. The RAP contractor should provide a RAP layout and detailed design calculations that are sealed by a professional engineer licensed in the State of Montana. The design parameters should be verified by a full-scale modulus test performed in the field. RAPs are installed by drilling a hole of a specified depth and diameter and constructing rock columns comprised of very dense, highly compacted aggregate. Ramming of thin lifts takes place with a high-energy beveled tamper that densifies the aggregate and forces it laterally into the sidewalls of the hole. This action increases the lateral stress in the surrounding soil, thereby providing a stabilized composite soil mass. The result of the RAP installation is a significant strengthening and stiffening of the subsurface soils that would then support conventional footings. This allows for improved performance of the clay/silt soils without requiring it to be completely removed thus potentially reducing the overall cost of the project. RAPs can be installed in a variety of ground water conditions using varying methods and may or may not require some level of site dewatering during construction. There is a local contractor located in Billings that designs and installs rammed aggregate piers. The company is Specialty Foundation Systems (SFS). It is suggested that they be contacted regarding the design and installation of rammed aggregate piers. SFS can be contacted at (406)-530-5424. Foundation Wall Backfill Approved backfill material should be placed and compacted between the foundation wall and the edge of the excavation. Structural fill is recommended as foundation wall backfill in all areas that will support concrete slabs-on-grade or asphalt paving improvements. The Lean Clay is suitable for foundation wall backfill in areas that will not have concrete or asphalt pavements, provided it is not to moist and is able to be compacted. If Lean Clay is to moist and/or unable to be compacted properly, it will need to be moisture conditioned to + 2 percent of its optimum moisture content or a suitable backfill material will need to be imported. The foundation wall backfill shall be placed in uniform lifts and be compacted to a minimum of 95 percent of the material’s maximum dry density, as determined by ASTM D698. The foundation wall backfill will Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 13 of 20 need to be compacted with either walk behind compaction equipment or hand operated compaction equipment in order to avoid damaging the foundation walls. If walk behind compaction equipment is used lifts should not exceed 8-inches (loose thickness) and if hand operated compaction equipment is used lifts should not exceed 4-inches (loose thickness). Site Grading Surface water should not be allowed to accumulate and infiltrate the soil near the foundation. Proper site grading will ensure surface water runoff is directed away from the foundation elements and will aid in the mitigation of excessive settlement. Please find the following as general site grading recommendations: • Finished grade must slope away from the building a minimum of 5 percent within the first 10 feet, in order to quickly drain ground surface and roof runoff away from the foundation walls. Please note that in order to maintain this slope; it is imperative that any backfill placed against the foundation walls be compacted properly. If the backfill is not compacted properly, it will settle and positive drainage away from the structure will not be maintained. • Permanent sprinkler heads for lawn care should be located a sufficient distance from the structure to prevent water from draining toward the foundation or saturating the soils adjacent to the foundation. • Rain gutter down spouts are to be placed in such a manner that surface water runoff drains away from the structure. • All roads, walkways, and architectural land features must properly drain away from all structures. Special attention should be made during the design of these features to not create any drainage obstructions that may direct water towards or trap water near the foundation. Interior Slabs-on-Grade Due to the very soft consistency and saturation of the Lean Clay during peak groundwater season, it is recommended that the entire footprint for each structure continue down to the native poorly graded gravel and utilize structural placed and compacted in controlled lifts to achieve the desired building elevations. The native subgrade then needs to be compacted to a minimum of 95 percent of its maximum dry density, as determined by ASTM D698. Following compaction of the native subgrade, structural fill be placed and compacted to within 6-inches of the desired bottom of slab elevation. For all interior concrete slabs-on-grade, preventative measures must be taken to stop moisture from migrating upwards through the slab. Moisture that migrates upwards through the concrete slab can damage floor coverings such as carpet, hardwood and vinyl, in addition to causing musty odors and mildew growth. Moisture barriers will need to be installed to prevent water vapor migration and capillary rise through the concrete slab. Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 14 of 20 Capillarity is the result of the liquid property known as surface tension, which arises from an imbalance of cohesive and adhesive forces near the interface between different materials. With regards to soils, surface tension arises at the interface between groundwater and the mineral grains and air of a soil. The height of capillary rise within a given soil is controlled by the size of the pores between the soil particles and not the size of the soil particles directly. Soils that have small pore spaces experience a higher magnitude of capillary rise than soils with large pore spaces. Typically, soils composed of smaller particles (such as silt and clay) have smaller pore spaces. In order to prevent capillary rise through the concrete slab-on-grade it is recommended that 6 inches of ¾- inch washed rock (containing less than 10 percent fines) be placed and compacted once the excavation for the slab is complete. The washed rock has large pore spaces between soil particles and will act as a capillary break, preventing groundwater from migrating upwards towards the bottom of the slab. Water vapor is currently understood to act in accordance with the observed physical laws of gases, which state that the water vapor will travel from an area of higher concentration to that of a lower concentration until equilibrium is achieved. Because Earth contains large quantities of liquid water, water vapor is ubiquitous in Earth’s atmosphere, and, as a result, also in soils located above the water table (referred to as the vadose zone). Typically, the concentration of water vapor in the vadose zone is greater than that inside the residence. This concentration difference may result in an upward migration of water vapor from the vadose zone through the concrete slab-on-grade and into the building. In order to prevent this upward migration of water vapor through the slab, it is recommended that a 15-mil extruded polyolefin plastic that complies with ASTM E1745 (such as a Stego Wrap 15-mil Vapor Barrier) be installed if moisture sensitive floor coverings will be utilized. The vapor barrier should be pulled up at the sides and secured to the foundation wall or footing. Care must be taken during and after the installation of the vapor barrier to avoid puncturing the material, and all joints are to be sealed per the manufacture’s recommendations. Once the excavation for any interior slabs-on-grade is completed as described in the first paragraph of this section, and the ¾ inch washed rock and moisture barriers have been properly installed, it will be acceptable to form and cast the steel reinforced concrete slab. It is recommended that interior concrete slabs-on-grade have a minimum thickness of 4 inches, provide all slab reinforcement is designed by a licensed structural engineer. Exterior Slabs-on-Grade For exterior areas to be paved with concrete slabs such as sidewalks and/or patios, it is recommended that, at a minimum, the organic soil be removed. The subgrade then needs to be compacted to a minimum of 95 percent of its maximum dry density, as determined by ASTM D698. If the native subgrade cannot be compacted, it may be necessary to install a thicker structural fill section that is mechanically reinforced with Tensar HX5.5 geogrid and a layer of geotextile fabric such as a Mirafi 500X. For non-vehicular traffic Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 15 of 20 areas, a minimum of 6 inches of ¾-inch minus rock needs to be placed, and 4 inches of 4000 pounds per square inch (psi) concrete placed over the ¾-inch minus rock. For areas with vehicular traffic, a minimum of 9 inches of ¾-inch minus rock should be placed, followed by 6 inches of 4000 psi concrete. Exterior slabs that will be located adjacent to the foundation walls need to slope away from the structure at a minimum grade of 2 percent and should not be physically connected to the foundation walls. If they are connected, any movement of the exterior slab will be transmitted to the foundation wall, which may result in damage to the structure. Asphalt Paving Improvements The following recommendations are intended for the interior roads and parking lots only. The pavement design for the extensions and/or improvements of Cattail Street, Baxter Lane, North 19th Avenue, and Thomas Drive/ N. 27th Ave. were not included in the scope of this report. For the pavement design it has been assumed that traffic for the interior roads and parking lots will be limited to standard passenger type vehicles with occasional truck traffic such as deliveries and/or trash collection. According to a recent traffic study conducted by Abelin Traffic Services (May 2025) the estimated traffic after subdivision build-out is expected to be approximately 11,548 trips per day. The portion of the subdivision covered in this report is expected to account for approximately 7.5 percent of the estimated trips. Based on this information we have estimated the maximum anticipated number of Equivalent Single Axle Load’s (ESALs) of 130,000 over a 20-year design life of the pavement. It is anticipated that the Lean Clay will be the subgrade material present beneath the interior roads and parking lots. A Standard Proctor was performed in accordance with ASTM D698 along with a California Bearing Ratio (CBR) was performed in accordance with ASTM D1883 on the bulk samples of the Lean Clay (CL) that were collected during the field investigation. The maximum dry density (Proctor) of this material was found to be 95.7 pcf and 97.4 pcf with an optimum moisture content of 22 percent and 23.1 percent. The CBR for this material was found to be 5 percent. However, the in-place moisture content of this material varied across the site that were outside the optimum range to achieve maximum compaction, a reduced CBR value of two percent was utilized in our analysis. This reduction also accounts for Montana’s climate which has seasonal low temperatures that subjects the pavement to freeze thaw cycles, as well as to account for any inconsistencies in the subsurface soils and conditions that may be encountered during construction. The proposed pavement cross section is based on the AASHTO Guide for Design of Pavement Structures (1993) and the assumptions listed above. Based on our analysis the following pavement cross section is recommended for the proposed interior roads and parking areas: Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 16 of 20 Material Type Material Thickness (inches) Asphalt Surface 3 1 Inch Minus Road Mix Base Course 6 4-inch Minus Subbase Course 12 Table 1. Recommended Pavement Section In general, the excavation for the parking areas must continue down through any organics or to the proposed subgrade elevation, whichever is deeper. Once the excavation is complete, the native subgrade shall be compacted to a minimum of 95 percent of its maximum dry density, as determined by ASTM D698. If any soft spots (areas that cannot be compacted properly) are encountered during compaction of the native subgrade they will need to be sub-excavated and re-placed with structural fill, which is recommended to consist of a Well Graded Gravel with Sand with a maximum particle size of 6 inches. The structural fill, if needed, shall be placed in a maximum of 12-inch-thck lifts and be compacted to a minimum of 95 percent of its maximum dry density, as determined by ASTM D698. It may also be necessary to install a layer of Tensar HX5.5 geogrid in these areas prior to placing the sub-base section. Following compaction of the native subgrade it is recommended that a layer of separation geotextile (such as a Miari 500X) be installed to prevent the Lean Clay from migrating up into the subbase course during compaction. Next a minimum of 12 inches of subbase course shall be placed and compacted. Once the subbase course has been installed, a minimum of 6 inches of base course shall be placed and compacted. Both gravel courses shall be compacted to a minimum of 95 percent of their maximum dry density, as determined by ASTM D698. If asphalt paving is to be placed on foundation wall backfill, the backfill must be compacted to 95 percent of its maximum dry density, as determined by ASTM D698. It is recommended the backfill be placed in uniform lifts and be compacted to an unyielding condition. Please note that construction traffic was not included in the pavement design analysis. If the pavement section gravels are to be utilized during construction for access roads, staging areas, and deliveries, the gavel sections shall be re-evaluated to account for the additional construction traffic loads. Underground Utilities Three corrosion tests were performed on the lean clay, with samples collected in TP-5, TP-8, and TP-14. The soil corrosion test results are summarized in the table below. Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 17 of 20 Summary of Corrosion Tests Using the corrosion test results and the Ductile Iron Pipe Research Association’s (DIPRA) “Design Decision Model (DDM) Two-Dimensional Matrix” the samples received likelihood scores of 35.5, 21.5, and 13.5 and a consequence score of 11. Table 1 provided by the DIPRA DDM indicates the results vary from just a shop coat to V-Bio wrap with joint bonds. If DIP is used the corrosion test results shall be reviewed by the ductile iron pipe representative to determine appropriate levels of corrosion protection. The DIPRA DDM indicates the corrosivity of lean clay to vary from minimal to mildly corrosive, we recommend specifying non-corrosive materials when applicable. A copy of the lab report and the DIPRA DDM can be found at the end of this report. It is recommended that ¾-inch minus gravel be used as a bedding material, where bedding material is defined as all material located within 6 inches of the utility pipe(s). The bedding material should be thoroughly compacted around all utility pipes. Trench backfill shall be compacted to a minimum of 95 percent of its maximum dry density in paved or landscaped areas and a minimum of 97 percent of its maximum dry density beneath foundation footings. Backfilling around and above utilities shall meet the requirements of Montana Public Works Standard Specifications. Conclusions The soils present at the site will be adequate to support the proposed structures, provided the recommendations made in this report are properly followed. Please find the following recommendations as particularly crucial: • In order to keep the footing out of the active frost zone it is recommended that the bottom of all footing elevations be a minimum of 48 inches below finished grade. • All foundation footings are to bear on the Poorly Graded Gravel with Sand and Cobbles or on a structural fill pad overlying this material. All foundation footings shall be dimensioned for an allowable bearing capacity of 2,500 pounds per square foot (psf). • Due to the very soft consistency and saturation of the Lean Clay soils during seasonal ground water peaks, it is recommended the entire foundation footprint continue down to native gravel and imported structural fill be utilized to achieve desired foundation elevations. Sample Resistivity (ohm-cm) Chlorides (ppm) Moisture Content% Ground Water Influence PH Sulfide Ions (ppm) Redox Potential (mv) Bi- Metallic TP-5 1010 9 24.4 Yes 7.8 NT 334 Yes TP-8 3420 61 17.9 Yes 7.8 NT 216 Yes TP-14 5560 9 24.1 Yes 8.2 NT 266 Yes Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 18 of 20 • It would also be acceptable to utilize a deep foundation such as rammed aggregated piers that are bearing on and/or within the Poorly Graded Gravel with Sand and Cobbles. • All site grading and drainage recommendations must be properly implemented. • The exposed subgrade must remain in a dry condition throughout construction of the foundation elements. • If construction takes place during the colder months of the year, the subgrade must be protected from freezing throughout construction. This may require the use of insulating blankets and/or ground heaters. Construction Administration The foundation is a vital element of a structure; it transfers all of the structure’s dead and live loads to the native soil. It is imperative that the recommendations made in this report are properly adhered to. A representative from IMEG shall observe the construction of any foundation or drainage elements recommended in this report and should verify proper compaction has been achieved in all structural fill lifts. The recommendations made in this report are contingent upon our involvement. If the soils encountered during the excavation differ than those described in this report or any unusual conditions are encountered, our office should be contacted immediately to examine the conditions and re-evaluate our recommendations. If construction and site grading take place during cold weather, it is recommended that approved winter construction practices be observed. All snow and ice shall be removed from cut and fill areas prior to site grading taking place. No fill should be placed on soils that are frozen or contain frozen material. No frozen soils can be used as fill under any circumstances. Please note that not following the preceding recommendations may potentially result in foundation settlement issues in the spring when the frost thaws and the snow melts. Additionally, concrete should not be placed on frozen soils and should meet the temperature requirements of ASTM C 94. Any concrete placed during cold weather conditions shall be protected from freezing until the necessary compressive strength has been attained. Once the footings are placed, frost shall not be permitted to extend below the foundation footings, as this could heave and crack the foundation footings and/or foundation walls. It is the responsibility of the contractor to provide a safe working environment with regards to excavations on the site. All excavations should be sloped or shored in the interest of safety and in accordance with local and federal regulations, including the excavation and trench safety standards provided by the Occupational Safety and Health Administration (OSHA). According to OSHA regulations (29 CFR 1926 Subpart P Appendix A) the subsurface soils encountered in the test pit excavations can be generally classified as Type C. For Type C soils, OSHA regulations state that cut slopes shall be no steeper than 1.5H:1V for excavations less than 20 feet deep. A trench box may also be used, provided the system extends at least 18 inches above the top of the trench walls. Please understand the preceding OSHA soil Gallatin Center LP – Geotechnical Investigation, Lots B-G, Gallatin Center Sub. Phase 6, Bozeman MT July 30, 2025 Page 19 of 20 classification is provided for planning purposes only and the actual classification of the onsite soils will need to be determined by the contractor onsite during excavation. Report Limitations and Guidelines for Use This report was prepared to be used exclusively by Gallatin Center LP for commercial improvements to be constructed on a Lots B-G of the Gallatin Center Subdivision Phase 6, located in the Southeast Quarter of Section 35, Township 1 South, Range 5 East in Bozeman, Montana. All of the work was performed in accordance with generally accepted principles and practices used by geotechnical engineers and geologists practicing in this or similar localities. This report should not be used by anyone it was not prepared for, or for uses it was not intended for. Field investigations and preparation of this report was conducted in accordance with a specific set of requirements set out by the client, which may not satisfy the requirements of others. This report should not be used for nearby sites or for structures on the same site that differ from the structures that were proposed at the time this report was prepared. Any changes in the structures (type, orientation, size, elevation, etc.) proposed for this site must be discussed with our company for this report to be valid. The recommendations made in this report are based upon data obtained from test pits excavated at the locations indicated on the attached Test Pit Location Map. It is not uncommon that variations will occur between these locations, the nature and extent of which will not become evident until additional exploration or construction is conducted. These variations may result in additional construction costs, and it is suggested that a contingency be provided for this purpose. If the soils encountered during the excavation differ than those described in this report or any unusual conditions are encountered, our office should be contacted immediately to examine the conditions and re- evaluate our recommendations and provide a written response. This report is valid as a complete document only. No portion of this report should be transmitted to other parties as an incomplete document. Misinterpretation of portions of this report (i.e. test pit logs) is possible when this information is transmitted to others without the supporting information presented in other portions of the report. The scope of our investigation did not include an environmental assessment for determining the presence or absence of hazardous or toxic materials on the site. If information regarding the potential presence of hazardous materials on the site is desired, please contact us to discuss your options for obtaining this information. If any questions arise with regards to any aspects of this report, please contact us at your convenience to avoid misinterpretation. Costly mistakes due to misinterpretation of geotechnical reports can usually be avoided by a quick phone call. OL CL GP 2.3 4.8 6.5 0 TO 2.3 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 2.3 TO 4.8 FEET: LEAN CLAY; (CL); grayish brown to brown; moist; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand; approximately 90 percent clayey fines. 4.8 TO 6.5 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark brown to grayish brown; moist; medium dense to dense; approximately 60 percent subrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 10percent clayey fines. Bottom of test pit at 6.5 feet. NOTES MW-1 GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 6.50 ft Seepage at 2.3' AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 1 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL 2.0 9.0 0 TO 2 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 2 TO 9 FEET: LEAN CLAY; (CL); grayish brown to brown; moist to saturated; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand;approximately 90 percent clayey fines. Bottom of test pit at 9.0 feet. NOTES MW-2, CBR GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 8.00 ft Seepage at 5' & 6' AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 7.5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 2 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL 1.0 9.0 0 TO 1 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 1 TO 9 FEET: LEAN CLAY; (CL); grayish brown to brown; moist to saturated; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand; approximately 90 percent clayey fines. Bottom of test pit at 9.0 feet. NOTES MW-3 GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 9.00 ft Seepage at 7' AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 7.5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 3 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL 2.5 9.0 0 TO 2.5 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 2.5 TO 9 FEET: LEAN CLAY; (CL); grayish brown to brown; moist to saturated; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand;approximately 90 percent clayey fines. Bottom of test pit at 9.0 feet. NOTES MW-4 GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 9.00 ft Seepage at 6' AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 7.5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 4 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL 2.0 9.0 0 TO 2 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 2 TO 9 FEET: LEAN CLAY; (CL); grayish brown to brown; moist to saturated; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand;approximately 90 percent clayey fines. Bottom of test pit at 9.0 feet. NOTES MW-5, CT GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 9.00 ft Seepage at 7.5' AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 7.5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 5 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL GP 1.3 4.0 7.0 0 TO 1.33 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 1.33 TO 4 FEET: LEAN CLAY; (CL); grayish brown to brown; moist to saturated; mediumplasticity; soft to very soft; approximately 10 percent fine to coarse grain sand;approximately 90 percent clayey fines; Soil Gleying observed at ~ 3.5 feet. 4 TO 7 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark brown to grayish brown; moist to wet; medium dense to dense; approximately 60 percent subrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 10 percent clayey fines. Bottom of test pit at 7.0 feet. NOTES MW-6 GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 6.00 ft AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 6 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL GP 2.5 5.0 7.8 0 TO 2.5 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 2.5 TO 5 FEET: LEAN CLAY; (CL); grayish brown to brown; moist to saturated; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand; approximately 90 percent clayey fines; Soil Gleying observed at ~ 4.0 feet. 5 TO 7.8 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark brown to grayish brown; moist to wet; medium dense to dense; approximately 60 percent subrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 10 percent clayey fines. Bottom of test pit at 7.8 feet. NOTES MW-7, Proctor GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 6.00 ft Seepage at 5' AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 7.5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 7 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL GP 2.3 5.0 7.0 0 TO 2.3 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 2.3 TO 5 FEET: LEAN CLAY; (CL); grayish brown to brown; moist to saturated; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand; approximately 90 percent clayey fines; Soil Gleying observed at ~ 3.5 feet. 5 TO 7 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark brown to grayish brown; wet; medium dense to dense; approximately 60 percent subrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 10 percent clayey fines. Bottom of test pit at 7.0 feet. NOTES MW-8, CT GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 5.00 ft AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 8 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL GP 2.4 6.5 8.5 0 TO 2.4 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 2.4 TO 6.5 FEET: LEAN CLAY; (CL); grayish brown to brown; moist to saturated; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand; approximately 90 percent clayey fines; Soil Gleying observed at ~ 4.0 feet. 6.5 TO 8.5 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark brown to grayish brown; wet; medium dense to dense; approximately 60 percent subrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 10percent clayey fines. Bottom of test pit at 8.5 feet. NOTES MW-9 GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 6.00 ft Seepage at 5.4' AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 7.5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 9 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL GP 2.5 6.0 7.0 0 TO 2.5 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 2.5 TO 6 FEET: LEAN CLAY; (CL); grayish brown to brown; moist to saturated; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand; approximately 90 percent clayey fines; Soil Gleying observed at ~ 4.0 feet. 6 TO 7 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark brown to grayish brown; wet; medium dense to dense; approximately 60 percent subrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 10 percent clayey fines. Bottom of test pit at 7.0 feet. NOTES MW-10 GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 6.00 ft Seepage at 5.8' AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 10 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL GP 3.0 5.5 7.0 0 TO 3 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 3 TO 5.5 FEET: LEAN CLAY; (CL); grayish brown to brown; moist to saturated; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand; approximately 90 percent clayey fines; Soil Gleying observed at ~ 3.5 feet. 5.5 TO 7 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark brown to grayish brown; wet; medium dense to dense; approximately 60 percent subrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 10 percent clayey fines. Bottom of test pit at 7.0 feet. NOTES MW-11 GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 5.00 ft Seepage at 3' AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 11 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL GP 3.0 5.0 7.0 0 TO 3 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 3 TO 5 FEET: LEAN CLAY; (CL); grayish brown to brown; moist; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand; approximately 90 percent clayey fines. 5 TO 7 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark brown to grayish brown; wet; medium dense to dense; approximately 60 percent subrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 10 percent clayey fines. Bottom of test pit at 7.0 feet. NOTES MW-12 GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 5.00 ft AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 12 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL GP 2.6 5.0 6.5 0 TO 2.6 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 2.6 TO 5 FEET: LEAN CLAY; (CL); grayish brown to gray; moist to saturated; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand;approximately 90 percent clayey fines; Soil Gleying observed at ~ 3.5 feet. 5 TO 6.5 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark brown to grayish brown; wet; medium dense to dense; approximately 60 percent subrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 10 percent clayey fines. Bottom of test pit at 6.5 feet. NOTES MW-13, Proctor GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 4.50 ft AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 13 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL GC GP 2.5 6.0 8.0 9.0 0 TO 2.5 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft; Wood post encountered at ~ 2.0 feet. 2.5 TO 6 FEET: LEAN CLAY; (CL); grayish brown to gray; moist to saturated; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand;approximately 90 percent clayey fines; Soil Gleying observed at ~ 4.0 feet. 6 TO 8 FEET: CLAYEY GRAVEL WITH SAND AND COBBLES; (GC); grayish brown; moist to wet; medium dense; approximately 50 percent subrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 20 percent clayey fines. 8 TO 9 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark brown to grayish brown; wet; medium dense to dense; approximately 60 percentsubrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 10 percent clayey fines. Bottom of test pit at 9.0 feet. NOTES MW-14, CT GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 6.00 ft Seepage at 4' & 5' AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 7.5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 14 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL GP 2.4 6.8 8.0 0 TO 2.4 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 2.4 TO 6.8 FEET: LEAN CLAY; (CL); grayish brown to gray; moist to saturated; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand; approximately 90 percent clayey fines; Soil Gleying observed at ~ 4.0 feet. 6.8 TO 8 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark brown to grayish brown; moist to wet; medium dense to dense; approximately 60 percentsubrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 10percent clayey fines. Bottom of test pit at 8.0 feet. NOTES MW-15 GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 7.00 ft Seepage at 4' & 5' AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 7.5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 15 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL GP 2.4 7.0 8.0 0 TO 2.4 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 2.4 TO 7 FEET: LEAN CLAY; (CL); grayish brown to gray; moist to saturated; medium plasticity; soft to very soft; approximately 10 percent fine to coarse grain sand; approximately 90 percent clayey fines; Soil Gleying observed at ~ 4.0 feet. 7 TO 8 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark brown to grayish brown; wet; medium dense to dense; approximately 60 percent subrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 10percent clayey fines. Bottom of test pit at 8.0 feet. NOTES MW-16, CBR GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 7.00 ft Seepage at 4' AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 7.5 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP 16 PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION OL CL GP 1.4 14.5 15.0 0 TO 1.4 FEET: SILTY CLAY ORGANIC SOIL; (OL); dark brown to black; moist; low plasticity; very soft. 1.4 TO 14.5 FEET: LEAN CLAY; (CL); grayish brown to brown; moist to saturated; mediumplasticity; soft to very soft; approximately 10 percent fine to coarse grain sand;approximately 90 percent clayey fines; trace gravel at ~ 9.0 feet. 14.5 TO 15 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark brown to grayish brown; wet; medium dense to dense; approximately 60 percent subrounded gravels; approximately 30 percent fine to coarse grain sand; approximately 10percent clayey fines. Bottom of test pit at 15.0 feet. NOTES GROUND ELEVATION LOGGED BY Noah J. Schaible, E.I. EXCAVATION METHOD Bobcat E88 EXCAVATION CONTRACTOR Elevation Excavating LLC GROUND WATER LEVELS: DATE STARTED 5/1/25 COMPLETED 5/1/25 AT TIME OF EXCAVATION 9.00 ft Seepage at 7' AFTER EXCAVATION --- AT END OF EXCAVATION ---DEPTH(ft)0.0 2.5 5.0 7.5 10.0 12.5 15.0 SAMPLE TYPENUMBERPAGE 1 OF 1 TEST PIT NUMBER TP A PROJECT NUMBER 25002287.00 CLIENT WWC Engineering PROJECT LOCATION Gallatin Center Sub, Bozeman MT PROJECT NAME Geotech Report GENERAL BH / TP / WELL - GINT STD US.GDT - 5/19/25 11:35 - \\FILES\ACTIVE\PROJECTS\2025\25002287.00\DESIGN\CIVIL\GEOTECHNICAL\TP LOGS & MAP\TEST PIT LOGS - GALLATIN CENTER SUB. (25002287.00).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION REVISIONS DATE DESCRIPTION No 1143 STONERIDGE DRIVE, SUITE 1 BOZEMAN, MONTANA GALLATIN CENTER SUB. LOT 3, MINOR SUB. 210 BOZEMAN MONTANA TEST PIT LOCATION MAP IMEG No. 25002287.00 Drawn By: NJS Checked By: MJW Date: 5.13.2025 A-1 Sheet 1 of 1 N Map Source: Google Earth Tested By: JC Checked By: TS COMPACTION TEST REPORT Dry density, pcf91.5 93 94.5 96 97.5 99 Water content, % 17 19 21 23 25 27 29 22.0%, 97.4 pcf ZAV for Sp.G. = 2.65 Test specification:ASTM D 698-12 Method A Standard 2.65 0 TP-2 25002287.00 IMEG Specific gravity is assumed at 2.65. 6/18/2025 Elev/Classification Nat.Sp.G.LL PI % >% < Depth USCS AASHTO Moist.#4 No.200 TEST RESULTS MATERIAL DESCRIPTION Project No.Client:Remarks: Project: Date: Source of Sample: GCS Sample Number: G25058 Pioneer Technical Services, Inc. 106 Pronghorn Trail, Suite A - Bozeman, MT 59718 Ph. 406-388-8578 - Fax 406-388-8579 Figure Maximum dry density = 97.4 pcf Optimum moisture = 22.0 % Gallatin Center Sub Tested By: JC Checked By: TS COMPACTION TEST REPORT Dry density, pcf90 91.5 93 94.5 96 97.5 Water content, % 15 17.5 20 22.5 25 27.5 30 23.1%, 95.7 pcf ZAV for Sp.G. = 2.65 Test specification:ASTM D 698-12 Method A Standard 2.65 0 TP-16 25002287.00 IMEG Specific gravity is assumed at 2.65. 6/18/2025 Elev/Classification Nat.Sp.G.LL PI % >% < Depth USCS AASHTO Moist.#4 No.200 TEST RESULTS MATERIAL DESCRIPTION Project No.Client:Remarks: Project: Date: Source of Sample: GCS Sample Number: G25059 Pioneer Technical Services, Inc. 106 Pronghorn Trail, Suite A - Bozeman, MT 59718 Ph. 406-388-8578 - Fax 406-388-8579 Figure Maximum dry density = 95.7 pcf Optimum moisture = 23.1 % Gallatin Center Sub CALIFORNIA BEARING RATIO TEST ASTM D 1883 / AASHTO T 193 PROJECT DATE:6/18/2025 SAMPLE DESCRIPTION USCS Classification:Boring Number: TP-2 Depth: MOISTURE-DENSITY RELATIONSHIP Procedure: ASTM D698, Method A Maximum Dry Density: 97.4 lb/ft 3 Optimum Moisture: 22.0 % Dry Density at Molding: 92 lb/ft 3 Relative Compaction: 95 % Moisture Content at Molding: 22.0 % SWELL TEST Soaking Period: 128 hrs Surcharge Weight: 10 lbs Surcharge Weight: 10 lbs Surcharge Pressure: 50.9 psf Surcharge Pressure 50.9 psf CBR @ 0.1" penetration: 5 Average Moisture Content After Soaking: 28.0 %CBR @ 0.2" penetration: 5 Swell, % of Initial Height of Specimen: 0.9 % CALIFORNIA BEARING RATIO TEST SAMPLE LOCATION Gallatin Center Sub. G25058 Lean Clay with Sand, CL (Visual Classification) 0 10 20 30 40 50 60 70 80 90 100 110 0 0.1 0.2 0.3 0.4 0.5 0.6Stress (pounds per square inch)Penetration (inches) CALIFORNIA BEARING RATIO TEST ASTM D 1883 / AASHTO T 193 PROJECT DATE:6/18/2025 SAMPLE DESCRIPTION USCS Classification:Boring Number: TP-16 Depth: MOISTURE-DENSITY RELATIONSHIP Procedure: ASTM D698, Method A Maximum Dry Density: 95.7 lb/ft 3 Optimum Moisture: 23.1 % Dry Density at Molding: 91 lb/ft 3 Relative Compaction: 95 % Moisture Content at Molding: 23.1 % SWELL TEST Soaking Period: 137 hrs Surcharge Weight: 10 lbs Surcharge Weight: 10 lbs Surcharge Pressure: 50.9 psf Surcharge Pressure 50.9 psf CBR @ 0.1" penetration: 5 Average Moisture Content After Soaking: 30.1 %CBR @ 0.2" penetration: 5 Swell, % of Initial Height of Specimen: 2.2 % CALIFORNIA BEARING RATIO TEST SAMPLE LOCATION Gallatin Center Sub. G25059 Lean Clay with Sand, CL (Visual Classification) 0 10 20 30 40 50 60 70 80 90 100 110 0 0.1 0.2 0.3 0.4 0.5 0.6Stress (pounds per square inch)Penetration (inches) ANALYTICAL SUMMARY REPORT The analyses presented in this report were performed by Energy Laboratories, Inc., 1120 So. 27th Street, Billings, MT 59101, unless otherwise noted. Any exceptions or problems with the analyses are noted in the report package. Any issues encountered during sample receipt are documented in the Work Order Receipt Checklist. The results as reported relate only to the item(s) submitted for testing. This report shall be used or copied only in its entirety. Energy Laboratories, Inc. is not responsible for the consequences arising from the use of a partial report. Energy Laboratories, Inc. verifies the reported results for the analysis has been technically reviewed and approved for release. If you have any questions regarding these test results, please contact your Project Manager. Lab ID Client Sample ID Collect Date Receive Date Matrix Test B25050570-001 GCS TP-5 05/01/25 00:00 05/07/25 Solid Conductivity, 1:X Water Extractable Anions, Water Extractable Moisture Oxidation Reduction Potential pH, 1:X Water Extractable DI Water Soil Extract ASA10-3 Resistivity B25050570-002 GCS TP-8 05/01/25 00:00 05/07/25 Solid Same As Above B25050570-003 GCS TP-14 05/01/25 00:00 05/07/25 Solid Same As Above IMEG Project Name:Gallatin Center Sub. #25002287.00 Work Order:B25050570 1817 South Ave W Ste A Missoula, MT 59801-6554 May 22, 2025 B16786Quote ID: Energy Laboratories Inc Billings MT received the following 3 samples for IMEG on 5/7/2025 for analysis. Page 1 of 19 Digitally signed by Brandy A. PelzelDate: 2025.05.22 16:42:12 -06:00 Project:Gallatin Center Sub. #25002287.00 CLIENT:IMEG Work Order:B25050570 CASE NARRATIVE 05/22/25Report Date: Tests associated with analyst identified as ELI-H were subcontracted to Energy Laboratories, 3161 East Lyndale Ave, Helena, MT, EPA Number MT00945. Page 2 of 19 LABORATORY ANALYTICAL REPORT Client:IMEG Project:Gallatin Center Sub. #25002287.00 Lab ID:B25050570-001 Client Sample ID:GCS TP-5 Collection Date:05/01/25 Matrix:Solid Report Date:05/22/25 DateReceived:05/07/25 Prepared by Billings, MT Branch Analyses Result Units Analysis Date / ByRLMethod MCL/ QCLQualifiers PHYSICAL CHARACTERISTICS 05/09/25 15:45 / eli-h0.2wt%24.4Moisture D2974 1:X SOIL:WATER 05/20/25 14:37 / eli-h0.1s.u.7.8pH, 1:2 ASA10-3 WATER EXTRACTABLE CONSTITUENTS 05/20/25 15:00 / eli-h0.1mmhos/cm1.0Conductivity, 1:2 ASA10-3 05/21/25 01:12 / eli-h2mg/kg-dry9Chloride, 1:2 E300.0 05/21/25 01:12 / eli-h2mg/kg-dry928Sulfate, 1:2 E300.0 PHYSICAL PROPERTIES 05/12/25 12:06 / jlw°C20.4ORP Measurement Temp A2580 BM 05/12/25 12:06 / jlwmV334Oxidation-Reduction Potential A2580 BM RESISTIVITY OF SOIL 05/21/25 17:02 / eli-h1ohm-cm1010Resistivity A2510 B Report Definitions: RL - Analyte Reporting Limit MCL - Maximum Contaminant Level QCL - Quality Control Limit ND - Not detected at the Reporting Limit (RL) Page 3 of 19 LABORATORY ANALYTICAL REPORT Client:IMEG Project:Gallatin Center Sub. #25002287.00 Lab ID:B25050570-002 Client Sample ID:GCS TP-8 Collection Date:05/01/25 Matrix:Solid Report Date:05/22/25 DateReceived:05/07/25 Prepared by Billings, MT Branch Analyses Result Units Analysis Date / ByRLMethod MCL/ QCLQualifiers PHYSICAL CHARACTERISTICS 05/09/25 15:45 / eli-h0.2wt%17.9Moisture D2974 1:X SOIL:WATER 05/20/25 14:38 / eli-h0.1s.u.7.8pH, 1:2 ASA10-3 WATER EXTRACTABLE CONSTITUENTS 05/20/25 15:01 / eli-h0.1mmhos/cm0.3Conductivity, 1:2 ASA10-3 05/21/25 01:27 / eli-h2mg/kg-dry61Chloride, 1:2 E300.0 05/21/25 01:27 / eli-h2mg/kg-dry82Sulfate, 1:2 E300.0 PHYSICAL PROPERTIES 05/12/25 12:33 / jlw°C21.1ORP Measurement Temp A2580 BM 05/12/25 12:33 / jlwmV216Oxidation-Reduction Potential A2580 BM RESISTIVITY OF SOIL 05/21/25 17:02 / eli-h1ohm-cm3420Resistivity A2510 B Report Definitions: RL - Analyte Reporting Limit MCL - Maximum Contaminant Level QCL - Quality Control Limit ND - Not detected at the Reporting Limit (RL) Page 4 of 19 LABORATORY ANALYTICAL REPORT Client:IMEG Project:Gallatin Center Sub. #25002287.00 Lab ID:B25050570-003 Client Sample ID:GCS TP-14 Collection Date:05/01/25 Matrix:Solid Report Date:05/22/25 DateReceived:05/07/25 Prepared by Billings, MT Branch Analyses Result Units Analysis Date / ByRLMethod MCL/ QCLQualifiers PHYSICAL CHARACTERISTICS 05/09/25 15:45 / eli-h0.2wt%24.1Moisture D2974 1:X SOIL:WATER 05/20/25 14:40 / eli-h0.1s.u.8.2pH, 1:2 ASA10-3 WATER EXTRACTABLE CONSTITUENTS 05/20/25 15:02 / eli-h0.1mmhos/cm0.2Conductivity, 1:2 ASA10-3 05/21/25 02:10 / eli-h2mg/kg-dry9Chloride, 1:2 E300.0 05/21/25 02:10 / eli-h2mg/kg-dry10Sulfate, 1:2 E300.0 PHYSICAL PROPERTIES 05/12/25 12:42 / jlw°C20.6ORP Measurement Temp A2580 BM 05/12/25 12:42 / jlwmV266Oxidation-Reduction Potential A2580 BM RESISTIVITY OF SOIL 05/21/25 17:02 / eli-h1ohm-cm5560Resistivity A2510 B Report Definitions: RL - Analyte Reporting Limit MCL - Maximum Contaminant Level QCL - Quality Control Limit ND - Not detected at the Reporting Limit (RL) Page 5 of 19 Work Order:B25050570 QA/QC Summary Report 05/22/25Report Date: Analyte Result %REC RPDLow Limit High Limit RPDLimitRLUnits Qual Prepared by Helena, MT Branch Method:A2510 B Batch: R205384 Lab ID:B25050570-003ADUP 05/21/25 17:02Sample Duplicate Run: SOIL EC_250521A Resistivity 101.0 2.55700ohm-cm Qualifiers: RL - Analyte Reporting Limit ND - Not detected at the Reporting Limit (RL) Page 6 of 19 Work Order:B25050570 QA/QC Summary Report 05/22/25Report Date: Analyte Result %REC RPDLow Limit High Limit RPDLimitRLUnits Qual Prepared by Helena, MT Branch Method:ASA10-3 Analytical Run: SOIL EC_250521A Lab ID:ICV_1_250520_1 05/20/25 14:50Initial Calibration Verification Standard Conductivity, 1:2 96 90 1100.101.35 mmhos/cm Lab ID:CCV1_1_250520_1 05/20/25 14:51Continuing Calibration Verification Standard Conductivity, 1:2 95 90 1100.100.950 mmhos/cm Lab ID:CCV_3_250520_1 05/20/25 14:59Continuing Calibration Verification Standard Conductivity, 1:2 98 90 1100.104.91 mmhos/cm Lab ID:ICV_1_250519_1 05/19/25 13:31Initial Calibration Verification Standard Conductivity, 1:2 94 90 1100.101.33 mmhos/cm Method:ASA10-3 Batch: 77845 Lab ID:MB-77845 05/20/25 14:52Method Blank Run: SOIL EC_250521A Conductivity, 1:2 0.05NDmmhos/cm Lab ID:LCS-77845 05/20/25 14:53Laboratory Control Sample Run: SOIL EC_250521A Conductivity, 1:2 102 70 1300.101.87 mmhos/cm Lab ID:H25050203-005ADUP 05/20/25 14:57Sample Duplicate Run: SOIL EC_250521A Conductivity, 1:2 100.10 0.70.311 mmhos/cm Lab ID:B25050570-003ADUP 05/20/25 15:03Sample Duplicate Run: SOIL EC_250521A Conductivity, 1:2 100.10 2.50.175 mmhos/cm Method:ASA10-3 al Run: SOIL PH METER - ORION A211_250521A Lab ID:ICV_1_250520_1 05/20/25 14:32Initial Calibration Verification Standard pH, 1:2 100 98.6 101.40.106.98 s.u. Lab ID:CCV_1_250520_1 05/20/25 14:33Continuing Calibration Verification Standard pH, 1:2 100 98.6 101.40.107.00 s.u. Lab ID:CCV1_1_250520_1 05/20/25 14:34Continuing Calibration Verification Standard pH, 1:2 100 97.5 102.50.104.02 s.u. Lab ID:ICV_1_250519_1 05/19/25 12:48Initial Calibration Verification Standard pH, 1:2 100 98.6 101.40.106.99 s.u. Method:ASA10-3 Batch: 77845 Lab ID:LCS-77845 05/20/25 14:36Laboratory Control Sample Run: SOIL PH METER - ORION A2 pH, 1:2 99 95 1050.107.82 s.u. Lab ID:B25050570-003ADUP 05/20/25 14:41Sample Duplicate Run: SOIL PH METER - ORION A2 pH, 1:2 200.10 0.78.09 s.u. Qualifiers: RL - Analyte Reporting Limit ND - Not detected at the Reporting Limit (RL) Page 7 of 19 Work Order:B25050570 QA/QC Summary Report 05/22/25Report Date: Analyte Result %REC RPDLow Limit High Limit RPDLimitRLUnits Qual Prepared by Helena, MT Branch Method:D2974 Batch: PMOIST_250509_A Lab ID:B25050570-001A DUP 05/09/25 15:45Sample Duplicate Run: SOIL DRYING OVEN 2_25050 Moisture 200.20 1.324.1 wt% Qualifiers: RL - Analyte Reporting Limit ND - Not detected at the Reporting Limit (RL) Page 8 of 19 Work Order:B25050570 QA/QC Summary Report 05/22/25Report Date: Analyte Result %REC RPDLow Limit High Limit RPDLimitRLUnits Qual Prepared by Helena, MT Branch Method:E300.0 Analytical Run: IC METROHM_250520A Lab ID:CCV 05/20/25 22:33Continuing Calibration Verification Standard Chloride 103 90 1101.051.5 mg/L Sulfate 103 90 1101.0205mg/L Lab ID:CCV 05/21/25 02:39Continuing Calibration Verification Standard Chloride 103 90 1101.051.6 mg/L Sulfate 101 90 1101.0202mg/L Method:E300.0 Batch: 77845 Lab ID:MB-77845 05/20/25 23:02Method Blank Run: IC METROHM_250520A Chloride, 1:2 0.0080.3 mg/kg-dry Sulfate, 1:2 0.080.4 mg/kg-dry Lab ID:LCS-77845 05/20/25 23:17Laboratory Control Sample Run: IC METROHM_250520A Chloride, 1:2 111 70 1301.0126mg/kg-dry Sulfate, 1:2 105 70 1301.01860mg/kg-dry Lab ID:H25050203-005ADUP 05/21/25 00:43Sample Duplicate Run: IC METROHM_250520A Chloride, 1:2 201.0 3.261.0 mg/kg-dry Sulfate, 1:2 201.0 1.856.3 mg/kg-dry Lab ID:B25050570-002AMS 05/21/25 01:41Sample Matrix Spike Run: IC METROHM_250520A Chloride, 1:2 103 90 1101.0318mg/kg-dry Sulfate, 1:2 102 90 1101.01100mg/kg-dry Lab ID:B25050570-003ADUP 05/21/25 02:24Sample Duplicate Run: IC METROHM_250520A Chloride, 1:2 201.0 7.89.50 mg/kg-dry Sulfate, 1:2 201.0 178.24 mg/kg-dry Qualifiers: RL - Analyte Reporting Limit ND - Not detected at the Reporting Limit (RL) Page 9 of 19 Shipping container/cooler in good condition? Custody seals intact on all shipping container(s)/cooler(s)? Custody seals intact on all sample bottles? Chain of custody present? Chain of custody signed when relinquished and received? Chain of custody agrees with sample labels? Samples in proper container/bottle? Sample containers intact? Sufficient sample volume for indicated test? All samples received within holding time? (Exclude analyses that are considered field parameterssuch as pH, DO, Res Cl, Sulfite, Ferrous Iron, etc.) Container/Temp Blank temperature: Containers requiring zero headspace have no headspace or bubble that is <6mm (1/4"). Water - pH acceptable upon receipt? Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No No 5 … … … 5 5 5 5 5 5 5 … … … … … … … … … … … … … Not Present Not Present Not Present … 5 5 No VOA vials submitted Not Applicable 5 5 20.7°C No Ice 5/7/2025Kyelie L. Pflock Hand Deliver KLP Date Received: Received by: Login completed by: Carrier name: dharris 5/12/2025 Reviewed by: Reviewed Date: Contact and Corrective Action Comments: None Temp Blank received in all shipping container(s)/cooler(s)?Yes No…5 Not Applicable … Lab measurement of analytes considered field parameters that require analysis within 15 minutes of sampling such as pH, Dissolved Oxygen and Residual Chlorine, are qualified as being analyzed outside of recommended holding time. Solid/soil samples are reported on a wet weight basis (as received) unless specifically indicated. If moisture corrected, data units are typically noted as –dry. For agricultural and mining soil parameters/characteristics, all samples are dried and ground prior to sample analysis. The reference date for Radon analysis is the sample collection date. The reference date for all other Radiochemical analyses is the analysis date. Radiochemical precision results represent a 2-sigma Total Measurement Uncertainty. For methods that require zero headspace or require preservation check at the time of analysis due to potential interference, the pH is verified at analysis. Nonconforming sample pH is documented as part of the analysis and included in the sample analysis comments. Trip Blanks and/or Blind Duplicate samples are assigned the earliest collection time for the associated requested analysis in order to evaluate the holding time unless specifically indicated. Standard Reporting Procedures: Work Order Receipt Checklist IMEG B25050570 Page 10 of 19 www.energylab.com Page 11 of 19 Last Revised: January 2024 Better Together! Corrpro and DIPRA Share Technical Resources for Corrosion Control ADVANCEMENTS IN PIPE LONGEVITY THE DESIGN DECISION MODEL Learn more at www.dipra.org 2 DIPRA has provided over 100 years of research data and decades of hands-on experience with water and wastewater utilities and their engineers. Corrpro brought their extensive knowledge in the control of corrosion, not just for pipe, but for all structures in water and wastewater systems. Together, in a synergistic learning experience covering more than three years, DIPRA gained a higher appreciation of the nuances of corrosion control, and Corrpro came to better understand those aspects of Ductile iron pipe that are an advantage in mitigating corrosion. Where gaps in knowledge or data were identified, the development of the DDM® was augmented by ongoing research efforts in the lab, in DIPRA test sites and in field investigations of existing pipelines. Moreover, those efforts did not stop with the introduction of the DDM® in 2003 and they continue today. The DDM® provided the first two-dimensional risk-based model for corrosion control of Ductile iron pipe—one that balances the likelihood of a corrosion-related concern against the consequences of such an occurrence. The DDM® provides the most practical and effective means of ensuring the century-long service life that users have come to expect as the benchmark for iron pipe. It is that benchmark of service that is the foundation of the life-cycle value for the strongest, most resilient pipe material available today for water and wastewater pipelines. Over the past 15 years, research has continued, and field experiences have increased. We have listened and learned from users of Ductile iron pipe and from other experts in the field. These additions to our collective knowledge have culminated in significant advancements to the DDM®. In 2003, the Ductile Iron Pipe Research Association (“DIPRA”) and Corrpro Companies (“Corrpro”), a subsidiary of Aegion Corporation, announced the development of a risk-based model for corrosion control of Ductile iron pipelines—the Design Decision Model® (“DDM®”). The DDM® leveraged the combined experiences, resources and data of DIPRA and its member company technical staffs with corrosion control experts from Corrpro. The DDM® provides a two-dimensional, risk-based model for corrosion control that utilities can use to achieve century-long service lives of their water pipelines. 3 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 4445 46 47 48 49 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 4445 46 47 48 49 50 DDM® Two-Dimensional Matrix FIGURE 1 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 3940 41 42 4344 45 46 474849 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 3940 41 42 4344 45 46 474849 50Design Decision Model® (DDM®) TABLE 1 4 Since the origin of the DDM®, innovations in polyethylene encasement and the availability of metallized zinc coatings provide options that offer active methods of controlling corrosion. This gives us the ability to design practical mitigation protocols that recognize the differences between transmission and distribution pipelines. Published Factors to Mitigate Corrosion Perhaps most importantly, DIPRA and Corrpro agreed the details of the DDM® should be published, allowing all users of Ductile iron pipe to fully understand the state-of-the- art in corrosion control for Ductile iron pipelines and use this well-founded design tool. In the two-dimensional DDM® model, individual test results for the various contributors to the aggressive nature of a soil result in the assignment of points that accumulate, taking the user along the x-axis in Figure 1: DDM® Two-Dimensional Matrix. Similarly, factors addressing the consequences of corrosion are identified and points accumulate moving the user up the y-axis of the grid in Figure 1. These will intersect in a zone that provides the appropriate design recommendation for mitigation, as shown in Table 1: Recommendations. The listing of the various factors for Likelihood and Consequence, along with their previously unpublished point counts, are found in Tables 2: Likelihood Score Sheet and 3: Consequence Score Sheet. V-Bio® Enhanced Polyethylene Encasement – The Active Inhibitor In 2013, based on a decade of research, DIPRA introduced V-Bio® enhanced polyethylene encasement, an innovative polyethylene made possible by co-extrusion technology in film production. This durable material is infused with a volatile corrosion inhibitor and an anti-microbial component that actively prevent the growth of galvanic corrosion cells and depolarizing bacteria in that minimal annular environment between the film and the pipe surface. As a result, V-Bio® enhanced polyethylene encasement is now a part of the DDM®. For the first time, point counts for the DDM® are published. This means users can access state- of-the-art data for corrosion control methods. V-Bio® enhanced polyethylene encasement is now a part of the DDM®. 5 < 500 ohm-cm 30 500 - 1000 ohm-cm 25 > 1000 - 1500 ohm-cm 22 > 1500 - 2000 ohm-cm 19 > 2000 - 3000 ohm-cm 10 > 3000 - 5000 ohm-cm 5 > 5000 ohm-cm 0 > 100 ppm = positive 8 50 - 100 ppm = trace 3 < 50 ppm = negative 0 > 15% = Wet 5 5 - 15% = Moist 2.5 < 5% = Dry 0 Pipe below the water 5 table at any time pH 0 - 4 4 pH > 4 - 6 1 pH 6 - 8, with sulfides and low or negative redox 4 pH > 6 0 positive ( 1 ppm) 4 trace ( > 0 and < 1 ppm) 1.5 negative ( 0 ppm) 0 = negative 2 = positive 0 - 100 mv 1 = positive > 100 mv 0 Connected to noble metals 2 (e.g. copper) - yes Connected to noble metals 0 (e.g. copper) - no TOTAL POSSIBLE POINTS Cinders, Mine Waste, Peat Bog, Landfill, Fly Ash, Coal RELATIVE IMPORTANCE 1 = Highest 5 = Lowest RESISTIVITY CHLORIDES MOISTURE CONTENT GROUND WATER INFLUENCE pH SULFIDE IONS REDOX POTENTIAL BI-METALLIC CONSIDERATIONS Known Corrosive Environments POINTS 30 8 5 5 4 4 2 2 60 21 * Soils with Known Corrosive Environments shall be assigned 21 points or the total of points for Likelihood Factors, whichever is greater. Likelihood Score Sheet TABLE 2 – > – > MAXIMUM POSSIBLE POINTS LIKELIHOOD FACTOR 6 3” to 24” 0 30” to 36” 8 42” to 48” 12 54” to 64” 22 Routine (Fair to good access, minimal traffic/other utility 0 consideration, etc.) Moderate (Typical business/ residential areas, some right 8 of way limitations, etc.) Difficult (Subaqueous crossings, downtown metropolitan business areas, 20 multiple utilities congestion, swamps, etc.) 0 to 10 feet depth 0 > 10 to 20 feet depth 3 > 20 feet depth 5 Alternate supply available - no 3 Alternate supply available - yes 0 TOTAL POSSIBLE POINTS RELATIVE IMPORTANCE 1 = Highest 5 = Lowest PIPE SERVICE LOCATION: Construction-Repair Considerations DEPTH OF COVER CONSIDERATIONS ALTERNATE WATER SUPPLY POINTS 22 20 5 3 50 Consequence Score Sheet TABLE 3 MAXIMUM POSSIBLE POINTS CONSEQUENCE FACTOR DIPRA and Corrpro again listened to the needs of utility operators and recognized the differences between long, large diameter, straight-run transmission mains and the more complicated networks of distribution pipelines that bring water to our neighborhoods and businesses. The result provides a more practical solution for pipeline networks that comprise the distribution systems within a utility’s service area. The use of V-Bio® enhanced polyethylene encasement in conjunction with metallized zinc provides water operators with an effective alternative to controlling corrosion in distribution systems. The revised DDM® recognizes the practical differences in corrosion control needs between transmission mains and distribution systems. 7 In recognition of best-practices in the water industry, DIPRA has also adopted and endorsed a method of installing polyethylene encasement that was first observed being used by several utilities. This learning experience resulted from individual utility innovations that DIPRA learned of through the very useful working relationships we strive to develop and maintain with utilities and their engineers. The result is an innovative method that greatly simplifies the installation of V-Bio® enhanced polyethylene, making proper installation much easier to achieve while also addressing concerns expressed by utility operators and corrosion professionals down through the years. Modified Method A, a preferred method for the installation of the V-Bio® film, is described in ANSI/AWWA C105/A21.5. Click here to see a short installation video from our website that will provide the step-by-step procedure. This simple innovation makes installation damage less likely and facilitates the overlap of the encasement across each joint. SUMMARY The DDM® offers a simple, practical means of determining the most economical way to ensure the long service life that utilities and engineers have come to expect from Ductile iron pipelines. The innovations that are now a part of the DDM®—from the use of V-Bio® enhanced polyethylene, to the practical recognition of the different needs for transmission and distribution pipelines, to the innovative new method of installation of the V-Bio® film are only examples of the ongoing efforts our industry is making to better serve the utilities who want and need the great strength and proven resilience of Ductile iron pipe for their water and wastewater systems. Combining the recommendations of the DDM® with an active and determined policy to ensure proper installation will allow those users to experience the unparalleled advantages of Ductile iron throughout its desired life of service. 7 For more information contact DIPRA or any of its member companies. For more information contact DIPRA or any of its member companies. Strength and Durability for LiFe® Copyright © 2024 by Ductile Iron Pipe Research Association Ductile Iron Pipe Research Association An association of quality producers dedicated to the highest pipe standards through a program of continuing research and service to water and wastewater professionals. P.O. Box 190306 Birmingham, AL 35219 205.402.8700 Tel www.dipra.org Member Companies AMERICAN Ductile Iron Pipe P.O. Box 2727 Birmingham, Alabama 35202-2727 www.american-usa.com Canada Pipe Company, Ltd. 55 Frid St. Unit #1 Hamilton, Ontario L8P 4M3 Canada www.canadapipe.com McWane Ductile P.O. Box 6001 Coshocton, Ohio 43812-6001 www.mcwaneductile.com U.S. Pipe Two Chase Corporate Drive Suite 200 Birmingham, Alabama 35244 www.uspipe.com Social Media Get in the flow with Ductile iron pipe by connecting with us on Facebook, Twitter, and LinkedIn. Visit our website, www.dipra.org and click on the YouTube icon for informational videos on Ductile iron pipe’s ease of use, economic benefits, strength and durability, advantages over PVC, and more. Stormwater Design Report Appendix J – Infrastructure Design Sheets (Preliminary) NORTH 19TH AVE.BAXTER LN.CATTAIL ST.MAX AVE.INTERSTATE 90 HWYRAWHIDE RIDGE RD.K:\Bozeman\Gallatin Center LP\2024381 Gallatin Center\05CAD\Sheets\Infrastructure\24381-COVER_NOTES.dwg COVER 1/15/2026 11:16:13 AM PROJECT LOCATIONLOCATION MAPINFRASTRUCTURE IMPROVEMENTSGALLATIN CENTER SUBDIVISION, PHASE 5DRAWING NO.REVISIONNO.PREPARED FOR:BYDATEC0.0PREPARED BY:T01 ST02 S R05 EENGINEERINGDESIGNED BY:DRAWN BY:CHECKED BY:DATE:JRHJRHEWR/STHMARCH 2026PROJECT NO. 2024381 HAVRESHELBYKALISPELLGLASGOWGLENDIVEMISSOULAHELENABUTTEBILLINGSHARDINBOZEMANDILLONGREATFALLSMILES CITY9090909415152222BOZEMAN, MT0SCALE: 1" = 500'500'250'895 TECHNOLOGY BLVD., SUITE 203BOZEMAN, MT 59718(406) 586-0262www.wwcengineering.comPROJECTLOCATIONP.O. BOX 906BOZEMAN, MT 59718GALLATIN CENTER LP BOBCAT LDP VERTICAL DATUM (NAVD88) WWWWWWWWWW NG NGNG NGNG NGNGFOSTST UGPUGPUGPUGP UGP UGPFO FOFO X XXXXUGP XXXXNGNGNGNGNGNGNGNGFOFOFOFOFOFOFOFOOHPOHPOHPOHPOHPOHPOHPOHPOHP SS SS SS SS SS SS SS SSSSSS SSSSWWWWWW W SSW WUGTVUGTVUGTVUGTV WWWWWWSSSSSSSSSSUGPUGP UGPNGNGNG WEST CATRON CREEK CATTAIL STREET (EXISTING)KIMBERWICKE DRIVE (EXISTING)RAWHIDE RIDGE ROAD (EXISTING)BAXTER LANE (EXISTING)FUTURE NORTH 27TH AVE. (C.O.B. CAPITOL IMPROVEMENT)FUTURE C.O.B.CAPITOL IMPROVEMENTSSEE SHEET C1.0SEE SHEET C1.1MAX AVENUE (EXISTING) NORTH 19TH AVENUE (EXISTING)EDGE OF DELINEATEDWETLANDS (TYPICAL)RAWHIDE RIDGE ROAD (PROPOSED)K:\Bozeman\Gallatin Center LP\2024381 Gallatin Center\05CAD\Sheets\Infrastructure\24381-COVER_NOTES.dwg NOTES 1/14/2026 3:08:04 PM DESIGNED BY:DRAWN BY:CHECKED BY:DATE:JRHJRHEWR/STHJAN. 2026SHEETC0.1NO.DATEREVISIONPREPARED BY BY NOTES AND OVERVIEW GALLATIN CENTER LP BOZEMAN, MT GALLATIN CENTER SUBDIVISION, PHASE 5 ENGINEERING PROJECT NO. 2024381 895 TECHNOLOGY BLVD., SUITE 203 BOZEMAN, MT 59718 (406) 586-0262 www.wwcengineering.com 1.ALL CONSTRUCTION WILL CONFORM TO MONTANA PUBLIC WORKS STANDARDS AND SPECIFICATIONS (MPWSS, LATESTEDITION), AND CITY OF BOZEMAN MODIFICATIONS TO MPWSS.2.CONSTRUCTION SHALL BE DONE BETWEEN 8:00 A.M. AND 5:00 P.M., MONDAY THROUGH FRIDAY.3.CONTRACTOR SHALL FIELD VERIFY LOCATION AND DEPTH OF ALL EXISTING UTILITIES WHERE NEW FACILITIES CROSS ORCONNECT. CONTRACTOR SHALL BE RESPONSIBLE FOR EXPOSING POTENTIAL UTILITY CONFLICTS FAR ENOUGH AHEAD OFCONSTRUCTION TO MAKE NECESSARY GRADE MODIFICATIONS WITHOUT DELAYING THE WORK. ALL UTILITY CROSSINGSSHALL BE POTHOLED AS NECESSARY PRIOR TO EXCAVATING OR BORING TO ALLOW THE CONTRACTOR TO PREVENTGRADE OR ALIGNMENT CONFLICTS.4.CONTRACTOR SHALL ERECT AND MAINTAIN BARRICADES, WARNING SIGNS, AND TRAFFIC CONES PER MDT REQUIREMENTSIN ACCORDANCE WITH THE MUTCD (INCLUDING MONTANA AMENDMENTS). ALL TRAFFIC CONTROL MEASURES SHALL BEAPPROVED AND IN PLACE PRIOR TO ANY CONSTRUCTION ACTIVITY.5.AT LEAST 2 BUT NOT MORE THAN 10 BUSINESS DAYS BEFORE BEGINNING ANY EXCAVATION, THE CONTRACTOR SHALL,ACCORDING TO MCA 69-4-501, NOTIFY ALL OWNERS OF UNDERGROUND FACILITIES AND COORDINATE THE WORK WITHTHE OWNERS OF SUCH UNDERGROUND FACILITIES. THE INFORMATION SHOWN OR INDICATED IN THE CONTRACTDOCUMENTS WITH RESPECT TO EXISTING UNDERGROUND FACILITIES IS BASED ON INFORMATION AND DATA OBTAINEDFROM THE OWNERS OF THE FACILITIES WITHOUT FIELD EXPLORATION, AND AS SUCH, OWNER AND ENGINEER ARE NOTRESPONSIBLE FOR THE ACCURACY OR COMPLETENESS OF SUCH INFORMATION OR DATA.6.BACKFILL MATERIAL UNDER IMPROVED AREAS SHALL BE PLACED IN 8 TO 12-INCH LIFTS AND COMPACTED IN ACCORDANCEWITH GEOTECHNICAL RECOMMENDATIONS.7.CONTRACTOR SHALL PROVIDE ALL MATERIALS, EQUIPMENT AND FACILITIES REQUIRED FOR TESTING ALL UTILITY PIPING INACCORDANCE WITH CITY CONSTRUCTION SPECIFICATIONS. COST OF ALL TESTING SHALL BE BORNE BY THECONTRACTOR. INSPECTOR SHALL BE ON SITE TO WITNESS ALL TESTING. CONTRACTOR SHALL NOTIFY INSPECTOR ANDCITY OF BOZEMAN ENGINEERING DEPARTMENT A MINIMUM OF 48 HOURS (2 BUSINESS DAYS) PRIOR TO TESTING.8.NO TRENCHES IN ROADS OR DRIVEWAYS SHALL BE LEFT IN AN OPEN CONDITION OVERNIGHT. ALL SUCH TRENCHES SHALLBE PLATED OR BACKFILLED, COMPACTED AND CLOSED BEFORE THE END OF EACH WORK DAY AND NORMAL TRAFFICFLOWS RESTORED.9.ALL ROAD CLOSURES SHALL BE COMMUNICATED THROUGH THE POLICE DEPARTMENT, RECORDS DIVISION WITH AMINIMUM OF 24 HOUR ADVANCE NOTICE WITH THE FOLLOWING INFORMATION:EXACT LOCATION: ADDRESS IF APPLICABLE OTHERWISE STREET NAME AND START AND END LIMITS.TYPE OF WORK: IE. TRENCHING, PAVEMENT SAWCUT.START DATE AND TIME AND ANTICIPATED CLOSURE DURATION.10.ALL PAVEMENT CUTS SHALL BE DONE IN SUCH A MANNER WHICH WILL RESULT IN A CLEAN SQUARE EDGE BY SAW. THETOP 12-INCHES OF THE EXCAVATED AREA WITHIN THE STREET SHALL BE FILLED WITH ROAD MIX AND COMPACTED.11. PRIOR TO PAVING CONTRACTOR SHALL SCHEDULE A PRE-PAVING WALK THRU WITH THE CITY AND DESIGN ENGINEER.GENERAL CONTRACTOR AND PAVING CONTRACTOR SHALL ALSO BE PRESENT.PIPE BEDDING AND BACKFILL1.ALL PIPES SHALL BE BEDDED WITH MINIMUM 4-INCHES OF TYPE 1 PIPE BEDDING AND BACKFILL WITH THE SAME MATERIALA MINIMUM OF 6-INCHES OVER THE TOP OF THE PIPE PER CITY OF BOZEMAN STANDARD DETAIL 02221-1.2.ALL LANDSCAPING DAMAGED DURING CONSTRUCTION SHALL BE REPLACED/REPAIRED TO PRE-CONSTRUCTION QUALITY.TRAFFIC CONTROL:1.CONTRACTOR SHALL PREPARE AND SUBMIT FOR APPROVAL TRAFFIC CONTROL DESIGN TO CITY AND ENGINEER PRIOR TOPRE-CONSTRUCTION CONFERENCE. A COPY OF THE APPROVED TRAFFIC CONTROL PLAN SHALL BE PROVIDED TO THEDESIGN ENGINEER. CONTRACTOR SHALL ERECT AND MAINTAIN BARRICADES, WARNING SIGNS, AND TRAFFIC CONES PERAPPROVED CITY REQUIREMENTS IN ACCORDANCE WITH THE MUTCD. TRAFFIC SHALL BE DIRECTED IN ACCORDANCE WITHTHE MDT FLAGGERS HANDBOOK. CONTRACTOR SHALL REFERENCE THE MDT TRAFFIC CONTROL AND PROTECTIONSTANDARD DETAIL DRAWINGS IN DEVELOPMENT OF THE TRAFFIC CONTROL PLAN. ALL TRAFFIC CONTROL MEASURESSHALL BE APPROVED AND IN PLACE PRIOR TO ANY CONSTRUCTION ACTIVITY WITHIN THE RIGHT OF WAY.EXISTING UTILITY NOTES:1.EXISTING UNDERGROUND INSTALLATIONS & PRIVATE UTILITIES SHOWN ARE INDICATED ACCORDING TO THE BESTINFORMATION AVAILABLE TO THE ENGINEER. THE ENGINEER DOES NOT GUARANTEE THE ACCURACY OF SUCHINFORMATION. SERVICE LINES (WATER, POWER, GAS, STORM, SEWER, TELEPHONE & TELEVISION) MAY NOT BE STRAIGHTLINES OR AS INDICATED ON THE PLANS. STATE LAW REQUIRES CONTRACTOR TO CALL ALL UTILITY COMPANIES BEFOREEXCAVATION FOR EXACT LOCATIONS.2.EXISTING UTILITY DEPTHS ARE BASED ON BEST AVAILABLE KNOWLEDGE, CONTRACTOR TO VERIFY DEPTH OF EXISTINGUTILITIES PRIOR TO CONSTRUCTION. IF CONFLICTS EXIST CONTACT DESIGN ENGINEER FAR ENOUGH IN ADVANCE TORESOLVE CONFLICT WITHOUT CREATING DELAY IN CONSTRUCTION.3.CONTRACTOR MUST FIELD-VERIFY LINE AND GRADE OF EXISTING CONNECTIONS.WATER1.WATER MAINS UP TO 12-INCHES SHALL BE CLASS 51 DUCTILE IRON. ALL WATER MAINS SHALL BE INSTALLED WITH AMINIMUM 6.5' OF COVER TO FINISH GRADE UNLESS OTHERWISE NOTED OR DIRECTED. ALL OTHER APPURTENANCES ANDINSTALLATION ARE TO CONFORM TO MDEQ AND CITY OF BOZEMAN SPECIFICATIONS.2.ANY EXISTING OR NEW VALVES WHICH CONTROL THE CITY OF BOZEMAN'S WATER SUPPLY MUST BE OPERATED BY CITYOF BOZEMAN PERSONNEL ONLY.3.THE CONTRACTOR MUST NOTIFY THE CITY OF BOZEMAN WATER DEPARTMENT A MINIMUM OF 48-HOURS PRIOR TOBEGINNING ANY WORK.4.2" MINIMUM ORIFICE REQUIRED FOR FLUSHING.5.INSTALL JOINT RESTRAINTS ON ALL PIPE JOINTS AND FITTINGS AS SPECIFIED IN THE DRAWINGS.6.ALL CROSSES, TEES, VALVES, AND BENDS SHALL BE MECHANICAL JOINTS WITH MEGA-LUG.GRADING, PAVING & DRAINAGE1.UNLESS OTHERWISE NOTED, ALL GRADING, ROCKING AND PAVING SHALL CONFORM TO MONTANA PUBLIC WORKSSTANDARD SPECIFICATIONS, MOST CURRENT ADOPTED EDITION, WITH CITY OF BOZEMAN MODIFICATIONS.2.CONTRACTOR OR DEVELOPER SHALL PREPARE AND PROCURE A DEQ STORM WATER POLLUTION PREVENTION PLAN(SWPPP) AND CITY OF BOZEMAN STORM WATER MANAGEMENT PERMIT.3.CONTRACTOR SHALL BE RESPONSIBLE FOR MANAGING CONSTRUCTION ACTIVITIES TO INSURE THAT PUBLIC AND PRIVATESTREETS AND PARKING LOTS ARE KEPT CLEAN OF MUD, DUST OR DEBRIS. DUST ABATEMENT SHALL BE MAINTAINED BYADEQUATE WATERING OF THE SITE BY THE CONTRACTOR TO SUBSTANTIALLY LIMIT DUST FROM THE CONSTRUCTION SITE.UNDER NO CIRCUMSTANCE SHALL THE CONTRACTOR ALLOW CONSTRUCTION DEBRIS, MUD OR GRAVELS TO BE LEFT ONTHE STREETS OVER NIGHT OR TO BE TRACKED FROM THE SITE.4.CLEAR AND GRUB WITHIN WORK LIMITS SHOWN ON THE DRAWINGS INCLUDES ALL SURFACE VEGETATION, TREES,STUMPS, BRUSH, ROOTS, ETC. STRIP WORK LIMITS, REMOVING ALL ORGANIC MATTER WHICH CANNOT BE COMPACTEDINTO A STABLE MASS. ALL BRUSH AND DEBRIS ASSOCIATED WITH CLEARING, STRIPPING OR GRADING SHALL BE REMOVEDAND DISPOSED OF OFF-SITE.5.FOLLOWING STRIPPING OPERATIONS, SUBGRADE SHALL BE COMPACTED PER GEOTECHNICAL REPORT SPECIFICATIONS.IF NO REPORT IS AVAILABLE SUBGRADE SHALL BE COMPACTED TO 95% OF THE MAXIMUM DRY DENSITY AT PLUS ORMINUS 2 PERCENTAGE POINTS OF OPTIMUM MOISTURE CONTENT PER ASTM D-698 TEST METHOD (STANDARD PROCTOR).6.SUBGRADE SHALL BE PROOF ROLLED AND SOFT AREAS SHALL BE OVER-EXCAVATED AND REPLACED WITH STRUCTURALFILL. SUBGRADE MUST BE INSPECTED AND APPROVED BY THE OWNER'S REPRESENTATIVE PRIOR TO PLACINGEMBANKMENTS, ENGINEERED FILLS OR FINE GRADING FOR BASE ROCK.7.ALL FILLS SHALL BE ENGINEERED EXCEPT FOR FILLS LESS THAN 18-INCHES IN DEPTH WHICH ARE LOCATED OUTSIDE THEPUBLIC RIGHT-OF-WAY, BUILDING PADS, PARKING LOTS OR OTHER AREAS TO BE IMPROVED. ENGINEERED FILLS SHALL BECONSTRUCTED IN LIFTS NO GREATER THAN 8-INCHES OVER APPROVED SUBGRADE. EACH LIFT SHALL BE COMPACTEDPER GEOTECHNCIAL REPORT SPECIFICATIONS. IF NO REPORT IS AVAILABLE EACH LIFT SHALL BE COMPACTED TO 95% OFTHE MAXIMUM DRY DENSITY AT PLUS OR MINUS 2 PERCENTAGE POINTS OF OPTIMUM MOISTURE CONTENT PER ASTMD-698 TEST METHOD (STANDARD PROCTOR).8.SUB BASE AND CRUSHED BASE ROCK SHALL CONFORM TO THE REQUIREMENTS OF SECTION 02234 (SUB BASE COURSE)AND SECTION 02235 (CRUSHED BASE COURSE) MONTANA PUBLIC WORKS STANDARD SPECIFICATIONS (MPWSS). COMPACTSUB BASE AND CRUSHED BASE ROCK PER GEOTECHNICAL REPORT SPECIFICATIONS. IF NO REPORT IS AVAILABLECOMPACT TO 95% OF THE MAXIMUM DRY DENSITY AT PLUS OR MINUS 2 PERCENTAGE POINTS OF OPTIMUM MOISTURECONTENT PER ASTM D-698 TEST METHOD (STANDARD PROCTOR).9.A.C. PAVEMENT SHALL CONFORM TO SECTION 02510 (ASPHALT CONCRETE PAVEMENT) MPWSS FOR TYPE B MIX. A.C.PAVEMENT SHALL BE COMPACTED PER GEOTECHNICAL REPORT SPECIFICATIONS. IF NO REPORT IS AVAILABLE THEAVERAGE DENSITY SHALL BE EQUAL TO OR GREATER THAN 93% OF THE THEORETICAL MAXIMUM RICE SPECIFIC GRAVITYAND NO INDIVIDUAL SAMPLE SHALL BE LESS THAN 92% OF THE THEORETICAL MAXIMUM RICE SPECIFIC GRAVITY.10.UNLESS OTHERWISE SHOWN ON THE DRAWINGS, STRAIGHT GRADES SHALL BE RUN BETWEEN ALL FINISH GRADEELEVATIONS AND/OR FINISH CONTOUR LINES SHOWN.11.ALL EXISTING OR CONSTRUCTED MANHOLES, CLEANOUTS, MONUMENTS, GAS VALVES, WATER VALVES AND SIMILARSTRUCTURES SHALL BE ADJUSTED TO MATCH FINISH GRADE OF THE PAVEMENT, SIDEWALK, OR LANDSCAPED AREAWHEREIN THEY LIE.12.UNLESS OTHERWISE SHOWN ON THE DRAWINGS, NO CUT OR FILL SLOPES SHALL BE CONSTRUCTED STEEPER THAN4H:1V.13.IF DIRECTED ON THE DRAWINGS, ALL PLANTER AREAS SHALL BE BACKFILLED WITH APPROVED TOP SOIL AT A MINIMUMTHICKNESS OF 6". STRIPPING MATERIALS SHALL NOT BE USED FOR PLANTER BACKFILL, UNLESS ALLOWED BY THE OWNER.14.CONTRACTOR IS RESPONSIBLE FOR COORDINATING WITH ENGINEER TO ASSURE COMPACTION TESTING IS COMPLETED INACCORDANCE WITH CITY STANDARDS. A MINIMUM OF 48 HOURS NOTICE IS REQUIRED.15. ALL SIGNAGE, STRIPING, OR PAVEMENT MARKINGS DAMAGED, DESTROYED OR REMOVED DURING CONSTRUCTIONOPERATIONS SHALL BE REPLACED OR RESTORED TO PRE-CONSTRUCTION CONDITIONS.CURBS & SIDEWALKS1.UNLESS OTHERWISE SHOWN OR INDICATED ON THE DRAWINGS, 6-INCHES NOMINAL CURB EXPOSURE SHALL BE FOR ALLCURBING.2.CONTRACTOR SHALL CONSTRUCT HANDICAP ACCESS RAMPS AND SIGNAGE IN ACCORDANCE WITH CURRENT ADA ANDLOCAL REQUIREMENTS.3.SIDEWALKS SHALL BE A MINIMUM OF 4-INCHES THICK. ALL SIDEWALKS SHALL BE CONSTRUCTED USING 4,000 PSICONCRETE OR AS DIRECTED ON DRAWINGS.4.CONTRACTOR IS RESPONSIBLE FOR COORDINATING WITH ENGINEER TO ASSURE CONCRETE TESTING IS COMPLETED INACCORDANCE WITH CITY STANDARDS. A MINIMUM OF 48 HOURS NOTICE IS REQUIRED.INSPECTION, TESTING & CERTIFICATION NOTES:1.CONTRACTOR SHALL NOTIFY CITY OF BOZEMAN PUBLIC WORKS OFFICE AND DESIGN ENGINEER A MINIMUM OF 48 HOURS(2 BUSINESS DAYS) PRIOR TO START OF CONSTRUCTION.2.COMPACTION TESTING OF SUBGRADE, BASE COURSE AND ASPHALT REQUIRED FOR ALL LIFTS. CONTRACTOR SHALLPROVIDE ACCESS TO INSPECTOR TO COMPLETE THE COMPACTION TESTS.3.CONTRACTOR SHALL NOTIFY DESIGN ENGINEER A MINIMUM OF 48 HOURS (2 BUSINESS DAYS) PRIOR TO THE REQUIREDINSPECTIONS.4.CONTRACTOR SHALL NOTIFY DESIGN ENGINEER FAR ENOUGH IN ADVANCE TO ALLOW THE INSPECTOR TIME TOCOMPLETE COMPACTION TESTING. CONTRACTOR SHALL NOT COVER ANY LIFT PRIOR TO COMPACTION TESTING BYINSPECTOR. LIFTS NOT TESTED WILL NOT BE CERTIFIED BY THE DESIGN ENGINEER OR ACCEPTED BY THE CITY.5.INSTALLATION OF WATER & SEWER MAINS SHALL BE INSPECTED AND CERTIFIED BY THE DESIGN ENGINEER. CONTRACTORSHALL NOTIFY DESIGN ENGINEER FAR ENOUGH IN ADVANCE TO ALLOW THE INSPECTOR TIME TO COMPLETE THEREQUIRED INSPECTION.6.NO PIPE, VALVES, BENDS, ETC. SHALL BE BURIED PRIOR TO INSPECTION BY DESIGN ENGINEER.7.PRESSURE, VELOCITY FLUSH, AND BAC-T TESTS ARE REQUIRED FOR THE WATER MAIN AND FIRE SERVICES. ALL TESTSSHALL BE PERFORMED PER C.O.B. STANDARDS BY THE CONTRACTOR AND WITNESSED BY THE DESIGN ENGINEER. CITYOF BOZEMAN SHALL OPERATE THE VALVES. PRESSURE TESTING AND TV INSPECTION ARE REQUIRED FOR ALL SANITARYSEWER MAINS AND MANHOLES.8.CONTRACTOR SHALL PROVIDE ALL MATERIALS, EQUIPMENT AND FACILITIES REQUIRED FOR TESTING ALL UTILITY PIPING INACCORDANCE WITH CITY CONSTRUCTION SPECIFICATIONS. COST OF ALL INITIAL AND RETESTING SHALL BE BORNE BYTHE CONTRACTOR.CONSTRUCTION NOTES1.UNLESS SPECIFICALLY SHOWN ON THE DRAWINGS, ALL WORK SHALL CONFORM TO MPWSS AND CITY OF BOZEMANMODIFICATIONS, LATEST EDITION, PROJECT SPECIFICATIONS, AND THESE PLANS.2.THE CONTRACTOR SHALL BE RESPONSIBLE FOR ALL PERMITS REQUIRED AND CONSTRUCTION TESTING FORCONSTRUCTION ACTIVITIES.3.THE CONTRACTOR SHALL RESTORE ALL ROADWAYS TO EQUAL OR BETTER CONDITION THAN EXISTED PRIOR TOCONSTRUCTION, AS DETERMINED BY THE OWNER AND THE ENGINEER.4.THE LOCATION, DEPTH AND SIZE OF EXISTING UTILITIES SHOWN ON THESE PLANS ARE APPROXIMATE. THE CONTRACTORSHALL FIELD VERIFY THE EXISTENCE, LOCATION, DEPTH, SIZE, LINE AND GRADE OF EXISTING UTILITY CONNECTIONSPRIOR TO CONSTRUCTION. THE CONTRACTOR SHALL BE RESPONSIBLE FOR ANY DAMAGE TO THE EXISTING FACILITIESDUE TO FAILURE TO LOCATE OR PROVIDE PROPER PROTECTION WHEN LOCATION IS KNOWN.5.THE CONTRACTOR IS RESPONSIBLE FOR CONTROLLING DUST AND EROSION DURING CONSTRUCTION AT CONTRACTOR'SEXPENSE. EROSION SHALL BE CONTROLLED IN ACCORDANCE WITH MONTANA DEPARTMENT OF ENVIRONMENTAL QUALITYREGULATIONS.6.ALL PROFILES REPRESENT EXISTING GROUND (DASHED LINE) AND FINISHED GRADE (SOLID LINE) ALONG THE ALIGNMENTSINDICATED ON THE PLANS. ELEVATIONS ARE FINISHED GROUND ELEVATIONS.7.ALL DISTURBED AREAS SHALL BE SEEDED BY THE CONTRACTOR USING A SEED MIX APPROVED BY THE OWNER OR THELOCAL USDA OFFICE.8.THE CONTRACTOR SHALL NOTIFY ONE CALL @ 1-800-424-5555 FOR ONSITE UTILITY LOCATION. ALL EXISTING UTILITIESSHALL BE MARKED BEFORE DIGGING.9.THE CONTRACTOR SHALL MAINTAIN SERVICE OF ALL EXISTING UTILITIES. IF SAID SERVICE IS DAMAGED, THECONTRACTOR SHALL IMMEDIATELY REPAIR THE DAMAGE AT THE CONTRACTOR’S EXPENSE.10.THE CONTRACTOR SHALL NOTIFY THE ENGINEER A MINIMUM OF 48 HOURS PRIOR TO BEGINNING ANY WORK.11.IF THE CONTRACTOR DETERMINES THE NEED TO DISTURB MORE THAN 1.0 ACRE DURING THE CONSTRUCTION OF THEPROJECT, THE CONTRACTOR SHALL BE RESPONSIBLE FOR OBTAINING AN MPDES PERMIT AND COMPLYING WITH ALLTERMS OF THE PERMIT. NO SEPARATE PAYMENT WILL BE MADE FOR THIS WORK.12.QUANTITIES SHOWN IN THESE PLANS ARE FOR INFORMATIONAL PURPOSES ONLY. THE CONTRACTOR SHALL BERESPONSIBLE FOR DETERMINING ACTUAL QUANTITIES.GENERAL NOTES:PROJECT OVERVIEW BOBCAT LDP VERTICAL DATUM(NAVD88)0SCALE: 1" = 200'200'100' © 2025 Microsoft Corporation © 2025 Maxar ©CNES (2025) Distribution Airbus DS WWWWWWWWWWWWWWWWWWWWWSTNGNGNGNGNGNGNGNGNGNGNGNGNGNGFOFOFOSTSTSTUGPUGPUGPUGPUGPUGPUGPUGPUGPUGPUGPUGPUGPFOFOFOFOFOFOXXXX X X X XXXXUGPUGPXXXXXXXXNG NG NG NG NG NG NG NG NG NG NG NG NG NG NG NG NG FO FOFOFOFOFOFOFO FO FOFO FOFOFOFOFOFO ST STOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS SS SS SS SS SSWWWWWWWWWWW W WWWWWWSSSSWWWWWWSSSSSSSS SS SSUGTVUGTVUGTVUGTVUGTVUGTVUGTVUGTVUGTVUGTV W W W W W W W W W W W W W W W WSSSSSSSSSSSSSSSSSSSSSSSS SSSTS S SSSSSS S UGP UGPUGPUGPUGPUGPUGPNGNGNGNGNGNGNGCATTAIL STREET (EXISTING)KIMBERWICKE STREET (EXISTING) RAWHIDE RIDGE ROAD (EXISTING)MAX AVENUE (EXISTING)THOMAS DRIVE (EXISTING)NORTH 19TH AVENUE (EXISTING)BAXTER LANE (EXISTING)PROPERTY LINEPROPERTY LINEPROPERTY LINEEXISTING EDGE OF WETLANDEXISTING EDGE OF WETLANDEXISTING EDGE OF WETLANDEXISTING UNDERGROUND POWEREXISTING CULVERTEXISTING UNDERGROUND GASEXISTING FIBER OPTICEXISTING 8" PVCSEWER MAINEXISTING 8" PVCSEWER MAIN STUBEXISTING 8" PVCSEWER MAINEXISTING 8" PVCSEWER MAINEXISTING 12" DIWATER MAINEXISTING 8" DIWATER MAINEXISTING 8" DIWATER MAINEXISTING 8" DIWATER MAINEXISTING 8" DIWATER MAINEXISTING 8" PVCSEWER MAINEXISTING 8" PVCSEWER MAIN STUBEXISTING HYDRANT(TYPICAL)EXISTING 8" PVCSEWER MAINEXISTING FIBER OPTICEXISTING 8" PVCSEWER MAIN STUBEXISTING 8" PVCSEWER MAIN STUBEXISTING 8" PVCSEWER MAIN STUBEXISTING 8" PVCSEWER MAIN STUBEXISTING 8" PVCSEWER MAIN STUBEXISTING 8" PVCSEWER MAIN STUBEXISTING 8" PVCSEWER MAINEXISTING OVERHEAD POWEREXISTING OVERHEAD POWEREXISTING32" X 36" RCP PIPEEXISTING18" PVC PIPEEXISTING26" X 30" RCP PIPEEXISTING16" X 20" RCP PIPEEXISTING 48" RCP PIPEEXISTING 26" X 44" RCPPERMITTED CULVERTCROSSINGEXISTING 26" X 44" RCPPERMITTED CULVERTCROSSINGEXISTING 14" X 24" RCPCULVERTEXISTING CULVERTEXISTING18" X 30" RCP (2)CULVERTEXISTING36" X 36" RCPCULVERTEXISTING24" X 44" RCPCULVERTEXISTINGPIPEEXISTING CULVERTEXISTING BURN PILE60'-0" PUBLIC ROADWAYAND UTILITY EASEMENTPER DOC. NO. 260445120'-0" UTILITYEASEMENT10'-0" R/W EASEMENT TOM.P.C. PER 67F18630'-0" DEDICATEDROADWAY FORPUBLIC USE20'-0" EASEMENT FORROADWAY PURPOSES20'-0" UTILITYEASEMENT20'-0" UTILITYEASEMENTFUTURE 60'-0" DEDICATEDPUBLIC STREET R.O.W.(FUTURE NORTH 27TH AVE.)30'-0" WATER LINE EASEMENTPER FILM 198, PAGES 4015-402030'-0" WATER LINE EASEMENTPER FILM 198, PAGES 4015-402021'-6.0" PUBLIC UTILITYEASEMENT PER DOC. NO.216413910'-0" UTILITYEASEMENT TO M.P.C.PER 98F441630'-0" WATER MAIN EASEMNTPER DOC. NO. 260445050'-0" ROADWAYEASEMENT PER COS 50060'-0" PUBLIC ACCESSAND UTILITY EASEMENTPER DOC. NO. 219921445'-0" WIDE PUBLICROAD DEDICATIONPER MINOR SUB. 21070'-0" WIDE PUBLIC OPENSPACE/LINEAR TRAIL & STREAMCORRIDOR EASEMENT45'-0" WIDE PUBLICROAD DEDICATIONPER MINOR SUB. 210EXISTING HYDRANT(TYPICAL)EXISTINGUNDERGROUNDGAS LINEEXISTINGUNDERGROUNDPOWERSTORMWATERDRAINAGEEASEMENTSTORMWATERDRAINAGEEASEMENTSTORMWATERDRAINAGEEASEMENTPUBLIC STREET& UTILITYEASEMENTPUBLIC USEEASEMENT PERDOC. NO. 2605726PUBLIC USEEASEMENT PERDOC. NO. 2605726PUBLIC USEEASEMENT PERDOC. NO. 2605726EXISTING 8" DIWATER MAIN STUBEXISTING 8" DIWATER MAIN STUB45'-0" ROADWAYEASEMENT PER COS 2856K:\Bozeman\Gallatin Center LP\2024381 Gallatin Center\05CAD\Sheets\Infrastructure\24381-EXST.dwg EXISTING CONDITIONS 1/9/2026 12:35:43 PM DESIGNED BY:DRAWN BY:CHECKED BY:DATE:JRHJRHEWR/STHJAN. 2026SHEETC0.2NO.DATEREVISIONPREPARED BY BY EXISTING CONDITIONS GALLATIN CENTER LP BOZEMAN, MT GALLATIN CENTER SUBDIVISION, PHASE 5 ENGINEERING PROJECT NO. 2024381 895 TECHNOLOGY BLVD., SUITE 203 BOZEMAN, MT 59718 (406) 586-0262 www.wwcengineering.com 0SCALE: 1" = 100'100'50' 470 2 . 04704.04702.04706.04704.04708.04706.04704.04702.04700.04700.04702.047 0 4 . 0 WWWWWWWWWWWOHPOHPOHPOHPOHPOHPOHPOHPOHPOHPSSSSSSSSSSSSSSSSSS SS SSSSSSSSSSSS SSSSSSWWWWWWWWWWWWWWWWWWWWWWWWWW W W W W W SS SSSSSSSSUGTVUGTVUGTVUGTVUGTVUGTVUGTVUGTVUGTVUGTV SSUGPUGPUGPUGPUGP NGNGNGNGNGNGNG ST STRAWHIDE RIDGE ROADNORTH 27TH AVENUE(FUTURE C.O.B. CAPITOL IMPROVEMENT)(BY OTHERS) MAX AVENUE (EXISTING)RAWHIDE RIDGE ROAD(EXISTING)70.0' PUBLIC OPEN SPACE/LINEAR TRAIL & STREAMCORRIDOR EASEMENT45.0' PUBLIC R.O.W. DEDICATIONWITH GALLATIN CENTER SUBDIVISIONPHASE 54703.04702.04701.54702.54703.04704.04704.54703.54707.54707.04706.54703.0 4702.54708.54703.54704.04704.04704.54705.04706.04706.54707.04707.54704.54704.54704.04705.5STA 0+00.00, OS 18.00' (L)TIE INTO NORTH 27TH AVE.ROADWAY DESIGN.BVC TBC 4707.60STA 0+00.00, OS 18.00' (R)BEGIN CURB. TIE INTONORTH 27TH AVE.ROADWAY DESIGN.TBC 4707.93STA 0+22.47, OS 18.00' (L)EVC TBC 4707.75STA 0+22.47, OS 18.00' (R)EVC TBC 4707.75STA 1+46.63, OS 18.00' (L)PC TBC 4707.01STA 1+46.63, OS 18.00' (R)PC TBC 4707.01STA 1+99.77, OS 18.00' (L)PT TBC 4706.69STA 2+09.58, OS 18.00' (L)PC TBC 4706.63STA 2+09.58, OS 18.00' (R)PC TBC 4706.63STA 2+76.18, OS 18.00' (L)PT TBC 4706.23STA 2+75.98, OS 18.00' (R)PT TBC 4706.23STA 6+53.66, OS 18.00' (L)PVI/ CURB INLET #2TBC 4703.9812" INV. IN = 4700.5212" INV. OUT = 4700.52STA 6+53.66, OS 18.00' (R)PVI/ CURB INLET #1TBC 4703.9812" INV. OUT = 4700.70STA 6+68.71, OS 18.00' (L)PC TBC 4704.05STA 6+78.13, OS ±18.00' (R)EVC/ TIE INTO EXISTING TBC ±4704.62CONTRACTOR TO VERIFY EXISTING TIE-INELEVATIONS PRIOR TO CONSTRUCTION. IFDISCREPANCY IS FOUND, NOTIFY ENGINEERIN ADVANCE TO NOT DELAY CONSTRUCTIONSTA 6+77.91, OS ±25.11' (L)PT/ EVC/ TIE INTO EXISTINGTBC ±4704.13CONTRACTOR TO VERIFYEXISTING TIE-IN ELEVATIONS PRIOR TO CONSTRUCTION.IF DISCREPANCY IS FOUND,NOTIFY ENGINEER INADVANCE TO NOT DELAYCONSTRUCTIONEDGE OF DELINEATED WETLANDSEDGE OF DELINEATED WETLANDS3' X 6' RCB CULVERT(REPLACE EXISTING CULVERT) OUTLET INV = 4698.73SEE SHEETS C2.1 AND C2.23' X 6' RCB CULVERT(REPLACE EXISTING CULVERT)INLET INV = 4700.08SEE SHEETS C2.1 AND C2.2EXISTINGHYDRANTEXISTING HYDRANTEXISTING 30.0' WATER MAINEASEMENTPER DOC. NO. 2604450PROPOSED WET DETENTIONPOND WITH FOREBAYSEE SHEET C2.3 FOR DETAILS60.0' PUBIC R.O.W. DEDICATIONWITH GALLATIN CENTERSUBDIVISION PHASE 512" RCP SD PIPE #1L = 36.0', S = 0.50%SAWCUT AND REMOVE EXISTINGCURB AND ASPHALT AS REQUIREDTO INSTALL SMOOTH TRANSITION20' X 20' WASHED ROCKTO BE EXCAVED DOWN TONATIVE GRAVELS.ENSURE PROPER DRAINAGE.SLOPE BOULEVARDAT A 1.5% FROM TBCUP TO EDGE OF ROW ℄ CURVE DATA:Δ = 11°53'54"R = 320.00'L = 66.45'CH = S84°23'31"E66.33'PROPOSED STOP SIGNAND STREET SIGNS(USE EXISTING SIGNS:R1-1 AND D3-1 X2)INSTALL STANDARD DRIVEAPPROACH AND CONCRETEBOULEVARD ADJACENT TORETENTION/INFILTRATION POND(±STA 5+40.00 TO ±STA 6+45.00 LT)SLOPE BOULEVARDAT A 1.5% FROM TBCUP TO EDGE OF ROWGRADE TO EXISTINGSURFACE AT MAXIMUM.4:1 (H:V) SLOPEGRADE TO EXISTINGSURFACE AT MAXIMUM.4:1 (H:V) SLOPE℄ CURVE DATA:Δ = 11°05'37"R = 275.00'L = 53.24'CH = S84°11'41"E53.16'STA 1+99.93, OS 18.00' (R)PT TBC 4706.6940' X 10' WASHED ROCKTO BE EXCAVED DOWN TONATIVE GRAVELS.ENSURE PROPER DRAINAGE.PROPOSED RETENTION/INFILTRATION POND.4:1 SIDE SLOPES (TYPICAL)0+501+502+503+504+505+506+504704.04704.5STA 0+11.24, OS 18.00' (R)PVI TBC 4707.82STA 0+11.24, OS 18.00' (L)PVI TBC 4707.82STA 6+29.99, OS 18.00' (R)BVC TBC 4704.124706.04705.04704.04703.04706.04705.04704.04703.04702.04701.5EXISTINGCONTOUR(TYPICAL)POND 1POND 212" RCP SD PIPE #2L = 35.0', S = 0.50%EXISTING STOPSIGN AND STREETSIGNS TO BEREMOVED ANDRELOCATED(R1-1 AND D3-1 X2)INSTALL"NO PARKING"SIGN (R7-1)INSTALL "NO PARKING"SIGN (R7-1)L1C1L2C2L3WEST CATRONCREEKINSTALL STOP SIGN (R1-1)AND STREET SIGNS (D3-1 X2)Rawhide RidgeRdN 27th AveRawhide RidgeRdMax AveFUTURE SIDEWALK(TO BE INSTALLEDWITH FUTURE ADJACENTSITE PLANS)FUTURE SIDEWALK(TO BE INSTALLEDWITH FUTURE ADJACENTSITE PLANS)24" WHITE THERMOPLASTICSTOP BAR24" WHITETHERMOPLASTICSTOP BARSTORMWATER DRAINAGE ANDMAINTENANCE ACCESS EASEMENT(GALLATIN CENTER SUBDIVISION PHASE 5)STORMWATER DRAINAGE ANDMAINTENANCE ACCESS EASEMENT(GALLATIN CENTER SUBDIVISION PHASE 5)0+001+002+003+004+005+006+006+804701.04700.010.0' UTILITY EASEMENT(TO BE CREATED WITH GALLATINCENTER SUBDIVISION PHASE 5)20.0' UTILITYEASEMENTElevationElevationStation4693469547004705 47104715469547004705471047150+000+501+001+502+002+503+003+504+004+505+005+506+006+507+000.90%-0.60%1.00%PVI STA: 0+11.24PVI ELEV: 4707.68K: 15.00 FT/%LVC: 22.47'BVCS: 0+00.00BVCE: 4707.58EVCS: 0+22.47EVCE: 4707.61PVI STA: 6+53.66PVI ELEV: 4703.84K: 30.00 FT/%LVC: 47.94'BVCS: 6+29.69BVCE: 4703.98EVCS: 6+77.63EVCE: 4704.08STA:6+53.66CURB INLETS (R & L)RIM ELEV = 4703.48' (L)RIM ELEV = 4703.48' (R)STA:1+70.743'X6' RCBCULVERT CROSSINGINV ELEV = 4699.43'ROADWAY ℄ FINISH GRADEEXISTING GRADESTA:0+00.00CONNECT TO RAWHIDE RIDGE ROADACCESS FROM NORTH 27TH AVENUE DESIGNS.CONNECTION MUST BE COORDINATED WITHCITY OF BOZEMAN AND NORTH 27TH AVENUEPROJECT ENGINEER TO ENSURE SMOOTHAND UNIFORM CONNECTIONELEV = ±4707.57'ROADWAY CENTERLINE DATALine No./Curve No.C1C2L1L2L3Length53.2466.45126.699.78377.58Direction/Delta11°05'36.51"11°53'53.94"N89°40'37"WN78°11'12"WN89°40'50"WRadius275.00320.00K:\Bozeman\Gallatin Center LP\2024381 Gallatin Center\05CAD\Sheets\Infrastructure\24381-ROAD-PP.dwg PLAN & PROFILE 3/9/2026 1:21:16 PM DESIGNED BY:DRAWN BY:CHECKED BY:DATE:JRHJRHEWR/STHMARCH 2026SHEETC1.0NO.DATEREVISIONPREPARED BY BY RAWHIDE RIDGE ROAD PLAN & PROFILE GALLATIN CENTER LP BOZEMAN, MT GALLATIN CENTER SUBDIVISION, PHASE 5 ENGINEERING PROJECT NO. 2024381 895 TECHNOLOGY BLVD., SUITE 203 BOZEMAN, MT 59718 (406) 586-0262 www.wwcengineering.com 0SCALE: 1" = 30'30'15'RAWHIDE RIDGE ROAD PLAN VIEWSCALE: 1" = 30'RAWHIDE RIDGE ROAD PROFILE VIEWHORIZONTAL SCALE: 1" = 30'VERTICAL SCALE: 1" = 5'NOTES:1.PRIOR TO CONSTRUCTION WITHIN WETLANDS, IF DISTURBANCE IS BEYOND 0.1ACRES, DISTURBANCE IS TO BE PERMITTED AND APPROVED BY REGULATORYAUTHORITIES. ADDITIONAL STRUCTURES, INCLUDING RETAINING STRUCTURESWITHIN WETLAND AREAS, ARE TO BE REVIEWED AND APPROVED BY REGULATORYAUTHORITIES.2.VERIFY EXISTING CURB ELEVATIONS TO ENSURE SMOOTH AND UNIFORMTRANSITION PER CITY OF BOZEMAN STANDARDS.3.RAWHIDE RIDGE ROAD CONNECTION TO NORTH 27TH AVENUE (CAPITOLIMPROVEMENTS) IS TO BE COORDINATED WITH THE CITY OF BOZEMAN AND NORTH27TH AVENUE PROJECT ENGINEER TO ENSURE SMOOTH AND UNIFORMCONNECTION PER CITY OF BOZEMAN STANDARDS. STSTSTST STSTST ST STSTSTSTSTSTSTSTSTSTSTSTST STSTSTSSSSSSSSSSSSSSSSSSSSSSSSSSSSSTSTSTWWWWWWWWWWWWWWWWWWWWWWW-0+001+002+002+660+501+502+50STA 0+00.00, OS 23.00' (R)TIE INTO NORTH 27TH AVENUEIMPROVEMENTS DESIGNAND EXISTING ROADWAYPC TBC ±4689.46CONTRACTOR TO VERIFY EXISTING TIE-INELEVATIONS PRIOR TO CONSTRUCTION.IF DISCREPANCY IS FOUND, NOTIFYENGINEER IN ADVANCE TO NOT DELAYCONSTRUCTION.STA 0+40.12, OS 23.00' (R)PT TBC± 4689.41STA 2+18.37, OS 23.00' (R)PC TBC ±4688.55STA 2+65.02, OS 23.00' (R)TIE INTO EXISTING CURBTBC ±4688.77 (APPROXIMATE)CONTRACTOR TO VERIFY EXISTING TIE-INELEVATIONS PRIOR TO CONSTRUCTION.IF DISCREPANCY IS FOUND, NOTIFY ENGINEERIN ADVANCE TO NOT DELAY CONSTRUCTIONCURB CUTINSTALL SWALE ANDSIDEWALK CHASE TO MAINTAINHISTORICAL FLOW PATTERNEXISTING ABANDONEDWEST CATRONCREEK CROSSING46884686469046884688469046904690469046904690468810.0'PROPOSED10.0' SHAREDUSE PATH468811.0'22.5'EXISTING ROADSIDEDRAINAGE DITCH(TO BE ABANDONED)EXISTING ROADSIDEDRAINAGE DITCHEXISTING DRIVE APPROACH(WINCO PARKING LOT)EXISTING 5.0'SIDEWALKEXISTING 15" RCPSD PIPEEXISTING CURB, GUTTER,AND PAVEMENT TO BEPROTECTED DURINGCONSTRUCTION (TYP.)EXISTINGSTRIPING (TYP.)EXISTING 18" PVCSD PIPE90.0'R.O.W.EXISTINGMEDIANEXISTINGDETENTIONPONDEXISTING EDGEOF PAVEMENTFUTURE C.O.B. IMPROVEMENTSTO CATTAIL STREET(NORTH 27TH AVENUE CAPITALIMPROVEMENTS PROJECT)FUTURE C.O.B. IMPROVEMENTSTO CATTAIL STREET(NORTH 27TH AVENUE CAPITALIMPROVEMENTS PROJECT)CATTAIL STREET (EXISTING)MAX AVENUE(EXISTING)EXISTINGROUNDABOUTEXISTING ROADSIDEDRAINAGE DITCHPROPERTY LINEPROPERTY LINESEED BOULEVARD WITHNATIVE COVER TO MATCHNORTH BOULEVARDEXISTING 12" DIWATER MAINEXISTING 8" PVCSEWER MAINEXISTING 15" RCPSD PIPEEXISTING CURB, GUTTER,AND PAVEMENT TO BEPROTECTED DURINGCONSTRUCTION (TYP.)TIE INTO PATH TO BE INSTALLED WITHC.O.B. CAPITAL IMPROVEMENTS PROJECT.INSTALL SMOOTH TRANSITION TO PROPOSEDSIDEWALKSAWCUT AND REMOVE EXISTING PAVEMENTAS NECESSARY TO INSTALL CURB AND GUTTER.RESTORE ALL PAVEMENT TO PREVIOUS ORIMPROVED CONDITIONSINSTALL IRRIGATION SLEEVEEVERY 30 FEET UNDER PROPOSEDSIDEWALK FOR FUTURE IRRIGATIONINSTALLATION (TYP.)TIE INTO EXISTING 5.0'SIDEWALK. TAPER PROPOSEDPATH TO ENSURE SMOOTHTRANSITIONEXISTINGSIDEWALK±3.00%±3.00%90' PUBLIC RIGHT-OF-WAYEXISTING ASPHALT SURFACE ±44.0'EXISTING5" ASPHALTIC CONCRETESURFACEEXISTING12" UNCRUSHED SUBBASE(3" MINUS)2.0'EXISTING5.0'SIDEWALKEXISTING18.0'BOULEVARD1.0'4:1 MAX2:1 MAX10.0'SHARED USE PATH11.0'BOULEVARD1.0'1.50%EXISTING ROADSIDEDRAINAGE DITCH.1.50%EXISTING6" CRUSHED GRAVELBASE COURSE (1-1.2" MINUS)COMPACTED SUBGRADECURB AND GUTTER6" LAYER OF CRUSHED GRAVELBASE COURSE (1-1.2" MINUS)12" LAYER OF UNCRUSHEDSUBBASE (3" MINUS)SAWCUT AND REMOVE EXISTING PAVEMENTAS NECESSARY TO INSTALL CURB AND GUTTER.RESTORE ALL PAVEMENT TO PREVIOUSOR IMPROVED CONDITIONSK:\Bozeman\Gallatin Center LP\2024381 Gallatin Center\05CAD\Sheets\Infrastructure\24381-ROAD-PLAN-CATTAIL.dwg CATTAIL STREET IMPROVEMENTS 3/9/2026 10:32:01 AM DESIGNED BY:DRAWN BY:CHECKED BY:DATE:JRHJRHEWR/STHJAN. 2026SHEETC1.1NO.DATEREVISIONPREPARED BY BY CATTAIL STREET IMPROVEMENTS GALLATIN CENTER LP BOZEMAN, MT GALLATIN CENTER SUBDIVISION, PHASE 5 ENGINEERING PROJECT NO. 2024381 895 TECHNOLOGY BLVD., SUITE 203 BOZEMAN, MT 59718 (406) 586-0262 www.wwcengineering.com 0SCALE: 1" = 20'20'10'CATTAIL STREET PLAN VIEWSCALE: 1" = 20'CATTAIL STREET TYPICAL CROSS SECTIONN.T.S.NOTES:1.CONTRACTOR TO MATCH EXISTING THICKNESSES PER PREVIOUS CATTAIL STREET CONSTRUCTION.2.ALL SIGNAGE, STRIPING, OR PAVEMENT MARKINGS DAMAGED DURING CONSTRUCTION OPERATIONS SHALLBE REPLACED OR RESTORED TO PRE-CONSTRUCTION CONDITIONS.3.CATTAIL STREET CONNECTION TO NORTH 27TH AVENUE (CAPITOL IMPROVEMENTS) TO BE COORDINATEDWITH OTHERS TO ENSURE SMOOTH AND UNIFORM CONNECTION PER CITY OF BOZEMAN STANDARDS. 6" BASEAS REQUIRED6"18" SUMPBLOCK OUT FORPIPING. SEE GRADINGPLAN FOR ACTUALPIPE LOCATIONSINLET CASTINGD&L I-3517OR APPROVED EQUAL5/8" SMOOTH RODCENTERED IN OPENING24"ADJUSTING RINGS ASREQUIREDPLAN VIEW - N.T.S.SECTION B - N.T.S.SECTION A - N.T.S.BASE COURSE6"6"8"6"<6"AVARIESNOTES:1. CONCRETE SHALL BE M-40002. COVERS MUST BOLT DOWN TO FRAMEIFCO STYLE S (SOLIDCOVER) TRENCH GRATINGWITH STYLE B FRAMEIFCO STYLE S (SOLID COVER)TRENCH GRATING WITH STYLE BFRAMEIFCO STYLE S (SOLID COVER) TRENCHGRATING WITH STYLE B FRAME.PROVIDE STEEL CENTER SUPPORTS FORCHASES WIDER THAN 16-INCHESTHICKENEDEDGESIDEWALKEXPANSION JOINTSCOMPACTEDBASE ROCKCOMPACTEDSUB-GRADE<B10.5"FLOWLINE SLOPE SEEGRADING PLAN4" SIDEWALKDETAIL3C2.0CONCRETE SIDEWALK CHASEDETAIL6C2.0CURB INLETS = 4%1.5"NOTES:24"9.5"2"3"R4"R4"12"6"TOPSOIL(TYP.)5.52"9"1/2" SLOPECRUSHED GRAVELBASE - 3" MIN.SUB BASE COURSEAS REQUIREDCATCH CURBSPILL CURBDEPRESS CURB TO THIS LINEFOR CURB DROP.COMPACTED SUBGRADE6.10"1. SUBGRADE AND SUB BASE COURSE COMPACTION SHALL CONFORM TO SECTION 02234 (MPWSS)2. CONTRACTION JOINTS SHALL BE PLACED AT 10' INTERVALS AND SHALL HAVE A MINIMUM DEPTH OF 3/4" ANDMINIMUM WIDTH OF 1/8".3. 1/2" EXPANSION JOINT MATERIAL SHALL BE PLACED AT ALL P.C.S, P.T.S, CURB RETURNS AND AT NOT MORETHAN 300' INTERVALS. THE EXPANSION MATERIAL SHALL EXTEND THROUGH THE FULL DEPTH OF THE CURB ANDGUTTER.4. CONCRETE SHALL BE CLASS M-4000.5. CRUSHED GRAVEL BASE SHALL MEET THE REQUIREMENTS OF SECTION 02235 (MPWSS).1. CONCRETE DEPTH FOR STD. SIDEWALKS SHALL BE 6" MIN.2. SIDEWALKS SHALL SLOPE AWAY FROM STRUCTURES AND BUILDINGS AS SHOWN ONGRADING PLAN. MAXIMUM CROSS SLOPE - 2%3. CONCRETE SHALL BE 4,000 PSI @ 28 DAYS.4. CONTRACTION JOINTS SHALL BE PLACED AT 5' INTERVALS5. EXPANSION JOINT MATERIAL SHALL BE PLACED AT 50' INTERVALS6. CRUSHED ROCK BASE SHALL MEET THE REQUIREMENTS OF SECTION 02235 (MPWSS).7.FOR AREAS WITH VEHICULAR TRAFFIC, A MINIMUM OF 9" OF 34" MINUS ROCK SHOULDBE PLACED FOLLOWED BY 6" OF 4000 PSI CONCRETE.NOTES:SEE SITE PLAN1/4"6"6" THICK P.C.C.SIDEWALKCOMPACTED SUBGRADEMIN. 12" CRUSHED BASE COURSETOOLED JOINT (1" DEEP)CONCRETE SIDEWALK ANDCURB BROOM FINISHCOMPACTED SUBGRADEMIN 12" CRUSHEDBASE COURSETOOLED CONTROL JOINT DETAILDETAIL1C2.0INTEGRAL CONCRETE CURB & GUTTERDETAIL5C2.0CONCRETE SIDEWALKS = 4%7.42"7' (MIN)2" PERFORATEDSQUARE TUBEPOST (TELSPAROR APPROVEDEQUAL)2' (MIN)ATTACH SIGNS TO POST WITH 38"DRIVE RIVETS (MIN. 2 PER SIGN)SIGN POST FOUNDATION DETAIL2" PERFORATED SQUARE TUBE POST (14GAUGE)FASTEN POST TO SLEEVE WITH 516"CORNER BOLT (A325) 1 12" ABOVE FINISHGRAGE. INSERT BOLT HEAD FROMOPPOSITE SIDE OF EXPECTED IMPACT.INSERT DRIVE RIVET INTO OPPOSITESIDE.FINISHGRADE2 14" X 30" 12 GAUGE NON-PERFORATEDSQUARE TUBE SIGN POST SLEEVE(TELSPAR "QUIK PUNCH" OR APPROVEDEQUAL)INSERT SIGN POST 18" INTO SLEEVEM-4000 CONCRETE ANCHOR4"2"24"9"SIGN BLANKSMOUNTEDBACK TO BACKON POSTDETAIL4C2.0TYPICAL SIGNAGEAABB12"18"12"7"TOP BACK OF CURBDEPRESSED FLOW LINEDEPRESSED FLOW LINETYPICAL CURB SECTIONSECTION B - BSECTION A - ADETAIL2C2.0CURB CUTGENERAL NOTES:1.CURB AND GUTTER TO BE CONSTRUCTED INCOMPLIANCE WITH MPWSS AND C.O.B. STANDARDDRAWING 02628-1.2.FINAL GRADE SHALL NOT EXTEND ABOVE CURBFLOW LINE OUTLET.6"6"K:\Bozeman\Gallatin Center LP\2024381 Gallatin Center\05CAD\Sheets\Infrastructure\24381-DETL.dwg DETAILS 1/9/2026 1:17:07 PM DESIGNED BY:DRAWN BY:CHECKED BY:DATE:JRHJRHEWR/STHJAN. 2026SHEETC2.0NO.DATEREVISIONPREPARED BY BY DETAILS GALLATIN CENTER LP BOZEMAN, MT GALLATIN CENTER SUBDIVISION, PHASE 5 ENGINEERING PROJECT NO. 2024381 895 TECHNOLOGY BLVD., SUITE 203 BOZEMAN, MT 59718 (406) 586-0262 www.wwcengineering.com 2.00%2.00%60' PUBLIC RIGHT-OF-WAYCOMPACTED SUBGRADE36' TBC TO TBCPLANT MIX ASPHALT SURFACING,3" MIN. DEPTH MIN. 6" DEPTH1" MINUS CRUSHED GRAVEL BASE COURSE,MIN. 12" DEPTH4" MINUSSUB-BASE COURSEROAD TYPICAL SECTIONNOT TO SCALE4:1 MAX10.5'TRAVEL LANE7.0'PARKING10.5'TRAVEL LANE7.0'PARKING2:1 MAX12.0'BOULEVARD1.50%9.0'(TYP.)4:1 MAX2:1 MAX12.0'BOULEVARD1.50%DETAIL1C2.1RAWHIDE RIDGE ROAD TYPICAL SECTION EXT'G NATIVEGRAVELS418 OZ. FILTER FABRIC. 2'OVERLAP11"VARIES(SEE PLANS)INSTALL 3"± DIA. FREE DRAINING ROUNDROCK FROM FINISH GRADE TO 12" BELOWEXT'G GRAVEL LAYER. ENGINEER SHALL BEON-SITE DURING EXCAVATION TO VERIFYFREE DRAINING GRAVEL MATERIAL DEPTH.GRASSED SLOPE3' MINFINISH GRADE.TOP OF ROCK6" TOP SOILNATIVE MATERIALDETAIL2C2.1STORMWATER POND DETAILNOTE: SIDEWALKS WILL BE INSTALLED WITHTHE ADJACENT SITE PLANS (SUBSEQUENTAPPLICATIONS)GRADE ESTABLISHED AS 1/4" RISE PER FOOT FROM TOP OF ADJACENT FULLHEIGHT CURB OR MATCH EXISTING SIDEWALK GRADE* OR MATCH EXISTING OR REQUIRED SIDEWALK WIDTHMIN. 6" THICKREINFORCEDM-4000 CONCRETEPROPERTY LINEPROPERTY LINE STREETSURFACECONTRACTION JOINTS TO BESPACED AT 10' INTERVALS INCURB & GUTTEREXPANSION JOINTS COMPLETELYAROUND SIDEWALK SECTIONCURB & APRON POURED MONOLITHIC UNLESSOTHERWISE APPROVED3'MIN., 5' MAX. TRANSITION SECTION FROMEXISTING CURB TO DROP CURB:DRIVEWAY THROAT WIDTHSEE SITE PLANEDGE OF GUTTERFLOW LINEBACK OF CURBEXPANSION JOINTS AT CURB RETURNSCONTRACTION JOINTVARIABLE(5.5' TYP.)5'1'EXPANSION JOINT MATERIAL SHALL BE 1/2" THICK PRE-FORMED BITUMINOUSTREATED FIBERBOARD FILLER. ALL CURB REPLACEMENT SHALL BE DONE WITHINTEGRAL CURB AND GUTTER UNLESS OTHERWISE APPROVED.SIDEWALK CONTRACTION JOINTSSPACED AT 5' INTERVALS - MIN.DEPTH 1". EXPANSION JOINTS TOBE PLACED AT 25' INTERVALS.1'SIDEWALK*5' TYPDRIVEWAY5.5' TYP(VARIES)WASHED ROCK3" MIN.COMPACTED SUBGRADEMAINTAINPROPERSIDEYARDSETBACKPERZONINGREGULATIONSSECTION ASECTION B1'5' TYP.VARIES3" MIN GRAVEL BASESIDEWALK BOULEVARD4" THICK M-4000 CONCRETEBBAA2% SLOPECURB AND GUTTER14" PER FOOT SLOPEDETAIL3C2.1RESIDENTIAL CONCRETE DRIVEWAY APPROACHSTSTSTSTWWWWWWRAWHIDE RIDGEROAD60.0' PUBLICROW3' TALL X 6' WIDEREINFORCED CONCRETEBOX CULVERTOUTLET STRUCTUREEDGE OFWETLANDS(TYP.)INLET STRUCTUREEDGE OFWETLANDS(TYP.)NOTES:1.PIPE BEDDING TO BE 1 12 " MINUS CRUSHED BASE COURSE (MDT GRADE E) COMPACTED BY PROOFROLLING WITH A VIBRATORY COMPACTOR IN 6" LOOSE LIFTS.2.EMBANKMENT TO COMPETENT IMPORTED FILL APPROVED BY ENGINEER AND COMPACTED IN 12" LOOSELIFTS TO 95% RELATIVE STANDARD PROCTOR AND WITHIN 3% OF OPTIMAL MOISTURE, PER ASTM D698.3.NO PARTICLES LARGER THAN 1" IN DIAMETER ALLOWED WITHIN 2' OF PIPE WALLS.4.TOP OF RIGID PIPE TO HAVE 2' MINIMUM COVER TO FINISHED GRADE.RCB PIPE INSTALLATION DETAIL18" OF 112" MINUSCRUSHED BASE COURSEElevationStationProfile View4700471047004710-0+100+000+100+200+300+400+500+600+700+800+901+0018" BEDDING OF 1 12" MINUSCRUSHED BASE COURSEEXTEND RIPRAP TOEND OF WING WALLSRIPRAPD50 = 18 INCHESSLOPE = 1.42%8 OZ. NONWOVENGEOTEXTILEFINISHEDGROUNDPUBLIC ROWRAWHIDE RIDGE ROAD(SEE SECTION VIEW DETAIL)COMPACTED FILLCULVERT INLETINVERT: 4700.083" STREAM BEDDING(NON-TRANSPORTABLECOBBLES)CULVERT OUTLETINVERT: 4698.73EXTEND RIPRAP TOEND OF WING WALLSRIPRAPD50 = 18 INCHES8 OZ. NONWOVENGEOTEXTILENOTE:1.ANCHOR OR TIE GEOTEXTILE PER MANUFACTURERS RECOMMENDATION.2.GEOTEXTILE FABRIC TO BE PLACED ON THE INSIDE (ROADSIDE) OF WEEP HOLES AND PROPERLYSECURED ON INTERIOR FACE.3.BOX CULVERT TO BE DESIGNED BY PRECAST MANUFACTURER FOR HL-93 AND HS-20 VEHICLE LOADING.3" PLANT MIX SURFACINGMIN. 6" LAYER OF1" MINUS GRAVEL BASE COURSE12" LAYER OF4" MINUS SUB-BASE COURSECOMPACTED FILL (VARIES)DETAIL4BC2.1CULVERT PROFILE VIEWDETAIL4AC2.1CULVERT CROSS SECTION VIEW3.0'6.0'3' TALL, 6' WIDEREINFORCED CONCRETEBOX CULVERT3" STREAM BEDDING(NON-TRANSPORTABLECOBBLES)UNIAXIAL MSE-RATEDGEOGRID SUCH AS SOLMAX, MIRAGRID 3XT, TENSAR,UX1100MSE, OR APPROVEDEQUAL. PLACE AT 12"DEPTH WITH 6' LENGTHUNIAXIAL MSE-RATEDGEOGRID SUCH AS SOLMAX, MIRAGRID 3XT, TENSAR,UX1100MSE, OR APPROVEDEQUAL. PLACE AT 12"DEPTH WITH 6' LENGTHK:\Bozeman\Gallatin Center LP\2024381 Gallatin Center\05CAD\Sheets\Infrastructure\24381-DETL.dwg DETAILS (2) 1/15/2026 8:35:38 AM DESIGNED BY:DRAWN BY:CHECKED BY:DATE:JRHJRHEWR/STHJAN. 2026SHEETC2.1NO.DATEREVISIONPREPARED BY BY DETAILS GALLATIN CENTER LP BOZEMAN, MT GALLATIN CENTER SUBDIVISION, PHASE 5 ENGINEERING PROJECT NO. 2024381 895 TECHNOLOGY BLVD., SUITE 203 BOZEMAN, MT 59718 (406) 586-0262 www.wwcengineering.com4AC2.14BC2.1CULVERT DETAILS W W W W W W WWWWWSTSTRAWHIDE RIDGE ROAD (PROPOSED)MAX AVENUE (EXISTING)TOP OF POND EL. 4703.40' RAWHIDE RIDGE ROAD (PROPOSED) 4:1 SIDE SLOPES (TYPICAL) 20' X 10' WASHED ROCK TO BE EXCAVATED DOWN TO NATIVE GRAVELS. ENSURE PROPER DRAINAGE 4703.0 4702. 0 4700. 0 4703. 0 4701.0 BOTTOM OF POND EL. 4699.51' STAGE STORAGE: LOT A RETENTION/INFILTRATION POND ELEV AREA (sq. ft.) DEPTH (ft) AVG END INC. VOL. (cu. ft.) AVG END TOTAL VOL. (cu. ft.) 4,701.6000 3,260.0554 N/A N/A 0.0000 4,701.8000 3,480.0819 0.2000 674.0137 674.0137 4,702.0000 3,703.3076 0.2000 718.3390 1392.3527 4,702.2000 3,929.7707 0.2000 763.3078 2155.6605 4,702.4000 4,159.4740 0.2000 808.9245 2964.5850 4,702.6000 4,392.3771 0.2000 855.1851 3819.7701 4,702.8000 4,628.1286 0.2000 902.0506 4721.8207 4,703.0000 4,867.0797 0.2000 949.5208 5671.3415 4,703.2000 5,109.3205 0.2000 997.6400 6668.9815 4,703.4000 5,364.9218 0.2000 1047.4242 7716.4057 4,699.6000 1,352.0429 N/A N/A 0.0000 WSSS 47044704 TOP OF POND EL. 4704.40' RAWHIDE RIDGE ROAD (PROPOSED) 4:1 SIDE SLOPES (TYPICAL) 40' X 10' WASHED ROCK TO BE EXCAVATED DOWN TO NATIVE GRAVELS. ENSURE PROPER DRAINAGE. STAGE STORAGE TABLE: TEMPORARY POND ELEV AREA (sq. ft.) DEPTH (ft) AVG END INC. VOL. (cu. ft.) AVG END TOTAL VOL. (cu. ft.) 4,703.8000 15,710.8456 N/A N/A 0.0000 4,704.0000 16,377.9756 0.2000 3208.8821 3208.8821 4,704.2000 17,048.6485 0.2000 3342.6624 6551.5445 4,704.4000 17,723.5499 0.2000 3477.2198 10028.7644 BOTTOM OF POND/ TOP OF ROCK 3"± DIA. FREE DRAINING ROUND ROCK FROM FINISH GRADE TO 12" BELOW NATIVE GRAVEL LAYER. 4H:1V 6" TOPSOIL TOP OF POND ELEV. 4703.40' BOTTOM OF CALCULATED STORAGE 4701.60' ELEV. 4699.51' (SEASONAL HIGH GW) 0' - 1.0' BGS SILTY CLAY ORGANIC SOIL (OL) 1.0' - 3.0' BGS LEAN CLAY (CL) 3.0' - 22.0' BGS POORLY GRADED GRAVEL (GP) BOTTOM OF POND/ TOP OF ROCK 3"± DIA. FREE DRAINING ROUND ROCK FROM FINISH GRADE TO 12" BELOW NATIVE GRAVEL LAYER. 4H:1V 6" TOPSOILTOP OF POND ELEV. 4704.40' ELEV. 4701.64' (SEASONAL HIGH GW) C2.3 4 SECTION VIEW DETAIL: LOT A RETENTION/INFILTRATION POND SCALE: 1" = 3' ELEV. 4703.80'0' - 1.3' BGS SILTY CLAY ORGANIC SOIL (OL) 1.3' - 4.0' BGS LEAN CLAY (CL) 4.0' - 7.0' BGS POORLY GRADED GRAVEL (GP)STST17.0' 14.6' 14.6' 10.0' WEIR CONCRETE BOTTOM FOR SEDIMENT ACCUMULATION AND REMOVAL FREE DRAINING ROCK UP SIDESLOPE CONNECT TO NATIVE GRAVELS 12" RCP PIPE INLET INV. ELEV. = 4700.30 REINFORCED CONCRETE FOREBAY CELL WALL 4.0'1.0' 1.0' 1.5' (TYP.) 3.5' TOP OF WALL ELEV. = 4701.51 WEIR CREST ELEV. = 4700.51 BOTTOM OF POND ELEV. = 4699.51 BOTTOM OF FOOTING ELEV. = 4697.01 REINFORCEMENT #4 AT 12" O.C. 1.5' 10.0' WEIR 17.0' COMPACTED GRAVEL BASE C2.3 1 SECTION VIEW DETAIL: LOT A WET DETENTION POND SCALE: 1" = 3' 1 C2.3 4C2.3PLAN VIEW OF LOT A WET DETENTION POND SCALE: 1" = 30' PLAN VIEW OF TEMPORARY RETENTION/INFILTRATION POND SCALE: 1" = 50'K:\Bozeman\Gallatin Center LP\2024381 Gallatin Center\05CAD\Sheets\Preliminary Plat\24381-STORM-POND_EXHB.dwg DETAILS (4) 4/3/2026 4:06:38 PMDESIGNED BY: DRAWN BY: CHECKED BY: DATE: JRH JRH EWR/STH MARCH 2026 SHEET C2.3NO.DATEREVISIONPREPARED BYBYDETAILSGALLATIN CENTER LPBOZEMAN, MTGALLATIN CENTER SUBDIVISION, PHASE 5ENGINEERINGPROJECT NO. 2024381 895 TECHNOLOGY BLVD., SUITE 203BOZEMAN, MT 59718(406) 586-0262www.wwcengineering.com2 C2.3 LOT A WET DETENTION POND DETAIL FOREBAY DETAIL SCALE: 1" = 10' C2.3 2 SECTION VIEW DETAIL: FOREBAY CELL WALL SCALE: 1" = 3' TEMPORARY RETENTION/INFILTRATION POND DETAILS C2.3 3 SECTION VIEW DETAIL: FOREBAY CELL WALL SCALE: 1" = 3' 3 C2.3 Stormwater Design Report Appendix K – Groundwater Mounding Calculations Lot A Pond Groundwater Mounding Calculations use consistent units (e.g. feet & days or inches & hours)Conversion Table Input Values inch/hour feet/day 8.0000 R Recharge (infiltration) rate (feet/day)0.67 1.33 0.150 Sy Specific yield, Sy (dimensionless, between 0 and 1) 80.00 K Horizontal hydraulic conductivity, Kh (feet/day)*2.00 4.00 10.000 x 1/2 length of basin (x direction, in feet) 10.000 y 1/2 width of basin (y direction, in feet)hours days 1.530 t duration of infiltration period (days)36 1.50 10.000 hi(0)initial thickness of saturated zone (feet) 11.765 h(max)maximum thickness of saturated zone (beneath center of basin at end of infiltration period) 1.765 Δh(max)maximum groundwater mounding (beneath center of basin at end of infiltration period) Ground- water Mounding, in feet Distance from center of basin in x direction, in feet 1.765 0 1.195 20 0.800 40 0.674 50 0.572 60 0.489 70 0.419 80 0.360 90 0.310 100 0.231 120 Disclaimer This spreadsheet solving the Hantush (1967) equation for ground-water mounding beneath an infiltration basin is made available to the general public as a convenience for those wishing to replicate values documented in the USGS Scientific Investigations Report 2010-5102 "Groundwater mounding beneath hypothetical stormwater infiltration basins" or to calculate values based on user-specified site conditions. Any changes made to the spreadsheet (other than values identified as user-specified) after transmission from the USGS could have unintended, undesirable consequences. These consequences could include, but may not be limited to: erroneous output, numerical instabilities, and violations of underlying assumptions that are inherent in results presented in the accompanying USGS published report. The USGS assumes no responsibility for the consequences of any changes made to the spreadsheet. If changes are made to the spreadsheet, the user is responsible for documenting the changes and justifying the results and conclusions. This spreadsheet will calculate the height of a groundwater mound beneath a stormwater infiltration basin. More information can be found in the U.S. Geological Survey Scientific Investigations Report 2010-5102 "Simulation of groundwater mounding beneath hypothetical stormwater infiltration basins". The user must specify infiltration rate (R), specific yield (Sy), horizontal hydraulic conductivity (Kh), basin dimensions (x, y), duration of infiltration period (t), and the initial thickness of the saturated zone (hi(0), height of the water table if the bottom of the aquifer is the datum). For a square basin the half width equals the half length (x = y). For a rectangular basin, if the user wants the water-table changes perpendicular to the long side, specify x as the short dimension and y as the long dimension. Conversely, if the user wants the values perpendicular to the short side, specify y as the short dimension, x as the long dimension. All distances are from the center of the basin. Users can change the distances from the center of the basin at which water-table aquifer thickness are calculated. Cells highlighted in yellow are values that can be changed by the user. Cells highlighted in red are output values based on user-specified inputs. The user MUST click the blue "Re-Calculate Now" button each time ANY of the user-specified inputs are changed otherwise necessary iterations to converge on the correct solution will not be done and values shown will be incorrect. Use consistent units for all input values (for example, feet and days) In the report accompanying this spreadsheet (USGS SIR 2010-5102), vertical soil permeability (ft/d) is assumed to be one-tenth horizontal hydraulic conductivity (ft/d). Re-Calculate Now 0.000 0.200 0.400 0.600 0.800 1.000 1.200 1.400 1.600 1.800 2.000 0 20 40 60 80 100 120 140 Groundwater Mounding, in feet Lot B Temp Pond Groundwater Mounding Calculations use consistent units (e.g. feet & days or inches & hours)Conversion Table Input Values inch/hour feet/day 8.0000 R Recharge (infiltration) rate (feet/day)0.67 1.33 0.150 Sy Specific yield, Sy (dimensionless, between 0 and 1) 80.00 K Horizontal hydraulic conductivity, Kh (feet/day)*2.00 4.00 5.000 x 1/2 length of basin (x direction, in feet) 20.000 y 1/2 width of basin (y direction, in feet)hours days 2.560 t duration of infiltration period (days)36 1.50 10.000 hi(0)initial thickness of saturated zone (feet) 11.768 h(max)maximum thickness of saturated zone (beneath center of basin at end of infiltration period) 1.768 Δh(max)maximum groundwater mounding (beneath center of basin at end of infiltration period) Ground- water Mounding, in feet Distance from center of basin in x direction, in feet 1.768 0 1.289 20 0.944 40 0.824 50 0.724 60 0.640 70 0.568 80 0.506 90 0.451 100 0.361 120 Disclaimer This spreadsheet solving the Hantush (1967) equation for ground-water mounding beneath an infiltration basin is made available to the general public as a convenience for those wishing to replicate values documented in the USGS Scientific Investigations Report 2010-5102 "Groundwater mounding beneath hypothetical stormwater infiltration basins" or to calculate values based on user-specified site conditions. Any changes made to the spreadsheet (other than values identified as user-specified) after transmission from the USGS could have unintended, undesirable consequences. These consequences could include, but may not be limited to: erroneous output, numerical instabilities, and violations of underlying assumptions that are inherent in results presented in the accompanying USGS published report. The USGS assumes no responsibility for the consequences of any changes made to the spreadsheet. If changes are made to the spreadsheet, the user is responsible for documenting the changes and justifying the results and conclusions. This spreadsheet will calculate the height of a groundwater mound beneath a stormwater infiltration basin. More information can be found in the U.S. Geological Survey Scientific Investigations Report 2010-5102 "Simulation of groundwater mounding beneath hypothetical stormwater infiltration basins". The user must specify infiltration rate (R), specific yield (Sy), horizontal hydraulic conductivity (Kh), basin dimensions (x, y), duration of infiltration period (t), and the initial thickness of the saturated zone (hi(0), height of the water table if the bottom of the aquifer is the datum). For a square basin the half width equals the half length (x = y). For a rectangular basin, if the user wants the water-table changes perpendicular to the long side, specify x as the short dimension and y as the long dimension. Conversely, if the user wants the values perpendicular to the short side, specify y as the short dimension, x as the long dimension. All distances are from the center of the basin. Users can change the distances from the center of the basin at which water-table aquifer thickness are calculated. Cells highlighted in yellow are values that can be changed by the user. Cells highlighted in red are output values based on user-specified inputs. The user MUST click the blue "Re-Calculate Now" button each time ANY of the user-specified inputs are changed otherwise necessary iterations to converge on the correct solution will not be done and values shown will be incorrect. Use consistent units for all input values (for example, feet and days) In the report accompanying this spreadsheet (USGS SIR 2010-5102), vertical soil permeability (ft/d) is assumed to be one-tenth horizontal hydraulic conductivity (ft/d). Re-Calculate Now 0.000 0.200 0.400 0.600 0.800 1.000 1.200 1.400 1.600 1.800 2.000 0 20 40 60 80 100 120 140 Groundwater Mounding, in feet Stormwater Design Report Appendix L – Conveyance Calculations 12" PVC SD Pipe at 0.5% Slope Project Description Manning FormulaFriction Method DischargeSolve For Input Data 0.010Roughness Coefficient ft/ft0.005Channel Slope in9.0Normal Depth in12.0Diameter Results cfs2.99Discharge ft²0.6Flow Area ft2.1Wetted Perimeter in3.6Hydraulic Radius ft0.87Top Width in8.9Critical Depth %75.0Percent Full ft/ft0.005Critical Slope ft/s4.73Velocity ft0.35Velocity Head ft1.10Specific Energy 0.975Froude Number cfs3.52Maximum Discharge cfs3.27Discharge Full ft/ft0.004Slope Full SubcriticalFlow Type GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth N/AProfile Description ft0.00Profile Headloss %0.0Average End Depth Over Rise %0.0Normal Depth Over Rise ft/s0.00Downstream Velocity ft/s0.00Upstream Velocity in9.0Normal Depth in8.9Critical Depth ft/ft0.005Channel Slope ft/ft0.005Critical Slope Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 12/16/2025 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution CenterUntitled1.fm8 Combination Curb Inlet in Sag (Major Storm) Project Description SpreadSolve For Input Data cfs2.26Discharge ft1.50Gutter Width ft/ft0.040Gutter Cross Slope ft/ft0.020Road Cross Slope in2.0Local Depression in36.0Local Depression Width ft1.50Grate Width ft3.0Grate Length P-50 mm (P-1 -7/8")Grate Type %0.0Clogging ft3.0Curb Opening Length ft0.5Opening Height HorizontalCurb Throat Type degrees90.00Throat Incline Angle Options Use BothCalculation Option Results ft6.3Spread in1.9Depth in0.4Gutter Depression in2.4Total Depression ft²4.0Open Grate Area ft6.0Active Grate Weir Length Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 12/16/2025 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution CenterUntitled1.fm8 Gutter Capacity - Spread to Crown of Street Project Description DischargeSolve For Input Data ft/ft0.006Channel Slope ft1.2Gutter Width ft/ft0.040Gutter Cross Slope ft/ft0.020Road Cross Slope ft17.5Spread 0.013Roughness Coefficient Results cfs10.26Discharge ft²3.1Flow Area in4.5Depth in0.3Gutter Depression ft/s3.33Velocity Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 12/16/2025 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution CenterUntitled1.fm8