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021 - Appendix M - Storm Report
Page 2 of 11 Table of Contents 1 Introduction ......................................................................................................................... 4 1.1 Description of Property ............................................................................................... 4 1.1.1 Project Location ...................................................................................................... 4 1.1.2 Area ........................................................................................................................ 4 1.1.3 Ground cover .......................................................................................................... 4 1.1.4 Existing Land Uses and Foreseeable Future Land Uses ......................................... 4 1.1.5 Topographic Features and Characterization ........................................................... 4 1.1.6 Geologic Features and Characterization ................................................................. 4 1.1.7 Existing Drainage Conditions and Facilities ............................................................ 5 1.1.8 Natural Watercourses (when present) ..................................................................... 5 1.1.9 Wetlands (when present) ........................................................................................ 5 1.1.10 Flood Hazard Zones (if applicable) ..................................................................... 5 1.2 Previous Drainage Studies (if any) .............................................................................. 5 1.3 State or Federal Regulations (if applicable) ................................................................ 5 2 Hydrology and hydrogeology............................................................................................... 5 2.1 Design Storm Rainfall ................................................................................................. 5 2.2 Summary of Geotechnical Evaluation ......................................................................... 6 3 Existing Stormwater drainage Conditions ............................................................................ 6 3.1 Existing Drainage Conditions ...................................................................................... 6 3.1.1 Existing Drainage Basin Runoff Characteristics ...................................................... 6 3.1.2 Off-Site Contributing Areas and Outfall ................................................................... 6 3.2 Hydrologic and Hydraulic Calculations or Modeling .................................................... 7 3.2.1 Hydraulic Methods and Computer Models Used ..................................................... 7 3.2.2 Hydraulic Capacity of Existing Drainage Features .................................................. 7 3.2.3 Hydraulic Capacity of Existing Outfall ..................................................................... 7 4 Proposed Stormwater Drainage Conditions ........................................................................ 7 4.1 Applicable Design Standards ...................................................................................... 7 4.2 Drainage System Design ............................................................................................ 7 4.2.1 Post-project Drainage Patterns Including Off-Site Contributing Areas and Outfall ... 7 4.2.2 Post-project Drainage Basin Runoff Characteristics ................................................ 8 4.2.3 Planned Drainage Features .................................................................................... 8 4.3 Hydrologic and Hydraulic Calculations or Modeling .................................................... 8 4.3.1 Hydraulic Methods .................................................................................................. 8 4.3.2 Post-project vs. Existing Runoff Rates and Volumes .............................................. 9 4.3.3 Stormwater Drainage System Elements ................................................................. 9 Page 3 of 11 4.3.4 Hydraulics Design vs Design Criteria ...................................................................... 9 4.3.5 Water Quality Treatment Design ............................................................................10 4.4 Runoff Control Facilities .............................................................................................10 4.5 Permanent Water Quality Treatment .........................................................................10 4.6 Erosion and Sediment Control ...................................................................................10 5 Evaluation of Major Storm Flood Risks ..............................................................................10 5.1 Major Storm Post-project Flood Hazards vs Existing .................................................10 5.2 Potential Flood Hazards and Mitigation Measures .....................................................10 6 Operation, Inspection, and Maintenance Considerations ...................................................10 7 References ........................................................................................................................11 8 Appendices ........................................................................................................................11 Page 4 of 11 1 INTRODUCTION This design report outlines the preliminary plan for managing stormwater runoff from the proposed Laurel Meadows subdivision in Bozeman, Gallatin County, Montana. The information contained in this report summarizes the basis of design for necessary storm drainage improvements. The methodology and analysis procedures used in designing the subdivision stormwater management improvements are based on the standards outlined in the City of Bozeman Design Standards and Construction Standards, dated October 2024 (COB CDS). 1.1 Description of Property 1.1.1 Project Location The following is the legal description for the property. Lot R1A through R1D of Phase 6 of Norton East Ranch Subdivision to be platted through an amended plat to be known as the Laurel Meadows Subdivision. Project is located in the N ½ of Section 9, Township 2 South, Range 5 East, Principal Meridian, Gallatin County, Montana. The Laurel Meadows development is a proposed 40-acre multi-family neighborhood bordered by the Valley West Subdivision to the east, Vaughn Drive (local) to the north, Laurel Parkway (collector) to the west and West Babcock (collector) to the south. This project is located within the City of Bozeman, Montana. See the vicinity map (Exhibit A) for location details. 1.1.2 Area The proposed project is 40.82 acres. 1.1.3 Ground cover Data on existing site soils is provided in Appendix A, a geotechnical report prepared by Castle Rock Geotechnical Engineering Inc. dated April 10, 2020 and supplementary comments dated August 30, 2022. According to information included in the report from the NRCS Web Soil Survey (WSS), the subdivision contains four separate soil profiles. Two of these profiles are located in the dedicated wetland easement (Doc No 2299907) located on the eastern side of the property and will be neglected for the purpose of this report because there will be no improvements in this area. The two soil profiles we will focus on are, 510B: Meadowcreek Loam, and 748A: Hyalite- Beaverton complex. Both soils are in the hydrologic soil group, C. 1.1.4 Existing Land Uses and Foreseeable Future Land Uses The southeast corner of the property was previously used for gravel extraction, while the remaining lot was previously used for agricultural. Currently, the land use is vacant. The proposed project will incorporate fee-simple lots, ROWs, open space, and park space. 1.1.5 Topographic Features and Characterization From the gravel extraction mentioned above, there is an existing pond located on the southeast corner of the property. Along the eastern edge of the property, there is an abandoned irrigation ditch. Baxter Creek is located east of the abandoned irrigation ditch. 1.1.6 Geologic Features and Characterization The geotechnical report prepared by Castle Rock Geotechnical Engineering, dated April 10, 2020 (Appendix A) indicates that the site consists of topsoil over lean clay loam and gravelly Page 5 of 11 clay, underlain by poorly graded gravels. Groundwater is typically found approximately 36 inches below grade, with seasonal fluctuations of about 1.5 feet. 1.1.7 Existing Drainage Conditions and Facilities There is a non-jurisdictional wetland in the center of the property. There are two permanent stormwater ponds located on the southeast portion of the property that collect water from Babcock Street and Norton East Ranch Subdivision. There is also one temporary retention pond that collects runoff from Laurel Parkway just south of Lot 1. 1.1.8 Natural Watercourses (when present) Baxter Creek is located on the eastern boundary of the property. 1.1.9 Wetlands A non-jurisdictional wetland is located in the center of the property, which is proposed to be mitigated in the southeast portion of the site. There is also a dedicated wetland easement that exists along the eastern and southwest boundaries of the site. Wetlands in these areas will be protected and are excluded from development and stormwater improvements. 1.1.10 Flood Hazard Zones A flood hazard analysis was conducted in May 2022 for Baxter Creek for the previous West Park Preliminary Submittal. The 100-yr flood zone remains in the proposed park area. This document is included in Appendix D. 1.2 Previous Drainage Studies Multiple drainage reports have been prepared for this property, including the following that have previously been reviewed by the City of Bozeman: • April 2021 (revised June 2021): Norton East Ranch Subdivision, prepared by Phase 5, C&H Engineering o Runoff data from Laurel Parkway included in this report has been used for the current design and analysis. • August 23, 2022: West Park Subdivision, prepared by Morrison-Maierle. 1.3 State or Federal Regulations No known additional state or federal regulations are required. 2 HYDROLOGY AND HYDROGEOLOGY 2.1 Design Storm Rainfall The property is divided into two drainage area basins, and each is larger than 5 acres. According to Table 6.6.1-Acceptable Runoff Calculation Methods, located in the COB CDS, the NRCS runoff calculation method will be used for the project. The NRCS requires the following three items before determining the resulting peak flows, and volume required, soil types, time of concentration, and curve numbers. A. Soil Types- This was described in section 1.1.3 of this report. We will use a hydrologic group C as determined by the NRCS Soil Survey. Page 6 of 11 B. Time of Concentration- The TR-55 method will used for the purpose of the design report. C. Curve Numbers- Curve Numbers for this project have been used from Table 6.6.2 of the COB CDS. Land Use Hydrologic Group C CN Value Open Space Fully Developed; Good condition 74 ROW Streets and Roads; paved with curbs and storm 98 Residential Lots Average % impervious: 38% 83 For this report the water quality storm (2), minor storm (10-year), and major storm (100-year) will be evaluated. Table 6.5.1-Precipitation Depth and Table 6.5.2-Precipitation Intensity will be used from the COB CDS. 2.2 Summary of Geotechnical Evaluation The geotechnical investigation for the West Park Subdivision, dated April, 2020, evaluated subsurface soil conditions, groundwater levels, and site suitability for residential and infrastructure development. The site is underlain by Pleistocene-aged alluvial fan deposits, consisting of topsoil, lean clay loam, gravelly clay, and poorly graded alluvial gravels. Twenty- three test holes were excavated to depths of 5 to 13 feet, revealing consistent soil profiles across the site, with groundwater typically encountered around 36 inches below grade. The southeast portion of the site was previously disturbed by gravel mining and spoil dumping, resulting in undocumented fill and deeper groundwater levels. These areas are considered less suitable for development without reclamation. The native gravels found at approximately 50 inches below grade are stiff and well-drained, making them ideal for structural support. 3 EXISTING STORMWATER DRAINAGE CONDITIONS 3.1 Existing Drainage Conditions 3.1.1 Existing Drainage Basin Runoff Characteristics The existing property is primarily vacant, agricultural land. The existing slopes range from 0% to 4%, generally draining from south to north. The existing site has been divided into two subbasins. Subbasin 1 has been evaluated in this report. Most of the undeveloped property flows to the non-jurisdiction wetland located towards the center north of the site and either infiltrates or evaporates or continues to flow northeast offsite to the neighboring wetlands. Subbasin 2.0 has not been evaluated in this report as it will not be disturbed. This subbasin has already been evaluated for previous Norton Ranch subdivisions. There are culverts located underneath Laurel Parkway that direct any stormwater runoff from Subbasin 2.See EX 1.0: Pre- Development Drainage Exhibit. 3.1.2 Off-Site Contributing Areas and Outfall Phase 1 of the previous Norton East Ranch subdivision created 10 stormwater ponds for detention and retention. Detention ponds 4 and 6 are located in the southwest corner of the property. Both ponds detain the 10-year, 2-hour storm with outlets that direct stormwater to the northwest and are conveyed under the Laurel Parkway right-of-way. These stormwater ponds Page 7 of 11 will remain as is and will be undisturbed during the construction of the Laurel Meadows subdivision. There is an additional retention pond is in the northwest corner of the property, south of Lot 1. According to the design report for Stormwater Management to the Norton East Ranch Subdivision, Phase 5, dated June 2021, prepared by C&H Engineering, runoff from Laurel Parkway is conveyed to this pond. Drainage areas, DA#9, and DA#10 from this report will be included into the Drainage Area A of Laurel Meadows. 3.2 Hydrologic and Hydraulic Calculations or Modeling 3.2.1 Hydraulic Methods and Computer Models Used Hydrologic and hydraulic calculations for existing conditions of the Laurel Meadows subdivision were performed using the NRCS TR-55 method, in accordance with the COB DSC. Hydraflow Hydrographs (an extension of Autodesk Civil 3D) was used to determine the existing conditions of the site. AutoCAD was used to calculate areas of the existing basins. According to the soil survey, the hydrologic soil group used was C. The existing conditions are herbaceous with greater than 70% of ground cover. The curve number used was 74 from Table 6.6.2 from the COB DSC. Calculations can be found in Appendix B. 3.2.2 Hydraulic Capacity of Existing Drainage Features The pre-existing drainage basin is 36.51 acres, and has a time of concentration of 44.1 minutes. The basin was evaluated for each storm event below. Storm Event Peak flow (cfs) Hydraulic Volume (cu.ft.) 2-year 0.372 7,476 10-year 3.24 28,942 100-year 10.34 68,359 3.2.3 Hydraulic Capacity of Existing Outfall Runoff to the northeast of the site located in The Lakes Subdivision eventually flows into the east lake of the subdivision before dispersing into Ajker Creek. 4 PROPOSED STORMWATER DRAINAGE CONDITIONS 4.1 Applicable Design Standards The City of Bozeman Design and Construction Standards, dated October 2024 (COB CDS) were used for this report. The COB CDS also references the Urban Drainage Design Manual, Fourth Edition and Montana Post Construction Storm Water BMP Design Guidance Manul. 4.2 Drainage System Design 4.2.1 Post-project Drainage Patterns Including Off-Site Contributing Areas and Outfall The proposed stormwater drainage plan for Laurel Meadows divides the site into two distinct subbasins, separated by Pond Lily Drive. Each subbasin will include its own forebay for initial treatment. Treated runoff from both forebays will then be conveyed to a shared wet pond located at the north end of the property. The wet pond will discharge to existing wetlands Page 8 of 11 northeast of the site, within The Lakes Subdivision, via a controlled outfall system. Energy dissipation measures will be implemented at the outfall to prevent erosion and protect downstream resources. Drainage basins are depicted in the post-development drainage exhibit, EX 2.0. These basins include runoff from the residential properties, open spaces, and rights-of-ways. Drainage Area 1 encompasses Phases 1 and 2 of the development and includes the offsite run-on from Laurel Parkway. Drainage Area 2 includes Phases 3 and 4 of the project and the ROW connection to Vaughn Drive north of the property. There are no proposed stormwater controls for the adjacent park area. The existing stormwater ponds located southwest of the property will remain undisturbed. Due to the phasing of this project, a temporary pond will need to be constructed north of Pond Lily and Donnor Drive. 4.2.2 Post-project Drainage Basin Runoff Characteristics The drainage areas described above are combined and evaluated in the table below for the 100-year storm event. As discussed in the Montana Post-Construction Storm Water BMP Design Guidance Manual, the wet detention basin will utilize forebays that hold a minimum of 10% of the runoff treatment volume. Calculations can be found in Appendix B. Drainage Areas Area (ac) CN Value Time of Conc. (min) 100yr Hydraulic Volume (cf) Forebay Required Volume (cf) Forebay Provided Volume (cf) Subbasin 1 17.24 88 15.6 77,972 7,797 9,888 Subbasin 2 12.43 87 14.3 53,187 5,319 6,159 4.2.3 Planned Drainage Features Curb and gutter will convey stormwater to inlets, which connect to an underground storm drain network routed to storage basins. These features are shown on EX 2.0: Post-Development Drainage Exhibit. 4.3 Hydrologic and Hydraulic Calculations or Modeling 4.3.1 Hydraulic Methods Major subbasin areas were delineated using AutoCAD Civil 3D based on proposed grading and parcel layout. This ensured accurate representation of contributing areas for each drainage basin. Hydraflow Hydrographs was used to calculate time of concentration using the TR-55 method. HydroCAD was used to determine hydraulic volumes, peak flows, and outflows for the 2-year, 10-year and 100-year storm events. Orifice sizing for the wet detention pond outlet was also determined using HydroCAD to meet predevelopment discharge rates. Calculations can be found in Appendix B. Conveyance elements, including inlets and pipes, will be analyzed using AutoCAD Storm and Sanitary Analysis (SSA). SSA allows for dynamic routing of flows through the proposed infrastructure and will ensure compliance with hydraulic grade line (HGL) and velocity Page 9 of 11 requirements. Conveyance elements are not calculated for this preliminary report, but will be prior to the final infrastructure submittal. 4.3.2 Post-project vs. Existing Runoff Rates and Volumes See table below for the predevelopment rates, compared to the post-development rates. Storm Event Qpre (cfs) Qpost (cfs) 2-year 0.372 0.36 10-year 3.24 2.49 100-year 10.64 10.17 4.3.3 Stormwater Drainage System Elements a. The inlets and pipes will be designed to open channel flow into the forebays. b. Storm drain hydraulics including hydraulic grade line (HGL) will be calculated prior to the infrastructure submittal storm report. SDR 35 PVC pipe will be used for all pipes that have a minimum of 2.0-feet of cover and will use a manning’s coefficient of 0.011. Pipes that are not able to maintain a minimum cover of 2.0-feet will be RCP and will use a manning’s coefficient of 0.013. c. There should not be any curb topping for the 10-year event. The lowest grate is 4782.98’ for the west forebay, and the peak elevation for the west forebay is 4782.16. The lowest grate is 4782.25’ for the east forebay, and the peak elevation for the east forebay is 4782.08. The maximum pond elevation for the 100-year event is 4782.20, and is less than 18-inches above the curb flowline. d. Storm inlet interception and bypass calculations will be completed during the infrastructure submittal phase of this project. This preliminary report will be updated accordingly. e. Erosion protection such as rip-rap will be used to dissipate the energy for the flows into forebays, the wet detention pond and the outlet to the north. f. The forebays were calculated using 10% of the required storage for each sub basin. The wet detention pond was sized according to detention calculations. The wet pond will have a maximum depth of 6 feet. A bench will be provided 2.0’ below the top of the water. The wetpond is designed to store a total depth of 2 feet of stormwater and should hold a minimum of 2.5’ of groundwater. The groundwater fluctuates 1.5 feet throughout the year. A controlled orifice will be placed at the outlet of the wet pond, distributing water at the 2 year, 10 year, and 100 year rate, less than the pre-existing storm event conditions g. The outfall drainage path will discharge to the existing wetland area to the northeast, north of Vaughn Drive in the Lakes at Valley West subdivision. h. Erosion protection measures will be sized by MDT standards prior to the infrastructure submittal. 4.3.4 Hydraulics Design vs Design Criteria The hydraulic design used the COB DCS and is in accordance with the criteria. Page 10 of 11 4.3.5 Water Quality Treatment Design The required water quality treatment is the 2-year storm event according to COB DCS. According to the Urban Drainage Design Manual for wetponds, a forebay needs to retain 10% of the treated volume of the retention pond. This is greater than the 2 year- storm event. 4.4 Runoff Control Facilities The wet detention pond will be discharged into the existing wetland corridor located northeast of the property maintaining natural hydrologic connectivity. This outfall will be controlled by an orifice sized for the 2-yr, 10-yr, and 100-yr predevelopment rate. There will be an additional overflow structure located in the boulevard that will connect to this outfall pipe. 4.5 Permanent Water Quality Treatment As discussed in the Montana Post-Construction Storm Water BMP Design Guidance Manual, the wet detention basin will utilize forebays for water quality. 4.6 Erosion and Sediment Control Flared end treatments (FETs) will be used to prevent erosion. Where flow velocities are above 10 fps during the Minor Storm, rip rap will be used per FHWA Hydraulic Engineering Circular (HEC) No. 15 in addition to MDT Standards Specifications for Construction, Division 700. 5 EVALUTION OF MAJOR STORM FLOOD RISKS 5.1 Major Storm Post-project Flood Hazards vs Existing The storm water management system for the proposed development utilizes a system of curb, gutter, inlets, piping, detention facilities, and surface retention basins to collect, convey, and store storm water runoff. Summaries of runoff estimates, inlet and piping capacities, and retention volumes are provided in the sections that follow. 5.2 Potential Flood Hazards and Mitigation Measures Storm water runoff analyses were performed using the Rational Method for post-development conditions. The analyses included evaluations of the 25-year design storm recurrence interval for inlet and piping system design. 6 OPERATION, INSPECTION, AND MAINTENANCE CONSIDERATIONS Storm drain inlets, catch basins, and piping should be inspected at least once per year and following large storm events by West Park Neighborhood Condominium Owners Association. Any necessary repair or maintenance should be prioritized and scheduled through the spring, summer, and fall. These items may include inspecting for any damage, removing blockages, cleaning and flushing the length of pipes, establishing vegetation on bare slopes at or near inlets, and sediment removal. Maintenance of the retention basin is also essential. General objectives of maintenance are to prevent clogging, standing water and the growth of weeds and wetland plants. This requires frequent unclogging of the outlets, inlets, and mowing. Cleaning out sediment with earth-moving equipment may also be necessary in 10 to 20 years. An Operation and Maintenance Manual is included in Appendix E. Maintenance responsibility and maintenance requirements of the two existing ponds that serve the initial phases of the Norton East Ranch Subdivision shall be determined by the City of Bozeman. Page 11 of 11 7 REFERENCES City of Bozeman Design and Construction Standards, October 2024 Montana Post Construction Storm Water BMP Design Guidance Manual Urban Drainage Design Manual, Fourth Edition (fhwa.dot.gov) 8 EXHIBITS EX 1.0: Pre-Development Drainage EX 2.0: Post-Development Drainage 9 APPENDICES Appendix A: Castle Rock Geotechnical Report and Supplement Appendix B: Stormwater Calculations Appendix C: Groundwater Data Appendix D: Flood Hazard Analysis Appendix E: O&M Manual BPBPNGXXXXXX XXXXXXXXXXXXXXXXXXXXOOOOOOOONG3054801 .36AC 2" FLUSH SAND -STEWARTDYH DYH DYH SDSSGSSSSSSWV WV WV WV WV WVWVWVWV WV TWVWV PT PTWVWVWWWW WWWWS201854780.033MHS-TEMPS WWWWWWWV WV WV DYHWVWVWV WVWVWVWVWVWVWVWVWVWVWVWVWVWVWVWVWWWWWWWWWW WWSSSSSWW W W W W S SSSSSSSSSSSDYHDYHS SBPBPBP BP BP BP BP BP BP BP BPBPBPBPBPBPBPBPBPBPBPBPBP PSFM FMFMFMFMFMFMFMSFMFMFMFMPARK2.74 acs.-1.19%-2.16%-1.32%-0.82% -1.29% -1.61%-2.17%-1.28%-1.64% -2.93%-2.94%-1.06%-1.60%-0.82%-0.57%479547854800-0.87%-3.24%FIGURE NUMBER©PROJECT NO.DRAWN BY:DSGN. BY:APPR. BY:DATE:COPYRIGHT MORRISON-MAIERLE,2025Plotted by rosie nickelson on Oct/4/2025engineers surveyors planners scientistsMorrisonMaierle2880 Technology Blvd WestBozeman, MT 59718406.587.0721www.m-m.netN:\10130\001.04-PDZandPPLAT\ACAD\Exhibits\10130.001.04_PostDevDrainage Exhibit.dwg 10130.001.04 EX 1.0LAUREL MEADOWS SUBDIVISION BOZEMANMONTANAPRE-DEVELOPMENTDRAINAGE EXHIBITRSNRSNCPK10/2025100200501000SCALE IN FEETEXISTING NON-JURISDICTIONWETLAND TO BE MITIGATEDDETENTION PONDS #4 & #6(NORTON RANCH PHASE 1)WETLAND EASEMENTBOUNDARYWETLAND EASEMENTBOUNDARYEXISTING WETLANDNO PROPOSEDDISTURBANCE)EXISTING WETLANDNO PROPOSEDDISTURBANCE)SUBBASIN 1AREA= 36.51 ACRESTC=44.10SUBBASIN 2*AREA= 4.32 ACRES*THIS AREA WAS NOT EVALUATED AS THE OVERFLOW FROM THE EXISTING PONDSAND WETLANDS ARE DESIGNED TO FLOW FREELY UNDERNEATH LAUREL PARKWAY.LAUREL MEADOWS VAUGHN DRIVEWEST BABCOCK STREETEXISTING CULVERTS FOR WETLANDS TOFLOW FREELY UNDER LAURELMEADOWS PER NORTON RANCH DESIGNEXISTING RETENTION POND #1(NORTON RANCH PHASE 5)ABANDONEDIRRIGATION DITCHBAXTER CREEKSUBBASIN 1SUBBASIN 2 BPBPNGXXXXXX XXXXXXXXXXXXXXXXXXXXOOOOOOOONG3054801 .36AC 2" FLUSH SAND-STEWART DYHDYH DYHSDSSGSSSSSSWVWVWVWVWVWVWVWVWVWVTWVWV P T PTWVWVWWWWWWWWS201854780.033MHS-TEMPSWW WWWWWV WV WV DYHWVWVWV WVWVWVWVWVWVWVWVWVWVWVWVWVWVWVWVWWWWWWWWWWWWSSSSSWWWWWWSSSSSSSSSSSSDYHDYHSSBPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBPBP PSFM FMFMFMFMFMFMFMSFMFMFMFMPARK2.74 acs.N18°00'44"E 575.40'SDSD SD SDSDSD SDSDSDSDSDSD SD SDSDSD SD SD DDD DDDDD DDDDDD DDDSDDD0+001+002+003+004+005+005+67Alignment - (1)47704775478047854790477047754780478547900+001+002+003+004+005+005+67-24.72%50.00% -50.00% 50.00% -50.00% 25.00 % -33.33% 33.33 %FIGURE NUMBER©PROJECT NO.DRAWN BY:DSGN. BY:APPR. BY:DATE:COPYRIGHT MORRISON-MAIERLE,2025Plotted by rosie nickelson on Oct/4/2025engineers surveyors planners scientistsMorrisonMaierle2880 Technology Blvd WestBozeman, MT 59718406.587.0721www.m-m.netN:\10130\001.04-PDZandPPLAT\ACAD\Exhibits\10130.001.04_PostDevDrainage Exhibit.dwg 10130.001.04 EX 2.0LAUREL MEADOWS SUBDIVISION BOZEMANMONTANAPOST DEVELOPMENTDRAINAGE EXHIBITRSNRSNCPK10/2025100200501000SCALE IN FEETDRAINAGE BASIN 1ON-SITE:AREA: 551,702 SF = 12.67 ACCOMPOSITE CN: 87OFFSITE RUN ON (LAUREL PARKWAY):DA#9 AREA: 3.15AC, CN=85DA#10A AREA: 1.17AC, CN=98ADD. LP AREA: 0.248 AC, CN=98TOTAL AREA=17.24 AC, CN=88DRAINAGE BASIN 2ONSITEAREA: 523,967 SF = 12.03 ACCOMPOSITE CN: 87NORTH ROWAREA:17,614 SF = 0.40 ACCOMPOSITE CN: 98TOTAL AREA = 12.43 AC, CN=87OPEN SPACE 03AREA: 0.85 ACNO PROPOSED DEVELOPMENTS IN THIS AREA.RESIDENTIAL LOTS WILL BE BUILT UP AND FLOW INTO BASIN A.PARKAREA: 11.28 ACSTORM WATER WAS NOT CONSIDERED IN THIS AREA. PARKIMPROVEMENTS ARE A GRAVEL TRAIL, THAT WILL SHEET FLOWTOWARDS THE PROPOSED WETLANDS. THE ONLY PROPOSEDSTRUCTURE IS THE PAVILION AND LESS THAN 5000 SF.OPEN SPACE 3PARKNORTH ROW1.11.21.31.41.51.61.71.81.92.112.122.142.13 2.152.162.182.172.192.212.20EAST FOREBAYWETPONDWEST FOREBAYOUTFALL PIPEPROPERTY BOUDARYDRAINAGE AREA #10(NORTON RANCH PHASE 5)DRAINAGE AREA #9(NORTON RANCH PHASE 5)LEGENDSUBBASIN 1SUBBASIN 2SUBBASIN: North ROWADDITIONAL LAURELPARKWAY RUN-ON(0.248 AC)FOREBAY WEIR ELEV: 4782.00BASIN BOTTOM: 4780.00YEAR ROUND MINIMUM GROUNDWATER LEVEL (LOW): 4778.50HIGH GROUNDWATER LEVEL: 4780.00POND BOTTOM: 4778.00POND BOTTOM: 4776.25BASIN TOP: 4782.25FREEBOARD: 4783.25NOTE: 4' BENCHES ARE NOT INCLUDED IN THIS PROFILE. THEY ARE INCLUDED ALONG THE EDGES OF THE WETPOND.1-FOREBAY/WET PONDCROSS SECTIONOUTLET STRUCTURE SUPPLEMENTARY TO GEO-REPORT D:\Jobs File\JBS 2020\020025CR\Geo Report Supplement, L@VW-South MT r.doc PROJECT: West Park Neighborhood Bozeman, Gallatin County Montana CLIENT: 8FC,LLC P.O. Box 11388 Bozeman, Montana 59719-1388 PROJECT NO.: 020025CR – Supplementary Comments DATE: August 30th, 2022 Introduction This letter is to serve as a supplement to the above referenced property. Andrew Pilskalns P.E. prepared a Geotechnical Report for the above referenced property on April 10th, 2020. The legal description of the project as given at the time of the Geotechnical investigation is a portion of the Southwest ¼ of the Northeast ¼ of Section 9, Township 2 South, Range 5 East, of the Bozeman, Montana Quadrangle in Gallatin County’. The Property Record Card reported at that time the Primary Owners as Norton Properties LLC and the Subdivision as Norton East Ranch Subdivision Phase III, Plat J-564. The property is currently being developed as the West Park Neighborhood and the Owners are 8FC, LLC. The site is located on the north side of west Babcock Street between Pond Lily Drive and Water Lily Drive. The Vicinity and Topographic Map are shown in Figure 1 of the letter. Figure 1 –Vicinity & Topographic Map Geologic Review of D:\Jobs File\JBS 2020\020025CR\Geo Report Supplement, L@VW-South MT r.doc 2 Part of the ‘Study of Grounds’ work was to evaluate the proposed development and the area shown in Figure 2 – Test Hole Map as the Open Pit Gravel Mining and Soil Spoils Deposit area. The Open Pit Gravel Mining and Soil Spoils Deposit area is adjacent to Baxter Creek, which trends in the northwest direction and also makes up the east property boundary. Deep gravel mining operations consisted of 20 to 30+ feet deep excavations, completed by Norton Properties LLC. The past Owners proceeded to backfill portions of the disturbed area with spoils from the mining operation with clayey-silt soils, and organics. The area within the disturbance is considered unsuitable for redevelopment or road development based on depth of excavation associated with gravel mining activities and the undocumented fill placed in the excavations. The best use of the land is creating wetland and park, which has environmental benefits and esthetic benefits for the people of the community. Figure 2 – Test Hole Map Conclusion Geologic Review of D:\Jobs File\JBS 2020\020025CR\Geo Report Supplement, L@VW-South MT r.doc 3 Based on the risk and cost to reclaim property that was initially used in gravel mining operations, we maintain the same position as first reported; the area should be used for natural open space, such as parks, wetlands, and ponds. If you have any questions or concerns about the contents of this letter, please contact our office. I appreciate the opportunity to work with you. Prepared by, ANDY PILSKALNS, P.E. LICENSED - Montana, Utah, Colorado, Idaho, Wyoming, Hawaii, Nevada PROVIDING THE WEST WITH GEOTECHNICAL SERVICES FOR 19 YEARS Castle Rock Geotechnical Engineering 9 Cedar Lake Drive Butte, Montana 59701 C: (406) 539-8439 O: (406) 209-5573 TR55 Tc Worksheet4Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2025Hyd. No. 4Existing Conditions 1.0DescriptionABCTotalsSheet FlowManning's n-value = 0.050 0.011 0.011Flow length (ft) = 150.0 0.0 0.0Two-year 24-hr precip. (in) = 0.05 0.00 0.00Land slope (%) = 2.50 0.00 0.00Travel Time (min) = 41.59 + 0.00 + 0.00 = 41.59Shallow Concentrated FlowFlow length (ft) = 300.00 0.00 0.00Watercourse slope (%) = 1.50 0.00 0.00Surface description = Unpaved Paved PavedAverage velocity (ft/s) =1.98 0.00 0.00Travel Time (min) = 2.53 + 0.00 + 0.00 = 2.53Channel FlowX sectional flow area (sqft) = 0.00 0.00 0.00Wetted perimeter (ft) = 0.00 0.00 0.00Channel slope (%) = 0.00 0.00 0.00Manning's n-value = 0.015 0.015 0.015Velocity (ft/s) =0.000.000.00Flow length (ft) ({0})0.0 0.0 0.0Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00Total Travel Time, Tc .............................................................................. 44.10 min Hydrograph ReportHydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2025 Saturday, 10 / 4 / 2025Hyd. No. 4Existing Conditions 1.0Hydrograph type = SCS Runoff Peak discharge = 0.372 cfsStorm frequency = 2 yrs Time to peak = 774 minTime interval = 2 min Hyd. volume = 7,476 cuftDrainage area = 36.511 ac Curve number = 74Basin Slope = 0.0 % Hydraulic length = 0 ftTc method = TR55 Time of conc. (Tc) = 44.10 minTotal precip. = 1.18 in Distribution = Type IIStorm duration = 24 hrs Shape factor = 4843012024036048060072084096010801200132014401560Q (cfs)0.00 0.000.05 0.050.10 0.100.15 0.150.20 0.200.25 0.250.30 0.300.35 0.350.40 0.400.45 0.450.50 0.50Q (cfs)Time (min)Existing Conditions 1.0Hyd. No. 4 -- 2 YearHyd No. 4 Hydrograph ReportHydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2025 Saturday, 10 / 4 / 2025Hyd. No. 4Existing Conditions 1.0Hydrograph type = SCS Runoff Peak discharge = 3.240 cfsStorm frequency = 10 yrs Time to peak = 746 minTime interval = 2 min Hyd. volume = 28,942 cuftDrainage area = 36.511 ac Curve number = 74Basin Slope = 0.0 % Hydraulic length = 0 ftTc method = TR55 Time of conc. (Tc) = 44.10 minTotal precip. = 1.70 in Distribution = Type IIStorm duration = 24 hrs Shape factor = 4846012024036048060072084096010801200132014401560Q (cfs)0.00 0.001.00 1.002.00 2.003.00 3.004.00 4.00Q (cfs)Time (min)Existing Conditions 1.0Hyd. No. 4 -- 10 YearHyd No. 4 Hydrograph ReportHydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2025 Saturday, 10 / 4 / 2025Hyd. No. 4Existing Conditions 1.0Hydrograph type = SCS Runoff Peak discharge = 10.34 cfsStorm frequency = 100 yrs Time to peak = 744 minTime interval = 2 min Hyd. volume = 68,359 cuftDrainage area = 36.511 ac Curve number = 74Basin Slope = 0.0 % Hydraulic length = 0 ftTc method = TR55 Time of conc. (Tc) = 44.10 minTotal precip. = 2.34 in Distribution = Type IIStorm duration = 24 hrs Shape factor = 4848012024036048060072084096010801200132014401560Q (cfs)0.00 0.002.00 2.004.00 4.006.00 6.008.00 8.0010.00 10.0012.00 12.00Q (cfs)Time (min)Existing Conditions 1.0Hyd. No. 4 -- 100 YearHyd No. 4 1S Subasin 1 4S Subbasin 2 3P Wetpond 5P East Forebay 6P West Forebay Routing Diagram for 10310.001.04_STORM Prepared by Morrison Maierle Inc, Printed 10/4/2025 HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Subcat Reach Pond Link 10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 2HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Rainfall Events Listing Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 2-YR Type II 24-hr Default 24.00 1 1.18 2 2 10-YR Type II 24-hr Default 24.00 1 1.70 2 3 100-YR Type II 24-hr Default 24.00 1 2.34 2 10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 3HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.250 98 LP (Additional Runoff) (1S) 1.170 98 LP DA#10 (1S) 1.340 74 LP DA#9 (OS) (1S) 0.510 83 LP DA#9 (OS) (1S) 1.300 98 LP DA#9 (ROW) (1S) 0.400 98 North ROW (4S) 1.770 74 OS (4S) 2.390 74 Openspace-Onsite (1S) 4.390 98 ROW (4S) 5.150 98 ROW-Onsite (1S) 5.870 83 Residential (4S) 5.130 83 Residential Lots-Onsite (1S) 29.670 88 TOTAL AREA 10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 4HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.000 HSG A 0.000 HSG B 0.000 HSG C 0.000 HSG D 29.670 Other 1S, 4S 29.670 TOTAL AREA 10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 5HydroCAD® 10.20-7a s/n 04318 © 2025 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 0.000 0.000 0.000 0.250 0.250 LP (Additional Runoff) 1S 0.000 0.000 0.000 0.000 1.170 1.170 LP DA#10 1S 0.000 0.000 0.000 0.000 1.850 1.850 LP DA#9 (OS) 1S 0.000 0.000 0.000 0.000 1.300 1.300 LP DA#9 (ROW) 1S 0.000 0.000 0.000 0.000 0.400 0.400 North ROW 4S 0.000 0.000 0.000 0.000 1.770 1.770 OS 4S 0.000 0.000 0.000 0.000 2.390 2.390 Openspace-Onsite 1S 0.000 0.000 0.000 0.000 4.390 4.390 ROW 4S 0.000 0.000 0.000 0.000 5.150 5.150 ROW-Onsite 1S 0.000 0.000 0.000 0.000 5.870 5.870 Residential 4S 0.000 0.000 0.000 0.000 5.130 5.130 Residential Lots-Onsite 1S 0.000 0.000 0.000 0.000 29.670 29.670 TOTAL AREA Type II 24-hr 2-YR Rainfall=1.18"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 6HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Time span=5.00-72.00 hrs, dt=0.05 hrs, 1341 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=17.240 ac 45.65% Impervious Runoff Depth=0.36"Subcatchment 1S: Subasin 1 Tc=15.6 min CN=88 Runoff=7.49 cfs 0.521 af Runoff Area=12.430 ac 38.54% Impervious Runoff Depth=0.33"Subcatchment 4S: Subbasin 2 Tc=14.3 min CN=87 Runoff=4.97 cfs 0.339 af Peak Elev=4,780.64' Storage=11,734 cf Inflow=4.18 cfs 0.526 afPond 3P: Wetpond Outflow=0.35 cfs 0.449 af Peak Elev=4,782.04' Storage=8,981 cf Inflow=7.49 cfs 0.521 afPond 5P: East Forebay Outflow=2.53 cfs 0.320 af Peak Elev=4,782.02' Storage=5,848 cf Inflow=4.97 cfs 0.339 afPond 6P: West Forebay Outflow=1.66 cfs 0.206 af Total Runoff Area = 29.670 ac Runoff Volume = 0.859 af Average Runoff Depth = 0.35" 57.33% Pervious = 17.010 ac 42.67% Impervious = 12.660 ac Type II 24-hr 2-YR Rainfall=1.18"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 7HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: Subasin 1 TC was calculated using Hydraflow Hydrographs-Subbasin 1 (Phases 1&2 + LP) Runoff = 7.49 cfs @ 12.09 hrs, Volume= 0.521 af, Depth= 0.36" Routed to Pond 5P : East Forebay Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Type II 24-hr 2-YR Rainfall=1.18" Area (ac) CN Description * 2.390 74 Openspace-Onsite * 5.130 83 Residential Lots-Onsite * 5.150 98 ROW-Onsite * 1.170 98 LP DA#10 * 0.250 98 LP (Additional Runoff) * 1.300 98 LP DA#9 (ROW) * 1.340 74 LP DA#9 (OS) * 0.510 83 LP DA#9 (OS) 17.240 88 Weighted Average 9.370 54.35% Pervious Area 7.870 45.65% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 15.6 Direct Entry, Subbasin 1 Subcatchment 1S: Subasin 1 Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)8 7 6 5 4 3 2 1 0 Type II 24-hr 2-YR Rainfall=1.18" Runoff Area=17.240 ac Runoff Volume=0.521 af Runoff Depth=0.36" Tc=15.6 min CN=88 7.49 cfs Type II 24-hr 2-YR Rainfall=1.18"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 8HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment 4S: Subbasin 2 TC was calculated using Hydraflow Hydrographs-Subbasin 1 (Phases 3&4 + North ROW) Runoff = 4.97 cfs @ 12.08 hrs, Volume= 0.339 af, Depth= 0.33" Routed to Pond 6P : West Forebay Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Type II 24-hr 2-YR Rainfall=1.18" Area (ac) CN Description * 1.770 74 OS * 5.870 83 Residential * 4.390 98 ROW * 0.400 98 North ROW 12.430 87 Weighted Average 7.640 61.46% Pervious Area 4.790 38.54% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14.3 Direct Entry, Hydraflow Hydrograph Subcatchment 4S: Subbasin 2 Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)5 4 3 2 1 0 Type II 24-hr 2-YR Rainfall=1.18" Runoff Area=12.430 ac Runoff Volume=0.339 af Runoff Depth=0.33" Tc=14.3 min CN=87 4.97 cfs Type II 24-hr 2-YR Rainfall=1.18"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 9HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Pond 3P: Wetpond Inflow Area = 29.670 ac, 42.67% Impervious, Inflow Depth = 0.21" for 2-YR event Inflow = 4.18 cfs @ 12.41 hrs, Volume= 0.526 af Outflow = 0.35 cfs @ 18.78 hrs, Volume= 0.449 af, Atten= 92%, Lag= 382.0 min Primary = 0.35 cfs @ 18.78 hrs, Volume= 0.449 af Routing by Stor-Ind method, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 4,780.64' @ 18.78 hrs Surf.Area= 31,106 sf Storage= 11,734 cf Flood Elev= 4,782.25' Surf.Area= 37,357 sf Storage= 66,837 cf Plug-Flow detention time= 554.2 min calculated for 0.449 af (85% of inflow) Center-of-Mass det. time= 489.7 min ( 1,458.2 - 968.5 ) Volume Invert Avail.Storage Storage Description #1 4,780.25' 66,837 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 4,780.25 29,659 0 0 4,782.00 36,216 57,641 57,641 4,782.25 37,357 9,197 66,837 Device Routing Invert Outlet Devices #1 Primary 4,780.35'9.0" W x 3.0" H Vert. 2-YR C= 0.600 Limited to weir flow at low heads #2 Primary 4,780.65'36.0" W x 6.0" H Vert. 10-YR C= 0.600 Limited to weir flow at low heads #3 Primary 4,781.10'30.0" W x 18.0" H Vert. 100-YR C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.35 cfs @ 18.78 hrs HW=4,780.64' (Free Discharge) 1=2-YR (Orifice Controls 0.35 cfs @ 1.88 fps) 2=10-YR ( Controls 0.00 cfs) 3=100-YR ( Controls 0.00 cfs) Type II 24-hr 2-YR Rainfall=1.18"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 10HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Pond 3P: Wetpond Inflow Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)4 3 2 1 0 Inflow Area=29.670 ac Peak Elev=4,780.64' Storage=11,734 cf 4.18 cfs 0.35 cfs Type II 24-hr 2-YR Rainfall=1.18"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 11HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Pond 5P: East Forebay Inflow Area = 17.240 ac, 45.65% Impervious, Inflow Depth = 0.36" for 2-YR event Inflow = 7.49 cfs @ 12.09 hrs, Volume= 0.521 af Outflow = 2.53 cfs @ 12.41 hrs, Volume= 0.320 af, Atten= 66%, Lag= 18.9 min Primary = 2.53 cfs @ 12.41 hrs, Volume= 0.320 af Routed to Pond 3P : Wetpond Routing by Stor-Ind method, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 4,782.04' @ 12.41 hrs Surf.Area= 5,608 sf Storage= 8,981 cf Plug-Flow detention time= 222.6 min calculated for 0.319 af (61% of inflow) Center-of-Mass det. time= 94.1 min ( 965.0 - 871.0 ) Volume Invert Avail.Storage Storage Description #1 4,779.75' 10,199 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 4,779.75 2,249 0 0 4,782.00 5,537 8,759 8,759 4,782.25 5,981 1,440 10,199 Device Routing Invert Outlet Devices #1 Primary 4,782.00'Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Elev. (feet) 4,782.00 4,782.25 Width (feet) 93.50 93.50 Primary OutFlow Max=2.33 cfs @ 12.41 hrs HW=4,782.04' (Free Discharge) 1=Custom Weir/Orifice (Weir Controls 2.33 cfs @ 0.64 fps) Type II 24-hr 2-YR Rainfall=1.18"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 12HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Pond 5P: East Forebay Inflow Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)8 7 6 5 4 3 2 1 0 Inflow Area=17.240 ac Peak Elev=4,782.04' Storage=8,981 cf 7.49 cfs 2.53 cfs Type II 24-hr 2-YR Rainfall=1.18"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 13HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Pond 6P: West Forebay Inflow Area = 12.430 ac, 38.54% Impervious, Inflow Depth = 0.33" for 2-YR event Inflow = 4.97 cfs @ 12.08 hrs, Volume= 0.339 af Outflow = 1.66 cfs @ 12.41 hrs, Volume= 0.206 af, Atten= 67%, Lag= 20.1 min Primary = 1.66 cfs @ 12.41 hrs, Volume= 0.206 af Routed to Pond 3P : Wetpond Routing by Stor-Ind method, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 4,782.02' @ 12.42 hrs Surf.Area= 3,370 sf Storage= 5,848 cf Plug-Flow detention time= 230.3 min calculated for 0.206 af (61% of inflow) Center-of-Mass det. time= 97.9 min ( 974.0 - 876.1 ) Volume Invert Avail.Storage Storage Description #1 4,779.75' 6,647 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 4,779.75 1,787 0 0 4,782.00 3,347 5,776 5,776 4,782.25 3,619 871 6,647 Device Routing Invert Outlet Devices #0 Primary 4,782.25'Automatic Storage Overflow (Discharged without head) #1 Primary 4,782.00'Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Elev. (feet) 4,782.00 4,782.25 Width (feet) 159.00 159.00 Primary OutFlow Max=1.23 cfs @ 12.41 hrs HW=4,782.02' (Free Discharge) 1=Custom Weir/Orifice (Weir Controls 1.23 cfs @ 0.44 fps) Type II 24-hr 2-YR Rainfall=1.18"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 14HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Pond 6P: West Forebay Inflow Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)5 4 3 2 1 0 Inflow Area=12.430 ac Peak Elev=4,782.02' Storage=5,848 cf 4.97 cfs 1.66 cfs Type II 24-hr 10-YR Rainfall=1.70"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 15HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Time span=5.00-72.00 hrs, dt=0.05 hrs, 1341 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=17.240 ac 45.65% Impervious Runoff Depth=0.73"Subcatchment 1S: Subasin 1 Tc=15.6 min CN=88 Runoff=15.73 cfs 1.049 af Runoff Area=12.430 ac 38.54% Impervious Runoff Depth=0.68"Subcatchment 4S: Subbasin 2 Tc=14.3 min CN=87 Runoff=10.94 cfs 0.702 af Peak Elev=4,781.01' Storage=23,500 cf Inflow=32.33 cfs 1.417 afPond 3P: Wetpond Outflow=2.70 cfs 1.340 af Peak Elev=4,782.16' Storage=9,671 cf Inflow=15.73 cfs 1.049 afPond 5P: East Forebay Outflow=19.61 cfs 0.848 af Peak Elev=4,782.08' Storage=6,061 cf Inflow=10.94 cfs 0.702 afPond 6P: West Forebay Outflow=12.82 cfs 0.570 af Total Runoff Area = 29.670 ac Runoff Volume = 1.751 af Average Runoff Depth = 0.71" 57.33% Pervious = 17.010 ac 42.67% Impervious = 12.660 ac Type II 24-hr 10-YR Rainfall=1.70"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 16HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: Subasin 1 TC was calculated using Hydraflow Hydrographs-Subbasin 1 (Phases 1&2 + LP) Runoff = 15.73 cfs @ 12.08 hrs, Volume= 1.049 af, Depth= 0.73" Routed to Pond 5P : East Forebay Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Type II 24-hr 10-YR Rainfall=1.70" Area (ac) CN Description * 2.390 74 Openspace-Onsite * 5.130 83 Residential Lots-Onsite * 5.150 98 ROW-Onsite * 1.170 98 LP DA#10 * 0.250 98 LP (Additional Runoff) * 1.300 98 LP DA#9 (ROW) * 1.340 74 LP DA#9 (OS) * 0.510 83 LP DA#9 (OS) 17.240 88 Weighted Average 9.370 54.35% Pervious Area 7.870 45.65% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 15.6 Direct Entry, Subbasin 1 Subcatchment 1S: Subasin 1 Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type II 24-hr 10-YR Rainfall=1.70" Runoff Area=17.240 ac Runoff Volume=1.049 af Runoff Depth=0.73" Tc=15.6 min CN=88 15.73 cfs Type II 24-hr 10-YR Rainfall=1.70"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 17HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment 4S: Subbasin 2 TC was calculated using Hydraflow Hydrographs-Subbasin 1 (Phases 3&4 + North ROW) Runoff = 10.94 cfs @ 12.07 hrs, Volume= 0.702 af, Depth= 0.68" Routed to Pond 6P : West Forebay Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Type II 24-hr 10-YR Rainfall=1.70" Area (ac) CN Description * 1.770 74 OS * 5.870 83 Residential * 4.390 98 ROW * 0.400 98 North ROW 12.430 87 Weighted Average 7.640 61.46% Pervious Area 4.790 38.54% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14.3 Direct Entry, Hydraflow Hydrograph Subcatchment 4S: Subbasin 2 Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)12 11 10 9 8 7 6 5 4 3 2 1 0 Type II 24-hr 10-YR Rainfall=1.70" Runoff Area=12.430 ac Runoff Volume=0.702 af Runoff Depth=0.68" Tc=14.3 min CN=87 10.94 cfs Type II 24-hr 10-YR Rainfall=1.70"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 18HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Pond 3P: Wetpond Inflow Area = 29.670 ac, 42.67% Impervious, Inflow Depth = 0.57" for 10-YR event Inflow = 32.33 cfs @ 12.11 hrs, Volume= 1.417 af Outflow = 2.70 cfs @ 12.89 hrs, Volume= 1.340 af, Atten= 92%, Lag= 47.0 min Primary = 2.70 cfs @ 12.89 hrs, Volume= 1.340 af Routing by Stor-Ind method, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 4,781.01' @ 12.89 hrs Surf.Area= 32,492 sf Storage= 23,500 cf Flood Elev= 4,782.25' Surf.Area= 37,357 sf Storage= 66,837 cf Plug-Flow detention time= 284.9 min calculated for 1.339 af (94% of inflow) Center-of-Mass det. time= 257.7 min ( 1,143.7 - 886.0 ) Volume Invert Avail.Storage Storage Description #1 4,780.25' 66,837 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 4,780.25 29,659 0 0 4,782.00 36,216 57,641 57,641 4,782.25 37,357 9,197 66,837 Device Routing Invert Outlet Devices #1 Primary 4,780.35'9.0" W x 3.0" H Vert. 2-YR C= 0.600 Limited to weir flow at low heads #2 Primary 4,780.65'36.0" W x 6.0" H Vert. 10-YR C= 0.600 Limited to weir flow at low heads #3 Primary 4,781.10'30.0" W x 18.0" H Vert. 100-YR C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=2.70 cfs @ 12.89 hrs HW=4,781.01' (Free Discharge) 1=2-YR (Orifice Controls 0.66 cfs @ 3.50 fps) 2=10-YR (Orifice Controls 2.05 cfs @ 1.92 fps) 3=100-YR ( Controls 0.00 cfs) Type II 24-hr 10-YR Rainfall=1.70"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 19HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Pond 3P: Wetpond Inflow Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=29.670 ac Peak Elev=4,781.01' Storage=23,500 cf 32.33 cfs 2.70 cfs Type II 24-hr 10-YR Rainfall=1.70"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 20HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Pond 5P: East Forebay [88] Warning: Qout>Qin may require smaller dt or Finer Routing Inflow Area = 17.240 ac, 45.65% Impervious, Inflow Depth = 0.73" for 10-YR event Inflow = 15.73 cfs @ 12.08 hrs, Volume= 1.049 af Outflow = 19.61 cfs @ 12.11 hrs, Volume= 0.848 af, Atten= 0%, Lag= 1.4 min Primary = 19.61 cfs @ 12.11 hrs, Volume= 0.848 af Routed to Pond 3P : Wetpond Routing by Stor-Ind method, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 4,782.16' @ 12.11 hrs Surf.Area= 5,822 sf Storage= 9,671 cf Plug-Flow detention time= 118.3 min calculated for 0.847 af (81% of inflow) Center-of-Mass det. time= 35.3 min ( 885.0 - 849.7 ) Volume Invert Avail.Storage Storage Description #1 4,779.75' 10,199 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 4,779.75 2,249 0 0 4,782.00 5,537 8,759 8,759 4,782.25 5,981 1,440 10,199 Device Routing Invert Outlet Devices #1 Primary 4,782.00'Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Elev. (feet) 4,782.00 4,782.25 Width (feet) 93.50 93.50 Primary OutFlow Max=18.12 cfs @ 12.11 hrs HW=4,782.15' (Free Discharge) 1=Custom Weir/Orifice (Weir Controls 18.12 cfs @ 1.28 fps) Type II 24-hr 10-YR Rainfall=1.70"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 21HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Pond 5P: East Forebay Inflow Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=17.240 ac Peak Elev=4,782.16' Storage=9,671 cf 15.73 cfs 19.61 cfs Type II 24-hr 10-YR Rainfall=1.70"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 22HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Pond 6P: West Forebay [88] Warning: Qout>Qin may require smaller dt or Finer Routing Inflow Area = 12.430 ac, 38.54% Impervious, Inflow Depth = 0.68" for 10-YR event Inflow = 10.94 cfs @ 12.07 hrs, Volume= 0.702 af Outflow = 12.82 cfs @ 12.10 hrs, Volume= 0.570 af, Atten= 0%, Lag= 1.8 min Primary = 12.82 cfs @ 12.10 hrs, Volume= 0.570 af Routed to Pond 3P : Wetpond Routing by Stor-Ind method, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 4,782.08' @ 12.10 hrs Surf.Area= 3,439 sf Storage= 6,061 cf Plug-Flow detention time= 117.0 min calculated for 0.570 af (81% of inflow) Center-of-Mass det. time= 34.1 min ( 887.4 - 853.4 ) Volume Invert Avail.Storage Storage Description #1 4,779.75' 6,647 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 4,779.75 1,787 0 0 4,782.00 3,347 5,776 5,776 4,782.25 3,619 871 6,647 Device Routing Invert Outlet Devices #0 Primary 4,782.25'Automatic Storage Overflow (Discharged without head) #1 Primary 4,782.00'Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Elev. (feet) 4,782.00 4,782.25 Width (feet) 159.00 159.00 Primary OutFlow Max=12.69 cfs @ 12.10 hrs HW=4,782.08' (Free Discharge) 1=Custom Weir/Orifice (Weir Controls 12.69 cfs @ 0.95 fps) Type II 24-hr 10-YR Rainfall=1.70"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 23HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Pond 6P: West Forebay Inflow Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=12.430 ac Peak Elev=4,782.08' Storage=6,061 cf 10.94 cfs 12.82 cfs Type II 24-hr 100-YR Rainfall=2.34"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 24HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Time span=5.00-72.00 hrs, dt=0.05 hrs, 1341 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=17.240 ac 45.65% Impervious Runoff Depth=1.25"Subcatchment 1S: Subasin 1 Tc=15.6 min CN=88 Runoff=27.04 cfs 1.790 af Runoff Area=12.430 ac 38.54% Impervious Runoff Depth=1.18"Subcatchment 4S: Subbasin 2 Tc=14.3 min CN=87 Runoff=19.26 cfs 1.221 af Peak Elev=4,781.63' Storage=44,435 cf Inflow=46.63 cfs 2.677 afPond 3P: Wetpond Outflow=10.18 cfs 2.599 af Peak Elev=4,782.20' Storage=9,888 cf Inflow=27.04 cfs 1.790 afPond 5P: East Forebay Outflow=26.92 cfs 1.588 af Peak Elev=4,782.11' Storage=6,159 cf Inflow=19.26 cfs 1.221 afPond 6P: West Forebay Outflow=19.69 cfs 1.088 af Total Runoff Area = 29.670 ac Runoff Volume = 3.010 af Average Runoff Depth = 1.22" 57.33% Pervious = 17.010 ac 42.67% Impervious = 12.660 ac Type II 24-hr 100-YR Rainfall=2.34"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 25HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: Subasin 1 TC was calculated using Hydraflow Hydrographs-Subbasin 1 (Phases 1&2 + LP) Runoff = 27.04 cfs @ 12.08 hrs, Volume= 1.790 af, Depth= 1.25" Routed to Pond 5P : East Forebay Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Type II 24-hr 100-YR Rainfall=2.34" Area (ac) CN Description * 2.390 74 Openspace-Onsite * 5.130 83 Residential Lots-Onsite * 5.150 98 ROW-Onsite * 1.170 98 LP DA#10 * 0.250 98 LP (Additional Runoff) * 1.300 98 LP DA#9 (ROW) * 1.340 74 LP DA#9 (OS) * 0.510 83 LP DA#9 (OS) 17.240 88 Weighted Average 9.370 54.35% Pervious Area 7.870 45.65% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 15.6 Direct Entry, Subbasin 1 Subcatchment 1S: Subasin 1 Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Type II 24-hr 100-YR Rainfall=2.34" Runoff Area=17.240 ac Runoff Volume=1.790 af Runoff Depth=1.25" Tc=15.6 min CN=88 27.04 cfs Type II 24-hr 100-YR Rainfall=2.34"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 26HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment 4S: Subbasin 2 TC was calculated using Hydraflow Hydrographs-Subbasin 1 (Phases 3&4 + North ROW) Runoff = 19.26 cfs @ 12.06 hrs, Volume= 1.221 af, Depth= 1.18" Routed to Pond 6P : West Forebay Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Type II 24-hr 100-YR Rainfall=2.34" Area (ac) CN Description * 1.770 74 OS * 5.870 83 Residential * 4.390 98 ROW * 0.400 98 North ROW 12.430 87 Weighted Average 7.640 61.46% Pervious Area 4.790 38.54% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14.3 Direct Entry, Hydraflow Hydrograph Subcatchment 4S: Subbasin 2 Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type II 24-hr 100-YR Rainfall=2.34" Runoff Area=12.430 ac Runoff Volume=1.221 af Runoff Depth=1.18" Tc=14.3 min CN=87 19.26 cfs Type II 24-hr 100-YR Rainfall=2.34"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 27HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Pond 3P: Wetpond Inflow Area = 29.670 ac, 42.67% Impervious, Inflow Depth = 1.08" for 100-YR event Inflow = 46.63 cfs @ 12.07 hrs, Volume= 2.677 af Outflow = 10.18 cfs @ 12.44 hrs, Volume= 2.599 af, Atten= 78%, Lag= 22.1 min Primary = 10.18 cfs @ 12.44 hrs, Volume= 2.599 af Routing by Stor-Ind method, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 4,781.63' @ 12.44 hrs Surf.Area= 34,823 sf Storage= 44,435 cf Flood Elev= 4,782.25' Surf.Area= 37,357 sf Storage= 66,837 cf Plug-Flow detention time= 179.7 min calculated for 2.597 af (97% of inflow) Center-of-Mass det. time= 165.0 min ( 1,021.2 - 856.2 ) Volume Invert Avail.Storage Storage Description #1 4,780.25' 66,837 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 4,780.25 29,659 0 0 4,782.00 36,216 57,641 57,641 4,782.25 37,357 9,197 66,837 Device Routing Invert Outlet Devices #1 Primary 4,780.35'9.0" W x 3.0" H Vert. 2-YR C= 0.600 Limited to weir flow at low heads #2 Primary 4,780.65'36.0" W x 6.0" H Vert. 10-YR C= 0.600 Limited to weir flow at low heads #3 Primary 4,781.10'30.0" W x 18.0" H Vert. 100-YR C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=10.17 cfs @ 12.44 hrs HW=4,781.63' (Free Discharge) 1=2-YR (Orifice Controls 0.97 cfs @ 5.17 fps) 2=10-YR (Orifice Controls 6.13 cfs @ 4.09 fps) 3=100-YR (Orifice Controls 3.08 cfs @ 2.33 fps) Type II 24-hr 100-YR Rainfall=2.34"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 28HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Pond 3P: Wetpond Inflow Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)50 45 40 35 30 25 20 15 10 5 0 Inflow Area=29.670 ac Peak Elev=4,781.63' Storage=44,435 cf 46.63 cfs 10.18 cfs Type II 24-hr 100-YR Rainfall=2.34"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 29HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Pond 5P: East Forebay Inflow Area = 17.240 ac, 45.65% Impervious, Inflow Depth = 1.25" for 100-YR event Inflow = 27.04 cfs @ 12.08 hrs, Volume= 1.790 af Outflow = 26.92 cfs @ 12.08 hrs, Volume= 1.588 af, Atten= 0%, Lag= 0.3 min Primary = 26.92 cfs @ 12.08 hrs, Volume= 1.588 af Routed to Pond 3P : Wetpond Routing by Stor-Ind method, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 4,782.20' @ 12.08 hrs Surf.Area= 5,888 sf Storage= 9,888 cf Plug-Flow detention time= 77.3 min calculated for 1.588 af (89% of inflow) Center-of-Mass det. time= 21.4 min ( 855.7 - 834.3 ) Volume Invert Avail.Storage Storage Description #1 4,779.75' 10,199 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 4,779.75 2,249 0 0 4,782.00 5,537 8,759 8,759 4,782.25 5,981 1,440 10,199 Device Routing Invert Outlet Devices #1 Primary 4,782.00'Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Elev. (feet) 4,782.00 4,782.25 Width (feet) 93.50 93.50 Primary OutFlow Max=26.52 cfs @ 12.08 hrs HW=4,782.20' (Free Discharge) 1=Custom Weir/Orifice (Weir Controls 26.52 cfs @ 1.45 fps) Type II 24-hr 100-YR Rainfall=2.34"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 30HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Pond 5P: East Forebay Inflow Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=17.240 ac Peak Elev=4,782.20' Storage=9,888 cf 27.04 cfs 26.92 cfs Type II 24-hr 100-YR Rainfall=2.34"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 31HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Summary for Pond 6P: West Forebay [88] Warning: Qout>Qin may require smaller dt or Finer Routing Inflow Area = 12.430 ac, 38.54% Impervious, Inflow Depth = 1.18" for 100-YR event Inflow = 19.26 cfs @ 12.06 hrs, Volume= 1.221 af Outflow = 19.69 cfs @ 12.06 hrs, Volume= 1.088 af, Atten= 0%, Lag= 0.0 min Primary = 19.69 cfs @ 12.06 hrs, Volume= 1.088 af Routed to Pond 3P : Wetpond Routing by Stor-Ind method, Time Span= 5.00-72.00 hrs, dt= 0.05 hrs Peak Elev= 4,782.11' @ 12.06 hrs Surf.Area= 3,469 sf Storage= 6,159 cf Plug-Flow detention time= 73.9 min calculated for 1.087 af (89% of inflow) Center-of-Mass det. time= 19.6 min ( 856.9 - 837.3 ) Volume Invert Avail.Storage Storage Description #1 4,779.75' 6,647 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 4,779.75 1,787 0 0 4,782.00 3,347 5,776 5,776 4,782.25 3,619 871 6,647 Device Routing Invert Outlet Devices #0 Primary 4,782.25'Automatic Storage Overflow (Discharged without head) #1 Primary 4,782.00'Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Elev. (feet) 4,782.00 4,782.25 Width (feet) 159.00 159.00 Primary OutFlow Max=19.08 cfs @ 12.06 hrs HW=4,782.11' (Free Discharge) 1=Custom Weir/Orifice (Weir Controls 19.08 cfs @ 1.09 fps) Type II 24-hr 100-YR Rainfall=2.34"10310.001.04_STORM Printed 10/4/2025Prepared by Morrison Maierle Inc Page 32HydroCAD® 10.20-7a s/n 04318 © 2025 HydroCAD Software Solutions LLC Pond 6P: West Forebay Inflow Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086Flow (cfs)22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=12.430 ac Peak Elev=4,782.11' Storage=6,159 cf 19.26 cfs 19.69 cfs TR55 Tc Worksheet Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2025 Hyd. No. 1 Phase 1&2 Description A B C Totals Sheet Flow Manning's n-value = 0.025 0.013 0.025 Flow length (ft) = 1.0 5.0 16.9 Two-year 24-hr precip. (in) = 1.18 1.18 1.18 Land slope (%) = 1.50 1.50 1.50 Travel Time (min) = 0.11 + 0.23 + 1.04 = 1.38 Shallow Concentrated Flow Flow length (ft) = 812.97 285.02 58.99 Watercourse slope (%) = 0.60 1.30 2.00 Surface description = Paved Paved Paved Average velocity (ft/s) =1.57 2.32 2.87 Travel Time (min) = 8.60 + 2.05 + 0.34 = 11.00 Channel Flow X sectional flow area (sqft) = 1.05 0.00 0.00 Wetted perimeter (ft) = 2.77 0.00 0.00 Channel slope (%) = 0.30 0.00 0.00 Manning's n-value = 0.011 0.013 0.015 Velocity (ft/s) =3.88 0.00 0.00 Flow length (ft) ({0})754.0 0.0 0.0 Travel Time (min) = 3.24 + 0.00 + 0.00 = 3.24 Total Travel Time, Tc .............................................................................. 15.62 min TR55 Tc Worksheet Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2025 Hyd. No. 2 Phase 3&4 Description A B C Totals Sheet Flow Manning's n-value = 0.025 0.013 0.025 Flow length (ft) = 1.0 5.0 16.7 Two-year 24-hr precip. (in) = 1.18 1.18 1.18 Land slope (%) = 1.50 1.50 1.50 Travel Time (min) = 0.11 + 0.23 + 1.03 = 1.37 Shallow Concentrated Flow Flow length (ft) = 766.11 0.00 0.00 Watercourse slope (%) = 0.80 0.00 0.00 Surface description = Paved Paved Paved Average velocity (ft/s) =1.82 0.00 0.00 Travel Time (min) = 7.02 + 0.00 + 0.00 = 7.02 Channel Flow X sectional flow area (sqft) = 1.05 0.00 0.00 Wetted perimeter (ft) = 2.77 0.00 0.00 Channel slope (%) = 0.30 0.00 0.00 Manning's n-value = 0.011 0.015 0.015 Velocity (ft/s) =3.88 0.00 0.00 Flow length (ft) ({0})1369.9 0.0 0.0 Travel Time (min) = 5.88 + 0.00 + 0.00 = 5.88 Total Travel Time, Tc .............................................................................. 14.28 min memo TO: City of Bozeman Engineering Department FROM: Morrison-Maierle DATE: November 26, 2025 JOB NO.: 10130.001.04 RE: Laurel Meadows – Groundwater Monitoring Data CC: MMI File Urgent For Review Please Comment Please Reply For Your Use Summary: The following document is intended to present and summarize groundwater data collected at the Laurel Meadows site by method of seven monitoring wells placed around the site. Data was collected in 2021 between the months of March and December; in 2022 between the months of January and March; and in 2025 between the months of April and August. Any data collected at the time of site dewatering was excluded from analysis. The data collected in Monitor Well 6 has been excluded entirely due to site dewatering and irregular data. Generally, high groundwater was observed in the spring between March and June, and low groundwater was observed between July and September. The location of each monitoring well can be seen in Appendix A. Appendix B includes a graph of the data collected in each monitoring well (not including Well 6) for 2021, 2022, and 2025. © 2022 Microsoft Corporation © 2022 Maxar ©CNES (2022) Distribution Airbus DS © 2022 TomTom 4780.26 4787.34 4783.98 4785.78 4790.53 4793.07 4792.68 4785 4790 47 9 5 4785 4790 4795 4800 TRACT 1 11.85 acs. TRACT 2 6.79 acs. TRACT 3 12.30 acs. TRACT 4 10.04 acs. © PROJECT NO. FIGURE NUMBER COPYRIGHT MORRISON-MAIERLE,2022 N:\10130\001.02 Site Plan\ACAD\Civil\Worksheet\groundwater\10130.002 Groundwater Exhibit.dwg Plotted by rosie nickelson on Apr/11/2022 DRAWN BY: DSGN. BY: APPR. BY: DATE:engineers surveyors planners scientists MorrisonMaierle 2880 Technology Blvd West Bozeman, MT 59718 406.587.0721 www.m-m.net 10130.001 EX-B WEST PARK SUBDIVISION GROUNDWATER MONITORING WELL MAP BOZEMAN MONTANA BTB BTB JRN 4/1/2022 100 2000 SCALE IN FEET GROUNDWATER MON. WELL #5 (TH-4) GROUNDWATER MON. WELL #6 (TH-1) GROUNDWATER MON. WELL #4 (TH-16) GROUNDWATER MON. WELL #3 (TH-18) GROUNDWATER MON. WELL #2 (TH-14) GROUNDWATER MON. WELL #7 (TH-8)GROUNDWATER MON. WELL #1 (TH-11) GROUNDWATER ELEVATION FROM MARCH. 2, 2022 (TYP) EXISTING GROUND (TYP) EXISTING DETETION POND #4, NORTON PHASE 1 WETLANDS (TYP) Appendix B Figure 1: The overall high for Well 1 was observed on March 2, 2022, and measured at 0.48 feet below ground surface. The low was measured at 2.51 feet on September 29, 2021. Figure 2: The overall high for Well 2 was observed on March 2, 2022, and measured at 0.06 feet below ground surface. The low was measured at 1.69 feet on September 29, 2021. 0.00 0.50 1.00 1.50 2.00 2.50 3.00 11/4 12/24 2/12 4/3 5/23 7/12 8/31 10/20 12/9 1/28 DepthDate WELL 1 2025 2022 2021 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 11/4 12/24 2/12 4/3 5/23 7/12 8/31 10/20 12/9 1/28 DepthDate WELL 2 2025 2022 2021 Figure 3: The overall high for Well 3 was observed on March 2, 2022, and measured at 2.51 feet below ground surface. The low was measured at 4.03 feet on August 7, 2025. Figure 4: The overall high for Well 4 was observed on May 5, 2025, and measured at 0.22 feet below ground surface. The low was measured at 2.44 feet on August 3, 2021. 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 11/4 12/24 2/12 4/3 5/23 7/12 8/31 10/20 12/9 1/28 DepthDate WELL 3 2025 2022 2021 0.00 0.50 1.00 1.50 2.00 2.50 3.00 11/4 12/24 2/12 4/3 5/23 7/12 8/31 10/20 12/9 1/28 DepthDate WELL 4 2025 2022 2021 Figure 5: The overall high for Well 5 was observed on May 5, 2025, and measured at 0.05 feet below ground surface. The low was measured at 2.30 on August 7, 2025. Figure 7: The overall high for Well 7 was observed on March 2, 2022, and measured at 0.39 feet below ground surface. The low was measured at 2.89 on September 29, 2021. 0.00 0.50 1.00 1.50 2.00 2.50 11/4 12/24 2/12 4/3 5/23 7/12 8/31 10/20 12/9 1/28 DepthDate WELL 5 2025 2022 2021 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 11/4 12/24 2/12 4/3 5/23 7/12 8/31 10/20 12/9 1/28 DepthDate WELL 7 2025 2022 2021 INTRODUCTION This report provides an analysis of the flood hazard for the proposed West Park Subdivision. The 40-acre development has one waterway, Baxter Creek, that runs south to north through the property. Baxter Creek runs through the eastern portion of the property and is classified as stream/ditch because it is fed by natural drainage and irrigation. Wetland plants surround the creek which meanders through cultivated pasture. METHOD Morrison-Maierle surveyed the 40-acre property, including the water ways with GPS survey equipment. Cross sections were developed approximately every 100 ft along each water way in AutoCAD. Bentley Flowmaster V10.02 was used to analyze each cross section to determine the water surface elevation for the given flow rate. The water surface elevation was then mapped in AutoCAD to show the extents of flooding in the current condition and areas that will require grading to contain flood waters. BAXTER CREEK Baxter Creek flows through the easterly portion of the proposed subdivision. There is not a defined floodplain associated with Baxter Creek as it has not been mapped as part of the FEMA process. The Baxter Creek corridor will be located in a proposed park as part of the subdivision. As part of the original Norton East Ranch Annexation and Phase 1 of Norton East Ranch Subdivision, the owner of the property at that time placed a covenant on the Baxter Creek corridor which limits almost all activity within the corridor and as such the floodplain impacts on the developable land within the proposed subdivision will be limited. Numerous engineering reports have been completed for Baxter Creek as part of the numerous development projects that exist above and below this project. The Valley West Subdivision identified the 100-year, 24 hour peak flow rate at Durston Road to be 114 cubic feet per second, that analysis reviewed upstream flow paths and looked at limiting restrictions, such as road crossing culverts. This value is documented in the Drainage Plan for the Valley West Subdivision. As part of Phase 1 of the Norton East Ranch Subdivision, Sanderson Stewart prepared a flood hazard evaluation of Baxter Creek which utilized a different approach in estimating the 100- year, 24 hour peak flow event. The methodology utilized the SCS method to determine the flow based on the area of the drainage basin. Based on that, the 100-year flow at Babcock was estimated to be 223 cubic feet per second. In the same report Sanderson Stewart describe the determination of n-values used to estimate channel flow rates. The value of 0.0045 used by Sanderson Stewart is also appropriate for the Baxter Creek reach flowing through the West Park subdivision, which is a winding natural channel with pools and shoals. The attached Exhibit C shows the limits of the 100-year flood hazard area. Cross section data is also attached. N89°31'09"E 1275.68'S1°13'56"W 1295.69'0+001+002+003 + 0 0 4 + 0 0 5+00 6+ 0 0 7+008+009+0010+0010+004781.0 4780.0 4781.0 4780.0 4779.0 4779.0 4781.0 4782.0 4785 4782 4783 4784 4786 478747 8 8 4780 478 5 4781 4 7 8 2 47 8 3 4784 4785 4784 47864787 478847894791 4792 4793 4794 4790. 0 4785 479047844786 4 7 8 7 478847894790.00 4787.17 4783.04784.04784.0 4785.0 LEGEND EXISTING MAJOR CONTOUR EXISTING MINOR CONTOUR PROPOSED MAJOR CONTOUR PROPOSED MINOR CONTOUR 100 YEAR FLOOD HAZARD LIMITS VERIFY SCALE! THESE PRINTS MAY BE REDUCED. LINE BELOW MEASURES ONE INCH ON ORIGINAL DRAWING. MODIFY SCALE ACCORDINGLY! 2022COPYRIGHT © MORRISON-MAIERLE, SHEET NUMBER PROJECT NUMBER DRAWING NUMBER DATEDESCRIPTIONNO.BY N:\10130\001.01 PREPLAT\ACAD\EXHIBITS\FLOOD HAZARD.DWGREVISIONS DRAWN BY: DSGN. BY: APPR. BY: DATE: Q.C. REVIEW DATE: BY: 2880 Technology Blvd West Bozeman, MT 59718 406.587.0721 www.m-m.net engineers surveyors planners scientists MorrisonMaierle PLOTTED BY:BEN BERRY ON Apr/29/2022 WEST PARK SUBDIVISION BOZEMAN MONTANA BAXTER CREEK FLOOD HAZARD MAP N10130.001 EX C BTB BTB JRN 30 6015300 SCALE IN FEET VAUGH N D R I V E PROPOSED GRAVEL TRAIL WEST PARK SUBDIVISION SITE B BAXTER CREEK 3+00 Flood Elevation Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope cfs223.00Discharge Section Definitions Elevation(ft)Station(ft) 4,788.10-0+62 4,787.00-0+30 4,785.500+00 4,786.390+21 4,787.990+42 4,787.390+56 Roughness Segment Definitions Roughness CoefficientEnding StationStart Station 0.045(0+56, 4,787.39)(-0+62, 4,788.10) Options Pavlovskii's MethodCurrent Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Results in14.5Normal Depth 4,785.5 to 4,788.1 ftElevation Range ft²31.3Flow Area ft49.4Wetted Perimeter in7.6Hydraulic Radius ft49.32Top Width in14.5Normal Depth in17.5Critical Depth ft/ft0.032Critical Slope ft/s7.12Velocity ft0.79Velocity Head ft2.00Specific Energy 1.576Froude Number SupercriticalFlow Type Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 3+00 Flood Elevation GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth N/AProfile Description ft0.00Profile Headloss ft/sInfinityDownstream Velocity ft/sInfinityUpstream Velocity in14.5Normal Depth in17.5Critical Depth ft/ft0.085Channel Slope ft/ft0.032Critical Slope Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Baxter Creek Cross Section for 3+00 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope in14.5Normal Depth cfs223.00Discharge Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/26/2022 FlowMaster [10.02.00.01]Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 4+00 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope cfs223.00Discharge Section Definitions Elevation(ft)Station(ft) 4,788.53-0+95 4,786.13-0+30 4,784.670+00 4,785.630+14 4,785.200+27 4,787.670+43 Roughness Segment Definitions Roughness CoefficientEnding StationStart Station 0.045(0+43, 4,787.67)(-0+95, 4,788.53) Options Pavlovskii's MethodCurrent Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Results in14.6Normal Depth 4,784.7 to 4,788.5 ftElevation Range ft²33.0Flow Area ft56.3Wetted Perimeter in7.0Hydraulic Radius ft56.19Top Width in14.6Normal Depth in17.2Critical Depth ft/ft0.033Critical Slope ft/s6.76Velocity ft0.71Velocity Head ft1.92Specific Energy 1.554Froude Number SupercriticalFlow Type Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 4+00 GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth N/AProfile Description ft0.00Profile Headloss ft/sInfinityDownstream Velocity ft/sInfinityUpstream Velocity in14.6Normal Depth in17.2Critical Depth ft/ft0.085Channel Slope ft/ft0.033Critical Slope Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Cross Section for 4+00 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope in14.6Normal Depth cfs223.00Discharge Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/29/2022 FlowMaster [10.02.00.01]Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 5+00 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope cfs223.00Discharge Section Definitions Elevation(ft)Station(ft) 4,786.87-0+85 4,785.90-0+61 4,785.11-0+42 4,783.110+00 4,784.600+13 4,784.690+26 4,784.700+42 4,784.800+54 4,786.340+65 4,786.440+79 Roughness Segment Definitions Roughness CoefficientEnding StationStart Station 0.045(0+79, 4,786.44)(-0+85, 4,786.87) Options Pavlovskii's MethodCurrent Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Results in16.8Normal Depth 4,783.1 to 4,786.9 ftElevation Range ft²29.4Flow Area ft42.0Wetted Perimeter in8.4Hydraulic Radius ft41.90Top Width in16.8Normal Depth in21.0Critical Depth ft/ft0.036Critical Slope ft/s7.59Velocity ft0.90Velocity Head Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 5+00 Results ft2.30Specific Energy 1.599Froude Number SupercriticalFlow Type GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth N/AProfile Description ft0.00Profile Headloss ft/sInfinityDownstream Velocity ft/sInfinityUpstream Velocity in16.8Normal Depth in21.0Critical Depth ft/ft0.085Channel Slope ft/ft0.036Critical Slope Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Baxter Creek Cross Section for 5+00 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope in16.8Normal Depth cfs223.00Discharge Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/29/2022 FlowMaster [10.02.00.01]Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 6+00 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope cfs223.00Discharge Section Definitions Elevation(ft)Station(ft) 4,789.80-0+80 4,786.21-0+68 4,785.02-0+56 4,784.98-0+46 4,784.41-0+32 4,782.740+00 4,783.020+10 4,783.510+34 4,783.390+49 4,783.090+63 4,784.290+80 4,784.250+93 Roughness Segment Definitions Roughness CoefficientEnding StationStart Station 0.045(0+93, 4,784.25)(-0+80, 4,789.80) Options Pavlovskii's MethodCurrent Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Results in11.5Normal Depth 4,782.7 to 4,789.8 ftElevation Range ft²39.7Flow Area ft89.6Wetted Perimeter in5.3Hydraulic Radius ft89.53Top Width in11.5Normal Depth in13.2Critical Depth ft/ft0.036Critical Slope Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 6+00 Results ft/s5.61Velocity ft0.49Velocity Head ft1.45Specific Energy 1.484Froude Number SupercriticalFlow Type GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth N/AProfile Description ft0.00Profile Headloss ft/sInfinityDownstream Velocity ft/sInfinityUpstream Velocity in11.5Normal Depth in13.2Critical Depth ft/ft0.085Channel Slope ft/ft0.036Critical Slope Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Baxter Creek Cross Section for 6+00 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope in11.5Normal Depth cfs223.00Discharge Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/29/2022 FlowMaster [10.02.00.01]Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 6+61 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope cfs223.00Discharge Section Definitions Elevation(ft)Station(ft) 4,787.34-0+45 4,784.10-0+35 4,785.73-0+29 4,783.15-0+06 4,782.200+00 4,783.250+16 4,783.500+46 4,783.460+60 4,782.970+88 4,783.471+00 4,783.991+05 4,784.301+12 Roughness Segment Definitions Roughness CoefficientEnding StationStart Station 0.045(1+12, 4,784.30)(-0+45, 4,787.34) Options Pavlovskii's MethodCurrent Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Results in16.7Normal Depth 4,782.2 to 4,787.3 ftElevation Range ft²43.4Flow Area ft111.3Wetted Perimeter in4.7Hydraulic Radius ft111.13Top Width in16.7Normal Depth in18.1Critical Depth ft/ft0.037Critical Slope Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 6+61 Results ft/s5.14Velocity ft0.41Velocity Head ft1.80Specific Energy 1.451Froude Number SupercriticalFlow Type GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth N/AProfile Description ft0.00Profile Headloss ft/sInfinityDownstream Velocity ft/sInfinityUpstream Velocity in16.7Normal Depth in18.1Critical Depth ft/ft0.085Channel Slope ft/ft0.037Critical Slope Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Baxter Creek Cross Section for 6+61 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope in16.7Normal Depth cfs223.00Discharge Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/29/2022 FlowMaster [10.02.00.01]Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 7+00 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope cfs223.00Discharge Section Definitions Elevation(ft)Station(ft) 4,787.04-0+59 4,784.48-0+48 4,784.01-0+36 4,782.87-0+24 4,782.63-0+13 4,782.140+00 4,781.950+03 4,782.630+10 4,783.360+48 4,782.990+75 4,782.900+90 4,783.181+00 4,783.931+10 Roughness Segment Definitions Roughness CoefficientEnding StationStart Station 0.045(1+10, 4,783.93)(-0+59, 4,787.04) Options Pavlovskii's Method Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Results in15.1Normal Depth 4,782.0 to 4,787.0 ftElevation Range ft²43.1Flow Area ft109.6Wetted Perimeter in4.7Hydraulic Radius ft109.48Top Width in15.1Normal Depth in16.7Critical Depth Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 7+00 Results ft/ft0.038Critical Slope ft/s5.18Velocity ft0.42Velocity Head ft1.68Specific Energy 1.454Froude Number SupercriticalFlow Type GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth N/AProfile Description ft0.00Profile Headloss ft/sInfinityDownstream Velocity ft/sInfinityUpstream Velocity in15.1Normal Depth in16.7Critical Depth ft/ft0.085Channel Slope ft/ft0.038Critical Slope Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Baxter Creek Cross Section for 7+00 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope in15.1Normal Depth cfs223.00Discharge Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/29/2022 FlowMaster [10.02.00.01]Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 7+60 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope cfs223.00Discharge Section Definitions Elevation(ft)Station(ft) 4,786.88-0+39 4,784.67-0+25 4,782.73-0+12 4,781.700+00 4,781.980+30 4,781.850+43 4,783.220+57 4,783.260+96 4,783.171+00 Roughness Segment Definitions Roughness CoefficientEnding StationStart Station 0.045(1+00, 4,783.17)(-0+39, 4,786.88) Options Pavlovskii's Method Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Results in9.7Normal Depth 4,781.7 to 4,786.9 ftElevation Range ft²33.6Flow Area ft58.9Wetted Perimeter in6.8Hydraulic Radius ft58.82Top Width in9.7Normal Depth in12.2Critical Depth ft/ft0.033Critical Slope ft/s6.64Velocity ft0.68Velocity Head ft1.49Specific Energy Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 7+60 Results 1.548Froude Number SupercriticalFlow Type GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth N/AProfile Description ft0.00Profile Headloss ft/sInfinityDownstream Velocity ft/sInfinityUpstream Velocity in9.7Normal Depth in12.2Critical Depth ft/ft0.085Channel Slope ft/ft0.033Critical Slope Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Baxter Creek Cross Section for 7+60 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope in9.7Normal Depth cfs223.00Discharge Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/29/2022 FlowMaster [10.02.00.01]Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 8+00 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope cfs223.00Discharge Section Definitions Elevation(ft)Station(ft) 4,785.72-0+62 4,786.26-0+55 4,784.90-0+52 4,784.34-0+41 4,782.90-0+18 4,781.200+00 4,781.200+11 4,781.700+24 4,781.770+35 4,782.820+49 4,783.460+66 Roughness Segment Definitions Roughness CoefficientEnding StationStart Station 0.045(0+66, 4,783.46)(-0+62, 4,785.72) Options Pavlovskii's Method Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Results in11.9Normal Depth 4,781.2 to 4,786.3 ftElevation Range ft²31.8Flow Area ft51.4Wetted Perimeter in7.4Hydraulic Radius ft51.34Top Width in11.9Normal Depth in14.7Critical Depth ft/ft0.032Critical Slope ft/s7.01Velocity Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 8+00 Results ft0.76Velocity Head ft1.75Specific Energy 1.569Froude Number SupercriticalFlow Type GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth N/AProfile Description ft0.00Profile Headloss ft/sInfinityDownstream Velocity ft/sInfinityUpstream Velocity in11.9Normal Depth in14.7Critical Depth ft/ft0.085Channel Slope ft/ft0.032Critical Slope Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Baxter Creek Cross Section for 8+00 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope in11.9Normal Depth cfs223.00Discharge Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/29/2022 FlowMaster [10.02.00.01]Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 8+40 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope cfs223.00Discharge Section Definitions Elevation(ft)Station(ft) 4,785.66-0+63 4,783.56-0+50 4,782.59-0+39 4,781.32-0+16 4,780.50-0+03 4,780.650+00 4,780.300+13 4,781.800+29 4,782.400+49 4,782.700+66 4,783.100+78 4,783.400+91 Roughness Segment Definitions Roughness CoefficientEnding StationStart Station 0.045(0+91, 4,783.40)(-0+63, 4,785.66) Options Pavlovskii's MethodCurrent Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Results in13.9Normal Depth 4,780.3 to 4,785.7 ftElevation Range ft²29.8Flow Area ft43.7Wetted Perimeter in8.2Hydraulic Radius ft43.56Top Width in13.9Normal Depth in17.3Critical Depth ft/ft0.031Critical Slope Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 8+40 Results ft/s7.48Velocity ft0.87Velocity Head ft2.03Specific Energy 1.594Froude Number SupercriticalFlow Type GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth N/AProfile Description ft0.00Profile Headloss ft/sInfinityDownstream Velocity ft/sInfinityUpstream Velocity in13.9Normal Depth in17.3Critical Depth ft/ft0.085Channel Slope ft/ft0.031Critical Slope Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Baxter Creek Cross Section for 8+40 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope in13.9Normal Depth cfs223.00Discharge Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/29/2022 FlowMaster [10.02.00.01]Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 9+00 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope cfs223.00Discharge Section Definitions Elevation(ft)Station(ft) 4,784.08-0+59 4,783.07-0+33 4,780.09-0+10 4,780.090+00 4,780.400+12 4,780.880+24 4,781.850+49 Roughness Segment Definitions Roughness CoefficientEnding StationStart Station 0.045(0+49, 4,781.85)(-0+59, 4,784.08) Options Pavlovskii's Method Current Roughness Weighted Method Pavlovskii's MethodOpen Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Results in12.1Normal Depth 4,780.1 to 4,784.1 ftElevation Range ft²30.9Flow Area ft47.7Wetted Perimeter in7.8Hydraulic Radius ft47.62Top Width in12.1Normal Depth in15.2Critical Depth ft/ft0.032Critical Slope ft/s7.22Velocity ft0.81Velocity Head ft1.82Specific Energy 1.580Froude Number SupercriticalFlow Type Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 9+00 GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth N/AProfile Description ft0.00Profile Headloss ft/sInfinityDownstream Velocity ft/sInfinityUpstream Velocity in12.1Normal Depth in15.2Critical Depth ft/ft0.085Channel Slope ft/ft0.032Critical Slope Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Baxter Creek Cross Section for 9+00 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope in12.1Normal Depth cfs223.00Discharge Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/29/2022 FlowMaster [10.02.00.01]Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 9+90 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope cfs223.00Discharge Section Definitions Elevation(ft)Station(ft) 4,782.44-0+82 4,781.93-0+72 4,779.20-0+14 4,778.610+00 4,779.420+14 4,779.890+23 4,779.920+32 4,779.960+44 4,780.000+63 4,780.000+75 4,779.680+87 4,779.941+00 4,780.771+17 Roughness Segment Definitions Roughness CoefficientEnding StationStart Station 0.045(1+17, 4,780.77)(-0+82, 4,782.44) Options Pavlovskii's Method Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Results in16.9Normal Depth 4,778.6 to 4,782.4 ftElevation Range ft²46.5Flow Area ft132.5Wetted Perimeter in4.2Hydraulic Radius ft132.39Top Width in16.9Normal Depth in18.0Critical Depth Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Worksheet for 9+90 Results ft/ft0.039Critical Slope ft/s4.80Velocity ft0.36Velocity Head ft1.76Specific Energy 1.428Froude Number SupercriticalFlow Type GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth N/AProfile Description ft0.00Profile Headloss ft/sInfinityDownstream Velocity ft/sInfinityUpstream Velocity in16.9Normal Depth in18.0Critical Depth ft/ft0.085Channel Slope ft/ft0.039Critical Slope Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/20/2022 FlowMaster [10.02.00.01] Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Baxter Creek Cross Section for 9+90 Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.085Channel Slope in16.9Normal Depth cfs223.00Discharge Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 4/29/2022 FlowMaster [10.02.00.01]Bentley Systems, Inc. Haestad Methods Solution CenterBaxter Creek Flood Plain.fm8 Storm Water Management System Operation & Maintenance Manual Laurel Meadows Subdivision Bozeman, Montana Prepared For: 8FC, LLC Prepared By: 2880 Technology Blvd. W. • PO Box 1113 • Bozeman, MT 59771 (406) 587-0721 • www.m-m.net Updated December 3, 2025 Laurel Meadows Subdivision Storm Water Operation & Maintenance Manual 1 Site Data Location: Laurel Meadows Subdivision Lot R1A through R1D of the Norton East Ranch Subdivision Phase 6, located in the NE 1/2 of Section 9, Township 2 South, Range 5 East, Principal Meridian, Gallatin County, Montana Approximate WGS84 Reference Latitude: 45° 40' 51" N Approximate WGS84 Reference Longitude: 111° 6' 45” W The Project lies in the south east corner of the property and encompasses about 40 acres. Ownership of Stormwater Facilities: Stormwater facilities within the public rights-of-way are to be owned by the City of Bozeman. Stormwater facilities outside of the public rights-of-ways are to be owned by the Laurel Meadows Home Owners Association. Responsible Party for Maintenance: For those storm water management system elements outside of dedicated public rights-of-way, the HOA, Laurel Meadows Home Owners Association shall designate a qualified professional entity or individual to perform all monitoring. The name, address and telephone number of the entity or individual shall be provided to the City of Bozeman Public Works Department. The owner's representative shall be required to keep a log of all required inspections and maintenance required. The log shall be made available to the City of Bozeman Public Works Department for review as requested. With respect to the existing Ponds 4 and 6, which were constructed as part of and serve the initial phases of Norton East Ranch Subdivision, they are to be maintained by the Norton East Ranch Homeowners Association. These ponds are located in Block 2, Open Space Lot 1. Land Use & Site Area: The proposed Laurel Meadows Subdivision project is located in Bozeman, Gallatin County, Montana. Generally, the property is bordered by Vaughn Drive to the north, the Valley West subdivision to the east, West Babcock Street to the south, and Laurel Parkway to the west. Laurel Meadows subdivision is proposed to include single family and multifamily residential uses. Laurel Meadows Subdivision Storm Water Operation & Maintenance Manual 2 Storm Water Management Systems: The proposed Laurel Meadows subdivision development is to include a system of storm drainage inlets, piping, and a wet detention pond system including. The project area is divided into two distinct major, post-development drainage basins including drainage from the street rights-of-way, residential lots, open spaces and a portion of Laurel Parkway. Inspection & Maintenance Storm water facilities and permanent Best Management Practices (BMPs) must be inspected in accordance with this document. All documentation on scheduled inspections, times of inspections, maintenance completed, remedial actions taken to make repairs, and any modifications or reconstruction of the storm system shall be maintained on-site. Disposal of the accumulated sediment must be in accordance with all applicable local, state, and federal guidelines and regulations. If any drainage structure or outfall indicates the presence of petroleum, the petroleum material shall be removed and disposed of immediately in accordance with applicable regulations. Pavement Sweeping & Vacuuming: All paved areas shall be swept twice a year, scheduled in spring and fall. Inlets & Catch Basins All inlets and catch basins shall be inspected to ensure they have adequate sump capacity, hoods are in place, frames and grates are not damaged, and internal concrete and grout is intact. ❑ Inspect catch basins four times per year and following large storm events. ❑ Clean sump annually or whenever basin sump becomes filled with sediment to half its depth (0’-4 1/2”). If inspection indicates the presence of petroleum, the petroleum material shall be removed and disposed of immediately in accordance with applicable regulations. Storm Drain Manholes & Overflow Control Structures All storm drain manholes and overflow control structures shall be inspected to ensure manhole frames and covers are not damaged, inlet and outlet pipes are draining freely, and internal manhole concrete and grout is intact. ❑ Inspect structures annually and following large storm events. Laurel Meadows Subdivision Storm Water Operation & Maintenance Manual 3 ❑ Clean structures as field determined. If inspection indicates the presence of petroleum, the petroleum material shall be removed and disposed of immediately in accordance with applicable regulations. Piping All storm drain piping shall be inspected for any damage and/or blockages. ❑ Inspect piping annually and following large storm events. ❑ Length of pipes should be cleaned and flushed as field determined. Wet Detention System: Maintenance of the forebay basins is also essential. General objectives of maintenance are to prevent clogging, standing water and the growth of weeds and wetland plants. This requires frequent unclogging of the outlets, inlets, and mowing. Cleaning out sediment with earth-moving equipment may also be necessary in 10 to 20 years. ❑ Inspect surface every three (3) months and following large storm events. ❑ Remove any accumulated trash. ❑ Sediment removal is to be provided as required. More frequent sediment removal via hand tools may reduce or eliminate the need for earth-moving equipment for sediment removal at a later date. If inspection indicates the presence of petroleum, the petroleum material shall be removed and disposed of immediately in accordance with applicable regulations. Life Cycle & Cost Estimates *Assumed Inflation Rate = 4% Maintenance Storm Feature Maintenance Task Frequency Estimated Cost (Present Value, 2025) Pond Sediment/Debris Removal Annually/ Post Large Storm $2,000 Outlet Structure Sediment/Debris Removal Annually/ Post Large Storm $2,000 Replacement Storm Feature Expected Lifespan (Years) Estimated Cost (Present Value, 2025) Estimated Cost (Future Value at First Replacement*) Pond 20 $25,000 $54,778 Outlet Structure 25 $6,000 $15,995 Laurel Meadows Subdivision Storm Water Operation & Maintenance Manual 4 Housekeeping Operations Good housekeeping and material management reduces the risk of spills or other accidental exposure of materials and substances to storm water runoff. ❑ All materials stored on-site must be stored in a neat, orderly manner in their appropriate containers and, if possible, under a roof or other enclosure. ❑ Products shall be kept in their original containers with the original manufacturer’s label. ❑ Substances should not be mixed with one another unless recommended by the manufacturer. ❑ Whenever possible, all of a product will be used up before disposing of a container. ❑ Original materials labels and material safety data sheets (MSDS) shall be kept by the Owner. ❑ Petroleum products: ▪ All on-site vehicles and parking areas shall be monitored weekly for leaks and spills. Spills shall be cleaned immediately. ▪ Petroleum products shall be stored under cover and shall be in tightly sealed containers that are clearly labeled. ❑ Fertilizers: ▪ Fertilizers shall only be used in the minimum amounts as recommended by the manufacturer. ▪ The contents of any unused fertilizer shall be transferred to a clearly labeled, sealable plastic bin to avoid spillage. ❑ Paints solvents. ▪ All paints and solvents shall be stored in original manufacturer’s containers in a covered location. ▪ The use of paints and solvents shall, whenever possible, be limited to service or storage bays. Where not possible, the work area shall be protected with impermeable drop clothes or tarps. At no point shall material be used in parking or access ways that are tributaries to the drainage system. Spill Control Practices ❑ Manufacturer's recommended methods shall be clearly posted for spill clean-up and hotel personnel shall be made aware of the procedures and the locations of cleanup information and supplies. ❑ Material and equipment necessary for spill clean-up will be kept on-site in a designated material storage area. Equipment will include, but not be limited to, brooms, dust pans, mops, rags, gloves, goggles, absorbent materials, sand, sawdust, and plastic & metal trash containers specifically kept and labeled for this purpose. ❑ All spills must be cleaned-up immediately after discovery. ❑ Spills of toxic or hazardous material must be reported to the appropriate state, local, or federal agency, as required by-law. Laurel Meadows Subdivision Storm Water Operation & Maintenance Manual 5 Winter Maintenance Activities ❑ Snow plowing operations shall stockpile snow, ice and accumulated materials in areas where snow melt will flow into the on-site drainage systems, including drainage basins. ❑ During winter conditions sand use site-wide shall be applied to the minimum extent possible to maintain safe conditions and limit accumulations within the storm water management systems. ❑ The usage of sodium chloride or chloride containing materials for snow and ice removal is not recommended so as to avoid the introduction of salts to the storm water management system. Emergency Contacts PLEASE CALL 9-1-1 FOR ALL POTENTIAL EMERGENCIES City of Bozeman Fire Department: (406) 582-2350 City of Bozeman Police Department: (406) 582-2000 Chapter 6 - Storm Drainage Design 6-42 City of Bozeman Design and Construction Standards The following acknowledgment form is provided as an example. _____________________________________________________________________________________ Acknowledgement of Stormwater Facilities Maintenance Requirements PROPERTY OWNER: NAME OF PLAN/DEVELOPMENT: LOT/BLOCK/SUBDIVISION: Property Owner hereby acknowledges that they are required to maintain all stormwater facilities on the Property pursuant to Bozeman Municipal Code sec. 40.04.720. This requirement is binding on any successor or assign of the Property Owner listed above. The City requires stormwater facilities be constructed and adequately maintained on the Property in order to maintain the health, safety and welfare of City residents. Adequate maintenance is defined as keeping the stormwater facilities and all components thereof in good working condition so that these stormwater facilities continue to perform in accordance with the design intent. Should the Property Owner fail to adequately maintain stormwater facilities, the City may enter upon the Property and take such steps as are necessary to correct deficiencies. The City may assess against the Property Owner for the cost of any repairs or necessary maintenance by any means provided for in the Bozeman Municipal Code. By signing below Property Owner acknowledges they have read this document and the applicable provisions of the Bozeman Municipal Code, and they agree to the maintenance requirements for all stormwater facilities on their Property. BY:______________________________ (Property Owner) DATE:___________________________ Chapter 6 - Storm Drainage Design 6-44 City of Bozeman Design and Construction Standards Stormwater Facility Inspection Form Section 1: General Information Facility ID: Facility Type: Choose an item. Date/Time: Click or tap to enter a date. Owner: Contact: Inspector’s Name, contact info: Choose an item. Location/Access info: Type of Inspection: ☐ Routine, Dry Weather ☐ Routine, Wet Weather ☐ Complaint Driven ☐ Other: __________________ Section 2: Weather and Discharge Information Most recent precipitation or melt: Temperature: Is a stormwater discharge occurring? ☐ Yes ☐ No If yes, what is the source and quality of discharge? Is an illegal discharge occurring? ☐ Yes ☐ No If yes, what is the source and quality of discharge? Section 3: Facility Maintenance Priority ☐ Low: Stormwater facility appears to be functioning as designed. Continue scheduled maintenance. ☐ Medium: Stormwater facility requires minor to moderate sediment and vegetation maintenance to mitigate the risk of flooding, waterway pollution, and infrastructure failure. ☐ High: Stormwater facility requires significant sediment dredging, vegetation removal, and/or infrastructure repairs to restore function. Notes, Findings & Recommendations: Inspector’s Signature: ________________________________ Date: ___________________ Chapter 6 - Storm Drainage Design 6-45 City of Bozeman Design and Construction Standards Section 4: Qualitative Analysis Components # Items Conditions Results Notes and Required Actions General Degraded, missing, or inadequate Yes 1.1 Accessibility maintenance access? No ☐☐ Trash, sediment, and waste within 1.2 Debris ☐Yes and around the facility? ☐ No Overgrown or dead cattails, Yes 1.3 Vegetation woody shrubs, weeds, grass, and ☐ trees? ☐ No Infrastructure Damaged inlet pipe, outlet pipe, Yes1.4 ☐ Condition outfall structure, or fencing? ☐ No Facility Condition Pretreatment Bay Clogged, obstructed, or filled 2.1 ☐ Yes or Facility pretreatment forebay or facility? ☐ No 2.2 Storage Bay Clogged or filled storage bay? ☐ Yes ☐ No Stagnant water with infiltration Groundwater or Yes 2.3 greater than 48 hours post-rain ☐ Standing Water event? ☐ No 2.4 Flow Path Clogged or obstructed flow path? ☐ Yes ☐ No Barren or exposed surfaces on Yes 2.5 Side Slopes ☐ Facility’s side slopes and bottom? ☐ No Maintenance Maintenance Plan Is there a written plan specific to ☐ Yes 3.1 or Agreement this facility? ☐ No Yes 3.2 Implementation Is there evidence of maintenance? ☐ ☐ No Chapter 6 - Storm Drainage Design 6-46 City of Bozeman Design and Construction Standards Section 5: Quantitative Analysis Vegetation Cover type % Within facility Notes Bare ground Aquatics Grasses/Herbaceou Trees >3” DBH Shrubs Total 100 Elevation Analysis Location Reading (ft) Elevation (ft) Notes SRV#CP Control Point SRV#1 Inlet SRV#2 Outlet SRV#3 Center SRV#4 North of Center SRV#5 East of Center SRV#6 South of Center SRV#7 West of center SRV#8 Berm or overflow SRV#9 Summary Chapter 6 - Storm Drainage Design 6-47 City of Bozeman Design and Construction Standards Section 6: Facility Maintenance Inspection Exhibit Chapter 6 - Storm Drainage Design 6-48 City of Bozeman Design and Construction Standards Photo 1 description Photo 2 description Section 7: Photo Log