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Home My WebLink About011 - Full Stormwater Drain Report ` � ' STORMWATER DRAINAGE REPORT Stites Office Building I M EG #24006341 .00 PLNAPP #24637 SUBMITTEDJULY2025 ..��. �1 `. L,,•. .ra ' 1=RIl<U.GARBERG �: �; No. 14108 P� . ':-a�.m�}a Og •ZO'z� •�3 • •!O <i O ,�•, •.,�: . C�,,,S� •�,�•. . SS��,R�E,N . 1143 Stoneridge Drive, Suite 1, Bozeman, MT > >imegcorp.com TABLE OF CONTENTS 1. Introduction......................................................................................................................................3 2. Hydrology and Hydrogeology...........................................................................................................3 3. Existing Stormwater Drainage Conditions.......................................................................................4 4. Proposed Stormwater Drainage System .........................................................................................5 5. Evaluation of Major Storm Flood Risks............................................................................................7 6. Operation, Inspection, and Maintenance Considerations................................................................7 7. References.......................................................................................................................................8 8. Appendix A- Amended Plat 9. Appendix B - Baxter Meadows, Phase II Storm Drain Design Report 10. Appendix C- The Modified Rational Method Calculations 11. Appendix D - Drainage Area Map 12. Appendix E - Operation, Maintenance, and Inspection Plan 13. Appendix F- Geotechnical Investigation Report Engineering Design Report ` Stites Office Building � Bozeman, MT . 2 May 27, 2025 Stormwater Drainage Report For the Stites Office Building Prepared for: City of Bozeman, MT I M EG #24006341.00 July 8, 2025 1. Introduction The Stites Office Building involves the development of a 5,100-square-foot office building and associated site features on the eastern half three adjacent parcels legally described as Lots 4—6, Block 20, Baxter Meadows Subdivision Phase 2A (Plat J-383) City of Bozeman, Gallatin County, MT. The project necessitates an amendment to the existing plat from three lots (Lot 4-6) into two (Lot 4A and 5A). The subject property, Lot 5A, is a 0.19-acre site situated north of Baxter Lane and west of Caballo Avenue. The amended plat is included in Appendix A. The existing ground cover is bare soil with little vegetative cover. According to historic satellite data from Google Earth, the surrounding lots began subdividing and developing from agricultural farmland to commercial development in 2004. Lot 5A is zoned for community business district use (B-2) and has remained an undeveloped, empty lot bordered by existing arterial streets. The ground cover condition changed from short vegetation to bare soil in 2023 based on aerial imaging. The topography is generally flat with a 1-2% slope toward the north. The site elevation is higher than the bordering paved areas and does not take on any additional offsite run-on. There are no existing watercourses on or adjacent to the site. This report provides background on the underlying stormwater system, presents runoff volume and flow rate calculations, and outlines the integration of the proposed storm drainage features. It details how the proposed stormwater facilities will adequately store, infiltrate, or convey runoff generated by the development. The development incorporates site grading and swales to convey stormwater to the proposed and existing detention and retention facilities. It is proposed to utilize a subsurface retention basin to capture the post- development runoff volume for the full range of storm events. The stormwater runoff (CFS) was determined by the Rational Method. The analysis follows the methodology and standards established by the City of Bozeman Design and Construction Standards (October 2024), Montana DEQ Circular 8 (2024), and the Federal Highway Administration HEC-22 Manual (4th Edition). 2. Hydrology and Hydrogeology The hydrology for Lot 5A is based on NRCS Type II temporal rainfall distribution data. The City of Bozeman precipitation depths for the post-development major storm duration and return interval are listed below (DCP Table 6.5.1). Engineering Design Report ` Stites Office Building � Bozeman, MT . 3 May 27, 2025 Table 6.5.1 - Precipitation Depth - Duration (Depth in Inches) Duration 2-year 5-year 10-year 25-year 50-year 100-year 24 hr 1.18 1.49 1.70 1.96 2.15 2.34 Precipitation intensity values (COB DCP Table 6.5.2) at the post-development major storm duration are below. Table 6.5.2- Precipitation Intensity- Duration (Intensity in Inches per Hour� Time (min) Time (hr) 2-year 5-year 10-year 25-year 50-year 100-year 1440 24 0.049 0.062 0.071 0.082 0.090 0.098 Runoff flow rates and runoff volumes were determined using The Rational Method by multiplying the major storm duration (24 hrs) by the post-development runoff flowrates. The Rational Method was selected due to the small lot area (under 5 acres) and homogeneous drainage area (DA). Soils on Lots 4A and 5A consist of undocumented clayey fill over an organic soil horizon, followed by lean clay soil, and pit run gravel. The depth to the pit run gravel horizon is 54 - 60 inches. The aquifer was observed approximately 6.5-7.33 feet below ground surface, with signs of seasonal groundwater depth at approximately 3 feet below grade, as recorded in the IMEG Geotechnical Investigation Report conducted on October 24, 2024. This report is included in the submittal documents for the City of Bozeman Site Plan Application #24637. The Baxter Meadows Phase 2A Plat J-383 recommends no basement to be constructed below 3 feet from the top of curb. Due to the seasonal shallow depth of the aquifer, storm facilities should be shallow or above ground to maximize recharge distance and minimize the surface water interaction with the aquifer. 3. Existing Stormwater Drainage Conditions Lots 4—6 are currently unimproved open lots within the Baxter Meadows Subdivision. The Phase II Baxter Meadows Subdivision Storm Drain Design Report by Robert Peccia &Associates (Appendix B) designed conveyance and storage systems to accommodate the known pre-development and estimated post-development runoff for the subdivision. The current general runoff pattern on the property is sheet flow. Stormwater runoff flows offsite northwest along the gutter in the right-of-way, then enters inlets at the corner of Trakker Trail and Vaquero Parkway before being conveyed to a manhole that directs flow to an offsite detention pond on the west side of Vaquero Parkway. The proposed development is within Basin 1, as defined on pages 7,14, 17, 18, and 19 in the underlying subdivision report; a summary of the contents is provided in Table 4-1. Engineering Design Report ` Stites Office Building � Bozeman, MT . 4 May 27, 2025 Table 4-1. Basin 1 Characteristics (from RPA Storm Drain Report) 100-year Basin 1 Area Rational Time of Intensity, i Peak Flow Runoff Volume, (Ac) Coefficient, C Concentration, Tc(min) (in/hr) Rate, q (CFS) Q (FT3) Pre-Development 2.9 0.2 29 1.03 0.6 893 Post-Development 2.9 0.5 25 1.64 1.64 2459 The Bain 1 subdivision infrastructure is not equipped to detain any runoff from Lot 5A. It is documented that the subdivision experiences challenges with high groundwater and surcharging inlets at the intersection of Trakker Trail and Vaquero Parkway per correspondence on January 17, 2025 with Russel Smith in the stormwater department. On-site mitigation must be provided to store generated runoff from development regardless of the underlying subdivision's plan. The following section will detail the accurate land use proposed for the site. 4. Proposed Stormwater Drainage System Per the City of Bozeman DCP's, the stormwater mitigated onsite by Lot 5A is the greater volume of two scenarios: (1) retention of total runoff from the post-development 100-year storm event or (2) the water quality design storm. The 100-year, 24-hour storm event exceeds the runoff reduction volume (RRV1. 4.1. Retention of Post- Development 100-year Storm Event The proposed land use includes asphalt/concrete, roof area, and landscaping. The post-development weighted runoff coefficient is 0.75. Pursuant to Section 6.8.1 of the Bozeman Design and Construction Standards, the storm design duration for the 100-year event retention is 24 hours. The peak runoff flowrate was calculated using the Rational Method, Q= Cr*C*I*A, where Q is the peak runoff flowrate (CFS), C is the runoff coefficient (0.75), I is the rainfall intensity (in/hr) for the 100-year 24-hour storm event, and A is the drainage area (acres). The rainfall intensity for the 100-year, 24-hour storm is 0.098 in/hr as listed in Table 6.5.2 in the Bozeman Design and Construction Standards. The rational method yields a peak runoff flowrate of 0.017 CFS for the 100-year, 24-hour storm. The runoff volume was calculated by multiplying the peak runoff flowrate (0.017 CFS) by the design duration (24 hours, converted to 86,400 seconds) resulting in a volume of 1,491 cubic feet (CF), per Rational Methodology following the guidance section 6.5.3 in the Design and Construction Standards. Calculations were done at each timestep duration for each storm event to produce peak runoff flowrates and volumes. Detailed calculations for the full range of storm events (2-year through 100-year) are provided in Appendix C. Table 4-3 below summarizes the runoff values for the 100-year, 24-hour event. Engineering Design Report ` Stites Office Building � Bozeman, MT . 5 May 27, 2025 Table 4-3. Summary of Post-Development 100-year Storm Runoff 100-year Rational Runoff Area Area Design Duration, D Intensity, i Peak Flow Basin 1 (Ac) (ft2) Coefficient, (min) (in/hr) Rate, q (CFS) Volume, Q C (FT3) Post- 0.193 8407.08 0.73 1440 0.098 0.017 1491 Development 4.2. Runoff Reduction Volume The runoff reduction volume (RRV) was calculated using post-development site conditions according to the Montana Post-Construction Storm Water BMP Design Manual. These calculations are in Appendix C. The water quality design storm generates a runoff volume of 238 ft3. 4.3. Proposed Stormwater Facility The proposed subsurface retention basin wraps around the building to the north, east, and west. The proposed capacity is 1502 CF. The basin consists of an 191.5 LF, 36-inch HDPE perforated pipe encased in 2" of gravel on either side, wrapped in geotextile filter fabric to provide screening, prevent migration of fines and mitigate blockages to the pipe perforations. The retention volume within the pipe is 1354 CF and the retention volume within the gravel is 151 CF. A recent Physical Properties of Aggregate Report by Rimrock Engineering (included in Appendix C) for 3/a" bedding was used a sample to determine a porosity value. The void content of the sample, e, is recorded as 37%. The porosity of the sample, n, was calculated using the following equation: n = e/(1+e), resulting in 27% porosity. This value was used for sizing the gravel storage area per Section 6.8.3.B.e of the City of Bozeman Design and Construction Standards. Vegetated landscape depressions convey runoff into five catch basin inlets with 10-inch sumps to capture sediments before entry into the buried pipe. The pipe invert will be buried shallower than seasonal high groundwater, found at 3 ft bgs, to minimize interaction. A drainage area map is provided in Appendix D showing the proposed runoff pattern and location of the retention facility on the site. To meet the 72-hour maximum drain-down time requirement, lean clay, located 2 to 5 feet below the ground surface across the site, must be excavated from the retention basin footprint and replaced with well-draining material. The 3-foot by 191.5-foot basin area should be excavated to the depth of poorly- graded gravel (approximately 5 ft bgs) and backfilled with materials having an infiltration rate of 1 in/hr or higher. Excavation beyond 3 feet below the ground surface may encounter saturated soils or groundwater. Please reference Appendix C for maximum drain down time calculations and Appendix F for the geotechnical investigation report. There are two areas of the subject property comprised of 747 ftz of landscaped area and 641 ftz of hardscaped area, that are not retained on-site. They are marked purple on the drainage area map. Runoff from these areas flows directly offsite into the curb inlet at the intersection of Cabello Ave and Trakker Trail, connecting to Basin 3 as outlined in the RPA Baxter Meadows Subdivision report. For a 100-year, 24-hour storm event, a peak runoff flowrate of 0.002 cfs and total runoff volume of 188 cu-ft is contributed to the subdivision's stormwater infrastructure as calculated according to the Rational Method. Runoff passes through landscaped filter strips before leaving the site. Refer to the table below Engineering Design Report ` Stites Office Building � Bozeman, MT . 6 May 27, 2025 for a summary of these drainage areas and Appendix C for calculations covering the full range of storm events. Please note that the peak runoff flowrate and retention volume calculated for the entire site is stored in the retention basin located in drainage area 1 and therefore there is no analysis on DA 1. Table 4-4. Summary of Drainage Areas Total Area 100-year 24-hr (acres) Total Impervious Area Pervious Rational 100-year 24-hr DA Area (sf) (sf)/% Area (sf)/ % Coefficient, C Runoff Volume Runoff (cfs) (cu ft) 1 0.161 7,039 5,227 1,812 0.73 See total See total 2 0.032 1,388 641 747 0.53 3.05 0.002 Total 0.193 8,427 5,868 2,559 0.73 1491 0.017 5. Evaluation of Minor& Major Storm Flood Risks Table 4-5. Summary of Post-Development Runoff by Storm Event for 24-hour duration Outputs: Post-Development 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr Intensit 0.05 0.06 0.07 0.08 0.09 0.10 Flow cfs 0.007 0.009 0.010 0.013 0.015 0.017 Volume cf 597 755 864 1098 1315 1491 The runoff from the 10-year, minor storm, is 864 ft3 and will be fully stored by the 1502 ft3 retention basin. The total runoff volume in the 100-year return interval storm is 1491 ft3 and will be retained onsite in the retention basin. If a storm larger than the 100-year return interval is to occur, the retention system will first fill as designed then as the system exceeds the designed capacity, three inlets are connected to 6-inch horizontal pipes that are designed to convey water offsite. Two pipes discharge to the north and one pipe discharges to the east, through the retaining wall, sheet flowing over the sidewalk, into the gutter, and enter the inlets at Vaquero Parkway &Trakker Trail, and Caballo Avenue &Trakker Trail. Runoff from drainage area 2 will be intercepted by Basin 3 (per RPA's subdivision stormwater report) if the storm event exceeds the 100-year return interval. There is no conveyance or connection to any existing storm infrastructure proposed during the major event as part of this lot development. The major storm is retained onsite and does not inundate buildings or roads. 6. Operation, Inspection, and Maintenance Considerations Please see OIM Plan in Appendix E. Engineering Design Report ` Stites Office Building � Bozeman, MT . 7 May 27, 2025 7. References City of Bozeman. (2024, October). City of Bozeman Design and Construction Standards. https://www.bozeman.net/home/showpublisheddocument/14823/638724483537270000. City of Bozeman. (2024, October). City of Bozeman Modifications to Montana Pu.blic Works Standard Specifications, �`' Edition. https://www.bozeman.net/home/showpublisheddocument/14824/638724489684800000. HDR, & Montana Department of Environmental Quality. (2017, September). Montana Post-Const�uction Storm WaterBMPDesign Guidance Manual. Montana. U.S. Department of Transportation, Federal Highway Administration. (2024, February). Hydraulic Engineering Circu/ar No. 22— Ur.ban Drainage Design, Fourth Edition. Engineering Design Report ` Stites Office Building � Bozeman, MT . 8 May 27, 2025 ` . APPENDIX A SURVEY REQUESTED BY OWNER TO CREATE TWO LOTS FROM THREE AMENDED PLAT OF LOTS 4, �J, AND 6 EXISTING LOTS AND RELOCATE THE COMMON BOUNDARY BETWEEN THE REMAINING EXISTING LOTS WITHIN A PLATTED SUBDIVISION, AND EXEMPT BAXT E R M EA D OWS S U B D I V I S I O N P H AS E 2A FROM REVIEW AS A SUBDIVISION PURSUANT TO 76-3-207 (1)(d) MCA. ' OWNER OF LOTS 4, 5, & 6 BLOCK 20: CYCLONE DEVELOPMENT, LLC DEED REF.: DOC N0. 2842351 LOCATED IN THE SE1/4 OF SECTION 34, T.1S., R.5E., P.M.M., CITY OF BOZEMAN, GALLATIN COUNTY, MONTANA � I TRAKKER TRAIL I CERTIFICATE o � CONSENT (90� R.�.W.� DETAIL 1 I, the undersigned property owner, do hereby certify that we have caused to be surveyed, aggregated, and FOUND MONUMENT 0.64' I platted into lots, as shown by this plat hereunto included, the following described tract of land, to wit: N89�24'53"E (R1) � BEARING N13°51'E FROM CALCULATED POINT I LEGAL D ESC R I PTI O N S89'06'45"E (F) 329.30' (R1&F) , - - - - _ _ _ 156.40 (R1&F) I ��6.9�' R1&F T Lots 4, 5, and 6, Block 20, Baxter Meadows Subdivision, Phase 2A, according to the plat thereof, on file C � 66.�0' (R1&F) , and of record in the office of the Clerk and Recorder, Gallatin County, Montana, and located in the SE1/4 I I � 73.�J3 82.87' I of Section 34, T. 1 S., R. 5 E. P.M.M., Gallatin County, Montana. I „ �� i. r- � � , ,� , �� i � � "� � Area = 15,905 square feet, 0.365 acres, more or less, and subject to all easements and rights-of-way as �` '� '� � shown, existing or of record. I I 15' UTILITY EASEMENT� i � i i i '�� , `- " -+ ` � �� G PER PLAT [J-383] �� " "I' � � NEW BOUNDARY I � � We hereby certify that the purpose of this survey is to depict the relocation and aggregation of lots within � I I ^ I a platted subdivision, therefore this division of land is exempt from review as a subdivision pursuant to r, � � � I � I V- section 76-3-207(1)(d), MCA to wit: "for five or fewer lots within a platted subdivision, the relocation of � � � � �, -�- � , ,� _,_ ��_ � common boundaries" and 76-3-207(1)(f), MCA, to wit: "aggregation of parcels or lots when a certificate of � I \ � I � � � � � � � � � � � �-, ' '` -'- '' � I survey or subdivision plat shows that the boundaries of the original parcels have been eliminated and the L_ \J I -t I I I I V\ � � J � v �- " ' �" I �_ .� � .. � boundaries of a larger aggregate parcel are established. a restriction or requirement on the original platted �� I I � � � � I lot or original unplatted parcel continues to apply to those areas , � � � I � O � t�p I � � further this plat is to be known and designated as: AMENDED PLAT OF LOTS 4, 5, AND 6, BLOCK 20, � I I r- � � O I BAXTER MEADOWS SUBDIVISION PHASE 2A. �, I o LOT 4A o LOT 5A � � , � � v � �'�� -�- � ,�, � ,, -�- ,, � 7 477 S Ft. �� 4 5 4 5' � �,,� w I �- �� -� I L �� < I + q• 8,427 S q.Ft. ^p C E R T I �I C A T E O F E X E M P T I O N � � W _0.172 AC � � +0.193 AC �� I AGGREGATION OF LOTS AND RELOCATION OF COMMON BOUNDARY Z �. I � � � �, � o . I ( ) I � / � I � Z � We certify that the purpose of this survey is to relocate the common boundary between adjoining properties � I � � and aggregate three existing lots into two new lot and being Lots 4, 5, and 6, BAXTER MEADOWS M O � � � �-- I SUBDIVISON PH2A, GALLATIN COUNTY, MONTANA, and that this exemption complies with all conditions imposed � p 0 JI O I � > on its use. Therefore, this survey is exempt from review as a subdivision pursuant to Section � Z I I � Z PREVIOUs BOUNDARY � PREVIOUS BOUNDARY � a I 76-3-207(1)(d) and 76-3-207(1)(f), MCA, and the Gallatin County Subdivision Regulations. � � I' O � � I I N O � �'�. I Dated this day of . 2025. Cyclone Development, LLC, � � I I J O a Montana Limited Liability Company � I I � ---� p I STATE OF MONTANA � , I I w � COUNTY OF GALLATIN By: Jon Stites, Registered Agent Q � _ _ _ _ 106.90 (R1&F) _ _ _ _ � _ _ 66.00' (R1&F) � 73.53' M - -L _ 82•$7� W I This instrument was signed or acknowledged before me on this day of , 2025, � O :^ � I I by Jon Stites, Registered Agent of Cyclone Development, LLC, a Montana Limited Liability Company. � � : � N89'06'45"W (F) 329.30' (R1&F) 156.40' (R1&F) � U ^ I Notary Public for the State of Montana N89'24'S3"E (R1) �- � � `� �� : Printed Name: w :� ALLEY � Residing at: � : rp �v: I My commission expires: � N89'24'S3"E (R1) � � � - - - - - - - - - - _S89'06'45"E F 329.30 R1&F) � � I I `\1� ��,,,u��••••.,,,��, _ - - - - - - ! ! �� N T q � CERTI �ICATE O � SUR�/EYOR Q � ` ` i , � � - - - - - - - - _ _ _ _ � �� ..��d"""��""""��.,,,,��= I, Matthew Jacobson, Professional Land Surveyor No. 13748LS, do hereby certify that between December 19, � O > 164.66 (R1&F� � - \� �: :,9 \ 2024 and March . 2025, this survey was made by me or under my direct supervision and that this I I 164.64' (R1&F) � � = MATTHEW =; FOUND 5/8" REBAR W/ � I �.* � JACOBSON � .�� ActP Sect ons 76 P3 S101S through 76 3 n625h M.0 A.c�andr he tBozeman rMunic paltCodeSubdivision and Platting � =- 13748 LS � � 2" ALUMINUM CAP ' "'��" ��`�� Dated this da of 2025. I (14535/13601 LS) � I � I � I � I I � =�q��q,,,p��F,�, O`\�� y Matthew Jacobson � ''�o� SUFZv�I�� Montana License No. 13748LS � i�� I I I I I I � i//////////llll � I CERTIFICATE O � GO�/ERNING BODY B � OCI� 20 � � � � � . . . . . I � I I � � I I I, Director of Community Development, City of Bozeman, Montana, do hereby certify that the exemption J � � 15' UTILITY EASEMENT � v claimed on the accompanying plat has been duly examined, and has found the same to conform to law, I � I � & PEDESTRIAN �� I I approves it. WALKWAY PER PLAT I � � I � I � [J-383] I ��1j I Dated this day of . 2025. O I Director of Community Development I � I � W �' I City of Bozeman, Montana � �. -�- �� ., -�- .. � � �_ �..� � �' ,'-�� I I �_ '„ ; ! ;; �_ �� ^ �� I CERTI �ICATE OF EXCLUSION FROM MONTANA I � I � I ;� � I � I DEPARTMENT OF EN�/IRONMENTAL QUALITY RE�/IEW �� O � I N � I I i I w� p r- I The accompany'ing plat is within the City of Bozeman, Montana, a first-class municipality, and within the � ao (n � I planning area of the Bozeman growth policy which was adopted pursuant to Section 76-1-601 et seq., � � ;n M.C.A., and can be provided with adequate storm water drainage and adequate municipal facilities. Therefore, I � � � I � I „Q� O I under the provisions of Section 76-4-125(2)(d)(iii) M.C.A., this subdivision is excluded from the requirement I Q � I I I � J N I for Montana Department of Environmental Quality review. �z w � � � � � I Dated this day of 2025. - � � w Director of Transportation and Engineering � - - - - - - - - - - - - - - - - - - - - - - - - - - - - - � - I- � - - - I � � I I City of Bozeman, Montana I --� I + - - - - - - - - - � - - - - - - - - - - - - - - - - - � _- _- _- - - - � � I I - - - - - - - - - CERTIFICATE O � COUNTY TREASURER � -� �� I- � - - - - _ _ _ _ _� I I, Maureen Horton, Treasurer of Gallatin County, Montana, do hereby certify that the accompanying Certificate of Survey has been duly examined and that all real property taxes and special assessments ' . I assessed and levied on the land to be divided have been paid. DETAIL 1 VICINITY MAP � Dated this day of . 2025. SCALE: 1" = 1' NOT TO SCALE SUBJECT PROPERTY � I Deputy Treasurer of Gallatin County c� . � . � � . I CLERK AND RECORDER � � I, Eric Semerad, Clerk and Recorder of Gallatin County, Montana, do hereby certify that the foregoing o L E G E N D . I instrument was filed in my office at o'clock _.M. this day of o � � A.D., 2025, and recorded in Book of Plats, on Page , records of the Clerk and Recorder, z (R�) RECORD OR ADDITIVE PER AMENDED PLAT J-383B �R�� . Gallatin County, Montana. '1' FOUND 5/8" REBAR I Q (F) FOUND THIS SURVEY BENT, NO CAP ��.� � 00 SET 5/8" REBAR W/ 1-1/4"YELLOW PLASTIC CAP, IMEG #13748LS � �R>>�, I Deputy Clerk and Recorder � � "� � FOUND MONUMENT AS NOTED � o �� , � R�,,�iC� N 0 5/8" REBAR WITH 2"ALUMINUM CAP#12249LS, FOUND S89'06'45"E (F) � N13°51 E � �jJ; . I O 0.64' (TIE) � w � 5/8" REBAR WITH 2"ALUMINUM CAP#14535LS, FOUND 82.g7' � � R� . I Note: BAXTER LANE � PROPERTY BOUNDARY LINE �� ) ' Pursuant to A.R.M. 24.183.1104 UNIFORM STANDARDS FOR CERTIFICATES OF SURVEY: Section (1)(f)(iii)(C) "The area that is � J being removed from one tract of record and joined with another tract of record is not itself a tract of record. Said j - - - - - SURROUNDING PROPERTY LINE j � � �� I area shall not be available as a reference legal description in any subsequent real property transfer after the initial �-' � transfer associated with the [certificate of survey or amended plat] on which said area is described, unless said area is � - - - - - - - EASEMENT LINE � z � J �J LOT 5A � � � Q • I included with or excluded from adjoining tracts of record." � > � � . "� U � CO � Q � . / I r,� z , Q ' N o 20 0 20 40 0 0 / � � FOUND 5 8" REBAR W I / RED PLASTIC CAP . 0 0 (ILLEG) � N � SCALE IN FEET � SHEET 1 OF 1 N o BASIS OF BEARING: BOZEMAN, MONTANA � � MTSTATEPLANE AMENDED PLAT OF LOTS 4, 5, AND 6 �j 1143 STONERIDGE DR PH: ZONE 25001/4 S E C. T. R. � N SUITE 1 www.imegcorp.com GROUND(TRUE)DISTANCES(GRID) BAXTER MEADOWS SUBDIVISION, PHASE 2A �% BOZEMAN,MT 59718 � 34 �s. 5E. AN AMENDED PLAT OF GALLATIN COUNTY L • L.L C� ` . APPENDIX B PHASE II BAXTER MEADOWS DESIGN REPORT Revised April 2004 TABLE OF CONTENTS City of Bozeman—Plans and Speci�cations Certified Checklist Response to Comments on Preliminary Design Report Review (M-M 1/19I04) Response to Comments on Preliminary Plat Submittal (M-M 12/12/03) Water System Design Report Revised Water Modeling Water Main DEQ Certified Checklist Sanitary Sewer System Design Report Sewer Main DEQ Certified Checklist Storm Drain Design Report Revised Storm Drainage Modeling Storm Drainage Maintenance Plan Traffic Impact Study Update PHASE II BAXTER MEADOWS STORM DRAIN DESIGN REPORT OCTOBER 2003 By: ROBERT PECCIA AND ASSOCIATES P.O. Box 5653 HELENA, MT 59604 �D�ERT PF�C'0 1 1 � � r ` � �qssOC1A'�`� For: CITY OF BOZEMAN BAXTER MEADOWS DEVELOPMENT Design Report— Storm Drain System A. GENERAL DESIGN CRITERIA 1. The storm water drainage plan was designed to limit storm water runoff from the developed sites to pre-developed runoff rates. There are seven drainage basins contained in Baxter Meadows - Phase II. Calculations of pre and post development runoff are included in this report. The calculations are used to determine the volume and area of the seven detention basins. The basins are designed to be self-draining and are therefore gradually sloped from inlet to outlet at which point the basin reaches a depth of eighteen inches. 2. Vegetation and settling action will help remove solids, silts, oils, grease, and other pollutants contained in storm drainage water that flows into the detention basins. 3. Storm Sewer design meets the City of Bozeman requirements: a. Alignment between manholes is straight. b. Pipe slopes are uniform. Design velocities are at least 3-ft/sec. c. Pond inlet and outlet piping is designed to protect against and prevent erosion. d. All storm drain pipe is RCP. Inlet laterals are 12-inch and mains are at least 15- inch diameter. e. Storm sewer pipe is designed to handle a 25-year storm event. f. Nine-inch sumps are used for sediment collection in inlets and manholes. B. STORM DRAIN PLAN A storm drain plan for the Baxter Meadows subdivision has been approved by the City of Bozeman. Components of the storm drain system (detention basins,pipes, and inlets) for Phase II have been designed according to the general guidelines contained in the storm drain plan. 1. The approved storm drainage plan included drawings showing the development's drainage features, ground surfaces, etc. 2. Topographic contours (one-foot intervals) and spot elevation data are included in the plans. 3. Storm water runoff from the Phase II sites drains into detention ponds. Settling removes suspended solids and other pollutants. The ultimate destination of storm water runoff from the site is Spring Ditch. Discharge from the detention ponds is limited to the pre-developed runoff rate by the pond outlet structures thereby minimizing impacts on down slope drainage facilities and water quality. 4. Design calculations showing runoff quantities and storage requirements are included in this report. 5. The approved storm drainage facilities maintenance plan a. identifies ownership of all facilities., b. establishes a schedule for maintenance activities, and c. identifies the responsible party in charge of the specific maintenance duties. 6. Details and specifications (including invert and other pertinent elevation information) for all stortn drainage improvements are included in the plans. C. STORAGE/TREATMENT FACILITIES The detention ponds for Phase II were sized based on a 10-year, 2-hour storm intensity. 1. Detention Basins The detention basins were designed for water storage. Outlet-discharge is controlled by a designed outlet structure. 2. Basin Sizing The detention basins were designed to hold the difference between the pre-developed and developed runoff volumes. The final design of the ponds meets or exceeds the City of Bozeman minimum basin area of 145-square feet per 1-cfs release rate used for sediment control. Likewise the detention ponds meets the City of Bozeman depth requirements of no more than 2.5-feet deep with 1.5-feet maximum water depth. 3. Basin Location The detention basins are located in open areas as shown on the attached drawings. 4. Additional Requirements Above ground earth formed detention basins not used in the project. D. DISCHARGE STRUCTURES 1. Orifice controlled discharge structures were designed to restrict detention pond discharge to pre-developed rates. Design calculations are included in this report. 2. Orifice calculations for controlling discharge to pre-development rate are included this report. 3. Fail/safe features are part of the design. They include: a. Emergency free-flowing overflow for rates exceeding design storm events. b. Discharge piping is at least six inches in diameter capable of conveying a 25-year storm event. c. Ponds are designed to avoid long-term standing water by sloping the basin floors toward the outlet structure. E. ESTIMATION OF RUNOFF 1. GENERAL The rational method was used to estimate runoff. The basic assumptions that apply are: a. Rainfall is uniformly distributed over area for duration of the storm. b. Peak runoff occurs when duration of storm equals time of concentration. c. Runoff coefficient for particular watershed is constant for a similar land use. Rational formula used to determine runoff coefficients: Q =CiA. 2. RUNOFF COEFFICIENTS Runoff coefficients used for the Phase II design are as follows: a. Open land--0.20 b. Low to medium density residential--0.35 c. Dense residential--0.50 d. Commercial neighborhood--0.60 e. Commercial downtown--0.80 f. Industrial--0.80 3. TIME OF CONCENTRATION The time of concentration is the flow time from the most remote point in the drainage to the point in question. It consists of overland flow time and the channel flow time. The overland flow time was estimated with the use of ineasured distances and figure I-1 included in part I of Appendix C. The channel flow time in pipes was determined by estimating the velocities with the Manning equation. V = (1.486*R^2/3*S^1/2)/n V=mean velocity(ft/sec) n=Manning roughness coefficient R=Hydraulic radius=cross sectional area/wetted perimeter The following typical "n"values from table I-2 were used for time of concentration calculations and are included in part I of Appendix C. a. Open unlined channels--0.035 b. Concrete and RCP pipe--0.013 4. STORM INTENSITY The intensity of the storm was determined form Figure I-2, I-3, and the City of Bozeman Design Frequencies for rainfall. Assuming equal to time of concentration. a. Open land, 2-year b. Residential, 10-year c. Commercial or industrial, 10-year 5. RLJNOFF RATES AND VOLUMES Values for peak runoff rates were computed using the rational formula. This rate occurs at the time of concentration. Values for runoff volume were calculated using the modified rational method. This method assumes the maximum runoff rate begins at the time of concentration and continues to the end of the storm. Maximum runoff rates are less than the peak runoff rate for durations greater than the time of concentration due to the decrease in storm intensity as duration increases. By multiplying the duration of the storm by the runoff rate the volume is computed. Baxter Meadows-Phase II Detention Basin 1 Design Storm Frequency 10 yr Basin Area(Ac) 2.90 Pre-Development Ccefficient C Post-Development Coefficient C Area(Ac) C Area(Ac) � Open Space 2.9 0.20 Open Space 0.20 Med. Res. 0.35 Med.Res. 0.35 Dense Res. 0.50 Dense Res. 2.9 0.50 Comm. Neigh. 0.60 Comm.Neigh. 0.60 Comm.Down 0.80 Comm.Down 0.80 Industrial 0.80 Industrial 0.80 Total Area: 2.9 Composite C: 0.2 Total Area: 2.9 Composite C: 0.5 Pre-Development Post-Development Runoff Distance 400 ft Runoff Distance 550 ft Average Slope 1.75% Average Slope 1.30% Time of Concentration 29 min Time of Concentration 25 min Average Rainfall Intensity 1.03 in/hr Average Rainfall Intensity 1.13 in/hr Maximum Runoff 0.60 cfs Maximum Runoff 1.64 cfs Storm Intensity Developed Developed Undeveloped Required Duration 10 Yr Flow Runoff Runoff Storage (min) (in/hr) (cfs) (c� (cf) (cfl 5 3.22 4.67 1400 179 1221 10 2.05 2.97 1784 357 1427 15 1.58 2.29 2057 536 1521 20 1.31 1.90 2274 715 1560 25;, ' t:13 ; 1.6d" 2459 893°. 15G6 30 1.00 1.46 2621 1072 1549 35 0.91 1.32 2766 1250 1516 40 0.83 1.21 2899 1429 1470 45 0.77 1.12 3021 1608 1413 50 0.72 1.04 3134 1786 1348 55 0.68 0.98 3241 1965 1276 60 0.64 0.93 3341 2144 1197 65 0.61 0.88 3436 2322 1113 70 0.58 0.84 3526 2501 1025 75 0.55 0.80 3612 2680 933 80 0.53 0.77 3695 2858 837 85 0.51 0.74 3774 3037 737 90 0.49 0.71 3850 3215 635 95 0.47 0.69 3924 3394 530 Minimum Basin Area Minimum Volume= 1566 cf Minimum Area(18"basin depth) 1044 sf Actual Area(shaped to drain)= 2088 sf Minimum Area for Sediment Control-->145 sf per 1 cfs Peak Developed Flow-> 1.64 cfs Minimum Area= 238 sf � Baxter Meadows-Phase II Detention Basin 2 Design Storm Frequency 10 yr Basin Area(Ac) 2.17 Pre-Development Coefficient C Post-Development Coe�cient C Area(Ac) C Area(Ac) � Open Space 2.17 0.20 Open Space 0.20 Med.Res. 0.35 Med.Res. 0.35 Dense Res. 0.50 Dense Res. 2.17 0.50 Comm.Neigh. 0.60 Comm.Neigh. 0.60 Comm.Down 0.80 Comm.Down 0.80 Industrial 0.80 Industrial 0.80 Total Area: 2.17 Composite C: 0.2 Totai Area: 2.17 Composite C: 0.5 Pre•Development Post-Development Runoff Distance 500 ft Runoff Distance 650 ft Average Slope 1.20% Average Slope p,gp�/, Time of Concentration 36 min Time of Concentration 32 min Average Rainfall Intensity 0.89 in/hr Average Rainfall Intensity 0.96 in/hr Maximum Runoff 0.39 cfs Maximum Runoff 1.04 cfs Storm Intensity Developed Developed Undeveloped Required Duration 10 Yr Flow Runoff Runoff Storage (min) (in/hr) (cfs) !c� (c� (c� 5 3.22 3.49 1048 116 931 10 2.05 2.23 1335 232 1103 15 1.58 1.71 1539 348 11 gp 20 1.31 1.42 1702 465 1237 25 1.13 1.23 1840 581 1259 30 : "t.Od 1.09 1961 897 `'` ° ; 1284 , " 35 0.91 0.99 2070 813 1257 40 0.83 0.90 2169 929 1240 45 0.77 0.84 2260 1045 1275 50 0.72 0.78 2345 1161 1184 55 0.68 0.73 2425 1278 1147 60 0.64 0.69 2500 1394 1106 65 0.61 0.66 2571 1510 1061 70 0.58 0.63 2638 1626 1012 75 0.55 0.60 2703 1742 961 80 0.53 0.58 2765 1858 906 85 0.51 0.55 2824 1974 850 90 0.49 0.53 2881 2091 790 95 0.47 0.52 2936 2207 729 100 0.46 0.50 2989 2323 666 105 0.44 0.48 3041 2439 602 110 0.43 0.47 3091 2555 535 115 0.42 0.45 3139 2671 468 120 0.41 0.44 3186 2787 399 125 0.40 0.43 3232 2904 328 130 0.39 0.42 3277 3020 257 135 0.38 0.41 3320 3136 184 140 0.37 0.40 3363 3252 111 145 0.36 0.39 3404 3368 36 150 0.35 0.38 3445 3484 -39 Minimum Basin Area Minimum Volume= 1264 cf Minimum Area(18"basin depth) 843 sf Actual Area(shaped to drain)= 1685 sf Minimum Area for Sediment Control->145 sf per 1 cfs Peak Developed F�ow-> 1.09 cfs Minimum Area= 158 sf Baxter Meadows -Phase II Detention Basin 3 Design Storm Frequency 10 yr Basin Area(Ac) 12.15 Pre-Development Coe�cient C Post-Development Coefficient C Area(Ac) C Area(Ac) C Open Space 12.15 0.20 Open Space 0.20 Med.Res. 0.35 Med.Res. 0.35 Dense Res. 0.50 Dense Res. 3.15 0.50 Comm.Neigh. 0.60 Comm.Neigh. 9 0.60 Comm.Down 0.80 Comm.Down 0.80 Industrial 0.80 Industrial 0.80 Totai Area: 12.15 Composite C: 0.2 Total Area: 12.15 Composite C: 0.57 Pre-Development Post-Development Runoff Distance 1300 ft Runoff Distance 1900 ft Average Slope 0.80 % Average Slope 0.50 % Time of Concentration 67 min Time of Concentration 38 min Average Rainfall Inte�sity 0.60 in/hr Average Rainfall Intensiry 0.86 in/hr Maximum Runoff 1.45 cfs Maximum Runoff 6.01 cfs Stortn Intensity Developed Developed Undeveloped Required Duration 10 Yr Flow Runoff Runoff Storage (min) (in/hr) (cfs) (c� (c� (c� 5 3.22 22.45 6735 434 6300 10 2.05 14.31 8584 869 7715 15 1.58 10.99 9892 1303 8590 20 1.31 9.12 10940 1737 9203 25 1.13 7.89 11829 2171 9658 30 1.00 7.00 12609 2606 10003 35 0.91 6.34 13308 3040 10268 40 0.83 5.81 13944 3474 10470 45 0.77 5.38 14531 3908 10623 50 0.72 5.03 15077 4343 10734 55 0.68 4.72 15588 4777 10811 60 0.64 4.46 16070 5211 10859 65 ; ' 0.61 4.24 76527 ' S645 ::1fl882 . 70 0.58 4.04 16961 6080 10882 75 0.55 3.86 17376 6514 10862 80 0.53 3.70 17773 6948 10824 85 0.51 3.56 18154 7383 10771 90 0.49 3.43 18521 7817 10704 95 0.47 3.31 18875 8251 10623 100 0.46 3.20 19216 8685 10531 105 0.44 3.10 19547 9120 10428 110 0.43 3.01 19868 9554 10314 115 0.42 2.92 20180 9988 10192 720 0.41 2.84 20483 10422 10060 125 0.40 2.77 20777 10857 9921 130 0.39 2.70 21065 11291 9774 135 0.38 2.64 21345 11725 9620 140 0.37 2.57 21618 12159 9459 145 0.36 2.52 21885 12594 9292 150 0.35 2.46 22147 13028 9119 Minimum Basin Area Minimum Volume= 10882 cf Minimum Area(18"basin depth) 7255 sf Actual Area(shaped to drein)= 14509 sf Minimum Area for Sediment Control->145 sf per t cfs Peak Developed Flow-> 4.24 cfs Minimum Area= 615 sf Baxter Meadows-Phase II Detention Basin 4 Design Storm Frequency 10 yr Basin Area(Ac) 3.18 Pre-Development Coefficient C Post-Development Coefficient C Area(Ac) C Area(Ac) C Open Space 3.18 0.20 Open Space 0.20 Med.Res. 0.35 Med.Res. 1.06 0.35 Dense Res. 0.50 Dense Res. 2.12 0.50 Comm.Neigh. 0.60 Comm.Neigh. 0.60 Comm.Down 0.80 Comm.Down 0.80 Industrial 0.80 Industrial 0.80 Total Area: 3.18 Composite C: 0.2 Total Area: 3.18 Composite C: 0.45 Pre-Development Post-Development Runoff Distance 500 ft Runoff Distance 600 ft Average Slope 1.60 % Average Slope 1.06 % Time of Concentration 33 min Time of Concentration 32 min Average Rainfall Intensity 0.94 in/hr Average Rainfall Intensity 0.96 in/hr Maximum Runoff 0.60 cfs Maximum Runoff 1.38 cfs Stortn Intensiry Developed Developed Undeveloped Required Duration 10 Yr Fiow Runoff Runoff Storage (min) (in/hr) (cfs) (c� (cf) (c� 5 3.22 4.61 1382 180 1202 10 2.05 2.94 1761 360 1401 15 1.58 2.26 2030 540 1489 20 1.31 1.87 2245 720 1524 25; 1.13 ' 1:82.' 2427 .` 901 1526"'"` 30 1.00 1.44 2587 1081 1506 35 0.91 1.30 2730 1261 1469 40 0.83 1.19 2861 1441 1420 45 0.77 1.10 2981 1621 1360 50 0.72 1.03 3093 1801 1292 55 0.68 0.97 3198 1981 1217 60 0.64 0.92 3297 2161 1136 65 0.61 0.87 3391 2341 1049 70 0.58 0.83 3480 2521 958 75 0.55 0.79 3565 2702 863 80 0.53 0.76 3646 2882 765 85 0.51 0.73 3724 3062 663 90 0.49 0.70 3800 3242 558 95 0.47 0.68 3872 3422 450 Minimum Basin Area Minimum Volume= 1526 cf Minimum Area(18"basin depth; 1017 sf Actuai Area(shaped to drein)= 2035 sf Minimum Area for Sediment Control-->145 sf per 1 cfs Peak Developed Flow-> 1.62 cfs Minimum Area= 235 sf Baxter Meadows-Phase II Detention Basin 5 Design Storm Frequency 10 yr Basin Area(Ac) 16.16 Pre-Development Coefficient C Post-Development Coefficient C Area(Ac) C Area(Ac) � Open Space 16.16 0.20 Open Space 0.20 Med.Res. 0.35 Med.Res. 16.16 0.35 Dense Res. 0.50 Dense Res. 0.50 Comm.Neigh. 0.60 Comm.Neigh. 0.60 Comm.Down 0.80 Comm.Down 0.80 Industrial 0.80 Industrial 0.80 Total Area: 16.16 Composite C: 0.2 Total Area: 16.16 Composite C: 0.35 Pre-Development Post-Development Runoff Distance 1200 ft Runoff Distance 1500 ft Average Slope 1.10 % Average Slope p,�z % Time of Concentration 58 min Time of Concentration 62 min Average Rainfall Intensity 0.65 in/hr Average Rainfall Intensity 0.63 in/hr Maximum Runoff 2.11 cfs Maximum Runoff 3.54 cFs Storm Intensity Developed DevelopedJndevelope Required Duration 10 Yr Flow Runoff Runoff Storage (min) (in/hr) (cfs) (cf) (c� (� 5 3.22 18.20 5461 634 4827 10 2.05 11.60 6960 1269 5692 15 1.58 8.91 8022 1903 6119 20 1.31 7.39 8872 2537 6334 25 " 1.13 fi.39, 9592. 3472 ` 8420..; , 30 1.00 5.68 10224 3806 6418 35 0.91 5.14 10791 4441 6350 40 0.83 4.71 11307 5075 6232 45 0.77 4.36 11783 5709 6074 50 0.72 4.08 12226 6344 5882 55 0.68 3.83 12641 6978 5662 60 0.64 3.62 13031 7612 5419 65 0.61 3.44 13402 8247 5155 70 0.58 3.27 13754 8881 4873 75 0.55 3.13 14090 9516 4574 SO 0.53 3.00 14412 10150 4262 85 0.51 2.89 14721 10784 3937 90 0.49 2.78 15018 11419 3600 95 0.47 2.69 15305 12053 3252 100 0.46 2.60 15583 12687 2895 105 0.44 2.52 15851 13322 2529 110 0.43 2.44 16111 13956 2155 Minimum Basin Area Minimum Volume= 6420 cf Minimum Area(18"basin dep� 4280 sf Actual Area(shaped to drein)= 8560 sf Minimum Area for Sediment Control-->145 sf per 1 cfs Peak Developed Fiow--> 6.39 cfs Minimum Area= 927 sf Baxter Meadows-Phase II Detention Basin B Design Stortn Frequency 10 yr Basin Area(Ac) 9.00 Pre-Development Coefficient C Post-Development Coefficient C Area(Ac) C Area(Ac) C Open Space 9 0.20 Open Space 0.20 Med.Res. 0.35 Med.Res. 0.35 Dense Res. 0.50 Dense Res. 2.56 0.50 Comm.Neigh. 0.60 Comm.Neigh. 6.14 0.60 Comm.Down 0.80 Comm.Down 0.80 Industrial 0.80 Industrial 0.80 Total Area: 9 Composite C: 0.2 Total Area: 9 Composite C: 0.5682222 Pre-Development Post-Development Runoff Distance 1000 ft Runoff Distance 7200 fl Average Slope 1.10 % Average Stope 0.80 % Time of Concentration 51 min Time of Concentration 40 min Average Rainfall Intensity 0.71 in/hr Average Rainfall Intensity 0.83 in/hr Maximum Runoff 1.28 cfs Maximum Runoff 4.26 cfs Storm intensity Developed Developed Jndevelope Required Duration 10 Yr Flow Runoff Runoff Storage (min) (in/hr) (cfs) (c� (c� (c� 5 3.22 16.46 4938 384 4554 10 2.05 10.49 6293 768 5525 15 1.58 S.O6 7253 1152 6101 20 1.31 6.68 8021 1536 6485 25 1.13 5.78 8673 1921 6752 30 1.00 5.14 9244 2305 6940 35 0.91 4.65 9757 2689 7068 40 0.83 4.26 10224 3073 7151 45 0.77 3.95 10654 3457 71 g7 54 ;- 0 72 3.68 Y 1£154; � 38d1"":.` 7243" 55 0.65 3.46 11429 4225 7204 60 0.64 3.27 11783 4609 7173 65 0.61 3.11 12117 4993 7124 70 0.58 2.96 12436 5377 7058 75 0.55 2.83 12740 5762 6978 80 0.53 2.71 13031 6146 6885 85 0.51 2.61 13310 6530 6780 90 0.49 2.51 13579 6914 6665 95 0.47 2.43 13839 7298 6541 100 0.46 2.35 14089 7682 6407 105 0.44 2.27 14332 8066 6266 110 0.43 2.21 14567 8450 6117 115 0.42 2.14 14796 8834 5961 120 0.41 2.09 15018 9219 5799 125 0.40 2.03 15234 9603 5631 130 0.39 1.98 15444 9987 5458 135 0.38 1.93 15650 10371 5279 140 0.37 1.89 15850 10755 5095 145 0.36 1.84 16046 11139 4907 150 0.35 1.80 16238 11523 4714 Minimum Basin Area Minimum Volume= 7213 cf Minimum Area(18"basin depth 4809 sf Actual Area(shaped to drain)= 9617 sf Minimum Area for Sediment Control->745 sf per 1 ds Peak Developed Flow-> 3.68 cfs Minimum Area= 534 sf Baxter Meadows-Phase II Detention Basin 7 Design Storm Frequency 10 yr Basin Area(Ac) 12.45 Pre-Development Coefficient C Post-Development Coefficient C Area(Ac) C Area(Ac) C Open Space 12.45 0.20 Open Space 0.20 Med.Res. 0.35 Med.Res. 0.35 Dense Res. 0.50 Dense Res. 0.50 Comm.Neigh. 0.60 Comm.Neigh. 12.45 0.60 Comm.Down 0.80 Comm.Down 0.80 Industrial 0.80 Industrial 0.80 Total Area: 12.45 Composite C: 0.2 Total Area: 12.45 Composite C: 0.6 Pre•Development Post-Development Runoff Distance 900 ft Runoff Distance 1300 ft Average Slope 1.10 % Average Slope 0.77 % Time of Concentration 49 min Time of Concentration 39 min Average Rainfail Intensity 0.73 in/hr Average Rainfail Intensity 0.85 in/hr Maximum Runoff 1.82 cfs Maximum Runoff 6.33 cfs Storm Intensity Developed Developed Jndevelope Required Duration 10 Yr Flow Runoff Runoff Storage (min) (in/hr) (cfs) (c� (c� (c� 5 3.22 24.04 7213 545 6667 10 2.05 15.32 9193 1091 8102 15 1.58 11.77 10595 1636 8959 20 1.31 9.76 11717 2181 9535 25 1.13 8.45 12669 2727 9942 30 1.00 7.50 13503 3272 10231 35 0.91 6.79 14252 3817 10435 40 0.83 6.22 14934 4363 10571 45 0.77 5.76 15562 4908 10654 50 0.72 5.38 16147 5453 10693 55�� . 0.68 - 5.Q6� - �16695 �°�� 5999� �- 1Q698 60 0.64 4J8 17211 6544 10667 65 0.61 4.54 17700 7089 10610 70 0.58 4.32 18165 7635 10530 75 0.55 4.14 18609 8180 10429 SO 0.53 3.97 19034 8726 10309 85 0.51 3.81 19442 9271 10171 90 0.49 3.67 19835 9816 10019 95 0.47 3.55 20214 10362 9852 100 0.46 3.43 20580 10907 9673 105 0.44 3.32 20935 11452 9482 110 0.43 3.22 21278 11998 9281 115 0.42 3.13 21612 12543 9069 120 0.41 3.05 21936 13088 8848 125 0.40 2.97 22252 13634 8618 130 0.39 2.89 22560 14179 8381 135 0.38 2.82 22860 14724 8135 140 0.37 2.76 23152 15270 7883 145 0.36 2.69 23438 15815 7623 150 0.35 2.64 23718 16360 7358 Minimum Basin Area Minimum Volume= 10696 cf Minimum Area(18"basin depth) 7131 sf Actual Area(shaped to drain)= 14261 sf Minimum Area for Sediment Control->145 sf per 1 cfs Peak Developed Flow-> 5.06 cfs Minimum Area= 734 sf � � � �l � +�. 1"'1. � . 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O � � 400 ,� 64 � F- , • o � dz a � J � W � 200 40 0 0 � 20_ , C 0 FIGURE I-1 TIME OF CONCENTRATION (Rational Formula) �_ ___�__ . 28 Baxter Meadows Phase II -Storm Drain Inlet Calcs -Basin 1 Inlet Overland Overland Overland Gutter Gutter Gutter Overland Gutter Total Rainfall 25 Year Inlet Area Coe�cient Flow Distance Flow Slope Flow Distance Flow Slope Flow Velocity Flow tc Flow tc tc Intensity Flow (acres) C (ft) (%) (ft) (%) (Ws)Fi .7-1 ) (min)* (in/hr 9 (min)Fig.I-1 (min ) (cfs) 1 0.11 0.50 0 2.00 230 0.60 1.57 0.0 2.4 10.0 2.46 0.14 2 1.70 0.50 360 2.00 200 0.60 1.57 23.0 2.1 25.1 1.36 1.16 3 0.82 0.50 140 2.00 270 0.60 1.57 13.0 2.9 15.9 1.83 0.75 4 0.27 0.50 0 2.00 340 0.60 1.57 0.0 3.6 10.0 2.46 0.33 Total 2.gp 'Minumum tc=10 min Baxter Meadows Phase II-Stortn Drein Pipe Calculations-Basin 1 Pipe/Gutter Segment Inlet Area Inlet Cumulative Pipe Pipe pipe Flow Pipe Segment Cumulative Rainfall 25 Year Flow From To Coefficient, Area C x Area Length Flow Diameter Depth Velocity tc tc Intensity At Downstream C (Acre) (Acre) (ft) (cfs) (i�) (i�) (ft/s) (min) (min) (1Nhr) Point(cfs) Baxter Parkway Gutter Inlets 1&2 0.50 �,g� p g� Inlets 1&2 Manhole 1 0.50 z5•1 25.1 1.36 �,23 �.91 60 1.23 15 5.1 3.37 0.3 25.4 1.35 �.22 Trakker Way Gutter Inlets 3&4 0.50 1.09 1.45 Inlets 3&4 Manhole 1 0.50 15.9 15.g �,g2 p gg 1.45 55 0.99 15 4.5 3.17 0.3 25.4 1.35 1.96 Totals At Manhole 1 2.90 1.45 Discharge Into Basin 25.4 1.35 1.96 1.96 15 6.5 3.83 � - _.�...._..�.........................._�___ � � 3�� I i i i ^ _....____.._....._........._�._...._....._._� � i l............._....._.............._.....__...._., I � ,.._. ...,_. _� _ .._....._ ,.�.._��._.:.....�,•_•....w , _ _._.. � �. , , . �H.�; - - _._..... _. ..._____....�____ : Y '.. . . .. -.._.___. 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Baxter Meadows Phase II -Storm Drain Inlet Calcs-Basin 2 Inlet Overland Overland Overland Gutter Gutter Gutter Overland Gutter Total Rainfall 25 Year Inlet Area Coefficient Flow Distance Flow Slope Flow Distance Flow Slope Flow Velocity Flow tc Fiow tc tc Intensity Flow (acres) C (ft) (°/a) (ft) (%) (ff/s)Fig.7-1 (min)Fig.I-1 (min) (min)• (in/hr) (cfs) 1 0.18 0.50 20 2.00 235 0.60 1.57 2.0 2.5 10.0 2.46 0.22 2 1.71 0.50 340 2.00 235 0.60 1.57 17.0 2.5 19.5 1.60 1.37 3 0.16 0.50 20 2.00 130 1.75 2.68 2.0 4 0.12 0.50 30 2.00 130 1.75 2.68 3.0 0.8 10.0 2.46 0.15 Total 2.17 'Minumum tc=10 min Baxter Meadows Phase II-Storm Drein Pipe Calculations-Basin 2 Pipe/Gutter Segment Inlet Area Inlet Cumulative Pipe Pipe Pipe Flow Pipe Segment Cumulative Rainfall 25 Year Flow From To Coefficient, Area C x Area Length Flow Diameter Depth Veloci tc � (A��e) 1Acre � tc Intensity At Downstream � �ft) (��) ('") ('�) (�S) (min) (min) (in/hr) Point(cfs) Charolais Gutter Inlets 1&2 0.50 1.89 0.95 Inlets 1&2 Manhole 1 0.50 19.5 19.5 1.60 1.5� Trakker Way Gutter Inlets 3&4 0.50 0�95 6� ��51 15 5.7 3.57 0.3 0.28 1.09 19.8 1.59 1.50 Inlets 3&4 Manhole 1 0.50 1.09 55 0.34 �5 2_0 ��'� z•46 0.34 3.39 0.3 19.8 1.59 1.72 Totals At Manhole 1 2�� Discharge Into Basin 1.09 1.72 15 6.1 3.70 18.8 1.59 1.72 � _ _ _ __ __ _ ___ __ ---- — - ----- _.._.__..._._.._.............._.._.___._ 1 _ .. 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' r � � , � � '� �1 '?% f� I --., i '; �. �-� �_,�� c I �_ ,�- � ,.,�`�^^-_ U � �� _... ❑ I ( � � ; � ; � _ , 1 `� � j __.._......_; ❑ # _ _ I ( � I j ---�-__ _ _ _-__-___________ _ __-____ --__-_ __-___ ______ - -�E _ -__-__-___-�-_J � -_____ __ � � .. �-- i� �� . �7 � . � Baxter Meadows Phase II -Storm Drain Inlet Calcs -Basin 3, Including Trakker Site Inlet Overland Overland Overland Gutter Gutter Gutter Overland Gutter Total Rainfall 25 Year Inlet Area Coefficient Flow Distance Flow Slope Flow Distance Flow Slope Flow Velocity Flow tc Flow tc tc Intensity Flow (acres) C (ft) (%) �ft� �a�o� (ft/s)Fig.7-1 (min)Fig. I-1 (min) (min)* (in/hr) (cfs) � 0.40 0.50 150 2.00 230 2 1.21 0.50 0.60 1.57 11.0 2.4 13.4 2.03 0.41 200 2.00 230 0.60 1.57 13.0 2.4 15.4 1.86 1.12 3 0.22 0.60 20 2.00 150 0.50 1.43 3.0 1.7 10.0 2.46 0.32 4 0.15 0.60 20 2.00 150 0.50 1.43 5 0.47 0.60 20 2.00 3.0 1.7 10.0 2.46 0.22 6 �•79 0.60 340 0.60 1.57 3.0 3.6 10.0 2.46 0.69 200 2.00 340 0.60 1.57 13.0 3.6 16.6 1.77 1,g1 7 0.76 0.60 20 2.00 360 8 0.98 0.60 0.50 1.43 3.0 4.2 10.0 2.46 1.12 270 2.00 360 0.50 1.43 14.0 4.2 18.2 1.67 0.98 9 0.26 0.60 10 2.00 230 0.60 1.57 2.0 2.4 10.0 2.46 0.38 10 1.95 0.60 310 2.00 230 0.60 1.57 14.0 2.4 16.4 1.79 2.09 �� 1•15 0.60 130 2.00 190 0.60 1.57 8.0 2.0 10.0 2.45 1.69 12 0.75 0.60 130 2.00 120 13 0.23 0.60 0.60 1.57 8.0 1.3 10.0 2.46 1.10 10 2.00 250 0.60 1.57 2.0 2.7 10.0 2.46 0.34 14 0.29 0.60 20 2.00 250 0.60 1.57 3.0 2.7 10.0 2.46 0.43 15 0.58 0.50 20 2.00 410 0.50 1.43 16 0.96 0.50 60 2.00 410 0.50 1.43 7.0 4.8 11�.8 2.21 1�.06 Total 12.15 'Minumum tc=10 min Baxter Meadows Phase II-Storm Drein Pipe Calculatio�s-Basin 3 Pipe/Gutter Segment Inlet Area Inlet Gumulative Pipe Pipe Pipe Flow Pipe Segment Cumulative Rainfall 25 Year Flow From To Coefficient, Area C x Area Length Flow Diameter Depth Velocity tc tc Intensity At Downstream C (Acre) (Acre) (ft) (cfs) (in) (in) (fUs) (min) (min) (in/hr) Point(cfs) Caspian Brench Caspian Gutter iniets 1&2 0:6(y 1,s1 ' 4.gj , Infefs 1&2 [Nanhole 1 0'5� ;0.81 5Q �� ;�:50 - �'15 ' 6:S_ �- � �. 15.4 154�, � 1:86 1.50 Trakker Gutter intets 3&4 ' 4.60 3.5& �2 � 95 8 �_ 1'.84 : 0.37" �`1.03 - �� " � 1.48 � Intets 3 8�4 Manhole 1 0.6Q " 1Q.a 2:46 0.55 � Manhole 1 � inlets 5&6 '� �0:&0 � i.03 80 �' 4.58 �` �15 3.4 � 2.88� ; 0.4� ��,� V.6 �� 1�.71 � 1J6� inlet9 5&6 Manhole 2 '_.' _ 0.60 2.25` 2.38 29a ; 1:78 15 8.1. 3.T2.: . . t,3" 18.8 ' 7.63. 2.38 70 '., ,3.�9 '1$ 9.9 4.51 0:3 3.89 Manhole 2 ', inlets T&8: 19.2 . i:62 3.88 " Inlets 7 8�8 �� 80 1.74�� -�3.43 400' `� 3.88 �15 � '9.9 4.50 1`5 ��20.6 ' 1:54 � ,_ � Manho►e 3 �� D;BQ �� '3.43 45.;: 5;29�" ��16 � �� 11.2 � 4.56 i ,.:,0.2 �' ��:� 20 8 .,.'. 1�.54 �' �5.27� Charolais Gutter Inlets 9&10 0.60 2.21 475 Inlets 9&10 Manhole 3 0.60 16.4 16.4 1 jg Z.g7 4 75 70 2.37 15 7 3 4 02 0.3 20.5 1.55 7.37 Menhole 3 InletS 15&1 B . 0!50 ' 1.54 5 52 �FOA T 37 21 Iniets 15&18 " � 4$4 4 97� 1-S 21.8 -` 1.48 8.23 Manhole 4" Q:SQ ' �X1..' Alley Brench w- � .. 6&2 _.._.. ' ;�23 , •w�y � . `;. rt34 .� ��T9�� ;;ik:'f � ;;?'21.8' '" 1:48 � 8:2U� Alley�c�tter . 1Net 11 ,_-. 0.60 � 1 15''.. 0.89 � ;- Inlet 11`� � .°�Inlet 12 . - 4.60 �� 0 75�� '� � . ; ��:inlett2 �� 114 � 125 � � 1.89 - � ��5 6.0 � �,3.88� 10.0 1Q 0 2.46 1.89 �IMet 13&14;°' tl;60 � � = 0i6 10.6 2'37 � `1.14 ° '° 170 2.74 � ��16 �:. � �� 7:B�, �� 0;4 .; ...1t.6 �`,,= 2:�31�� . 2.63 Baxter Pkwy Gutter Inlets 13&14 0.60 \ "�� ° Itll@tS":13&74 MBRhole 4 `. , 0;80, 0.52 1.45 10.0 11.0 2.31 3.35 � � .�_:8.98�� 80 3:35 ,,, 15 �"�,.. ; .90�.: " 43T�`; _�.. -�11:3 - �� 2t.$. '_`� � �1.�9 _ f6:37 Totals At Manhole 4 12.75 6.98 Discharge Into Basin 21.9 1.49 10.37 10.37 21 14.8 5.72 Baxter Meadows Phase II-Storm Drain Pipe Calculations-Basin 3 Pipe/Gutter Segment Inlet Area Inlet Cumulative Pipe Pipe Pipe Flow Pipe Segment Cumulative Rainfall 25 Year Flow From To Coefficient, Area C x Area Length Flow Diameter Depth Velocity tc tc Intensity At Downstream C (Acre) (Acre) (ft) (cfs) (in) (in) (ffls) (min) (min) (in/hr) Point(cfs) Caspian Branch CaspianGutter inleYst&2 G.�(i 1.61 , tt.8i ` 15.4 i5.4 4.88 1<50 �fnieGs 1&2 . Manhole-�- 0.50 � � �� D.81 7< 50 � i.50 � �S� � �� 5.6 < �3.�6..� �A.2. 15.8�� 1.84.� 1:48 Trak[cer Gutter: �Iniets 3&4 �� 0.6� � 0.37 1.Q3 � � �� 3Q.0. �� 2 46 . � p.55 K .lniets 3&4� Ma�hote T �0.60 > = � 9.03 °66� �� q,65 �- t2`�, �.& ' � �2:74�� 0.4 17.6�' �� i.71 � �q.76 Maohflfe 1 - lnlets 5&8 �.Bfl =2.26 r 2.38 29t1 . 1:76 15 B.�E ' 3.�2 4 3 " ; '•�8.8= 1,83 ; , -3,89 �.., .' Inlets 5&s � � Manhole 2�� 0.60 � � " ° 2.38 -- 7Q 3.85 1b 9,8 - d.59 ' 0.3 19.2 ' i.82 3.86 . Manhote 2 Inists 7&8 p.60 1<74 ,. ' 3.43 4pU 3:86 15 8.9 ' 4.�Q :1.5 20.& ' 2.54 5.28 ��_ r.r. `iniefs 7&.8 ��Man6o(e 3� o.60 � :. �� °: ;: s ._,: 3.43 ex� 4� ��,2v �-., 18_,. . 11.2_�' . � A:58 :U 2„ '� 2CM.&;;,;�� , �1 54 � -. 5,27 Charolais Gutter Inlets 9&10 � 0.60 221 4]5 16.4 16.4 1.79 2.37 Inlets 9&10 Manhole 3 0 60 4 75 70 2.37 15 7.3 4.02 0 3 20 5 1 55 7.37 Manhoie 3 in(ets 15&16 0 50 � �.�•>.,._,�,„y, �, � . , ,�� ' ' '' y ''�, , iNets 15&36,,� , � Manbole:A; „_ . ��3� t- . .. ,., :._: ��;��k ,.� �� YB� �. . „-' ;��_�, � r,£#,. �„>��a Alley Branch �� ; AligY Gutfgr tniet 91 U st? 1.15 Cr.Bs 9�0 1Q.Q 248 1.89 ' � l�tlet 1'i ; tniet 12"" �6� {3.75 1.94 125 1.a9 7S 8.0 ' 9.6� Q 6 10.8 2 37 2.70 , � � � �� Ba�e�t.�.�.,r� . .,b.�nI4t.13&1� - _ tl$�.��:: .�z �. ,' � � i.9� .�� .. �ji6 �70. �r 15,.. ,�.; 7.8 �� 4.15, �q4 �7t0" �239 �2,83 , Pkwy Gutter Inlets 13&14 0 60 0 52 1 45 90 0 11.0 �2 31 3.35 ;�s�r�il��3;$��}+F:� ..,.._.,,��..4„ , a60. ,;. �aa , ._. .. ._.. . .._.�,� �«w.�.....a"�.wrmf, �.�,.�.��:'..� F..w.i;.;�s��.s' �"'k1..�..-'-�^�'`.'i`�.Q A'� ^,� L'Z3.a"A�"s`�'� �-�..x1� .n::> ti� tfi�'x . �,a ?,�4�.�':... e .:`!dfl "� �°1�_�- <�..�� Totals At Manhole 4 12.15 6.98 21.9 1.49 10.37 Discharge Into Basin 10.37 21 14.6 5.72 �c ,1��.�� - ,�� Z v�u�.� �-�.a .�t c�...c��>3 �%� n�� 1�-� :: . , �,,�. ��.��. cw�- ��:-� � ��#.� -� : I� 3, ..'� �1: ' �j�, ✓ F s.:�. : f`� �_...-------- ---- — -- - --— — - --------------— --------- — --------_. ..----- --- _.------_ _. —�---- — -- --- I , —- t; �t ,i ..__..._,_ , ._..__. .._,....__� _...__..,: -�� r :, �:- r ; l F I �� _ . ;_ �. . ; ; � � ,�� F- � � , ; '�. i � � Y ,-;. - !�.\ �y,, I �� ` * =r^, I T � ._ i +� ` �� L �;r � ,.!'� (y- � � � �E: - � �___.�.___.._ _�..�._.__�.__. �� I ' -- - ` �j. �� -� � ` �` �--��--_.� ; . -, ; -- _-..�_ _ ,: _..� ,4,� � �� z b, y� ��v� �' �-�,�T � � , . ------------ --------. _ _______.___ -- _ ____ __------ - -----__�.W_� _____ __ .__ _ _._ _ - - --___. ... _ ____ , 6-_ _ _ � _: _._ _ ,_:. _ _, __� - --.... ._____,��` � 2 ,... , . ; ` . 7 ' ; � . � ' ; ^'�� x.;: � -- _;�__ - - - - - - --- - i � � � . �1 " � -/ _ ��.��s i - ;� � �- - �_;�^ �- 7. o,�6 ,. , - . , ,� _ - �. ,� . < , � �. ,� � � . _._ t�. .��y. , � � �� ,i � ��% . � I y; � _ • ,_:rl � `___ , . � -..- ------_____..---._._ __ _____.__ . _. ;� � (�,�! - -; ,`.� _ _....._.�___ ______ _ . ___..._. __ � ---�-� - -�--- ` -—� 3 � � D �;� �' ; �Jf �,� �, y f ,��, i �. l r � z �rr�'�, � T � � �� . �� /. � � � � ��' ..: ,�?, '� S ii �.k /,� � ! r 5� t.� � � � I % � / ' � � �.. � /, `l�J . �t_.C./ i �� . E — lJ� .�t�.�li � `ia , it E �� . __ 11 �! � . M � E--- / L L ' � � 6 v < 1 ", ,.j i _� �,. - /.d• , - � o .. _ ��` �..v-- � �`-- , (f;:�� - :--�� p.'j�`rw�- l �� , � ; 0 " !� � , '; , a � . � ,,- , _.., . ' " , � � -� ,� � � --..�� t _ l � : � u � _ r� �n.�. � ., , .�. / - . " ;,, 1 _ �;;t: � , � � � � � / � ,. � �` o ��, , - � . , ,� __ � ,, , ;�' � :. ,. � , l . '� : � , - _. _- �.;�`, _ � ) � �f ` � o ; . , , . �' � _ ..___ _. _..___._______�. . _ , ,. .__ __ _� _.. _.__._______...__...__._ . .._____ _.:. _ � . -- - k � ,; . , .- � , /,, ;, � . , t.... , ��/ J� : ,'r. . �. , < <.. , ,; /t= �. � 'Jr /"!tit '7 �A 1 1 _i� �i , , ; � i.. % , /�'1 ( =- ! �� 'f��o_� `, '�,�` �' �'�L ;� �'� �� < ;, ; . ) : � . __... _� �__. _.� , __._.._ _._ --- ------- _._.._... ��._.__-----_ _ ------ -__. ...___-' -------------- -... _ . , —__ _-�: __ :,_ �; _ .. _._. ! , ;- . . ; _ _...� �� ' � ` � -- . , ; � . � rG � ,, T ; I. Z. � _ , � , , , , � ; ._ . _ � = i ,:�,,� � , .. ; .. , � � � : �� ; � - - ; �: ; _ � �° � / � ; � , ' � t , �� ; � �:`� �� ` (i � �'i'�-c,� � � � i , �� . . � .. i y ,_ : ,. + � � _ � , - 5 � _ N — `��;, � I � T n\ ' j � � � � I � , ; �, , ' � � I � ( � � , � I I � � � ' I I ^- ' -- .. _ - ---- , -- . . _; ---__ ---:--- ::�.:_.�_ .:� _.::. --- -:::------ -.. -_ , j ,, ; L , ____ ____ _.._ _. :_ ; „ _. _ �.�: i i __ � _.__.._. ._. _.. �.------------- - — --- -�..:-�t..�.___ ..._-,�.. i _ I I I r - i _.. ._____ ..___ _.._. _.__. .-- - . ....._ ._.� ._�---. _---,-----_ __ ____. ____ __.._ . _ .___. .__.. .. ..__. __... _.� . _._._... ._____ . . —-- - -- - ------ ' Baxter Meadows Phase II -Storm Drain Inlet Calcs -Basin 4 Inlet Overland Overland Overland Gutter Gutter Gutter Overland Gutter Total Rainfall 25 Year Inlet Area Coeffcient Flow Distance Flow Slope Flow Distance Flow Slope Flow Velocity Flow tc Flow tc tc Intensity Flow (acres) C (ft) (%) (ft) (%) (ft/s)Fig.7-1 (min)Fig. I-1 (min) (min)* (in/hr) (cfs) � �•�$ 0.35 20 2.00 260 0.60 1.57 4.0 2.8 10.0 2.46 0.15 2 0.27 0.35 35 2.00 260 0.60 1.57 4.0 2.8 10.0 2.46 0.23 3 0.61 0.35 60 2.00 380 0.88 1.90 6.0 3.3 10.0 2.46 0.52 4 1.79 0.50 210 2.00 380 0.88 1.90 16.0 3.3 19.3 1.61 1.44 5 0.12 0.50 25 2.00 190 0.60 1.57 4.0 2.0 10.0 2.46 0.15 6 0.21 0.50 40 2.00 190 0.60 1.57 5.0 2.0 10.0 2.46 0.26 Total 3.18 'Minumum tc=10 min Baxter Meadows Phase II-Storm Drain Pipe Calculations-Basin 4 Pipe/Gutter Segment Inlet Area Inlet Cumulative Plpe Pipe Pipe Flow Pipe Segment Cumulative Rainfall 25 Year Flow From To Coefficient, Area C z Area Length Flow Diameter Depth Velocity tc tc Intensity At Downstream C (Acre) (Acre) (ft) (cfs) (in) (in) (ft/s) (min) (min) (in/hr) Point(cfs) Rawhide Gutter Inlets 1&2 Q.35 O.AS., 0.16 iniets 1&2 Manhole 1 0.35 , p £ ' F't 1p:d ,10.0� 2.A6 0.39: Gallatin Green Gutter Inlets 3&4 ��'18 ' �� `�� 0:�� "�'�' ,�` :'��, x.r� .2.A�..�� 0;$ ��-19.5 1.60�� 02S 0 46 0:33� � 1.26 � � `� Inlets 3&4 2.40 Manhole 1 0.50 19.3 �g,3 �.g� � 78 Manhple 1 �:. � -�IltleFs 5&8��.; � 1.26 40 1.78 15 6.2 3.73 0.2 19.5 1.60 0.60 "' 2.02 ` 1:q3 ,.150, ; : 2.Q2'., . 'l5 `6,�'.;,,. . �.86 :�J �" ,Q1S, �20.1 1.5fi 2.24..._ Totals Atlnlets 5&8 3.18 1.43 Discharge Into Basin 20-1 �.57 2.24 2.24 15 7.0 3.96 Baxter Meadows Phase II-Storm Drain Pipe Calculations-Basin 4 Pipe/Gutter Segment Inlet Area Inlet Cumulative Pipe Pipe Pipe Flow Pipe Segment CumulaUve Rainfall 25 Year Flow From To Coefficient, Area C x Area Length Flow Diameter Depth Velocity tc tc Intensity At Downstream c (Acre) (,4cre) (ft) (cfs) (In) (in) (tUs) (min) (min ) (in/hr) Point(cfs) � a= �+�.Nw.. ,;:, a .1 p�t :; ,. _c�n VuiIOF•�.o- ,,,,��1.4 1 Si.G n�t' 'ci `£0 ew' 4ci» ��P�r�� K ....�„ '{k o ..¢�� -rx"n. <x �' ��.'�� h01er1 � � ��i Gallatin Green Gutter Inlets 3&4 0.46 2.40 1.26 19.3 ^ 19.3 1.61 1.78 Inlets 3 8 4 Manhole 1 0 50 1.26 40 1.78 15 6.2 3.73 0.2 19.5 1.60 2.02 �,�, ��: ., ... r,_: .w ,- ,= e. � . �;��x� �,��, �.� _ ,„_�. �� ' ,� �. _ _ Totals Atlnlets 5 8 6 3.18 1.43 20.1 1.57 2.24 Discharge Into Basin 2.24 15 7.0 3.96 �1�.r�d�c.�.Cvr� �, 5;� Lo ( Z c.v�i.�-� c�.� �f c��-`� > 3 �., �. ��1� �l�F� cc� -r�.e.� � c �� _ l� �-�� < n �, . n �4SLC�`"tJ�-G� �'\vt%✓11. �UC�� -- , ----�— -- --- _ -�,� _�__, .- � ._._'� _� i .._�.__,.. 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� Y ,� i_��,�,-�....-...___•___.._.. �.�._� �..................._,..___��.._�..�___....._._._..........._............_ " ,�_'.__�_.......__....`.._ �_,......_.�..._................._».�.�._.r � ._._._.._.....�.�� _r.__..._.........`......�.� _.._.___.._.._......__......._.._.__ _�____'_..___._...................._.�.._ ` ____..___.............._............._..___... -.`.--...__.....�_..._�_...............___.... _... _ ��,� �`�` j � , �- ___ -----_ _ .. � �.____ ---__.__ ....�---------. _�___ _ __ _____ ____� - , _________-----__ __ ____ .____, - . , _____�_....._ _ __._._ ,..________.__..__�__.__ _ __ __ __.___ ___ __ ___.___. __ � ; � I � � I � � � � ; ; I ; , , I ' I � i � Baxter Meadows Phase II-Storm Drain Iniet Calcs-Basin 5 Inlet Overland Overland Overland Gutter Gutter Gutter Overland Gutter Total Rainfall 25 Year Inlet Area Coefficient Flow Distance Flow Slope Flow Distance Fiow Slope Flow Velocity Flow tc Flow tc tc Intensity Flow (acres) C (ft) (%) (ft) (%) (ft/s)Fig.7-1 (min)Fig.I-1 (min) (min)* (in/hr) (cfs) � 1.05 0.35 110 2.00 380 0.70 1.70 11.0 3.7 14.7 1.92 0.70 2 1.05 0.35 110 2.00 380 0.70 1.70 11.0 3.7 14.7 1.92 0.70 3 1.22 0.35 130 2.00 380 0.80 1.81 12.0 3.5 15.5 1.86 0.79 4 1.40 0.35 150 2.00 380 0.80 1.81 13.0 3.5 16.5 1.78 p.g7 5 1.26 0.35 130 2.00 380 0.60 1.57 12.0 4.0 16.0 1.81 0.80 6 2•2� 0.35 205 2.00 380 0.60 1.57 16.0 4.0 20.0 1.57 1.25 7 0.32 0.35 40 2.00 280 0.50 1.43 4.0 3.3 10.0 2.46 0,27 8 0.13 0.35 5 2.00 280 0.50 1.43 2.0 3.3 10.0 2.46 0.11 9 0.34 0.35 40 2.00 250 0.80 1.81 4.0 2.3 10.0 2.46 0.29 10 0.11 0.35 5 2.00 250 0.80 1.81 2.0 2.3 10.0 2.46 0.09 11 0.93 0.35 110 2.00 340 0.80 1.81 11.0 3.1 14.1 1.97 0.64 12 0.93 0.35 110 2.00 270 0.80 1.81 11.0 2.5 13.5 2.03 0.66 13 0.64 0.35 110 2.00 230 0.50 1.43 11.0 2.7 13.7 2.01 0.45 14 0.63 0.35 110 2.00 230 0.50 1.43 11.0 2.7 13.7 2.01 0.44 15 1.66 0.35 120 2.00 500 0.80 1.81 12.0 4.6 16.6 1.78 1.03 16 1-84 0.35 140 2.00 500 0.80 1.81 13.0 4.6 17.6 1,7'I 1.1 p 17 0.27 0.35 40 2.00 230 0.57 1.53 4.0 2.5 10.0 2.46 0.23 18 0.11 0.35 10 2.00 230 0.57 1.53 2.0 2.5 10.0 2.46 0.09 Total 16.16 *Minumum tc=10 min Baxter Meadows Phase II-Storm Drein Pipe Calculations-Basin 5 Pipe/Gutter Segment Inlet Area Inlet Cumulative Pipe Pipe Pipe Flow Pipe Segment Cumulative Rainfall 25 Year Flow From To Coefficient, Area C x Area Length Flow Diameter Depth Velocity tc tc Intensity At Downstream C (Aere) (Acre) (ft) (cfs) (in) (in) (ff/s) (min) (min) (in/hr) Point(cfs) Milkhouse Branch Milkhouse Gutter inlets 5&6 0.35 3.53 1,24 � 20.0 2D,0 1.58 1.95 intefs 5&6 InleEs 8&10 Q.3S 0.45 � 1.39 31Q � ; 1,95 -� �1 S-� �6.0 �� 4 28 � ��1.2 ��21.2 �� 1.52� � 2.11 S.Fele�o&Gutter In ets 3&4 �� 0.3� � � � � � nhole 2 0.3fi , 1.3,� �45•�� `� 2.71.- 15� � 6.3 - 4.34 '� - � 03 �-_21.4 1.5'! 2:?0 9 5 2.62 2.31 16.5 21.4 1.78 1.63 Inlets 3&4 Manhole 2 0.35 2.31 50 1 63 15 5.5 4.05 0.2 21.4 1.51 3.49 Manhole 2 Inlets 7&8 0.35 O.A5 2.47 Z9Q 3.48 18'� "°`8.7 4.74 0:9 ' 22.3 t:47 3;67 ' INets7&8 Manhole 3 0.35 .'` ` 2:47 ., 4a . 3.62 18 8.9 4,18 d:2 22.b 1.49 3.61 Lasso Gutter Inlets 1&2 0.35 2.10 3.20 14.7 22.5 1.92 1.41 Inlets 1 &2 Manhole 3 0.35 3.20 50 1.41 15 5.2 3.70 0.2 22.5 1.46 4.68 Manhole 3 Inlets 11&12 0.35 1.86 3.85 280 4.68 18 10.3 4,44 ' 1.1 23.6 1:42 5.47 Iniets 11&12 Inlets 13&14 0.35 1.27 4.30 230: b.47 21 10.4 4.63 D.8 24.4 1.39 5.97 Iniets�l3&14' Ma�hole5 �� :U,3�5. �4.30' � ��SO � � 5.8,7"��. °� 21�� 10,9 � 4.73 � �- ��tl.2 ;�24.8- �� 1:38� 5.84 Ferguson Brench N.Ferguson Gutter Inlets 15&16 , 0.35 3.&0 1,23 � � � ..l7;6 `17.8,, � � 1.21 �2.09 Infets 15&16 � inlets 17&18 D.�B - 0.38 �1.38�� 290 �I 2.09 �� 15 _ ��71 ; �� 3.64 �� 1.3�, - 18,8 1:83 � 2.2?�� Inlets 17&18 Manhole 5 0-35 1.86 4U 2.22 : 1S 6.7. . 3.78 '' 0.2 ' 19.1 � 1:82 2.20"; : Totals At Manhole 5 16.16 5.68 24.8 1.38 7.81 Discharge Into Basin 7.81 21 12.9 5.04 .i � � ' - � Ri : .. i � � � t � �. h . .- , � � � � _ ; � -'� �' �..4 � ;i :r`:�. € . . .i . 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Baxter Meadows Phase II-Storm Drain Inlet Calcs-Basin 6 Inlet Overland Overland Overland Gutter Gutter Inlet Area Coefficient Flow Distance Flow Slope Flow Distance Flow Slope Flow Veeocity OFlow tc Flowtc Ttcal Intensaty 2 Flow r (acres) C lft) (%) �ft) �%) (ft/s)Fig.7-1 (min)Fig.I-1 (min) (min)' (in/hr) (cfs) 1 0.51 0.50 100 2.00 270 0.80 1.81 8.0 2.5 10.5 2.38 0.61 2 1.16 0.60 180 2.00 270 0.80 1.81 13.0 2.5 15.5 1.86 1.29 3 3.64 0.60 400 2.00 300 0.50 1.43 16.0 3.5 19.5 1.60 3.50 4 0.74 0.60 170 2.00 300 0.50 1.43 11.0 3.5 14.5 1.94 0.86 5 1.62 0.50 300 2.00 150 1.35 2.35 17.0 1.1 18.1 1.68 1.36 6 0.45 0.50 50 2.00 310 1.35 2.35 8.0 2.2 10.2 2.43 0.55 7 0.28 0.50 20 2.00 290 0.90 1.92 2.0 2.5 10.0 2.46 0.34 8 0.60 0.60 110 2.00 290 0.90 1.92 10.0 2.5 12.5 2.13 0.77 Total 9.00 'Minumum tc=10 min Baxter Meadows Phase II-Storm Drain Pipe Calculations-Basin 6 Pipe/Gutter Segment Inlet Area Inlet Cumulative Pipe Pipe Pipe Flow Plpe Segment Cumulative Rainfall 25 Year Flow From To Coefficient, Area C x Area Length Flow Diameter Depth Velocity tc tc Intensity At Downstream C (Acre) (Acre) (ft) (cfs) (in) (in) (ft/a) (min) (min) (in/hr) Point(cfs) Rawhide Gutter Inlets 3&4 0.60 4.38 2.63 Inlets 3&4 Manhole 1 0.60 19.5 19.5 1.60 4.21 2.63 35 4.21 15 11.4 4.22 0.1 19.6 1.59 4.19 Charolais Gutter Inlets 1&2 0.57 1.67 3.58 Inlets 1&2 Manhole 1 0.50 15.5 15.5 1.85 1.77 3.58 60 1.77 15 5.7 4.14 0.2 19.6 1.60 5.71 Manhole 1 Inlets 5&6 0.50 2.07 4.61 290 5.71 15 9.8 6.73 0.7 20.3 1.56 �,Zp Inlets 5&6 Manhole 2 0.50 4.61 45 7.20 18 9.9 7.19 0.1 20.4 1.55 7.�7 Baxter Pkwy Gutter Inlets 7&8 0.50 0.88 5.05 Inlets 7&8 Manhole 2 0.50 10.0 10.0 2.46 �,pg 5.05 70 1.08 15 4.3 3.76 0.3 20.4 1.56 7,gg Totals At Manhole 2 9.00 5.05 Discharge Into Basin 20.4 �.56 7.86 7.86 18 12.1 6.25 (_' u=�!.; 1 ;� /� / � ! i � �-� r ; , � , �_� :_, , �� '.� , ;:1 � ,: �, � y � \ 4 �, . 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' , �. � . . � � . - - .. . _ . . .. . . . . . . . . . . . ., . � � I I ��f �I F. � i��E 1�� E �. �' F: �'• ' .� 1 �F�� M ( � � . .6 �� ! # x �� €�f 1� � � �� Et 'f-. i �� 6�P � Ei F i f � } �: s i �s t L � � . .c �. �?�f � s : � �!� r �� t �' .� 4 c,i..�7.. ': .. . ..s..�_:.�` ' '.. . .�< e..1: . `+' � �`f'i � I im e.c E� 2.E:..J..� /.� � [ � � f ! �''~ � �'ii'i � •i' �Y .a f ��' � l � -.,. . -4i� f I':. 6 � �: � ` t �# i � p {� �E- {� � Et� � i 4 � i` F � � _ � t #� E s i �' � € " :� � � � ��'� �:�.�i � �f �`dT 4 �: r � f �' �:t_ , � .�.�,.�� .+�.;` F_ �.r .�. �x��..�� "5 � �s �• � _ F ��.k.P ,�.$E 1_. 1..J, lt-.,&..r.�... .�, ..f�` . � t-., r� x �-. � s� y^ . . L �i \ t �1 b k [� �` ��.�. �. G �r ��- � E 1 �s� � t��r- k E r�" E.�7�� F . .. �� '�.f �t� �t ��r J 6��,�t i �E i� . � . � ._._ �'��::_ . �t � ALLIED ENGINEERING SERVICES, INC. 32 Discover}� Drive . Bozeman, Montana �9718 . Phone: . Fax: ''� BAXTER MEADOVVS SUBDIVISION STOKI��VVATER MASTER PLAN AND PHASE I STORMWATER FACILITIES DESIGN REPORT ADDENDUM #1 � � .� Prepared By Paul J. Sanford,P.E. Allied Engineering Services, Inc. Prepared For Baxter Meadows Development, LP July 30, 2002 � BAXTER MEADOWS SUBDIVISION STORMVVATER MASTER PLAN A1VD PHASE I DESIGN REPORT—ADDENDUM #] � TABLE OF CONTENTS APPET'DIX DESCRIPTION A.l Phase 1—Flood Hazard Evaluation and Design Report Spring Ditch Output Input Baxter-Border Ditch ; Output Input B.1 Comparison of 36-inch Arch Pipe to Round Pipe � Culvert Master: Culvert #1 —Arch Pipe � Culvert Master: Culvert#1 —Round Pipe Culvert Master: Culvert#2 —Arch Pipe ' Culvert Master: Culvert#2—Round Pipe Culvert Master: Culvert#3—Arch Pipe Culvert Master: Culvert#3 —Round Pipe � HEC-R.AS: Round Pipe vs. Arch Pipe D.l Revised Storm Drainage Facilities Maintenance Plan � I - i ; � � June 30,2002 TC-] Project O]-24] BAXTER MEADOWS SUBD7VISION STORMWATER—ADDENDUM #] i � ' i � � I APPENDIX D.1 �� Revised - Storm Draina e Facilities Maintenance Plan g � � i i i _.' � I i �I � . STORM SE�'ER FACILITIES � MAINTENANCE FLAN BAXTER ME�iDOV�'S SUBDI�ISION The storm drainage control facilities for Baxter Meadows Subdivision consists of storm sewer co]]ection systems which direct storm runoff to on-site detention or retention ponds. The storm water drainage design limits storm water runoff from the developed site to the pre-development runoff rates. The storm water drainage design will utilize vegetated swales upstream and downstream of the detention ponds, whenever possible to remove solids, silt, oils, and other pollutants prior to discharge to the receiving water body. Storm water runoff from the project � flows into the Baxter Border Ditch or the Spring Ditch, eventually reaching the East Gallatin River. Both of these watercourses are considered Stream/Ditches (flow is sowced by both imgation & natura] drainage). Impacts to water quality are minimized by designing the detention ponds to settle out at a minimum particles 40 microns (1/635th5 of an inch) and larger. , Furthermore, detention pond outlet structures are designed to trap oils. k The City of Bozeman wil] be responsible for maintaining storm sewer facilities located within $ the publicly maintained public right-of-way. Operation and maintenance responsibilities of the City should include the following (Thomas, Dean &Hoskins, 1982): � • Cleaning inlets, manholes, and storm sewer pipes. • Street sweeping and cleaning to remove debris to reduce the sediment loading to detention ponds and thereby reduce the amount of particulate discharged to receiving streams. • City administration as needed to assure the proper operation of the storm drain utility. The I3ome-Owners or Property Owners Association shall be responsible for maintenance of the detention ponds and other storm drainage facilities not located in the publicly maintained public right-of-way which includes all facilities located.in the privately maintained streets. Operation and maintenance responsibilities shall include the following: • Cleaning, mowing, and maintenance of outfal] ditches/swales. • Cleaning, mowing, and maintenance of detention ponds. • Cleaning and maintenance of outlet structures and outlet pipes To retain the capacity of the detention ponds, the Home-Owners or Property Owners Association shall remove any fill or other materials placed in the ponds and any accumulated sediment. The Home-Owners or Property Owners Association should at a minimum, perform bi-annual inspections of the detention ponds, outfall ditches/swales, and outlet structures and pipes and maintain them as needed. � ` . APPENDIX C PROPOSED POST-DEVELOPMENT CONDITION Contributing Area C Area(Ac) C'Area Lawns:sandy soil, 022 0.06 0.01 average,2-7% Drives,walks,and roofs 0.95 0.13 0.13 Total 0.19 0.14 Runoff Coefficient C 0.73 Area A 0.193 Ac Time of Concentration T c 1440 min 2-year 5-year 10-year 25-year 50-year 100-year Storm Duration Intensity Flow Rate Runoff Volume Intensity Flow Rate Runoff Volume Intensity Flow Rate Runoff Volume Intensity Flow Rate Runoff Volume Intensity Flow Rate Runoff Volume Intensity Flow Rate Runoff Volume (hrs) (min) I (in/hr) Q;�(cfs) (ft') I (in/hr) Q;,,(cfs) (ft') I (in/hr) Q;,,(cfs) (ft') I (in/hr) Q;�(cfs) (ft') I (in/hr) Q;,,(cfs) (ft') I (in/hr) Q;�(cfs) (ft') 0.08 5.00 2.08 0.293 87.9 3.16 0.445 133.6 3.87 0.545 164 4.76 0.738 221.3 5.43 0.765 229.5 6.09 1.073 322 0.17 10.00 1.53 0.216 129.4 2.31 0.325 195.3 2.83 0.399 239 3.48 0.539 323.6 3.97 0.559 335.6 4.45 0.784 470 0.25 15.00 1.24 0.175 157.3 1.87 0.263 237.1 2.29 0.323 290 2.83 0.439 394.8 3.22 0.454 408.3 3.61 0.636 572 0.33 20.00 0.99 0.139 167.4 1.50 0.211 253.6 1.84 0.259 311 2.26 0.350 420.3 2.58 0.364 436.2 2.89 0.509 611 0.42 25.00 0.84 0.118 177.5 1.28 0.180 270.5 1.56 0.220 330 1.93 0.299 448.7 2.20 0.310 465.0 2.46 0.433 650 0.50 30.00 0.75 0.106 190.2 1.13 0.159 286.6 1.38 0.194 350 1.70 0.263 474.3 1.94 0.273 492.0 2.18 0.384 691 0.58 35.00 0.66 0.093 195.3 0.99 0.139 292.9 1.22 0.172 361 1.50 0.232 488.2 1.71 0.241 506.0 1.92 0.338 710 0.67 40.00 0.59 0.083 199.5 p,gg 0.125 301.0 �,pg 0.154 369 1.35 0.209 502.2 1.53 0.216 517.4 �,72 0.303 727 0.75 45.00 0.54 0.076 205.4 0.81 0.114 308.2 1.00 0.141 380 1.23 0.191 514.7 1.40 0.197 532.6 1.57 0.277 747 0.83 50.00 0.49 0.069 207.1 0.74 0.104 312.8 0.91 0.128 385 1.12 0.174 520.8 1.28 0.180 541.1 1.44 0.254 761 0.92 55.00 0.45 0.063 209.2 0.69 0.097 320.8 0.84 0.118 391 1.04 0.161 531.9 1.18 0.166 548.7 1.33 0.234 773 1.00 60.00 0.42 0.059 213.0 0.64 0.090 324.6 p,7g 0.111 401 p,g7 0.150 541.2 1.10 0.155 558.0 �,24 0.218 786 2.00 120.00 0.24 0.034 243.5 0.34 0.048 344.9 0.41 0.058 416 0.49 0.076 546.8 0.55 0.077 558.0 0.61 0.107 774 2.50 150.00 0.19 0.027 240.9 0.25 0.035 317.0 0.29 0.041 368 0.34 0.053 474.3 0.37 0.052 469.2 0.41 0.072 650 6.00 360.00 0.12 0.017 365.2 0.15 0.021 456.5 0.17 0.024 517 0.19 0.029 636.1 0.21 0.030 639.1 0.22 0.039 837 12.00 720.00 0.08 0.011 487.0 0.09 0.013 547.8 0.10 0.014 609 0.12 0.019 803.5 0.13 0.018 791.3 0.14 0.025 1065 24.00 1440.00 0.05 0.007 596.5 0.06 0.009 754.8 0.07 0.010 864 0.08 0.013 1098.1 0.09 0.015 1314.8 0.10 0.017 1491 Table 6.6.3-Frequency Correction Factors Recurrence Interval Adjustment Factor (years) Cf 2 through 10-year 1 25-year 1.1 50-year 1.2 100-year 1.25 Pond Report Hydraflow Hydrographs Extension for Autodesk0 Civil 3D0 by Autodesk, Inc.v2023 Tuesday,07/1 /2025 Pond No. 3 - Retention Syst Pond Data UG Chambers-Invert elev. =100.00 ft, Rise x Span=3.00 x 3.00 ft, Barrel Len= 191.50 ft, No. Barrels= 1, Slope=0.00%, Headers=No Encasement-Invert elev.= 100.00 ft, Width=3.33 ft, Height=3.00 ft, Voids=27.00% Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft) 0.00 100.00 n/a 0 0 0.30 100.30 n/a 103 103 0.60 100.60 n/a 141 244 0.90 100.90 n/a 160 404 1.20 101.20 n/a 171 576 1.50 101.50 n/a 177 753 1.80 101.80 n/a 177 929 2.10 102.10 n/a 171 1,101 2.40 102.40 n/a 160 1,261 2.70 102.70 n/a 141 1,402 3.00 103.00 n/a 103 1,505 Culvert/Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise(in) = 0.00 0.00 0.00 0.00 Crest Len(ft) = 0.00 0.00 0.00 0.00 Span(in) = 0.00 0.00 0.00 0.00 Crest EI.(ft) = 0.00 0.00 0.00 0.00 No.Barrels = 0 0 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33 Invert EI.(ft) = 0.00 0.00 0.00 0.00 Weir Type = --- --- --- --- Length(ft) = 0.00 0.00 0.00 0.00 Multi-Stage = No No No No Slope(%) = 0.00 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.100(by Contour) Multi-Stage = n/a No No No TW Elev.(ft) = 0.00 Note:Culvert/Orifice outflows are analyzed under inlet(ic)and outlet(oc)control.Weir risers checked for orifice conditions(ic)and submergence(s). Stage(ft) Stage/Storage Elev(ft) 3.00 103.00 2.00 102.00 1.00 101.00 0.00 100.00 0 200 400 600 800 1,000 1,200 1,400 1,600 Storage Storage(cuft) Pond Report Hydraflow Hydrographs Extension for Autodesk0 Civil 3D0 by Autodesk, Inc.v2023 Tuesday,07/1 /2025 Pond No. 3 - Retention Syst Pond Data UG Chambers-Invert elev. =100.00 ft, Rise x Span=3.00 x 3.00 ft, Barrel Len= 191.50 ft, No. Barrels= 1, Slope=0.00%, Headers=No Encasement-Invert elev.= 100.00 ft, Width=3.33 ft, Height=3.00 ft, Voids=27.00% Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft) 0.00 100.00 n/a 0 0 0.30 100.30 n/a 103 103 0.60 100.60 n/a 141 244 0.90 100.90 n/a 160 404 1.20 101.20 n/a 171 576 1.50 101.50 n/a 177 753 1.80 101.80 n/a 177 929 2.10 102.10 n/a 171 1,101 2.40 102.40 n/a 160 1,261 2.70 102.70 n/a 141 1,402 3.00 103.00 n/a 103 1,505 Culvert/Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise(in) = 0.00 0.00 0.00 0.00 Crest Len(ft) = 0.00 0.00 0.00 0.00 Span(in) = 0.00 0.00 0.00 0.00 Crest EI.(ft) = 0.00 0.00 0.00 0.00 No.Barrels = 0 0 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33 Invert EI.(ft) = 0.00 0.00 0.00 0.00 Weir Type = --- --- --- --- Length(ft) = 0.00 0.00 0.00 0.00 Multi-Stage = No No No No Slope(%) = 0.00 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.100(by Contour) Multi-Stage = n/a No No No TW Elev.(ft) = 0.00 Note:Culvert/Orifice outflows are analyzed under inlet(ic)and outlet(oc)control.Weir risers checked for orifice conditions(ic)and submergence(s). Stage/Storage/Discharge Table Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs 0.00 0 100.00 --- --- --- --- --- --- --- --- 0.000 --- 0.000 0.30 103 100.30 --- --- --- --- --- --- --- --- 0.001 --- 0.001 0.60 244 100.60 --- --- --- --- --- --- --- --- 0.001 --- 0.001 0.90 404 100.90 --- --- --- --- --- --- --- --- 0.001 --- 0.001 1.20 576 101.20 --- --- --- --- --- --- --- --- 0.001 --- 0.001 1.50 753 101.50 --- --- --- --- --- --- --- --- 0.001 --- 0.001 1.80 929 101.80 --- --- --- --- --- --- --- --- 0.001 --- 0.001 2.10 1,101 102.10 --- --- --- --- --- --- --- --- 0.001 --- 0.001 2.40 1,261 102.40 --- --- --- --- --- --- --- --- 0.001 --- 0.001 2.70 1,402 102.70 --- --- --- --- --- --- --- --- 0.001 --- 0.001 3.00 1,505 103.00 --- --- --- --- --- --- --- --- 0.001 --- 0.001 Runoff Reduction Volume (RRV) Montana Post-Construction Storm Water BMP Design Manual (2017) Section 3.2.1 Water Quality Rainfall Depth P 0.5 in Dimensionless Runoff Coefficient R� 0.677 Percent Impervious Area I 0.696 Site Drainage Area A 0.193 ac Equations: PRVA RRV = 12 Outputs Runoff Reduction Volume RRV 0.005 ac-ft 238 ft3 Maximum Drain Down Time Calculations Dimensions diameter(ft) length (ft) width (ft) depth (ft) Perforated Pipe 3 191.5 - - Total (Pipe+Gravel) - 191.5 3.33 3 Gravel Void Ratio 27% Volume (cu-ft) %Storage Total 1913 100% Perforated Pipe 1354 71% Gravel 559 Gravel Void 151 8% Total Void 1505 79% 72-hour Maximum Drain Down Time Surface Area (ft2) 638 Depth of Water(ft) 3.00 Infiltration Rate (in/hr) 1.1 Drain Down Time (hr) 32.73 < 72 hrs RIMROCK ENGINEERING, INC. PHYSICAL PROPERTIES OF AGGREGATE Client Name: Knife River—Billings_ Project No: 03101 Address: P.O. Box 80066 __ Date of Report: __09/27/2018 _________ Billin s, Montana 59108 Project Name: 2018 Aggregate Tests Sample_No:_ See Below Pro'ect Location: Billin s, Montana Date Received: 09/26/2018 Sampled By__ Client ___ Type of Aggre9ate: _ _ See Below Submitted B : Client Source of Sam le: Bi erstaff Pit Bulk Density (Unit igh ) and Voids in gregate ASTM C29 Sam le No. 18-W3057-S1 18-W3057-S2 18-W3057-S3 18-W3069-S1 Descri tion -3/8"Chi s -3/4" Beddin -1"Concrete Rock -1-1/2"Washed Rock Void Content, % 39 37 38 34 Void Ration = 0.37 Porosity = Void Ratio/(1+Void Ratio)x100 Porosity = 0.37/1.37*100 = 27% � �; ", Reviewed By: .'/U i,(.. /_ C'��i RIMROCK ENGINEERING, INC. 5440 Holiday Avenue. Billings, MT 59101. Phone: Fax: ` . APPENDIX D W H Q � � � Z (E) STORM CURB INLET o 0 T R A K K E R T RA 1 L SUBSURFAVPRo oE��ENT1050BAFT3 � � 20 10 0 20 40 a o VREQUIRED — �49� FT SCALE: 1�� = 20� (P) 191.5 LF OF 36" DA #2 BURIED PERFORATED PIPE . LANDSCAPE = 747 SQ. FT. Z � �� HARDSCAPE = 641 SQ. FT. S 89'06'45 E 82.87 � � � I - I I r T —�— -----_ T_�-- v ^ o0 LANDSCAPE = 1812 SQAFT1 I � � � (P) INLETS HARDSCAPE = 5227 SQ. FT. I "E � � � � � II � I I I (P) 6" EMERGENCY W �3 I y � � I I I I OUTFLOW (TYP.) I W W W � I I � � � � HARDSCAPED I I yyyyW � I~I � I � N � y y � � m � I yWW � � � o � .n � � � LANDSCAPED y W y � I � .� � W „ °w� � I I � ��m � DA# � � .. I I �' y �' W W I~� �, I � � I y W � � � 8. A• � a � pA# 2 � � � � � y � � � • � ;c; I�� ' � I � _ � _ LANDSCAPED � � � � � p I O FLOW PATTERN � � �. � I ,,8. " ' _r�. � 24" PERFORATED I I yyWW L I I ---- - `�' `�' � Z a HDPE PIPE � � � �. � � � � � � Q I � y y W y W .� •� � � Q Q I � � I yWWWW � I � � m w 0 � � � WW � WW � �� a � � Q i , � � Q � i �. �. �. V o w a ..................... . �, o z ................. ---�. �. �. - N 89'06'45" � ' � 0° � � � o � ` ALLEY g � IMEG Project No: � 24006341 File Name: � ............... ............... 24006341.00 DA Map.dwg � ...........................................................�....... � , . .................................................................... COPVRIGHT 2025 *S ALL RIGHTS RESERVED �-,� Field Book No: N/A �q ❑ Drawn B �� v PRB Checked By: EDG �g . . • Date: 6/30/25 �� DA 6� Sheet 1 of 1 ` . APPENDIX E ` . OPERATION, MAINTENANCE, AND INSPECTION PLAN Stites Office Building IMEG #24006341 .00 PLNAPP #24637 1143 Stoneridge Drive, Suite 1, Bozeman, MT : :imegcorp.com TABLE OF CONTENTS 1. Parties Responsible..........................................................................................................................3 2. Contact Information .........................................................................................................................3 3. Site Plan ...........................................................................................................................................3 4. Maintenance and Inspection Activities ............................................................................................3 4.1. Construction Inspection ......................................................................................................3 4.2. Post-Construction Inspection..............................................................................................4 4.3. Maintenance Activities and Inspection Schedule ...............................................................4 5. Stormwater Facility Inspection Form...............................................................................................4 6. Replacement Schedule....................................................................................................................5 7. Cost Estimate...................................................................................................................................5 8. Financial Plan....................................................................................................................................6 9. References.......................................................................................................................................7 Engineering Design Report ` Stites Office Building � Bozeman, MT . 2 June 30, 2025 Operation, Inspection, and Maintenance Plan For the Stites Office Building Prepared for: City of Bozeman, MT I M EG #24006341.00 June 30, 2025 1. Parties Responsible Stormwater conveyance systems connected to the site include City of Bozeman infrastructure, such as curbs, gutters, inlets, manholes, and detention ponds. Facilities within public rights-of-way will be maintained by the City of Bozeman, while those outside public rights-of-way, such as the off-site pond are the responsibility of the Homeowners or Property Owners Association, as outlined in the Baxter Meadows Storm Sewer Facilities Maintenance Plan. Maintenance, inspection, and records-keeping of the proposed onsite storm facilities are the responsibility of the property owner. Responsibilities will transfer to successive owners automatically. Each property owner shall ensure that stormwater facilities remain in compliance with applicable regulations. 2. Contact Information Responsible Party: Jon Stites— Property Owner Phone Number: (406) 994-9189 Email Address: Mailing Address: 3970 Valley Commons Drive Unit 2 Bozeman, MT 59718 3. Site Plan Please see the civil site plan associated with City of Bozeman PLN APP#24637, specifically the detailed site grading and drainage sheet, C5.0. 4. Maintenance and Inspection Activities 4.1. Construction Inspection The current site entrances are unpaved. Gravel will be placed at the site entrance to minimize sediment transport during construction. If necessary, tires may be washed on the gravel surface to further reduce sediment tracking onto city streets. During construction, filter fabric shall be placed between the rim and frame of existing storm drain inlets, as indicated in the demolition plan, to prevent sediment from entering the drainage system. The contractor shall install straw wattles or a silt fence along the west and north sides of the disturbance area to prevent sediment from entering the adjacent roadway. Permanent BMPs will include landscaping, Engineering Design Report ` Stites Office Building � Bozeman, MT . 3 June 30, 2025 hardscape improvements, a subsurface retention basin, and storm drain inlets to minimize sediment transport. The contractor is responsible for inspecting and maintaining BMPs during construction. BMPs must be inspected and maintained at least once every fourteen days and within 24 hours of a rainfall event of 0.5 inches or greater. Any visible erosion or sedimentation must be addressed within 24 hours. Disturbed soil must be stabilized within 14 days of clearing or inactivity. Soil stockpiles must be stabilized or covered daily. If wind erosion is observed, soil piles should be watered or covered. Solid waste and construction debris will be stored in dumpsters and transported to the Bozeman or Gallatin County Dump as needed. The contractor is responsible for daily site cleanup. Chemicals, paints, petroleum products, fertilizers, and pesticides must be stored in approved containers in enclosed areas. Hazardous waste must be disposed of per label instructions. The contractor shall also ensure proper disposal of concrete washout water and provide portable toilets on-site during construction, with waste periodically hauled to the local wastewater treatment plant. 4.2. Post-Construction Inspection Post-construction, the project owner will assume responsibility for stormwater facility inspection and maintenance. Permanent erosion control measures will include landscaping, finished asphalt, and concrete surfaces. Stormwater will be collected in on-site subsurface retention basins. 4.3. Maintenance Activities and Inspection Schedule Catch Basins—At least annually, inspect the inside of each catch basin for a depth of deposits exceeding one-third the depth from the basin to the invert of the lowest outlet invert (i.e. sump) (Storm Water 0 and M Fact Sheet Catch Basin Cleaning 1999). If deposits exceed this depth, clean out basin either manually or with a truck equipped with a vacuum pump. If deposits greatly exceed this depth, begin inspecting more regularly. Given the small size of the proposed catch basins, it may be more economical to clean out by hand. Test sediments for pollutants if contamination is suspected, debris can typically be disposed of in the landfill, however hazardous waste disposal may be required if sediment presents contamination. Retention Basin—At least annually, inspect the underground basin for sediments. Observe that the retention basin is draining properly (i.e. no ponding occurring at catch basin inletsl. Maintain pretreatment structures by removing sediment and debris from catch basins and landscaped depressions. Vacuum and jet the pipe if sediment is observed and the function of the structure is impaired. Swales/Landsca,oe Depressions—Inspect and remove debris from drainage swales and retention basins after storms to ensure rainwater has drained and there is no erosion. Seasonally, mow grass no shorter than 3 to 6 inches and remove clippings. Monitor health of vegetation and stabilize eroded areas with new vegetation or reseeding. Maintain original condition of side slopes and minimize use of fertilizer, pesticides, and herbicides (How to Maintain your Grass Drainage Swale 2019). 5. Stormwater Facility Inspection Form Record annual inspections, maintenance activities, test results, and follow-up actions. An inspection form detailing these activities and observations is provided with this application. Engineering Design Report ` Stites Office Building � Bozeman, MT . 4 June 30, 2025 6. Replacement Schedule The following design life of each component is as follows. 24" HDPE Pipe—50- 100 years. 6" HDPE Pipe—50-100 years. 12" Landscape Catch Basin —30 years. 7. Cost Estimate Retention Basin—The estimated capital cost for an infiltration basin is equal to 13.2*Volume069. Using a regional cost adjustment factor of 1.04 for Montana, the base capital cost for the proposed basin is $619.71. The base annual maintenance cost of an infiltration basin is between 1% and 10% of the base construction cost, resulting in a projected annual maintenance cost between $6.20 and $61.97 (Strassler et al., 1999). According to the U.S. Bureau of Labor Statistics Consumer Price Index Inflation Calculator, the equivalent buying power today is $4,178.36 and therefore base annual maintenance present-day is between $21.35 and $213.55. Table 1-1 and 1-2 summarize the estimated costs for the proposed infiltration basin. Table 1-1. Infiltration Basin Annual Base Capital Cost Storage Cost of Facility Adjusted for Adjusted for Volume Montana 2025* Infiltration V C C C Basin Capital Cost ft3 C = 13.2Vo.69 1.04C 1502 $ 2,0553.41 $ 2,135.55 $ 4,178.36 Table 1-2. Infiltration Basin Annual Base Maintenance Cost Infiltration Basin 0.01C 0.1C Maintenance Cost $ 21.35 $ 213.55 Swales/Landscape Dep�essions—The vegetative BMPs proposed for the site include swales and landscape depressions however, the intent is to convey water rather than infiltrate and therefore this cost analysis is based on filter strips. The estimated capital cost for filter strips are $13,800/acre for seed and $29,000/acre for sod. The total landscaped area intended to pretreat and convey stormwater is 0.05 acres. The base capital cost for seed is $690 and $1,450 for sod. These projected costs adjusted for today's buying power is equivalent to between $1,31 1.75 and $2,756.57. The base maintenance cost for either capital scenario is $320/acre, resulting in total maintenance costs of $30.42 (Strassler et al., 1999). Table 1-3 and 1-4 summarize the estimated costs for the proposed vegetative BMPs. Engineering Design Report ` Stites Office Building � Bozeman, MT . 5 June 30, 2025 Table 1-3. Vegetated BMP Annual Base Capital Cost Vegetative Cost, Sod Cost, Seed Land Area BMP Capital C C A Cost C = $29,000 *A C = $13,800 *A ac Base Cost $ 1,450.00 $ 690.00 0.05 Adjusted for Montana $ 1,508.00 $ 717.60 Adjusted for 2025* $ 2,756.57 $ 1,311.75 Table 1-4. Vegetated BMP Annual Base Maintenance Cost Vegetated Cost BMP Maintenance Cost C = $320 *A Base Cost $ 16.00 Adjusted for Montana $ 16.64 Adjusted for 2025* $ 31.63 *Value adjusted from August 1999 to January 2025 buying power. The average cost for vacuum truck services is $75 to $150/ hr hour. Prices may vary with local providers and the size and extent of sediment deposits. The average hourly rate of a landscape laborer is $25.00/ hr. Annual observation and inspection, seasonal site upkeep of vegetated areas including mowing and removal of grass clippings will be assessed as needed. The facilities are intended to be low maintenance and have no associated operational costs. 8. Financial Plan The proposed commercial office building development will generate revenue to fund routine site services including inspection and maintenance of onsite stormwater facilities. Engineering Design Report ` Stites Office Building � Bozeman, MT . 6 June 30, 2025 9. References Environmental Protection Agency. (1999, September). Storm Wate�O and M Fact Sheet Catch Basin Cleaning. EPA. https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=200044BA.txt Environmental Protection Agency. (1999, September). Storm Water O and M Fact Sheet Preventive Maintenance. EPA. https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=200044A0.txt Department of Public Works Watershed Protection & Restoration Program. (2019, March). How to Maintain you�Grass D�ainage Swale. Anne Arundel County Maryland Department of Public Works. https://www.aacounty.org/sites/default/files/2023- 04/Grass_Swale_Maintenance_FINAL.pdf HDR, & Montana Department of Environmental Quality. (2017, September). Montana Post-Construction Storm WaterBMPDesign Guidance Manual. Montana. Strassler, E., Pritts, J., & Strellec, K. (1999, August). Prelimina�y Data Summary of Urban Stormwate� BestManagementPractices. EPA. https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=9100PXC1.txt U.S. Bureau of Labor Statistics. (2025, January). CPl lnf/ation Calculator. U.S. Bureau of Labor Statistics. https://www.bls.gov/data/inflation_calculator.htm Engineering Design Report ` Stites Office Building � Bozeman, MT . 7 June 30, 2025 ` . ACKNOWLEDGEMENT OF STORMWATER FACILITY MAINTENANCE REQUIREMENTS Stites Office Building IMEG #24006341 .00 PLNAPP #24637 FEBRUARY 2025 , � , �. , . , , . , � , , , , � , � , , . , - , , , . . , , . , ' �---- 1143 Stoneridge Drive, Suite 1, Bozeman, MT : :imegcorp.com Acknowledgement of Stormwater Facilities Maintenance Requirements PROPERTY OWNER: Jon Stites NAME OF PLAN/DEVELOPMENT: Stites Office Building LOTBLOCK/SUBDIVISION: Lot 6A, Block 20 Baxter Meadows 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: ` . STORMWATER FACILITY INSPECTION FORM Stites Office Building IMEG #24006341 .00 PLNAPP #24637 FEBRUARY 2025 1143 Stoneridge Drive, Suite 1, Bozeman, MT : :imegcorp.com 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 oflnspection: ❑ 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,Findinqs&Recommendations: Inspector's Signature: Date: Section 4:Qualitative Analysis Components # Items Conditions Results Notes and Required Actions 1.1 Accessibility Degraded,missing,or inadequate ❑Yes maintenance access? ❑ No 1.2 Debris Trash,sediment,and waste within and ❑Yes around the facility? ❑ No General 1.3 Vegetation Overgrown or dead cattails,woody ❑Yes shrubs,weeds,grass,and ❑ No trees? 1.4 Infrastructure Damaged inlet pipe,outlet pipe,outfall ❑Yes Condition structure,or fencing? ❑ No 2.1 Pretreatment Bay or Clogged,obstructed,or filled ❑Yes Facility pretreatment forebay or facility? ❑ No 2.2 Storage Bay Clogged or filled storage bay? ❑Yes ❑ No Groundwater or Stagnant water with infiltration greater ❑Yes 2.3 Standing Water than 48 hours post-rain event? ❑ No Facility ❑Yes 2.4 Flow Path Clogged or obstructed flow path? ❑ No 2.5 Side Slopes Barren or exposed surfaces on Facility's ❑Yes side slopes and bottom? ❑ No 3.1 Maintenance Plan or Is there a written plan specific to this ❑Yes Agreement facility? ❑ No Maintenance 3.2 Implementation Is there evidence of maintenance? ❑Yes ❑ No Section 5:Quantitative Analysis Cover type %Within Notes facility Bare ground Aquatics Vegetation Grasses/Herbaceou Trees>3" DBH Shrubs Total 100 Location Reading(ft) Elevation(ft) Notes SRV#CP Control Point SRV#1 Inlet SRV#2 Outlet SRV#3 Center SRV#4 North of Center Elevation Analysis SRV#5 East of Center SRV#6 South of Center SRV#7 West of center SRV#8 Berm or overflow SRV#9 Summary Section 6: Facility Maintenance Inspection Exhibit Section 7: Photo Log Photo 1 Photo 2 Date: Date: Description: Description: ` . APPENDIX F ` � . February 25, 2025 Jonathan Stites 15 Meridian Road Three Forks, Montana 59752 Email: RE: Geotechnical Investigation Fieport Lots 4-6, Block 20 Baxter Meadows Subdivision Phase 2A Bozeman, Montana IMEG#24006453.00 Dear Jonathan, Per your request, IMEG has conducted a subsurface soils investigation for the above referenced property located in Bozeman, Montana. The scope of services was to conduct a subsurface soils investigation and provide a soils investigation report for a new commercial structure. The report documents the subsurface conditions, soil properties, and provides foundation design and general earthwork recommendations. Proposed Construction A commercial office building is proposed for construction. The structure will utilize a slab-on-grade with stem wall foundation. The structure is planned to have a total height of 14.5 feet and will be a single story. In determining the allowable bearing capacity and settlement estimates, it has been assumed that the foundation footings will not be subjected to unusual loading conditions such as eccentric loads. A footing is eccentrically loaded if the load transferred to the footing is not directed through the center of the footing. If any of the foundation footings will be eccentrically loaded, please contact this office so we can appropriately revise our allowable bearing capacity and settlement estimates. Subsurface Soil and Conditions On October 24, 2024 a member of the staff of IMEG visited the site to conduct a subsurface soils investigation. The subsurface soils investigation consisted of examining three exploratory test pit excavations. The exploratory test pits were excavated with tracked excavator provided by Elevation Excavating. The soil profile revealed by the exploratory excavation was logged and visually classified according to ASTM D 2488, which utilizes the nomenclature of the Unified Soil Classification System 1143 Stoneridge Drive, Suite 1, Bozeman, MT : :imegcorp.com Jonathan Stites—Geotechnical Investigation February 25, 2025 Page 2 of 12 (USCS). The relative density of each soil layer was estimated based on probing of the excavation sidewalls with a rock hammer and penetration tests performed with a static cone penetrometer. Any evidence of seepage or other groundwater conditions were also noted. The location of the exploratory test pits are shown on the included Test Pit Location Map. The following paragraphs briefly summarize the subsurface soils and conditions observed in the exploratory test pits excavated for the field investigation. The soil horizons are described as they were encountered in the test pit excavations, starting with the horizon nearest the surface and proceeding with each additional horizon encountered with depth. Please refer to the attached test pit logs for more detailed information. The first soil horizon encountered in each exploratory excavation was undocumented fill, which was present to depths varying from approximately 0.83 feet below grounds surface (bgs) to 1.25 feet bgs. This material was a mix of clay, gravel and sand. This material must be removed from beneath all foundation elements and in any area that will receive asphalt or concrete pavements. The second soil horizon encountered in each exploratory excavation was an Organic Soil of Low plasticity (OL). This material was black in color, moist and soft. This material was encountered to depths varying from 2.0 feet bgs to 2.41 feet bgs. Organic soils are highly compressible and are not suitable for foundation support. This material must be removed from beneath all foundation elements and in any area that will receive asphalt or concrete pavement. Underlying the Organic Soil in each exploratory excavation was a Lean Clay (CL), which was present to depths varying form 4.0 feet bgs to 4.5 feet bgs. This material was tan to grayish white in color and was moist to very moist. Penetration tests performed on this material with a static cone penetrometer indicated it was very soft in consistency. This material is moisture sensitive and not suitable for foundation support and must be removed from beneath the structure's foundation. Underlying the Lean Clay in each exploratory excavation was a Poorly Graded Gravel with Sand and Cobbles (GP), the typical bearing material for most structures within the City of Bozeman. This material was found to be in a medium dense condition and is suitable for foundation support. Groundwater was encountered within this material at depths varying from 6.50 feet bgs to 7.33 feet bgs. Based on the subsurface investigation, it is recommended that the proposed structure bear on the Poorly Graded Gravel with Sand and Cobbles or on properly placed and compacted structural fill overlying the Poorly Graded Gravel with Sand and Cobbles. Groundwater Groundwater was encountered at depths varying from 6.5 feet bgs to 7.33 feet bgs in the exploratory excavations. Evidence of seasonally high groundwater (such as a lack of calcium deposits, gleyed soils, ` �. Jonathan Stites—Geotechnical Investigation February 25, 2025 Page 3 of 12 increase in moisture content and lack of organic roots) was observed starting at a depth of approximately 3.0 feet bgs, suggesting groundwater may be rising up to near this elevation seasonally. Seismicity The general Bozeman area is located in an earthquake zone known as the intermountain seismic belt, which is a zone of earthquake activity that extends from northwest Montana to southern Arizona. In general, this zone is expected to experience moderately frequent, potentially damaging earthquakes. With that in mind, it is important that the structure be designed to withstand horizontal seismic accelerations that may be induced by such an earthquake, as is required by the International Building Code. The USGS provides seismic design parameters for the design of buildings and bridges across the United States.These parameters are based on the 2015 National Earthquake Hazards Reduction Program (NEHRP) Recommended Seismic Provisions. The primary intent of the NEHRP Recommended Seismic Provisions is to prevent, for typical buildings and structures, serious injury and life loss caused by damage from earthquake ground shaking. The following seismic design parameters were determined for the subject property using the USGS Seismic Design Application: Approximate site Location: Latitude = 45.700° N Longitude = 111.087°W Maximum Considered Earthquake (MCE) Spectral Response Acceleration Parameters: Short Period (Ss) = 0.717g 1-Second Period (S,) = 0.222g Site Coefficients and Adjusted MCE Spectral Response Acceleration Parameters: SMs = 0.879g SM, = 0.479g Design Spectral Response Acceleration Parameters: Sps = 0.586g So, = 0.319g The seismic site class for this project is D. ` �. Jonathan Stites—Geotechnical Investigation February 25, 2025 Page 4 of 12 Foundation Recommendations Based on the subsurface soils encountered in the exploratory excavations, it will be acceptable to utilize a slab-on-grade with stem wall foundation as planned. Please find the following as general recommendations for all foundation elements: • The foundation footings are to bear on the Poorly Graded Gravel with Sand and Cobbles or on properly placed and compacted structural fill overlying this material. • If construction takes place during the colder months of the year, the subgrade must be protected from freezing. This may require the use of insulating blankets and/or ground heaters Allowable Bearing Capacity The bearing capacity of a soil is defined as the ultimate pressure per unit area by the foundation that can be supported by the soil in excess of the pressure caused by the surrounding soil at the footing level. Bearing capacity is determined by the physical and chemical properties of the soil located beneath the proposed structure's footings and can also be influenced by the water table. It is recommended that the loads from the proposed structure be transmitted to the Poorly Graded Gravel with Sand and Cobbles or on properly placed and compacted structural fill overlying the Poorly Graded Gravel with Sand and Cobbles. For this scenario it is recommended that an allowable bearing capacity of 2,500 pounds per square foot be used to dimension the foundation footings. The allowable bearing capacity may be increased by one third for short term loading conditions such as those from wind or seismic forces. Settlement While the soil at the site may be able to physically support the footings, it is also important to analyze the possible settlement of the structure. When a soil deposit is loaded by a structure, deformations within the soil deposit will occur. The total vertical deformation of the soil at the surface is called total settlement. Total settlement is made up of two components: elastic settlement and consolidation settlement. Elastic settlement is the result of soil particles rearranging themselves into a denser configuration due to a load being imposed on them and usually occurs during the construction process and shortly after. Consolidation settlement occurs more slowly and over time as water within the pore spaces of a soil are forced out and the soil compresses as the stress from the load is transferred from the water molecules to the soil particles. Consolidation settlement is more of a concern with fine-grained soils with low permeability and high in-situ moisture contents. The degree of settlement is a function of the type of bearing material, the bearing pressure of ` �. Jonathan Stites—Geotechnical Investigation February 25, 2025 Page 5 of 12 the foundation elements, local groundwater conditions, and in some cases determines the allowable bearing capacity for a structures' footings. In addition to analyzing total settlement, the potential for differential settlement must also be considered. Differential settlement occurs in soils that are not homogeneous over the length of the foundation or in situations where the foundation rests on cut and fill surfaces. If the foundation rests on structural fill overlaying properly compacted gravelly soils, differential settlement is expected to be well within tolerable limits. Areas that have significantly more fill under the foundation footings (four feet of more)create greater potential for differential settlement. In these cases the structural fill must be installed properly and tested frequently. Compaction efforts and structural fill consistence are vital in minimizing differential settlement. A settlement analysis based on conservative soil parameter estimates, the recommended allowable bearing capacity, and the assumption that all recommendations made in this report are properly adhered to, indicates the total and differential settlement are expected to be 1/2-inch or less. Structures of the type assumed can generally tolerate this amount of movement, however, these values should be checked by a licensed structural engineer to verify that they are acceptable. Please note that the settlement estimates are based on loads originating from the proposed structure. If additional loads are introduced, such as the placement of large quantities of fill, our office should be contacted to re-evaluate the settlement estimates. Lateral Pressures Lateral pressures imposed upon foundation and retaining walls due to wind, seismic forces, and earth pressures may be resisted by the development of passive earth pressures and/or frictional resistance between the base of the footings and the supporting soils. If a foundation or retaining wall is restrained from moving, the lateral earth pressure exerted on the wall is called the at-rest earth pressure. If a foundation or retaining wall is allowed to tilt away from the retained soil, the lateral earth pressure exerted on the wall is called the active earth pressure. Passive earth pressure is the resistance pressure the foundation or retaining wall develops due to the wall being pushed laterally into the earth on the opposite side of the retained soil. Each of these pressures is proportional to the distance below the earth surface, the unit weight of the soil, and the shear strength properties of the soil. It is recommended that all foundation and retaining walls be backfilled with well-draining granular material. Well-draining granular backfill has a more predictable behavior in terms of the lateral earth pressure exerted on the foundation or retaining wall and will not generate expansive related forces. If backfill containing significant quantities of clayey material is used, the seepage of water into the backfill could potentially generate horizontal swelling pressures well above at-rest values. Additionally, seepage into a clayey backfill material will also cause significant hydrostatic pressures to build up against the foundation wall due to the low permeability of clay soils and will make the backfill susceptible to frost action. ` �. Jonathan Stites—Geotechnical Investigation February 25, 2025 Page 6 of 12 Subsurface walls that are restrained from moving at the top are recommended to be designed for an equivalent fluid pressure of 70 pounds per cubic foot (pcf) (at-rest pressure); the equivalent fluid pressure is the product of the retained soils unit weight and its coefficient of active or at-rest earth pressure. Any subsurface walls that are allowed to move away from the restrained soil, such as cantilevered retaining walls, are recommended to be designed for an equivalent fluid pressure of 55 pcf (active pressure). For passive pressures, an equivalent fluid pressure of 275 pcf is recommended, and the coefficient of friction between the cast-in-place concrete and the Poorly Graded Gravel with Sand and Cobbles is 0.5. These recommended values were calculated assuming a near horizontal backfill and that a mix of the Lean Clay, Undocumented Fill and Poorly Graded Gravel with Sand and Cobbles will be used as foundation wall backfill. It is also assumed that the backfill will be compacted as recommended in this report. Also, please note that these design pressures do not include a factor of safety and are for static conditions, they do not account for additional forces that may be induced by seismic loading. Subgrade Preparation and Structural Fill In general, the excavation for the foundation must be level and uniform and continue down to the Poorly Graded Gravel with Sand and Cobbles. If any soft spots or undocumented fill are encountered, they will need to be removed and backfilled with structural fill. The excavation width must extend out from the footing a minimum distance equal to one footing width or to a distance equal to '/�the height of the required structural fill; for example, if 6 feet of structural fill is required, the excavation must extend outwards from the foundation footings a minimum distance of 3 feet. Structural fill is defined as all fill that will ultimately be subjected to structural loadings, such as those imposed by footings, floor slabs, pavements, etc. The Poorly Graded Gravel with Sand and Cobbles may be reused as structural fill, provided any cobbles larger than 6 inches in size are removed. Structural fill may also be imported for this project, if needed. Imported structural fill is recommended to be a well graded gravel with sand that contains less than 15 percent of material that will pass a No. 200 sieve and that has a maximum particle size of 3.0 inches. Also, the fraction of material passing the No. 40 sieve shall have a liquid limit not exceeding 25 and a plasticity index not exceeding 6. The gravel and sand particles also need to be made up of durable rock materials that will not degrade due to moisture or the compaction effort; i.e. no shale or mudstone fragments should be present. Structural fill must be placed in lifts no greater than 12-inches (uncompacted thickness) and be uniformly compacted to a minimum of 97 percent of its maximum dry density, as determined by ASTM D698. Typically, the structural fill must be moisture conditioned to within ± 2 percent of the materials optimum moisture content to achieve the required density. It is recommended that the structural fill be compacted with a large vibrating smooth drum roller. Please note that if a moisture-density relationship test (commonly referred to as a proctor) needs to be performed for a proposed structural fill material to determine its maximum dry density in accordance with ASTM D698, a sample of the material must be delivered to this office a minimum of three full working days prior to density testing being needed. ` �. Jonathan Stites—Geotechnical Investigation February 25, 2025 Page 7 of 12 At no time should surface water runoff be allowed to flow into and accumulate within the excavation for the foundation elements. If necessary, a swale or berm should be temporarily constructed to reroute all surface water runoff away from the excavation. Excavation should not proceed during large precipitation events. If any of the foundation footings are found to be located on a test pit, the area will need to be excavated down to the full depth of the test pit and structural fill be placed and compacted in controlled lifts as described in this report to bring the area back up to the desired grade. Foundation Wall Backfill Approved backfill material should be placed and compacted between the foundation wall and the edge of the excavation. The organic soil shall not be used as foundation wall backfill. The Lean Clay, Poorly Graded Gravel with Sand and Cobbles and Undocumented Fill encountered during the field investigation are all suitable for reuse as foundation wall backfill along the exterior of the foundation in areas that will not have concrete or asphalt pavements, provided they are not too moist and any cobbles larger than 6 inches in size are removed. Structural fill is recommended as foundation wall backfill in all areas that will support concrete slabs-on-grade or asphalt paving improvements. The foundation wall backfill shall be placed in uniform lifts and be compacted to a minimum of 95 percent of the material's maximum dry density, as determined by ASTM D698. The foundation wall backfill will need to be compacted with either walk behind compaction equipment or hand operated compaction equipment in order to avoid damaging the foundation walls. If walk behind compaction equipment is used lifts should not exceed 8-inches (loose thickness) and if hand operated compaction equipment is used lifts should not exceed 4-inches (loose thickness). Interior Slabs-on-Grade For any interior slabs-on-grade, it is recommended that the excavation continue down through the Undocumented fill, Organic soil and Lean Clay to the Poorly Graded Gravel with Sand and Cobbles or to a depth of 6 inches below the proposed bottom of slab elevation, whichever is deeper. If needed structural fill can then be placed and compacted to within 6 inches of the bottom of slab elevation. For all interior concrete slabs-on-grade, preventative measures must be taken to stop moisture from migrating upwards through the slab. Moisture that migrates upwards through the concrete slab can damage floor coverings such as carpet, hardwood and vinyl, in addition to causing musty odors and mildew growth. Moisture barriers will need to be installed to prevent water vapor migration and capillary rise through the concrete slab. Capillarity is the result of the liquid property known as surface tension, which arises from an imbalance of cohesive and adhesive forces near the interface between different materials.With regards to soils, surface ` �. Jonathan Stites—Geotechnical Investigation February 25, 2025 Page 8 of 12 tension arises at the interface between groundwater and the mineral grains and air of a soil. The height of capillary rise within a given soil is controlled by the size of the pores between the soil particles and not the size of the soil particles directly. Soils that have small pore spaces experience a higher magnitude of capillary rise than soils with large pore spaces. Typically, soils composed of smaller particles (such as silt and clay) have smaller pore spaces. In order to prevent capillary rise through concrete slabs-on-grade it is recommended that 6 inches of 3�4- inch washed rock (containing less than 10 percent fines) be placed and compacted once the excavation for the slab is complete. The washed rock has large pore spaces between soil particles and will act as a capillary break, preventing groundwater from migrating upwards towards the bottom of the slab. Water vapor is currently understood to act in accordance with the observed physical laws of gases, which state that the water vapor will travel from an area of higher concentration to that of a lower concentration until equilibrium is achieved. Because Earth contains large quantities of liquid water, water vapor is ubiquitous in Earth's atmosphere, and, as a result, also in soils located above the water table (referred to as the vadose zonel. Typically, the concentration of water vapor in the vadose zone is greater than that inside the residence. This concentration difference may result in an upward migration of water vapor from the vadose zone through the concrete slab-on-grade and into the building. In order to prevent this upward migration of water vapor through the slab, it is recommended that a 15-mil extruded polyolefin plastic that complies with ASTM E1745 (such as a Stego Wrap 15-mil Vapor Barrier) be installed.The vapor barrier should be pulled up at the sides and secured to the foundation wall or footing. Care must be taken during and after the installation of the vapor barrier to avoid puncturing the material, and all joints are to be sealed per the manufacture's recommendations. Once the excavation for any interior slabs-on-grade is completed as described in the first paragraph of this section, and the 3/4 inch washed rock and moisture barriers have been properly installed, it will be acceptable to form and cast the steel reinforced concrete slab. It is recommended that interior concrete slabs-on-grade have a minimum thickness of 4 inches, provided the slab reinforcement is designed by a licensed structural engineer. Exterior Slabs-on-Grade For exterior areas to be paved with concrete slabs such as sidewalks and/or patios, it is recommended that, at a minimum, the Undocumented Fill and Organic Soil be removed. The subgrade then needs to be compacted to a minimum of 95 percent of its maximum dry density, as determined by ASTM D698. Then for non-vehicular traffic areas, a minimum of 6 inches of 3/4-inch minus rock needs to be placed, and 4 inches of 4000 pounds per square inch (psi) concrete placed over the 3/4-inch minus rock. For areas with vehicular traffic, a minimum of 9 inches of 3/4-inch minus rock should be placed, followed by 6 inches of 4000 psi concrete. ` �. Jonathan Stites—Geotechnical Investigation February 25, 2025 Page 9 of 12 Exterior slabs that will be located adjacent to the foundation walls need to slope away from the structure at a minimum grade of 2 percent and should not be physically connected to the foundation walls. If they are connected, any movement of the exterior slab will be transmitted to the foundation wall, which may result in damage to the structure. Site Grading Surface water should not be allowed to accumulate and infiltrate the soil near the foundation. Proper site grading will ensure surface water runoff is directed away from the foundation elements and will aid in the mitigation of excessive settlement. Please find the following as general site grading recommendations: • Finished grade must slope away from the building a minimum of 5 percent within the first 10 feet, in order to quickly drain ground surface and roof runoff away from the foundation walls. Please note that in order to maintain this slope; it is imperative that any backfill placed against the foundation walls be compacted properly. If the backfill is not compacted properly, it will settle and positive drainage away from the structure will not be maintained. • Permanent sprinkler heads for lawn care should be located a sufficient distance from the structure to prevent water from draining toward the foundation or saturating the soils adjacent to the foundation or adjacent to any paving improvements. • Rain gutter down spouts are to be placed in such a manner that surface water runoff drains away from the structure and any paving improvements. • All roads, walkways, and architectural land features must properly drain away from all structures and paving improvements. Special attention should be made during the design of these features to not create any drainage obstructions that may direct water towards or trap water near the foundation or paving improvements. Asphalt Paving Improvements For areas to be paved with asphalt, it is recommended that, as a minimum, the Undocumented fill and Organic Soil be removed. The native subgrade then needs to be compacted at ± 2 percent of its optimum moisture content to 95 percent of its maximum dry density. Following compaction of the native subgrade a layer of separation geotextile shall be installed (such as a Mirafi 160N), followed by a 12-inch layer of compacted 6-inch minus gravel, followed by a 6-inch layer of compacted 1-inch minus road mix. Both gravel courses must be compacted at ± 2 percent of their optimum moisture content to 95 percent of their maximum dry density. A 3-inch-thick layer of asphalt pavement can then be placed and compacted over this cross-section. It is recommended that following compaction of the native subgrade, a loaded dump truck or other heavy piece of equipment should be driven over it to determine the stability of the subgrade. If any isolated soft ` �. Jonathan Stites—Geotechnical Investigation February 25, 2025 Page 10 of 12 spots are found, these areas should be sub-excavated and replaced with compacted fill. If widespread unstable conditions are present (i.e. significant rutting or pumping is observed) the sub-base component of the road section will need to be increased and a geotextile may also be required, especially if moisture related issues are the cause of the instability. In severe cases, geogrid may also be required. If asphalt paving is to be placed on foundation wall backfill, it is imperative that the backfill be compacted to a minimum of 95 percent of its maximum dry density, as determined by ASTM D698. The backfill must be placed in uniform lifts and be compacted as described in the foundation wall backfill section of this report. Underground Utilities We recommend specifying non-corrosive materials or providing corrosion protection due to the presence of clay soils at the site. It is recommended that 3/4-inch minus gravel be used as a bedding material, where bedding material is defined as all material located within 6 inches of the utility pipe(s). The bedding material should be thoroughly compacted around all utility pipes. Trench backfill shall be compacted to a minimum of 95 percent of its maximum dry density in paved or landscaped areas and a minimum of 97 percent of its maximum dry density beneath foundation footings. Backfilling around and above utilities should meet the requirements of Montana Public Works Standard Specifications. Construction Administration The foundation is a vital element of a structure; it transfers all of the structure's dead and live loads to the native soil. It is imperative that the recommendations made in this report are properly adhered to. A representative from IMEG should observe the construction of any foundation or drainage elements recommended in this report. The recommendations made in this report are contingent upon our involvement. If the soils encountered during the excavation differ than those described in this report or any unusual conditions are encountered, our office should be contacted immediately to examine the conditions, re-evaluate our recommendations and provide a written response. If construction and site grading take place during cold weather, it is recommended that appropriate winter construction practices be observed. All snow and ice shall be removed from cut and fill areas prior to site grading taking place. No fill should be placed on soils that are frozen or contain frozen material. No frozen soils can be used as fill under any circumstances. Additionally, Concrete should not be placed on frozen soils and should meet the temperature requirements of ASTM C 94. Any concrete placed during cold weather conditions shall be protected from freezing until the necessary compressive strength has been attained. Once the footings are placed, frost shall not be permitted to extend below the foundation footings, as this could heave and crack the foundation footings and/or foundation walls. ` �. Jonathan Stites—Geotechnical Investigation February 25, 2025 Page 1 1 of 12 It is the responsibility of the contractor to provide a safe working environment with regards to excavations on the site. All excavations should be sloped or shored in the interest of safety and in accordance with local and federal regulations, including the excavation and trench safety standards provided by the Occupational Safety and Health Administration (OSHA). Report Limitations and Guidelines for Use This report was prepared to be used exclusively by Jonathan Stites for commercial improvements to be constructed on Lots 4-6, Block 20 of the Baxter Meadows Subdivision Phase 2A in Bozeman, Montana. All of the work was performed in accordance with generally accepted principles and practices used by geotechnical engineers and geologists practicing in this or similar localities. This report should not be used by anyone it was not prepared for, or for uses it was not intended for. Field investigations and preparation of this report was conducted in accordance with a specific set of requirements set out by the client, which may not satisfy the requirements of others. This report should not be used for nearby sites or for structures on the same site that differ from the structures that were proposed at the time this report was prepared. Any changes in the structures (type, orientation, size, elevation, etc.) proposed for this site must be discussed with our company for this report to be valid. The recommendations made in this report are based upon data obtained from test pits excavated at the locations indicated on the attached Test Pit Location Map. It is not uncommon that variations will occur between these locations, the nature and extent of which will not become evident until additional exploration or construction is conducted. These variations may result in additional construction costs, and it is suggested that a contingency be provided for this purpose. If the soils encountered during the excavation differ than those described in this report or any unusual conditions are encountered, our office should be contacted immediately to examine the conditions and re-evaluate our recommendations and provide a written response. This report is valid as a complete document only. No portion of this report should be transmitted to other parties as an incomplete document. Misinterpretation of portions of this report (i.e. test pit logs) is possible when this information is transmitted to others without the supporting information presented in other portions of the report. The scope of our investigation did not include an environmental assessment for determining the presence or absence of hazardous or toxic materials on the site. If information regarding the potential presence of hazardous materials on the site is desired, please contact us to discuss your options for obtaining this information. If any questions arise with regards to any aspects of this report, please contact us at your convenience to avoid misinterpretation. Costly mistakes due to misinterpretation of geotechnical reports can usually be avoided by a quick phone call. If you have any questions or if you need further assistance with your project, please contact the undersigned. ` �. Jonathan Stites —Geotechnical Investigation February 25, 2025 Page 12 of 12 Sincerely �b° r�� '>�,{�� /� a��°°"�' �+��`�� ,�,%� s,d;� i�� p �**` .�.J � � A • . � „fl�fCH�,E(.J.�'a� Michael J. Welch, P.E. `�_ ��';�° �` ? ` � — ,� ;..: ° c� _ Project Executive � Principal =�' �'�1�. ��.�6�:;AF ° �r_ =�° 'te�,= ��i�°!��r� ��„ti- Enc Test Plit Logation Map ��d��'��R�,��`�`' AFl��,a2t,. �` ' ` TEST PIT NUMBER TP1 �� PAGE 1 OF 1 CLIENT Jonathan Stites PROJECT NAME Geotechnical Investiqation PROJECT NUMBER 24006453.00 PROJECT LOCATION Lots 4-6 Blk 20 Baster Meadows PH 2A DATE STARTED 10/24/24 COMPLETED 10/24/24 GROUND ELEVATION EXCAVATION CONTRACTOR Elevation Excavatinq GROUND WATER LEVELS: EXCAVATION METHOD Bobcat E88 �AT TIME OF EXCAVATION 6.50 ft LOGGED BY Michael J.Welch, P.E. AT END OF EXCAVATION --- NOTES AFTER EXCAVATION --- w _ ~W � _ W� J g � Q O MATERIAL DESCRIPTION p �� Q Z (� � �.� 0 TO 0.83 FEET: UNDOCUMENTED FILL; (GP-GC); dark brown; moist; soft. GC 0.8 — 0.83 TO 2 FEET: ORGANIC SOIL; (OL); black; moist; very soft. a — � � OL — o — J - � a — 2.0 � 2 TO 4.5 FEET: LEAN CLAY; (CL); tan to grayish white; moist to very moist; very moist and Q 2.5 gleyed starting at a depth of 3.0 feet.. U Z U F � CL J � U Z C7 N W 0 � 4.5 M a 4.5 TO 6.5 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark o ��° N 5.0 o p brown; moist to saturated. N O O 0�O � C'P o D W Q o � � o ° a "' o D > � Q 6.5 N Bottom of test pit at 6.5 feet. W J LL lf1 N � N 7 N N F 0 � N 7 0 r � � z c� J J W � a � x m Jq LL W Z W C7 ` TEST PIT NUMBER TP2 �� PAGE 1 OF 1 CLIENT Jonathan Stites PROJECT NAME Geotechnical Investiqation PROJECT NUMBER 24006453.00 PROJECT LOCATION Lots 4-6 Blk 20 Baster Meadows PH 2A DATE STARTED 10/24/24 COMPLETED 10/24/24 GROUND ELEVATION EXCAVATION CONTRACTOR Elevation Excavatinq GROUND WATER LEVELS: EXCAVATION METHOD Bobcat E88 �AT TIME OF EXCAVATION 6.83 ft LOGGED BY Michael J.Welch, P.E. AT END OF EXCAVATION --- NOTES AFTER EXCAVATION --- w _ ~W � _ W� J g � Q O MATERIAL DESCRIPTION p �� Q Z (� � �.� 0 TO 1 FEET: UNDOCUMENTED FILL; (GP-GC); dark brown; moist; soft. GC 1.0 ; = 1 TO 2.2 FEET: ORGANIC SOIL; (OL); black; moist; very soft. � — � — ° OL — � — a — � — W — 2.2 Q 2 5 2.2 TO 4.83 FEET: LEAN CLAY; (CL); tan to grayish white; moist to very moist; very moist Z and gleyed starting at a depth of 3.0 feet.. U F O C7 > CL U Z C7 W 0 0 0 ri u� � 0 4.8 N 5�0 �o 4.83 TO 6.83 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark N o p brown; moist to saturated. � � � �° ° GP oOD w � o�° � N O� 6.s LL Bottom of test pit at 6.8 feet. � N � N 7 N N F 0 � N 7 0 r � � z c� J J W � a � x m Jq LL W Z W C7 ` TEST PIT NUMBER TP3 �� PAGE 1 OF 1 CLIENT Jonathan Stites PROJECT NAME Geotechnical Investiqation PROJECT NUMBER 24006453.00 PROJECT LOCATION Lots 4-6 Blk 20 Baster Meadows PH 2A DATE STARTED 10/24/24 COMPLETED 10/24/24 GROUND ELEVATION EXCAVATION CONTRACTOR Elevation Excavatinq GROUND WATER LEVELS: EXCAVATION METHOD Bobcat E88 �AT TIME OF EXCAVATION 7.33 ft LOGGED BY Michael J.Welch, P.E. AT END OF EXCAVATION --- NOTES AFTER EXCAVATION --- w _ ~W � _ W� J g � Q O MATERIAL DESCRIPTION p �� Q Z (� � �.� 0 TO 1.25 FEET: UNDOCUMENTED FILL; (GP-GC); dark brown; moist; soft. GC � 1.3 ; = 1.25 TO 2.41 FEET: ORGANIC SOIL; (OL); black; moist; very soft. o — J a OL — � — �n — W — � 2.5 — 24 2.41 TO 5 FEET: LEAN CLAY; (CL); tan to grayish white; moist to very moist; very moist � and gleyed starting at a depth of 3.5 feet.. � 0 � J � Z CL c� w 0 'o 0 ci u� 7 � O a 5.0 5.0 `' 5 TO 7.33 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); dark N O�O �, op brown; moist to saturated. U w O o�° � ; C,p o0 0 3 ��° `� 0 0 w O � o ° �n 7.3 � Bottom of test pit at 7.3 feet. � N 7 N N F 0 � N 7 0 r � � z c� J J W � a � x m Jq LL W Z W C7 w .�- . � . , � �w �, � � - w . �� '��•r a ^� �;.�'1 � �. . � [ ��•. . � o , . ,� �� _ , � , �, � , . r. p . �. � ,. ��; .: . . N o - . . � � , �.. „ ., ,� ,� #, � : � � +�' � - " �� . • - . 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