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Home My WebLink About18 - Design Report - Gran Cielo - Sewer �� T l NOV 2 6 2018 SEWER MAIN By:_____________ DESIGN REPORT FOR: GRAN CIELO SUBDIVISION BOZEMAN, MT Prepared By: MADISON - 1 ENGINEERING " s' rn_ A.J Madison Engineering 895 Technology Blvd Ste 203 `J Bozeman, MT 59718 - (406) 586-0262 i NOVEMBER 2018 ` to \I D SEWER MAIN DESIGN REPORT FOR: GRAN CIELO SUBDIVISION BOZEMAN, MT 0"ATA)V ,ecEtArsz� �0 r Madison Engineering 895 Technology Blvd Ste 203 Bozeman, MT 59718 (406) 586-0262 NOVEMBER 2018 GRAN CIELO SUBDIVISION SEWER MAIN DESIGN REPORT A. General This report will give an overview of the proposed wastewater flow generation from the new development of the Gran Cielo Major Subdivision. The site is situated at the intersection of S. 27th Ave and Graf St in Bozeman. The 48.75-acre subdivision is zoned R-3 and R-4, and will consist of one-unit, two-unit, and multi-unit residences. The proposed improvements are anticipated to be phased, with the first phase being constructed during the fall of 2018. This report will provide a description of the proposed wastewater collection system and design parameters. Once the wastewater system is constructed and approved, the system will become a part of the City of Bozeman system. The following references were used in the wastewater facilities design and capacity analysis: a. COB Design Standards and Specifications Policy, 2004,Addendum#6 b. COB Modifications to Montana Public Works Standard Specifications(MPWSS),Addendum#3 c. City adopted MPWSS and Adopted Addenda d. COB Wastewater Facility Plan, 2015 e. WQB Circular No. 2 f. City of Bozeman Zoning Map g. City of Bozeman Infrastructure Viewer The procedures and parameters outlined in the COB Design Standards and Specifications Guide were used in the design of the sewer infrastructure for the proposed development. B. Capacity Analysis The proposed wastewater collection system consists of 6,466 linear feet (1.22 miles) of new sewer main and will provide service to Gran Cielo Subdivision and the 40.78-acre parcel of undeveloped land south of the subdivision, known as Tract A COS 1861. Effluent generated will ultimately flow north and east into an existing manhole on the east side of S. 27th Ave, and then into an existing 15" PVC sewer main. Sanitary sewer main stubs are provided at the southern limits of the project at S. 29th Ave and S. 31 st Ave to serve the future development of the 40.78- acre parcel south of Gran Cielo Subdivision. The proposed sewer main has been sized to flow at no more than 75% of full capacity at peak hour conditions at full buildout. An infiltration rate of 150-gallons/acre/day was added to the design flow. A Manning coefficient of 0.013 was used for PVC pipe. The proposed subdivision totals 39.80 acres of R-3 zoned land and 8.95 of R-4 zoned land. Tract A COS 1861 is not currently within the City limits, but it was assumed that the parcel would become zoned R-4 when annexed into the City. The capacity requirement of the proposed sewer mains was determined based on the proposed buildout of the entire Gran Cielo Subdivision, plus the future full build out of the 40.78 acres to the south. The City of Bozeman's Design Standards specify an average daily flow rate of 1,220 gal/acre/day for R-3 development and 1,950 Gran Cielo Subdivision Sewer Main Design Report Page 1 of 4 gal/acre/day for R-4 development, as obtained from Table V-1, and 89-gallons per capita per day. The sanitary sewer system is broken into three drainage basins, as outlined in the Drainage Basin Exhibit in the Appendix. Basin 1 and 2 flow into the existing manhole at 27th and Bennett Boulevard while Basin 3 flows into the existing manhole at Apex Drive. Table 1 shows the estimated wastewater demands of each drainage basin at full build out. Peaking factors were calculated based on the following formula: Qmax/Qave= (18 + P0-5)/(4 + P0-5) (P =Population/thousands) The calculated peaking factors are included in the appendix of this report. The peak flow rate anticipated from the development was calculated by multiplying the average flow rate by the peaking factor. The peak flow rate was then converted from gpd to cfs. Table 1 Peak Flow Rates Wastewater Area Peak Average Flow Peaking Peak Flow Drainage Basin Zoning Loading Served I Rate (gpd) Factor Rate (gpd), Flow (gpd/acre) (acres �., Rate (cfs) Gran Cielo Phase 1 R-3 1,220 29.48 35,966 -- -- -- 1 Tract A COS R-4 1,950 40.78 79,521 -- -- -- 1861 Total -- -- 70.26 115,4874,_) r 3.72 429,613/z? 3 0.665 2 Gran Cielo R-3 1,220 19.59 23,900 4.10 97,990 0.152 Future Phase 3 Gran Cielo R-4 1,950 8.95 17,453 4.15 72,430 0.112 Future Phase Infiltration calculations are provided in Table 2, and added to the peak flow to determine the total flow capacity required. Table 2 Infiltration Rates Drainage Area Infiltration Infiltration Infiltration Max Peak Flow: Capacity Basin Served Rate Rate (gpd) Rate (cfs) Infiltration + Provided (cfs) acres (gpd/acre) Peak Flow cfs) 1 70.26 150 10,539 0.016 0.681 3o-i.7 1.15 (Basin 1) 2 19.59 150 2,939 0.005 0.157 0.70 (Basin 2) 1.26 (Basin 1+2 3 8.95 150 1,343 0.002 0.114 0.70 Basin 3 �Y41Z/ Gran Cielo Subdivision Sewer Main Design Report Page 2 of 4 An 8-inch PVC sewer main at minimum slope of 0.4% and a Manning Coefficient of 0.013 has a capacity of 0.70 cfs at 75% of full flow capacity. This is sufficient accommodate the peak flows for Drainage Basin 1 (0.681 cfs), Drainage Basin 2 (0.157 cfs), and Drainage Basin 3 (0.114 cfs). In order to be conservative for Drainage Basin 1, a design slope of 1.30% was used at the location of maximum peak capacity. At 75% full flow capacity, an 8-inch PVC at 1.30% slope and a Manning Coefficient of 0.013 can accommodate 1.15 cfs. This is sufficient capacity to accommodate the wastewater demand of 0.681 cfs from Drainage Basin 1. Drainage Basins 1 and 2 ultimately combine into a 10-inch PVC, which can accommodate 1.26 cfs at a slope of 0.40% and Manning Coefficient of 0.013. This is enough capacity to accommodate the combined wastewater demand of 0.84 cfs from Drainage Basins 1 and 2. The sewer main capacity calculations are provided in the appendix of this report. C. Proposed Collection System PVC pipe meeting COB specifications will be used for all the sewer mains. All sewer mains proposed as part of this project will be 8-inch diameter with a maximum manhole spacing 400 feet and a minimum manhole barrel-size of 48-inches. Manholes will be constructed according to COB specifications. Sewer services will be stubbed to each individual lot and will be a minimum of 4-inch diameter. A site plan showing the proposed sewer mains is included in this submittal. All sewer mains will be located within a 30-foot wide utility easement and be located a minimum of 10-feet from the proposed public water main. D. Upstream and Downstream Capacity Analysis The system is part of the Cattail Creek Drainage Basin. It is anticipated that the City of Bozeman sanitary sewer system has enough capacity to accommodate the main extension. It was assumed that the 40.78-acre lot to the south of Gran Cielo Subdivision (Tract A COS No. 1861) would reasonably be served by the proposed main in Gran Cielo Subdivision. This was accounted for in the design, and shown in the Sanitary Sewer Drainage Basins Exhibit provided in the appendix. Based on the City of Bozeman Wastewater Improvement Plan, it is not anticipated that any other areas will be served by the mains in Gran Cielo Subdivision. A contour area map is provided in the appendix. The contours show that the 40-acre lot to the west of Gran Cielo Subdivision is graded such that wastewater will flow into Fowler Ln. The contour area map was obtained from the City of Bozeman Infrastructure viewer. E. Conclusion As outlined above, the proposed 8-inch and 10-inch sanitary sewer mains have the capacity for the effluent generated by the proposed Gran Cielo Subdivision and COS No 1861. This project will require the approval of the City Engineer and MDEQ. Gran Cielo Subdivision Sewer Main Design Report Page 3 of 4 Appendix 1. Sewer Main Capacity Calculations 2. Peaking Factor Calculations 3. Drainage Basin Exhibit 4. City of Bozeman Wastewater Improvement Plan 5. Area Contour Map Gran Cielo Subdivision Sewer Main Design Report Page 4 of 4 E. Conclusion As outlined above, the proposed 8-inch and 10-inch sanitary sewer mains have the capacity for the effluent generated by the proposed Gran Cielo Subdivision and COS No 1861. This project will require the approval of the City Engineer and MDEQ. Appendix 1. Sewer Main Capacity Calculations 2. Peaking Factor Calculations 3. Drainage Basin Exhibit 4. City of Bozeman Wastewater Improvement Plan 5. Area Contour Map Gran Cielo Subdivision Sewer Main Design Report Page 4 of 4 10-Inch PVC Pipe Capacity Pro)ect Description Friction Method Manning Formula Solve For Discharge Input Data Roughness Coefficient 0.013 Channel Slope 0.40 % Normal Depth 7.5 in Diameter 10.0 in Results Discharge 1.26 fl'/s Flow Area 0.44 ftz Wetted Perimeter 1.75 ft Hydraulic Radius 3.0 in Top Width 0.72 ft Critical Depth 0.50 ft Percent Full 75.0 `h j Critical Slope 0.00-128 ft/ft Velocity 2.88 ft is Velocity Head 0.13 ft Specific Energy 0.75 ft Froude Number 0.65 Maximum Discharge 1.49 ft'/s Discharge Full 1.39 ft'/s Slope Full 0.00333 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0,0 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.0 in Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 Normal Depth Over Rise 75.00 % Downstream Velocity Infinity ft/s Bentley Systems,Inc. Haestad Methods Soh@iztdl®pfitewMaster V81(SELECTseries 1) [08.11.01.03] 7/1612018 11:31:24 PM 27 Slemons Company Drive Suite 200 W Watertown,CT 06795 USA +1-203-755-1666 Page 1 of 2 10-Inch PVC Pipe Capacity GVF'Output Data Upstream Velocity Infinity Ws Normal Depth 7.5 in Critical Depth 0.50 ft Channel Slope 0.40 % Critical Slope 0,00728 ft/ft Bentley Systems,Inc. Haested Methods SoldtbdId�pFtewMaeter V8l(SELECTeerles 1) [08.11.01.031 7/1612018 11:31:24 PM 27 Slemons Company Drive Suite 200 W Watertown,CT 06795 USA +1-203-755-1666 Page 2 of 2 8-Inch PVC Pipe Capacity Project'Description Friction Method Manning Formula Solve For Discharge Input Data Roughness Coefficient 0.013 Channel Slope 1,30000 Normal Depth 5.6 In Diameter 8.0 in Results Discharge 1.15 ft'/s Flow Area 0.26 ft2 Wetted Perimeter 1.32 ft Hydraulic Radius 2.4 in Top Width 0.61 ft Critical Depth 0.51 ft Percent Full 70.0 %, Critical Slope 0.01051 ft/ft Velocity 4.42 ft/s Velocity Head 0.30 ft Specific Energy 0.77 ft Froude Number 1.19 Maximum Discharge 1.46 Wis Discharge Full 1.38 ft3/s Slope Full O.OD911 ft/ft Flow Type SuperCrltical BVP,InPuf QW Downstream Depth 0.0 in Length 0.00 ft Number Of Steps 0 Upstream Depth 0.0 in Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 70.00 % Downstream Velocity Infinity f/s Bentley Systems,Inc. Haestad Methods SoldlW416p6teouMaster V81(SELECTserles 1) [08.11.01.031 7h1612018 11:43:35 PM 27 Slemons Company Drive Suite 200 W Watertown,CT 06796 USA +1-203-755-1666 Page 1 of 2 8-Inch PVC Pipe Capacity Upstream Velocity Infinity ft/s Normal Depth 5.6 in Critical Depth 0.51 ft Channel Slope 1.30000 % Critical Slope 0.01051 ft/ft Bentley Systems,Inc. Hassled Methods Soldtletl®pfitewMaster VBI(SELECTserles 1) [08.11.01.03] 711612018 11:43:35 PM 27 Slemons Company Drive Suite 200 W Watertown,CT 06796 USA +1-203-785-1666 Page 2 of 2 8-inch PVC Pipe Capacity Project Description Friction Method Manning Formula Solve For Discharge Input Data Roughness Coefficient 0.013 Channel Slope 0.40 % Normal Depth 6 in Diameter 8 in Results Discharge 0.70 4 Flow Area 0.28 ft' Wetted Perimeter 1.40 ft Hydraulic Radius 2 in Top Width 0.58 ft Critical Depth 0.39 ft Percent Full 75 0 rl Critical Slope 0.00773 ft/ft Velocity 2.48 ft/s Velocity Head 0.10 ft Specific Energy 0.60 It Froude Number 0.63 Maximum Discharge 0.82 Q'Is Discharge Full 0.76 ft°/s Slope Full 0.00333 ft/ft Flow Type SubCdtical GVF Input Data Downstream Depth 0 in Length 0.00 ft Number Of Steps 0 GVF Output Date Upstream Depth 0 in Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 75.00 % Downstream Velocity Infinity fVs Bentley Systems,Inc. Haestad Methods Sd6wWJP% khMMaeterV81(SELECTserles 1) 100.11.01.031 1/16/2014 8:28:10 PM 27 Slemons Company Drive Suite 200 W Watertown,CT 06796 USA a1-203-766.1666 Page 1 of 2 Sewer Main Extension Gran Cielo Subdivision Peaking Factor for Drainage Area 1 Total Wastewater Flow Rate= 115,487 gpd Residential Usage per person = 89 gpd Equivalent Population= 1,298 Q(max) = 18 +P 0.50 P=Population/thousands Q(ave) 4 +P 0.50 P= 1.298 Peaking Factor = 3.72 Peaking Factor for Drainage Area 2 Wastewater Daily Flow Rate= 1,220 gpd/acre Acres= 19.59 acres Total Wastewater Flow Rate= 23,900 gpd Residential Usage per person= 89 gpd Equivalent Population= 269 Q(max) = 18 +P 0.50 P=Population/thousands Q(aVe) 4 +P 0.50 P= 0.269 Peaking Factor = 4.10 Peaking Factor for Drainage Area 3 Wastewater Daily Flow Rate= 1,950 gpd/acre Acres= 8.95 acres Total Wastewater Flow Rate= 17,453 gpd Residential Usage per person= 89 gpd Equivalent Population= 196 Q(max) = 18 +P 0.50 P =Population/thousands Q(ave) 4 +P 0.50 P= 0.196 Peaking Factor = 4.15 Peaking Factor for Gran Cielo Subdivision Q m Z 3 a SCALE I iiic}i= 15U Ices z SA\rr.kRY SMVLR I I xl DRAINAGF.AREA 3 DRAWN BY:BLB x 'LUNInG:R4 S: W 1N1TAR1'SliP'ER REVIEWED BY:CGB — I1.•i 1,1.•2 —S.i8'fH 1 A'l+. DRAINAGE AREA 1 PHASE]+"TRACT.\ PROJECT ENGINEER:BLB •I III \\ \ II 70.1 O 1r DESIGNED BY:CGB PHASE 1 TRACr A l ZOKI?�G:R3 s l COS\O1861 LL 29.h8AC40.78 AC — — — — — — — ILL L AL J,7cri 1 l— � � 29TH: VC :?.27'r1I.\1°H; — SAYITARY SEWER DRAINAGE.Al}YA 2 F� F ZON NG:I23 19.59 AC f. Q ot I` n I s .IIST ACf II - IT zo F M � . 0 Wo�r :.� t 0 c0 o J r SHIM S.S. BASINS aR,1S C1 R1.o r�Irlxrr 3 PROJECT:17-130 Y DATE:10-20-17 Hidden Valley Lift Station - t�• :pi LLong-Term Improvement Spring Hill Lift Station - - Long-Term Improvement L Gooch Hill Lift Station Long-Term Improvement r_;,�ts' >r - ----.__._._.._._ N ,.,.._..«•.,.....».._......_... _ w �r1 iL .• Davis Lane Lift Station x * t d Near-Term Improvement and a 18 Creek �' � Long-Term Expansion t ��r ,.... m / - Z ' s frlI��1r Croek water Reclamation Facility Door { r. 1 Creek ' YS Baxter 6 +r r 8 Creek rl A 1 r ..,1 :a_ ✓' j ...,.. I W �O it V . , m Bridger Creek Golf e a 2° to North Frontage Rd Long-Term Improvement Circe, Syr• -•� �_ �� i° 127thAvenue/Cattail Creek Interceptor 'ai ac L.e _ -+ l Aajaker Creek Basin Diversion L 'Lon -Term Improvement - ,••„`". -'• `s p'� (Long-Term Improvement »ea L 9 P - - _ '��\ Bridget Dr to North Rouse Ave ik »� i cJI tt's•,z Long-Term Improvement j'� North Frontage Road Interceptor .,..-'• -t` r m r e Near-Term Improvement - •- } f Norton East Ranch Outfall Diversion I ""•,� N „ `- r c Long-Term Improvement t.. ,��Davis-Fowler Interceptor, "4,i Front Street Interceptor Bridge r,• ' r'. Long-Term Improvement F` Near-Term Improvement creek . ' k is •'4'. '� — - East r ' Gallatin 21 Upper m_ 1•:._ River - 3 t _ Rouse - n "'• � 41A A4 - 3i t ✓.- ,f 1 '^ ;._.. ! 15 17 U Upper �O ��_..0 eok .9 ' � � �' • • oton an non :, Creek Aajker Creek tSpnng Bozeman •\• ;�.. . r Creek, Trail m - Baxter r Crea t k to m 0 , Line Capacity at Modeled Peak Available Peak .� a Location 75%d/D(gpm) Flow 2014 Flow Capacity Contributing Basins m o (8Pm) 2014(gpm) _ i..... Lo»ar ozeman Front Street ] 590 60 Upper Bozeman Creek i BcreelN ' North Frontage Road 3,600 2.790 820 Lower Bozeman Creek •- +»••• +,««..,«..,.t and all basins east Baxter Creek and ! 27th Avenue/Cattail Creek 3,870 1,180 2,690 Cattail Creek ;-,•„) «• WWTP Inr orceptm 11,880 9,600 2,280 All basins ' i Baxter Creek and •-{ ° t! Davis-Fowler 3,300 620 2,680 i Cattail Creek Norton East Ranch(15" '' '•"'"'"' section) 1,000 40 960 Baxter Creek i Bridger or to North Rouse ; Ave 670 50 620 Bridger Creek } } Bridger Creek Golf Course 740 320 420'Bridger Creek to North Frontage Rd Valley West 1,620 Soo 1,120 Cattail Creek Legend [� Treatment Plant (�+] Existing Lift Station Near-Term Pipe Improvement City of Bozeman Existing Collector LM Near-Term Lift Station Improvement Near-Term Extension Wastewater Improvement Plan Existing Trunk Sewer Long-Term Lift Station Improvement Long-Term Pipe Improvement 2014 Wastewater Facility Plan Existing Interceptor _,_, City Limits Long-Term Extension F)l for the City of Bozeman Community Plan Boundary Lon Term Force Main ��M�RRISON v ry 9- AA MA�RLE,INC. Last Updated:5/27/2015 Legend' 1.' - .. _ r•.•� ., i ' mot. ... '. - 1 .1 '- � � �_ � +"�( _. /. �r 1 ••- _a .' _ t-'4, --- y.. _ •.j�. 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