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HomeMy WebLinkAbout14 - Design Report - Partridge Downs - Water, Sewer, Stormwater DESIGN REPORT WATER, SEWER & STORMWATER MANAGEMENT PARTRIDGE DOWNS SUBDIVISION Prepared for: Vision Development, Inc. PO Box 1858, Bozeman, MT 59771 Prepared by: C&H Engineering and Surveying, Inc. 1091 Stoneridge Drive, Bozeman, MT 59718 (406) 587-1115 Project Number: 13798 March 2014 INTRODUCTION The proposed Partridge Downs Subdivision is a 30-lot major subdivision located on a 6.21 acre parcel legally described as Tract 2A of Certificate of Survey No. 501, together with the strip of land described in Document No. 2268861, on file and of record in the office of the Clerk and Recorder, Gallatin County, Montana, and located in the Southeast Quarter of Section 3, Township 2 South , Range 5 East of P.M.M., Gallatin County, Montana. It is located on the northwest corner of Durston Road and Hanson Street. The proposed subdivision will connect to existing City of Bozmean water and sewer mains. WATER DISTRIBUTION SYSTEM Current water mains and stubs in the area utilized for this project include an 8-inch ductile iron pipe (DIP) located in Durston Road at the south subdivision boundary, and an 8-inch DIP in Hanson Avenue along the east subdivision boundary. A WaterCAD analysis is enclosed (Appendix A of this report) analyzing all mains installed with this project. The connection to the existing system is modeled as a pump with characteristics matching pressure/flow data measured by the City of Bozeman Water Department. Water Distribution System Demands The design parameters used herein are according to the City of Bozeman Design Standards and Specifications Policy (DSSP) dated March 2004. Average Daily Residential Usage = 170 gallons per capita per day Average Population Density = 2.11 persons/dwelling unit Minimum Fire Hydrant Flow = 1,500 gpm Residual Pressure Required = 20 psi for Fire Flow Average Day Demand (Peaking Factor= 1.0) Maximum Day Demand (Peaking Factor= 2.3) Design Report- Page 2 of 12 Peak Hour Demand (Peaking Factor= 3.0) Water Demands (30 dwelling units) Average Day Demand = 30 d.u. x 2.11 persons/d.u. x 1.70 gpcpd = 10761 gpd = 7.47 gpm Maximum Day Demand = 7.47 gpm x 2.3 = 17.19 gpm Peak Hour Demand = 7.47 gpm x 3.0 = 22.42 gpm Water Distribution System Hydraulic Analysis A water distribution model was created using WaterCAD Version 6.5 for demand forecasting and describing domestic and fire protection requirements. In order to model the system, each junction node of the water distribution system was assessed a demand based on its service area. The table shown below quantifies the demands placed at the junction nodes and calculates the demands for Average Day, Maximum Day and Peak Hour within the subdivision. The peaking factor for each case is 1.0, 2.3 and 3.0 respectively. JUNCTION #OF AVG. DAY MAX. DAY PEAK HOUR NODE LOTS GPM GPM GPM J-8 22 5.48 12.60 16.44 J-9 8 1.99 4.58 5.98 Total 30 7.47 17.19 22.42 Static, residual and pitot pressures were measured by the City of Bozeman Water Department for the 8-inch water main in Hanson Street. These measurements were taken on the low pressure side of the existing pressure reducing valve (PRV) in Hason Street. The Hydrant Pressure/Flow Request Form is attached in Appendix A of this report. The results are shown below: Location Hydrant# Static Pressure Pitot Pressure Residual Pressure Hanson/Durston 2335 76# 64# Hanson 2293 62#(1320 gpm) Static pressure for the Durston water main was also measured and found to be 141# at the Sheridan/Durston hydrant(#993). This hydrant is on the high pressure side. Since this project will Design Report- Page 3 of 12 connect to the Durston water main, it is anticipated that a PRV will need to be installed as part of this project. For the purposes of this report and WaterCAD model, it is assumed that the proposed PRV will be adjusted to give the same pressure/flow data as found in Hanson Street. This flow/pressure information was used to develop relationships between static head and flow at the tie in points. This relationship was simulated in the WaterCAD model using pumps at the connection points. The pumps are connected to reservoirs which act as a source of water. The elevations of the reservoirs are fixed at the elevation of the pumps, which is also equivalent to the elevation of the tie in point. The reservoir does not create any head on the system; the head is generated entirely by the pumps. The input data and the pump curves are included in Appendix A of this report. Water Distribution System Design Summary The 8-inch DIP water mains provide adequate capacity with regards to the Peak Hour Demands. The flows and pressures within the system for the Peak Hour Demands were generated using WaterCAD and can be found in Appendix A of this report. The capacity of the system to meet fire flow requirements was tested by running a steady state fire flow analysis for all junctions at fire hydrant locations. The model shows that all hydrant junctions satisfy fire flow constraints (residual pressure > 20 psi, flow rate > 1500 gpm), while providing service to lots at peak hour.The results of the analysis at peak hourly flow are given in Appendix A of this report. SANITARY SEWER SYSTEM Sewer main lines will be installed in Hanson Street, Rose Street, and Sheridan Avenue and will flow into the existing 8-inch main in Hanson Street near the northeast boundary of the subdivision. Sanitary Sewer Design Load The flow rates used herein are according to the City of Bozeman Design Standards and Specifications Policy, March 2004. The peaking factor for the design area is determined by Design Report-Page 4 of 12 calculating the equivalent population and inserting the population into the Harmon Formula. An 8-inch main is the minimum diameter allowed within the City of Bozeman. All new sewer lines shall be sized to flow at no more than 75% of capacity for peak hour conditions. Using the city average of 2.11 persons per household the equivalent population for the service area is calculated. Partridge Downs: Equivalent Population. (2.11 persons/d.u.)(30 d.u.) = 64 persons Assumed infiltration rate: (150 gal/acre/day) (6.21 acres) = 932 gal/day Adjacent Land: It is anticipated that the 3.54 acre parcel to the east may also be serviced through the Hanson Street sewer main. This parcel is not zoned. It is designated as a residential area per the 2020 Plan and therefore has a design density of 5.5 dwelling units/acre. Equivalent Population: (2.11 persons/d.u.)(5.5 d.u./acre)(3.54 acres) =41 persons Assumed infiltration rate: (150 gal/acre/day) (3.54 acres) = 531 gal/day Total Design Load: The peak flow rate is calculated by multiplying the City's design generation rate of 89 gallons per capita per day by the population,multiplying by the peaking factor, and adding the infiltration rate: Harmon Formula: Peaking Factor= (18 + Pos)/(4 +Po.$) where: P = Population in thousands Peaking Factor= (18 + 0.1051.5)/(4 + 0.1050.5) Peaking Factor=4.24 Peak Flow Rate: (89 gal/person/day)(105 persons)(4.24) + 1463 gal/day =41,085 gal/day =28.53 gpm (0.0636 cfs) Design Report- Page 5 of 12 Sanitary Sewer Hydraulic Analysis The capacity of an 8-inch main is checked using Manning's Equation: Q = (1.486/n)AR"'S"2 For an 8-inch PVC sewer main: Manning's n = 0.013 for PVC Minimum Slope = 0.004 ft/ft A = area= (3.14/4)d 2= (3.14/4)(8/12)2=0.34907 ft2 P=perimeter= 2(3.14)r= 2(3.14)(4/12) = 2.0944 ft R = hydraulic radius = A/P= 0.34907/2.0944 = 0.16667 ft R211 =0.30105 ft S = 0.004 ft/ft S1/2 = 0.0632 ft/ft Qft,11= (1.486/0.013)(0.34907)(0.30105)(0.0632) = 0.7592 cfs Qoas = (0.75)(0.7592) = 0.5694 cfs Based on these calculations, an 8-inch sewer main is more than adequate to carry the design flows for the subdivision and the adjacent property. STORMWATER MANAGEMENT Stormwater runoff from the subdivision will be conveyed to a storage facility in the open space at the northwest corner of the property. Since there is no established drainage way for the stormwater facility to discharge to, a retention pond will be provided. A map showing drainage areas is included in Appendix B of this report. Retention Pond Drainage Area #1 encompasses the majority of the property. It does not include the 45' Durston Road Right-of-Way which will drain to the existing storm sewer mains in Durston Road or the Design Report-Page 6 of 12 portion of Hanson Street north of the intersection with Rose Street which will drain north on the existing Hanson Street and into existing storm sewer inlets on Annie Street. Required Volume The retention pond will be sized according to meet the requirements of the City of Bozeman Design Standards and Specifications Policy, March 2004. The pond will be sized based on a 10-yr, 2-hr storm intensity. Q =CIA V=7200Q Contributing Area C Area (ft2) C * Area ROW Hardscape 0.95 46559 44231 ROW Boulevard 0.2 17827 3565 Open Space/Park 0.2 6061 1212 Lots 0.35 164403 57541 i Total 234849 106549 C = Weighted C Factor 0.45 I=intensity(in/hr) 0.41 A =Area (acres) 5.39 Q =runoff(cfs) 1.00 V = volume (ft3) 7221 Detention Pond A will have a volume of 7,300 ft3 which is adequate to handle the runoff from the subdivision. Inlet Pipe Sizing The storm sewer pipes are designed to handle a 25-year storm event. The post-development time of concentration is first calculated to determine the peak discharge. Then required flow capacity is checked for the 25-yr storm. Finally, the flow capacity of the proposed pipe is checked. Overland Flow Tc = 1.87 (1.1-CCf)D1/2/SI/3 Design Report- Page 7 of 12 S = Slope of Basin (%) 2.78 C = Rational Method Runoff Coefficient 0.35 Cf= Frequency Adjustment Factor 1.1 D = Length of Basin (ft) 90 Tc = Time of concentration (minutes) 9.02 Gutter Flow Tc = L/V/60 V = (1.486/n)R113 S v2 n =Mannings Coefficient 0.013 (0.15'below top of R=Hydraulic Radius A/P (ft) 0.13 curb) S = slope (ft/ft) 0.015 L= length of gutter (ft) 732 V = mean velocity (ft/s) 3. 3 Tc=Time to concetration(minutes) 3.36 Tc Total = 12.38 Required Flow Capacity (25-yr Storm) Q = CIA C =Weighted C Factor 0.45, (calculated above) I= 0.78 Tc-0.64(in/hr) 0.16 A= area (acres) 5.39 Q = runoff(cfs) 0:38 Provided Flow Capacity Q = (1.486/n)AR2i3Si/2 d=nominal diameter(in) 12 n =Mannings Coefficient 0.013 Design Report-Page 8 of 12 A = area (ft) 0.7854 R =Hydraulic Radius A/P (ft) 0.2500 (for full pipe) S = slope (ft/ft) 0.05 Q =flow capacity (cfs) 7.97 ' Overland Flow Tc= 1.87 (1.1-CCf)D 112/S 11 S = Slope of Basin (%) 2.78 C = Rational Method Runoff Coefficient 0.35 Cf=Frequency Adjustment Factor 1.1 D=Length of Basin(ft) 90 Tc =Time of concentration (minutes) 9.02` Gutter Flow Tc = L/V/60 V = (1.486/n)R213 S1/2 n=Mannings Coefficient 0.013 R = Hydraulic Radius A/P (ft) 0.13 (0.15'below top of curb) S = slope (ft/ft) 0.015 L=length of gutter (ft) 732 V=mean velocity(ft/s) 3.63 Tc =Time to concetration (minutes) 3.36 Tc Total = 12.38'` Required Flow Capacity (25-yr Storm) Q= CIA C =Weighted C Factor 0.45 (calculated above) I= 0.78 Tc-0.64(in/hr) 0.16 A = area (acres) 5.39 Design Report- Page 9 of 12 Q =runoff(cfs) 0.38 Provided Flow Capacity Q = (1.486/n)AR2"S i i2 d = nominal diameter (in) 12 n = Mannings Coefficient 0.013 A = area (ft2) 0.7854` R= Hydraulic Radius A/P (ft) 0.'2500 j (for full pipe) S = slope (ft/ft) 0.05 Q = flow capacity (cfs) 7,97 Design Report-Page 10 of 12 APPENDIX A WATERCAD MODEL & COB HYDRANT DATA Design Report- Page 11 of 12 Scenario: Peak Hour J-11 -o N J-g P-1 J-9 Aft C PMP-1 PMP-2 nnT Title:Partridge Downs Project Engineer:Taylor Balian g:\...\13798 partridge downs watercad.wcd C&H Engineering&Surveying,Inc. WaterCAD v6.5[6.5120] 02/25/14 03:30:35 PM ©Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 USA +1-203-755-1666 Pace 1 of 1 t Itolow"- 4e 1 � 2 O 2 O CITY OF BOZEMAN Shaping Our Future Together HYDRANT PRESSURE/FLOW REQUEST FORM Date: 2/14/14 Location Hydrant# Static Pressure Pito Pressure Residual Pressure Hanson/Durston 2335 76# 64# Hanson 2293 62# Sheridan/Durston 993 141# Requested By: Taylor Balian C&H Fax # Nozzle Size Flowed: 2.5" Done By: ES /RC Comments:. 1320 GPM F 2055 ° i �_ > 21$$ Y.11 i �1824 1'825 _7 j s 1 ' �2294 °�`1 822 ,' N1E S 1' 2044 - s 218612043 }__... - -1823 I 2292 � I �1510 .. F2293 . .m w2241 1.097 2042 1514 1513 2245 % I W 1515 - ST 3 2244 2335 ,1516 8— 1735-- \�!784..._993 23612=115 C . LI — L - 1. T? S ' . 2116 2166 3 �732 ,783825 992 991 t Detailed Report for Pump: PMI✓-1 Scenario Summary Scenario Peak Hour Active Topology Alternative Base-Active Topology Physical Alternative Base-Physical Demand Alternative Base-Demand Initial Settings Alternative Base-Initial Settings Operational Alternative Base-Operational Age Alternative Base-Age Alternative Constituent Alternative Base-Constituent Trace Alternative Base-Trace Alternative Fire Flow Alternative Base-Fire Flow Capital Cost Alternative Base-Capital Cost Energy Cost Alternative Base-Energy Cost User Data Alternative Base-User Data Global Adjustments Summary Demand <None> Roughness <None> Geometric Summary X 4,883.24 ft Upstream Pipe P-14 Y 4,680.24 ft Downstream Pipe P-16 Elevation 0.00 ft Pump Definition Summary Pump Definition Pump Definition-Low Pressure Side PRV Initial Status Initial Pump Status On Initial Relative Speed Facto 1.00 Calculated Results Summary Time Control IntakeDischargEDischarge Pump RelativeCalculated (hr) Status Pump Pump (gpm) Head Speed Water Grade Grade (ft) Power (ft) (ft) (Hp) 0.00 On -0.00 173.08 11.33 73.08 1.00 0.50 Pump Head Curve 180.0 PMP-1 (Relative Speed Factor = 1.00) 160.0 140.0 - 120.0 -0 100.0 Cz N, 2 80.0- 60.0 40.0 20.0 0.0 500.0 1000.0 1500.0 2000.0 2500.0 3000.0 3500.0 4000.0 Discharge (gpm) Title:Partridge Downs Project Engineer:Taylor Balian g:\...\13798 partridge downs watercad.wcd C&H Engineering&Surveying,Inc. WaterCAD v6.5[6.5120] 02/25/14 03:37:42 PM ©Haestad Methods,Inc. 37 Brookside Road Waterbury.CT 06708 USA +1-2n1-755-1f;RF pang 1 of 1 Detailed Report for Pump: PMP-2 Scenario Summary Scenario Peak Hour Active Topology Alternative Base-Active Topology Physical Alternative Base-Physical Demand Alternative Base-Demand Initial Settings Alternative Base-Initial Settings Operational Alternative Base-Operational Age Alternative Base-Age Alternative Constituent Alternative Base-Constituent Trace Alternative Base-Trace Alternative Fire Flow Alternative Base-Fire Flow Capital Cost Alternative Base-Capital Cost Energy Cost Alternative Base-Energy Cost User Data Alternative Base-User Data Global Adjustments Summary Demand <None> Roughness <None> Geometric Summary X 5,120.35 ft Upstream Pipe P-15 Y 4,678.19 ft Downstream Pipe P-13 Elevation 0.00 ft Pump Definition Summary Pump Definition Pump Definition-Low Pressure Side PRV Initial Status Initial Pump Status On Initial Relative Speed Facto 1.00 Calculated Results Summary Time Control IntakeDischargEE)ischargePump RelativeCalculated (hr) Status Pump Pump (gpm) Head Speed Water Grade Grade (ft) Power (ft) (ft) (Hp) 0.00 On -0.00 173.08 11.09 73.08 1.00 0.48 Pump Head Curve 180.0 PMP-2 (Relative Speed Factor = 1.00) 160.0 140.0 120.0 100.0 _ 80.0 60.0- 40.0 20.0 0.0 f - i 0.0 500.0 1000.0 1500.0 2000.0 2500.0 3000.0 3500.0 4000.0 Discharge (gpm) Title:Partridge Downs Project Engineer:Taylor Balian g.\...\13798 partridge downs watercad.wcd C&H Engineering&Surveying,Inc. WaterCAD v6.5[6.51201 02/25/14 03:38:10 PM ©Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 USA +1-203-755-1666 Page 1 of 1 Calculation Results Summa,' Scenario:Peak Hour [Analysis Started] Tue Feb 25 15:31:48 2014 {Fire Flow] Failed to Converge.......0 Satisfied Constraints....3 Failed Constraints.......0 Total Nodes Computed.....3 [Steady State] 0:00:00 Balanced after 4 trials;relative flow change=OA00083 Trial 1:relative flow change=774.241394 Trial 2:relative flow change=0.632667 Trial 3:relative flow change=0.014297 Trial 4:relative flow change=0.000083 Flow Summary Flow Supplied 22.42 gpm Flow Demanded 22.42 gpm Flow Stored 0.00 gpm 0:00:00 Reservoir R-1 is emptying [Analysis Ended] Tue Feb 25 15:31:48 2014 Title:Partridge Downs Project Engineer:Taylor Balian g:\...\13798 partridge downs watercad.wcd C&H Engineering&Surveying,Inc. WaterCAD v6.5[6.51201 02/25/14 03:35:55 PM ©Haestad Methods,Inc. 37 Brookside Road Waterbury,CT 06708 USA +1-203-755-1666 Page 1 of 1 Scenario: Peak Hour Fire Flow Analysis Fire Flow Report Label Zone Base Flow Fire Flo Fire Flow Satisfies Needed Available Total Total Residual Calculatec Ainimum Zon Calculatec Minimum (gpm) IterationsBalanced? Fire Flow ire Flo Fire Flow Flow Pressure Residual Pressure Minimum Zone onstraints. (gpm) Flow Needed Available (psi) Pressure (psi) Zone Junction (gpm) (gpm) (gpm) (psi) Pressure (psi) J-8 Zone 16.44 15 true true 1,500.00 1,385.83 1,516.44 1,402.27 20.00 20.00 20.00 27.68 J-9 J-9 Zone 5.98 16 true true 1,500.00 4,387.01 1,505.98 1,392.99 20.00 20.00 20.00 20.00 J-11 J-11 Zone 0.00 15 true true 1,500.00 3,523.22 1,500.00 3,523.22 20.001 20.00120.00 1 38.24 1 J-9 Title:Partridge Downs Project Engineer:Taylor Balian g:\...\13798 partridge downs watercad.wcd C&H Engineering&Surveying,Inc. WaterCAD v6.5[6.5120) 02/25/14 03:47:03 PM ©Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 USA +1-203-755-1666 Paoe 1 of 1 Scenario: Peak Hour Fire Flow Analysis Junction Report Label Elevation Zone Type Base Flow Pattern Demand Calculated Pressure (ft) (gpm) Calculate ydraulic Grad (psi) (gpm) (ft) J-11 0.00 Zone Demand 0.00 Fixed 0.00 173.07 74.88 J-9 0.00 Zone Demand 5.98 Fixed 5.98 173.07 74.88 J-8 0.00 Zonel Demand 16.44 Fixed 16.44 173.07 74.88 Title:Partridge Downs Project Engineer:Taylor Balian g:\...\13798 partridge downs watercad.wcd C&H Engineering&Surveying,Inc. WaterCAD v6.5[6.51201 02/25/14 03:50:45 PM ©Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 USA +1-203-755-1666 Page 1 of 1 Scenario: Peak Hour Fire Flow Analysis Pipe Report Label Length Diametet Material Hazen- Check Minor Control Dischargd Ipstrearn StructLf aDwnstream Structui Pressure Headloss (ft) (in) William Valve? Loss Status (gpm) Hydraulic Grade Hydraulic Grade Pipe Gradient C Coefficien (ft) (ft) Headlos (ft/1000ft) (ft) P-1 244.00 8.0 Ductile fro 130.0 false 0.00 Open -5.11 173.07 173.07 0.00 0.00 P-12 224.00 8.0 Ductile fro 130.0 false 0.00 Open 0.00 173.07 173.07 0.00 0.00 P-13 587.00 8.0 Ductile fro 130.0 false 0.00 Open -11.09 173.07 173.08 0.00 0.00 P-14 148.00 100.0 Ductile Iro 130.0 false 0.00 Open 11.33 0.00 -0.00 0.00 0.00 P-15 282.00 100.0 Ductile fro 130.0 false 0.00 Open 11.09 0.00 -0.00 0.00 0.00 P-16 1585.001 8.01 Ductile fro 130.0 false 1 0.00 1 Open 1 11.331 173.081 173.071 0.001 0.00 Title:Partridge Downs Project Engineer:Taylor Balian g:\...\13798 partridge downs watercad.wcd C&H Engineering&Surveying,Inc. WaterCAD v6.5[6.5120] 02/25/14 03:54:22 PM ©Haestad Methods,Inc. 37 Brookside Road Waterbury,CT 06708 USA +1-203-755-1666 Page 1 of 1 APPENDIX B ST® MWATER DRAINAGE MAP Design Report-Page 12 of 12 00 rn rr w �f 0 in - ( w N L Q SS / SS I $S SS � SS SS - a-- SS ---e- co _ o SS SS SS SS ® O O CIO in z z c-- m Q� w� DQ Q Q OH U-1 z a OZ;' cc z °8-� F- Q '8 v`OC Ln ccN I �N� ooil cool I i 1 z t � Q I II o Iw-z \ M " Ow — — — — LO of �- of I � L 1 QQ II w0 U Q D ^ I I C U zco l \ JI m ~ m _.;. - - ot f 'l / ` r p v i I r` ri ,fall will € f , , # r s :-.. �, .. .. .. a ,. \ k _..,.. ... .. a .,_.,...,.,.E .._......._ ,__ .:l Y;... ..._.;f _. _. (_ � �.0 C m W ° a