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HomeMy WebLinkAbout003 Water Sewer Storm Design Report JOB NO. B14-008 MONTANA | WASHINGTON | IDAHO | NORTH DAKOTA | PENNSYLVANIA FEBRUARY 2022 406.586.0277 tdhengineering.com 234 East Babcock Street Suite 3 Bozeman, MT 59715 CLIENT ENGINEER Scott Hacker Montana Crestview 4200 Expressway Missoula, MT 59808 TD&H Engineering 234 East Babcock Street, Suite 3 Bozeman, MT 59715 Engineer: Cody Croskey, PE TROUT MEADOWS PHASE 3 BOZEMAN, MONTANA BASIS OF DESIGN REPORT 2/17/22 B14-008 Trout Meadows Phase 3 Page 1 of 3 TROUT MEADOWS PHASE 3 DESIGN REPORT February 2022 Purpose and Introduction The purpose of this report is to explain how water, sanitary sewer, and storm drainage improvements will be designed or have been previously designed to meet the City of Bozeman requirements and Montana Public Works Standard Specifications (MPWSS) to provide service to the Trout Meadows Phase 3 apartment project proposed within the Cattail Lake Subdivision in Bozeman, Montana. The report will provide information on the detailed design of the above-mentioned infrastructure. Trout Meadows Phase 3 is a continuation of the overall Trout Meadows apartment development and is located on 4 existing multi-family lots with the Cattail Lake Subdivision. The north lots are located south of Trout Meadows Road and west of Davis Lane. The south lots are located north of Catamount Street between Fen Way and Blackbird Drive. The 4 lots were originally platted as 21 single-family lots (10 detached homes and 11 attached townhomes). A change in the development plan from 21 single- family lots to 4 multi-family lots was approved in 2014 with Amended Plat J-471-A. Each lot will contain one multi-family building with the following dwelling units: • Lot 1A, Block 5: 1-bedroom apartments (6), 2-bedroom apartments (12) • Lot 6A, Block 5: 1-bedroom apartments (6), 2-bedroom apartments (12) • Lot 1A, Block 6: 1-bedroom apartments (8), 2-bedroom apartments (4) • Lot 7A, Block 6: 1-bedroom apartments (8), 2-bedroom apartments (4) The lots are currently vacant. Proposed site improvements include the construction of apartment buildings with associated parking, landscape, hardscape, utility services, and on-site stormwater management systems. Off-site infrastructure improvements are not proposed with this project. The water, sewer, streets, and storm drain infrastructure for this development was installed with the original Cattail Lake Subdivision. Installation of new, or extension of existing, water, sewer, or storm drain mains is not required for Trout Meadows Phase 3. Design Report Water As mentioned above, existing water mains have already been extended to each lot during construction of the Cattail Lake Subdivision. Existing water improvements were reviewed and approved by the City of Bozeman and the Montana Department of Environmental Quality (DEQ) and were installed in accordance with the approved plans and specifications. Several existing 3/4" water service lines were originally stubbed to the single family lots prior to the plat amendment. These services were properly abandoned and new 1.5” domestic and 4” fire service lines were stubbed into each of the 4 multi-family lots in 2017. These services will be extended to each multi-family structure with the building improvements in accordance with the City of Bozeman Design Standards and Modifications to Montana Public Works Standard Specifications B14-008 Trout Meadows Phase 3 Page 2 of 3 (MPWSS). The estimated domestic water demands for the project are provided in Appendix A as calculated in accordance with C.O.B. DSSP Section V.A.4. Sewer As mentioned above, existing sewer mains have already been extended to each lot during construction of the Cattail Lake Subdivision. Existing sewer improvements were reviewed and approved by the City of Bozeman and the Montana Department of Environmental Quality (DEQ) and were installed in accordance with the approved plans and specifications. Several existing 4" sewer service lines were originally stubbed to the single family lots prior to the plat amendment. One existing 4” sewer service line will be extended to each multi-family structure in accordance with the City of Bozeman Design Standards and Modifications to Montana Public Works Standard Specifications (MPWSS). The estimated sewer demands for each building are provided in Appendix B as calculated in accordance with C.O.B. DSSP Section V.B. and using information from the City’s 2015 Wastewater Facilities Plan. Storm Drainage An engineering design report discussing storm water conveyance, retention/detention, and infrastructure was completed in July of 2006 under the title “Design Report, Cattail Lake Subdivision, Bozeman, Montana.” This report provides details on design storms, stormwater pond sizing, and storm drain sizing for the entire Cattail Lake development. The Trout Meadows Phase 3 project areas were included within the stormwater design for the subdivision using an assumed post-development runoff coefficient “C-Value” of 0.5. Therefore, an analysis was required to compare the assumed values with actual designed conditions and verify adequate storage volume and conveyance capacity exists within the subdivision stormwater system to accommodate this development. Copies of the relevant pages from the 2006 Cattail Lake Subdivision design report are included in Appendix C with annotation clarifying the values used in this evaluation. Additionally, some on-site stormwater retention facilities or existing pond modifications have been designed to address the current standards with respect to capturing the first 1/2" of rainfall from these sites. Both the north and south project sites consist of vacant land that slopes generally to the north that were included within the West Pond drainage basin in the original 2006 design report. Using measurements of the actual designed impervious areas for these sites, it was determined that they will have a slightly higher composite “C-Value” than the assumed 0.5. Therefore, higher runoff flow rates and volumes would be expected from these sites than what was originally planned for with the subdivision stormwater infrastructure design. However, in order to address the first 1/2" of rainfall requirement, stormwater retention chambers at the south site and additional pond retention volume at the north site have been designed that also result in a reduction of runoff volumes and flow rates from these sites before entering the subdivision storm system. The following table summarizes the assumed vs. actual runoff volumes and flow rates from the Trout Meadows Phase 3 B14-008 Trout Meadows Phase 3 Page 3 of 3 project areas, and demonstrates how the addition of on-site retention facilities to address the first 1/2" of rainfall also reduce the off-site 10-yr runoff storage volumes and 25-yr flow rates. This comparison demonstrates that the subdivision storm drain and pond system is adequate to support this development in combination with the new or improved on-site retention facilities. (See also the drainage basin map in Appendix C). Table 1 – Assumed vs. Actual Site Runoff Comparison Drainage Basin RRV First 0.5” (CF) RRV Storage Facility South 1,471 New Subsurface Infiltration Chambers North (a) 612 Over-excavate existing (Pond 13) to 6” below outfall North (b) 379 Surplus storage in existing (West Pond) 9” below outfall Drainage Basin C-Value 10-Yr Runoff 1 Volume V10 (CF) 25-Yr Runoff 1 Flow Rate Q25 (CFS) Assumed Actual Assumed Actual Assumed Actual South 0.50 0.60 1,864 756 1.10 0.81 North (a) 0.50 0.68 673 303 0.34 0.21 North (b) 0.50 0.48 618 588 0.31 0.29 1. Off-site runoff volumes and flow rates after initial on-site RRV (First 0.5”) capture. Stormwater design calculations for the “C-Value” determinations, RRV (First 0.5”) retention volumes, existing pond volume analysis, off-site runoff flow rates, and new storm pipe conveyance capacities are provided in Appendix C. Groundwater Geotechnical drilling investigations were conducted for the Cattail Lake Subdivision that also included seasonal high groundwater monitoring at several locations in 2004 and 2006. The monitoring locations and highest recorded groundwater elevations are shown on the boring location map provided in Appendix C. A groundwater surface was interpolated between these monitoring locations to estimate groundwater levels at the proposed stormwater facility locations. The estimated seasonal high groundwater elevations are shown on the drainage basin map as they relate to the subsurface infiltration chambers and the proposed over-excavation of Pond 13, and they are expected to be sufficiently below these features to allow for a successful retention/infiltration strategy at the site. APPENDIX A Water Calculations Trout Meadows Phase 3 Stormwater Design Calculations Date: 12.16.2022 Water Demand Calculation Domestic Water Demand - North Buildings: Residential Use: Residential Units =24 units People =50.6 people (2.11 people/unit per COB Design Standards) Residential Flow =8,609 GPD (170 gpcd per COB Design Standards) Peak Hour Demand: Average Day Demand =8,609 GPD (All Uses) Average Day Demand =6.0 gpm (GPD / 1,440 minutes) Maximum Day Demand =13.8 gpm (Ave. Day x Peaking Factor = 2.3) Peak Hour Demand =17.9 gpm (Ave. Day x Peaking Factor = 3) Domestic Water Demand - South Buildings: Residential Use: Residential Units =36 units People =76.0 people (2.11 people/unit per COB Design Standards) Residential Flow =12,913 GPD (170 gpcd) Peak Hour Demand: Average Day Demand =12,913 GPD (All Uses) Average Day Demand =9.0 gpm (GPD / 1,440 minutes) Maximum Day Demand =20.6 gpm (Ave. Day x Peaking Factor = 2.3) Peak Hour Demand =26.9 gpm (Ave. Day x Peaking Factor = 3) APPENDIX B Sewer Calculations Trout Meadows Phase 3 Stormwater Design Calculations Date: 12.16.2022 Sewer Demand Calculation Average Day Sewer Demand - NW Building Block 6, Lot 6A: Residential Use: Residential Units =12 units People =26.0 people (2.17 people/unit) Residential Flow =1,677 GPD (64.4 gpcd) Average Day Sewer Demand - NE Building Block 6, Lot 7A: Residential Use: Residential Units =12 units People =26.0 people (2.17 people/unit) Residential Flow =1,677 GPD (64.4 gpcd) Average Day Sewer Demand - SW Building Block 5, Lot 1A: Residential Use: Residential Units =18 units People =39.1 people (2.17 people/unit) Residential Flow =2,515 GPD (64.4 gpcd) Average Day Sewer Demand - SE Building Block 5, Lot 6A: Residential Use: Residential Units =18 units People =39.1 people (2.17 people/unit) Residential Flow =2,515 GPD (64.4 gpcd) Total Development Average Day Demostic Demand: Total Domestic =8,385 GPD Total Development Infiltration Flow: Property Size =2.11 acres (All lots) Infiltration Flow =317 GPD (150 gpd/acre per COB Design Standards) Total Development Peak Sewer Flow: Average Day Demand =8,385 GPD (residential + commercial) P =0.130 (population/1,000) Peaking Factor =4.21 Peak Sewer Demand =35,304 GPD (avg. day demand)*(peaking factor) + Infiltration Flow =317 GPD (not peaked) Total Peak Flow =35,620 GPD (residential + commercial + infiltration) Peak Sewer Flow =24.74 GPM (peak flow)/(24 hrs/day)/(60 min/hr) Values per C.O.B. 2015 Wastewater Facilities Plan Values per C.O.B. 2015 Wastewater Facilities Plan Values per C.O.B. 2015 Wastewater Facilities Plan Values per C.O.B. 2015 Wastewater Facilities Plan 𝑄𝑚𝑎𝑥 𝑄𝑎𝑣𝑔 =18 +𝑠ℎ𝑛𝑠𝑠𝑎𝑛𝑑𝑠𝑛𝑑𝑛𝑑𝑛𝑛𝑙𝑑1/2 4 +𝑠ℎ𝑛𝑠𝑠𝑎𝑛𝑑𝑠𝑛𝑑𝑛𝑑𝑛𝑛𝑙𝑑1/2 Trout Meadows Phase 3 Stormwater Design Calculations Date: 12.16.2022 4" Sewer Service Pipe Capacity Input Values d =0.33 ft =4" y =0.250 ft =75% Calculated Values (Equations from Fluid Mechanics by Chow) Theta (Θ)4.19 rad 2*arccos(1-y/(d/2)) Area (A)0.07 ft2 (1/8)*(Θ-sinΘ)d2 Wetted Perimeter (P)0.70 ft 0.5Θd Hydraulic Radius (R )0.10 ft (.25)*(1-(sinΘ)/Θ)d Top Width (T)0.29 ft (sin 0.5Θ)d Mannings Equation (Equation from Fundamentals of Mechanics by Munson) n =0.013 (per COB Design Standards) S0 =0.0208 ft/ft (1/4" per foot for 4" services) Q =0.25 cfs Q = 1.49/n*A*R2/3*S00.5 Q =112.42 gpm Q gpm = (Q cfs)(7.48 gal/ft3)(60 sec/min) V =3.58 ft/s V = Q/A Results A 4" diameter sewer sewervce at the min. 1/4" per foot slope flowing 75% full has the capacity for 112 gpm. J:\2014\B14-008 Trout Meadows Phase 3\DOCUMENTS\DESIGN REPORT\B14-008 Water & Sewer Calcs.xls1 OF 1 Appendix C Storm Water Calculations • Pages from 2006 Cattail Lake Subdivision Design Report • Trout Meadows Phase 3 Stormwater Calculations • Groundwater Monitoring Results Pages from 2006 Cattail Lake Subdivision Design Report The bottom 9"volume of the West SW Pond is retained and infiltrated through he bottom of the wetland feature. 1234567811121314109a9b9cPOND13WESTPONDEASTPONDDAVISPOND1b1aBASIN AREA (SF) AREA (ACRE)11a1b23456789a9b9c101112131420089.409326.9729452.1489801.7923595.9331758.56148856.1572690.5829093.1022123.8326647.9427156.39224774.2920905.09103586.7117733.20170573.3623955.360.4610.2140.6762.0620.5420.7293.4171.6690.6680.5080.6120.6235.1600.4792.3780.4073.9160.550SHEET OF CAD NO.DESIGNED BY:QUALITY CHECK:JOB NO.FIELDBOOKDRAWN BY:DATE:THOMAS, DEAN & HOSKINS, INC. ENGINEERING CONSULTANTS REVISIONS BY BY BY DATE DATE DATE DESCR DESCR DESCR .DWGCRESTVIEW LAKE SUBDIVISION BOZEMAN, MONTANA DRAINAGE BASIN MAP1 1557drainB05-0577.25.06JLNDJCSouth Site Ph3NorthSite Ph3WestSW PondBasinsaccountedforinWest SWPond: Assumed post-development C-Values for the Phase 3 Lots. Assumed 25-yr Peak Flow Tc values for the Phase 3 Lots. Iteratedstormdurationresultinginmax.requiredstoragevolumeintheWest SWPond Trout Meadows Phase 3 Stormwater Calculations CATAMOUNT STREETBLACKBIRD DRIVE FEN WAYBLOCK 5LOT 1ABLOCK 5LOT 6AOSPA 2BLOCK 6LOT 6ABLOCK 6LOT 7AOSPA 1AFEN WAYDAVIS LANETROUT MEADOWS ROADCATTAIL LAKEREVISIONSHEETDESIGNED BY:QUALITY CHECK:JOB NO.FIELDBOOKDRAWN BY:DATE:B14-008 SW BASIN MAPREV DATE NOT FORCONSTRUCTION TROUT MEADOWS PHASE 3 BOZEMAN, MONTANA DRAINAGE BASIN MAP SOUTH SITES (BLOCK 5, LOTS 1A & 6A)B14-0082.16.22.DWGEX-1CJCCJCEngineering 234 E. BABCOCK ST., SUITE 3 • BOZEMAN, MONTANA 59715 406.586.0277 • tdhengineering.com BASIN - SOUTH:CAVE = 0.60A = 1.33 AC.RRV = 1,471 CFV10 = 756 CF*Q25 = 0.81 CFS**(RELEASED OFF-SITEAFTER RRV CAPTURE)BASIN - NORTH (A):CAVE = 0.68A = 0.48 AC.RRV = 612 CFV10 = 303 CF*Q25 = 0.21 CFS**(RELEASED OFF-SITEAFTER RRV CAPTURE)BASIN - NORTH (B):CAVE = 0.48A = 0.44 AC.RRV = 379 CFV10 = 588 CFQ25 = 0.29 CFSSOUTH SITE DRAINAGE BASINNORTH SITE DRAINAGE BASINS Trout Meadows Phase 3 Stormwater Design Calculations Date: 12.16.2022 Basin Runnoff Coeff. (C-Value) Determinations Rational Formula "C" Values Per MTDEQ 8 "C" Impervious Area/Pond Surface 0.9 Gravel Area 0.8 Unimproved Area 0.3 Lawn/landscape 0.1 Assumed Post-Development Basin C Values (per 2006 Subdivision Design Report): Basin ID Basin Description Total Area (SF) Total Area (Acres) Impervious Area (SF) Gravel Area (SF) Unimproved Area (SF) Landscape Area (SF) Composite Cave South Block 5 - Lots 1A, 6A, OSPA 2 57,937 1.33 0.50 North (a)Block 6 - Lots 6A, 7A, OSPA 1A (south half)20,915 0.48 0.50 North (b)Block 6 - Lots 6A, 7A, OSPA 1A (north half)19,207 0.44 0.50 Actual Post-Development Basin C Values: Basin ID Basin Description Total Area (SF) Total Area (Acres) Impervious Area (SF) Gravel Area (SF) Unimproved Area (SF) Landscape Area (SF) Composite Cave South Block 5 - Lots 1A, 6A, OSPA 2 57,937 1.33 36,014 0 0 21,923 0.60 North (a)Block 6 - Lots 6A, 7A, OSPA 1A (south half)20,915 0.48 15,165 0 0 5,750 0.68 North (b)Block 6 - Lots 6A, 7A, OSPA 1A (north half)19,207 0.44 9,030 0 0 10,177 0.48 Trout Meadows Phase 3 Stormwater Design Calculations Date: 12.16.2022 Basin RRV (First 0.5") Calculations Post-Development Condition: Basin #Description Total Area (SF) Total Area (AC) Impervious Area (SF) Gravel Area (SF) Unimproved Area (SF) Landscape Area (SF) South Block 5 - Lots 1A, 6A, OSPA 2 57,937 1.33 36,014 0 0 21,923 Runoff Reduction Volume (First 0.5" of Rainfall): P =0.5 Inches (Water Quality Rainfall Depth) Rv =0.61 (Dimensionless Runoff Coefficient, Rv=0.05+0.9(I) I =62.2%(Percent Impervious Area Draining to Facility) A =1.33 AC (Total Drainage Area) RRV =0.034 AC-FT (Runoff Reduction Volume)* 1,471 CF Post-Development Condition: Basin #Description Total Area (SF) Total Area (AC) Impervious Area (SF) Gravel Area (SF) Unimproved Area (SF) Landscape Area (SF) North (a)South 1/2 of Block 6 - Lots 6A, 7A, OSPA 1A 20,915 0.48 15,165 0 0 5,750 Runoff Reduction Volume (First 0.5" of Rainfall): P =0.5 Inches (Water Quality Rainfall Depth) Rv =0.70 (Dimensionless Runoff Coefficient, Rv=0.05+0.9(I) I =72.5%(Percent Impervious Area Draining to Facility) A =0.48 AC (Total Drainage Area) RRV =0.014 AC-FT (Runoff Reduction Volume)* 612 CF Post-Development Condition: Basin #Description Total Area (SF) Total Area (AC) Impervious Area (SF) Gravel Area (SF) Unimproved Area (SF) Landscape Area (SF) North (b)North 1/2 of Block 6 - Lots 6A, 7A, OSPA 1A 19,207 0.44 9,030 0 0 10,177 Runoff Reduction Volume (First 0.5" of Rainfall): P =0.5 Inches (Water Quality Rainfall Depth) Rv =0.47 (Dimensionless Runoff Coefficient, Rv=0.05+0.9(I) I =47.0%(Percent Impervious Area Draining to Facility) A =0.44 AC (Total Drainage Area) RRV =0.009 AC-FT (Runoff Reduction Volume)* 379 CF *RRV = PRvA/12 per Montana Post-Construction Storm Water BMP Design Guidance Manual Eq. 3-1 Trout Meadows Phase 3 Stormwater Design Calculations Date: 12.16.2022 Subdivision Pond Storage Volume Comparison Assumed 10-yr Runoff Volume Provided in the West Pond for each site (per 2006 Subdivision Design Report): Basin #Basin Description Total Area (SF) Total Area (Acres) (Assumed) Cave Tc1 (min) 10-yr i (in/hr) Flow Q10 (cfs) Volume V10 (cf) South Block 5 - Lots 1A, 6A, OSPA 2 57,937 1.33 0.50 105.06 0.445 0.30 1,864 North (a)Block 6 - Lots 6A, 7A, OSPA 1A (south half)20,915 0.48 0.50 105.06 0.445 0.11 673 North (b)Block 6 - Lots 6A, 7A, OSPA 1A (north half)19,207 0.44 0.50 105.06 0.445 0.10 618 Total Storage Provided in West Pond =3,155 Actual 10-yr Runoff Volume Needed in the West Pond: Basin #Basin Description Total Area (SF) Total Area (Acres) (Actual) Cave Tc1 (min) 10-yr i (in/hr) Flow Q10 (cfs) Volume V10 (cf) South Block 5 - Lots 1A, 6A, OSPA 2 57,937 1.33 0.60 105.06 0.445 0.35 2,227 Less RRV (First 0.5") Captured On-Site =1,471 Storage Volume Needed in West Pond =756 North (a)Block 6 - Lots 6A, 7A, OSPA 1A (south half)20,915 0.48 0.68 105.06 0.445 0.15 915 Less RRV (First 0.5") Captured On-Site =612 Storage Volume Needed in West Pond =303 North (b)Block 6 - Lots 6A, 7A, OSPA 1A (north half)19,207 0.44 0.48 105.06 0.445 0.09 588 Less RRV (First 0.5") Captured On-Site =0 Storage Volume Needed in West Pond =588 Total Storage Needed in West Pond =1,647 Total Surplus Storage Provided in West Pond =1,508 1. Tc is the interpolated storm duration resulting in the maximum required pond storage from the 2006 Subdivision Design Report. 𝑖10 =0.64 ⋅𝑇𝑐−.65 Trout Meadows Phase 3 Stormwater Design Calculations Date: 12.16.2022 Subdivision Design 25-yr Flow Comparison Assumed 25-yr Runoff Flow Rate for each site (per the 2006 Subdivision Design Report): Basin #Basin Description Total Area (SF) Total Area (Acres) (Assumed) Cave CCf (Cf = 1.1) Tc1 (min) 25 yr i (in/hr) Flow Q25 (cfs) South Block 5 - Lots 1A, 6A, OSPA 2 57,937 1.33 0.50 0.55 21.59 1.50 1.10 North (a)Block 6 - Lots 6A, 7A, OSPA 1A (south half)20,915 0.48 0.50 0.55 28.05 1.27 0.34 North (b)Block 6 - Lots 6A, 7A, OSPA 1A (north half)19,207 0.44 0.50 0.55 28.05 1.27 0.31 Actual 25-yr Runoff Flow Rate for each site: Basin #Basin Description Total Area (SF) Total Area (Acres) (Actual) Cave CCf (Cf = 1.1) Tc1 (min) 25 yr i (in/hr) Flow Q25 (cfs) South Block 5 - Lots 1A, 6A, OSPA 2 57,937 1.33 0.60 0.66 21.59 1.50 1.31 Q25 after RRV (First 0.5") Capture (see hydrograph) =0.81 North (a)Block 6 - Lots 6A, 7A, OSPA 1A (south half)20,915 0.48 0.68 0.75 28.05 1.27 0.46 Q25 after RRV (First 0.5") Capture (see hydrograph) =0.21 North (b)Block 6 - Lots 6A, 7A, OSPA 1A (north half)19,207 0.44 0.48 0.52 28.05 1.27 0.29 1. Tc is the reported value for 25-yr Drainage Basin Runoff Calculations in the 2006 Subdivision Design Report. 𝑖25 =0.78 ⋅𝑇𝑐 −.64 Hydrology Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Feb 16 2022 South Basin 25-yr Flow Rate after RRV Capture Hydrograph type = Rational Peak discharge (cfs) = 1.365 Storm frequency (yrs) = 25 Time interval (min) = 1 Drainage area (ac) = 1.330 Runoff coeff. (C) = 0.66 Rainfall Inten (in/hr) = 1.555 Tc by User (min) = 22 IDF Curve = BZN IDF.IDF Rec limb factor = 1.00 Hydrograph Volume = 1,801 (cuft); 0.041 (acft) 0 5 10 15 20 25 30 35 40 45 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 Q (cfs) Time (min) Runoff Hydrograph 25-yr frequency Runoff Hyd - Qp = 1.36 (cfs) Q25 = 0.81 after RRV capture = 1,471 CF Hydraflow Express - South Basin 25-yr Flow Rate after RRV Capture - 02/16/22 1 Runoff Hydrograph Outflow Hydrograph Time Q Volume Q (min)(cfs)(cuft)(cfs) 0 0.000 0.00 0.000 1 0.062 1.86 0.000 2 0.124 7.44 0.000 3 0.186 16.75 0.000 4 0.248 29.77 0.000 5 0.310 46.52 0.000 6 0.372 66.99 0.000 7 0.434 91.18 0.000 8 0.496 119.09 0.000 9 0.558 150.73 0.000 10 0.620 186.08 0.000 11 0.682 225.16 0.000 12 0.744 267.96 0.000 13 0.806 314.48 0.000 14 0.868 364.72 0.000 15 0.930 418.69 0.000 16 0.992 476.37 0.000 17 1.054 537.78 0.000 18 1.116 602.91 0.000 19 1.179 671.76 0.000 20 1.241 744.33 0.000 21 1.303 820.62 0.000 22 1.365 900.64 0.000 23 1.303 980.65 0.000 24 1.241 1,057 0.000 25 1.179 1,130 0.000 Hydraflow Express - South Basin 25-yr Flow Rate after RRV Capture - 02/16/22 2 Runoff Hydrograph Outflow Hydrograph Time Q Volume Q (min)(cfs)(cuft)(cfs) 26 1.116 1,198 0.000 27 1.054 1,263 0.000 28 0.992 1,325 0.000 29 0.930 1,383 0.000 30 0.868 1,437 0.000 31 0.806 1,487 0.000 32 0.744 1,533 0.000 33 0.682 1,576 0.000 34 0.620 1,615 0.000 35 0.558 1,651 0.000 36 0.496 1,682 0.000 37 0.434 1,710 0.000 38 0.372 1,734 0.000 39 0.310 1,755 0.000 40 0.248 1,772 0.000 41 0.186 1,785 0.000 42 0.124 1,794 0.000 43 0.062 1,799 0.000 44 0.000 1,801 0.000 Hydrology Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Feb 16 2022 North (a) Basin 25-yr Flow Rate after RRV Capture Hydrograph type = Rational Peak discharge (cfs) = 0.415 Storm frequency (yrs) = 25 Time interval (min) = 1 Drainage area (ac) = 0.460 Runoff coeff. (C) = 0.7 Rainfall Inten (in/hr) = 1.289 Tc by User (min) = 28 IDF Curve = BZN IDF.IDF Rec limb factor = 1.00 Hydrograph Volume = 697 (cuft); 0.016 (acft) 0 10 20 30 40 50 60 Q (cfs) 0.00 0.00 0.05 0.05 0.10 0.10 0.15 0.15 0.20 0.20 0.25 0.25 0.30 0.30 0.35 0.35 0.40 0.40 0.45 0.45 0.50 0.50 Q (cfs) Time (min) Runoff Hydrograph 25-yr frequency Runoff Hyd - Qp = 0.42 (cfs) Q25 = 0.21 after RRV capture = 612 CF Hydraflow Express - North (a) Basin 25-yr Flow Rate after RRV Capture - 02/16/22 1 Runoff Hydrograph Outflow Hydrograph Time Q Volume Q (min)(cfs)(cuft)(cfs) 0 0.000 0.00 0.000 1 0.015 0.44 0.000 2 0.030 1.78 0.000 3 0.044 4.00 0.000 4 0.059 7.12 0.000 5 0.074 11.12 0.000 6 0.089 16.01 0.000 7 0.104 21.79 0.000 8 0.119 28.46 0.000 9 0.133 36.02 0.000 10 0.148 44.48 0.000 11 0.163 53.81 0.000 12 0.178 64.04 0.000 13 0.193 75.16 0.000 14 0.208 87.17 0.000 15 0.222 100.07 0.000 16 0.237 113.86 0.000 17 0.252 128.53 0.000 18 0.267 144.10 0.000 19 0.282 160.56 0.000 20 0.297 177.90 0.000 21 0.311 196.14 0.000 22 0.326 215.26 0.000 23 0.341 235.27 0.000 24 0.356 256.18 0.000 25 0.371 277.97 0.000 Hydraflow Express - North (a) Basin 25-yr Flow Rate after RRV Capture - 02/16/22 2 Runoff Hydrograph Outflow Hydrograph Time Q Volume Q (min)(cfs)(cuft)(cfs) 26 0.385 300.65 0.000 27 0.400 324.22 0.000 28 0.415 348.68 0.000 29 0.400 373.15 0.000 30 0.385 396.72 0.000 31 0.371 419.40 0.000 32 0.356 441.19 0.000 33 0.341 462.10 0.000 34 0.326 482.11 0.000 35 0.311 501.23 0.000 36 0.297 519.47 0.000 37 0.282 536.81 0.000 38 0.267 553.27 0.000 39 0.252 568.84 0.000 40 0.237 583.51 0.000 41 0.222 597.30 0.000 42 0.208 610.20 0.000 43 0.193 622.21 0.000 44 0.178 633.33 0.000 45 0.163 643.55 0.000 46 0.148 652.89 0.000 47 0.133 661.34 0.000 48 0.119 668.91 0.000 49 0.104 675.58 0.000 50 0.089 681.36 0.000 51 0.074 686.25 0.000 Hydraflow Express - North (a) Basin 25-yr Flow Rate after RRV Capture - 02/16/22 3 Runoff Hydrograph Outflow Hydrograph Time Q Volume Q (min)(cfs)(cuft)(cfs) 52 0.059 690.25 0.000 53 0.044 693.37 0.000 54 0.030 695.59 0.000 55 0.015 696.92 0.000 56 0.000 697.37 0.000 Trout Meadows Phase 3 Stormwater Design Calculations Date: 12.16.2022 25-yr Pipe Conveyance Flows 25-Year Flow Calcs: Location Basin Size (Acres)Cave CCf Tc (min) 25 yr i (in/hr) Flow Q25 (cfs) SD Inlet Pipe Valley (12")0.42 0.60 0.66 5 3.83 1.06 SD Inlet Pipe West (12")0.46 0.60 0.66 5 3.83 1.16 SD Pipe to Chambers West (12")2.22 SD Inlet Pipe East (12")0.46 0.60 0.66 5 3.83 1.16 Combined Inlet Flows (Above) = IDF curve equation for 25-yr storm Tc = time to concentration in hours Rational Method Cf = 1.1 for 25-yr eventAiCCQf= 64. 25 78.0 −=cTi Trout Meadows Phase 3 Stormwater Design Calculations Date: 12.16.2022 12" Storm Pipe Capacity Input Values d =1.00 ft =12" y =0.940 ft =94% Calculated Values (Equations from Fluid Mechanics by Chow) Theta (Θ)5.29 rad 2*arccos(1-y/(d/2)) Area (A)0.77 ft2 (1/8)*(Θ-sinΘ)d2 Wetted Perimeter (P)2.65 ft 0.5Θd Hydraulic Radius (R )0.29 ft (.25)*(1-(sinΘ)/Θ)d Top Width (T)0.47 ft (sin 0.5Θ)d Mannings Equation (Equation from Fundamentals of Mechanics by Munson) n =0.013 (per COB Design Standards) S0 =0.0050 ft/ft (0.5% Min. Slope) Q =2.72 cfs Q = 1.49/n*A*R2/3*S00.5 Q =1219.5 gpm Q gpm = (Q cfs)(7.48 gal/ft3)(60 sec/min) V =3.55 ft/s V = Q/A Results A 12" diameter storm pipe flowing 94% full at a min. slope of 0.5% has a carrying capacity of 2.72 cfs. J:\2014\B14-008 Trout Meadows Phase 3\DOCUMENTS\DESIGN REPORT\B14-008 Storm Water Calcs.xls 1 OF 1 Groundwater Monitoring Results South Site Ph3NorthSite Ph3High GWMeasurements:2004: -4.58 (4635.29)2006:-4.11 (4635.76)High GWMeasurements:2004: -2.48 (4637.10)2006: -2.66 (4636.92)High GWMeasurement:2006: -4.43 (4631.79)High GWMeasurements:2004: -5.26 (4627.39)2006: -5.25 (4627.40)TopofCattailLakeDesign = 4621.50 2004 GW Monitoring Data (Morrison Maierle) TABLE 1 Cattail Lake Subdivision Groundwater Monitoring Survey Information TD&H Monitor Well Elevation Top of Pipe Distance to Ground Ground Elevation Old MW#1 4634.13 1.25 4632.88 Old MW#2 4637.65 1.33 4636.32 Old MW#3 4641.37 1.50 4639.87 Old MW#4 4634.85 2.20 4632.65 Old MW#5 4641.37 1.79 4639.58 TP-101 4641.27 2.05 4639.22 TP-102 4637.39 1.69 4635.70 TP-106 4629.95 1.01 4628.94 TP-111 4637.89 1.67 4636.22 Initials MAE JJC MAE MAE Date 6/15/2006 6/26/2006 7/20/2006 8/10/2006 Monitor Well Old MW#1 9.73 Dry Dry Dry GW Elevation 4624.40 n/a n/a n/a bgs 8.48 Dry Dry Dry Old MW#2 8.82 9 9.32 9.71 GW Elevation 4628.83 4628.65 4628.33 4627.94 bgs 7.49 7.67 7.99 8.38 Old MW#3 5.61 5.8 6.07 6.44 GW Elevation 4635.76 4635.57 4635.30 4634.93 bgs 4.11 4.30 4.57 4.94 Old MW#4 7.45 7.7 8.13 8.46 GW Elevation 4627.40 4627.15 4626.72 4626.39 bgs 5.25 5.50 5.93 6.26 Old MW#5 4.45 4.45 4.97 5.35 GW Elevation 4636.92 4636.92 4636.40 4636.02 bgs 2.66 2.66 3.18 3.56 TP-101 6.89 7.2 7.43 7.71 GW Elevation 4634.38 4634.07 4633.84 4633.56 bgs 4.84 5.15 5.38 5.66 TP-102 7.66 7.95 8.46 9 GW Elevation 4629.73 4629.44 4628.93 4628.39 bgs 5.97 6.26 6.77 7.31 TP-106 9 9.7 Dry Dry GW Elevation 4620.95 4620.25 n/a n/a bgs 7.99 8.69 Dry Dry TP-111 6.1 6.2 6.52 6.96 GW Elevation 4631.79 4631.69 4631.37 4630.93 bgs 4.43 4.53 4.85 5.29 File: 502GWData.xls 2006 GW Monitoring Data (TD&H)