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HomeMy WebLinkAboutENG #12 - Drainage Report 06-24-2020Page 1 of 5 Storm Drainage Calculations Bozeman Gateway – Phase 5 June 23, 2020 1 Introduction This summary report provides hydrologic and hydraulic calculations for sizing of detention storage facilities and other storm drainage structures for development of the Bozeman Gateway Phase 5 Lots 1 & 2, in accordance with the City of Bozeman Design Standards. The proposed site consists of a hotel and a fast food restaurant located northwest of the intersection of Fowler Ave. and Technology Blvd West. Pre-development topography is gradual, about 1 to 2 percent slope from south to north. Existing ground cover is undeveloped, previously agricultural fields. The purpose of the report and calculations is to demonstrate the following: - Post- development peak runoff does not exceed pre-construction (historic) conditions for the 10-year storm event - The 25-year peak runoff is conveyed by underground storm drain facility with no surface overflow - Storm water treatment is provided to intercept and contain sediment and floating debris on site, for eventual removal and disposal. 2 Drainage Patterns Existing Conditions – On Site Flows The existing site includes a drainage area of approximately 5.42 acres (236,196 ft2). The pre-development, existing (historic) runoff is illustrated on Figure 1 (Pre-Development Drainage Map). Runoff for Basin H1 drains to the west off the property and is eventually piped north across Huffine. Runoff from H2 drains to the east and is collected in an existing 31”x51” concrete arch pipe (RCPA) storm drain culvert with conveyance north across Huffine. Existing Conditions – Off Site Flows Rosauers and Building F Flows Flows from the Bozeman Gateway Phase 1 development contribute to the offsite flows onto Phase 5 during larger storms. The previously approved drainage submittals for the associated Phase 1 projects are attached and highlighted in Appendix A. - Bozeman Gateway – Phase 1, Block 2 (May 2, 2006) - Bozeman Gateway – Building F Site Plan (June 19, 2014) The Storm Drainage Calculations for Bozeman Gateway Phase 1, Block 2 indicate that runoff from Sub-basins 1.1 and 1.2 is collected at the northwest corner of Phase 1, crossing under Fowler Ave. through a 30” concrete arch pipe (see Figure 3 from Bozeman Gateway – Phase 1, Block 2). These flows are then conveyed north under Huffine Lane by the existing 31”x51” RCPA culvert under Huffine Lane. Additionally, with the construction of Building F, a portion of the Site F flows will drain to a proposed underground detention facility which discharges into an existing storm drain Page 2 of 5 under Technology Boulevard West and through the Rosauers storm drain. Site F runoff bypasses the previously constructed Rosauers detention facilities. The contributing area from Sub-basin D1.3 is shown in Fig 2 of the Bozeman Gateway – Building F Site Plan. The total offsite flows from Bozeman Gateway Phase 1 will be used to evaluate the capacity of the Huffine Culvert during the 25-year storm event. Based on the previously approved storm reports the 25-year flows for Sub-basin 1.1 is 9.21cfs, Sub-basin 1.2 is 12.26cfs and Sub-basin D1.3 is 4.36cfs, for a total 25-year peak runoff of 25.83 cfs. This is a conservatively high estimate because there is a small amount of overlap between Rosauers sub-basin D1.2 and Site F sub-basin D-3. Irrigation Flow There are two existing head gates that convey Farmers Canal irrigation flows north through existing on-site drainage ditches to discharge through the existing 31”x51” RCPA culvert under Huffine Lane. The Montana Bureau of Mines and Geology has monitored the flow in the Farmer’s canal ditch at the location of the head gates from June of 2017 to October 2018. The maximum combined rate that could discharge to the Site A irrigation ditch from these measurements was 21.41cfs on June 2017. This offsite flow rate will be used to conservatively estimate the 25-year conveyance calculations for Site A. Existing Pond The existing pond in Phase 5 has been designed to detain flows from the North portion of Fowler Street. The flows from the outlet structure in this existing pond will be used to evaluate the 25-year conveyance for the Huffine culvert. The 25-year conveyance from Fowler was calculated to be 3.12 cfs; see calculations in Appendix B. Proposed Improvements: The proposed site development is to include a system of storm drainage inlets, sidewalk chases, piping, and subsurface storm water detention systems. Post-development runoff is illustrated on Figure 2 (Post development Drainage Map). Runoff from sub-basins D1, D2.3a, D2.3b and D2.3c cannot be intercepted onsite; these areas drain offsite as direct runoff, similar to existing conditions. Sub-basin D2.1 drains into an underground detention system located in the northern portion of D2.1. Sub-basins D2.2 and D2.4 are treated by an underground detention system located in the southeast portion of sub- basin D2.1. Sub-basins are linked by surface or piped overflow to allow excess runoff to continue downstream without flooding surface improvements. Runoff in excess of detention volumes is routed downstream. To address City of Bozeman development standards, 25-year peak runoff flows offsite via underground piping to the existing culvert underneath Huffine Lane. 3 Approach It will be shown that proposed detention and treatment facilities will limit the post- development 10-year peak runoff rate of Phase 5 to the pre-development rate, and will provide effective treatment of storm runoff. All storm drain pipes have been sized to convey the 25-year peak runoff. Page 3 of 5 The Rational Method was used to calculate peak runoff and detention requirements in accordance with City of Bozeman design standards. The peak runoff table (Appendix B) is an Excel spreadsheet with formulas that calculate post-development discharge values. The values used in each column of the table are as follows: Area: Calculated in AutoCAD from Figures 1 and 2 C (Rational Method runoff coefficient): Runoff coefficients were calculated using 0.20 for pervious areas (pre-development and developed landscape areas) and 0.90 for impervious areas (pavement, concrete and rooftops). Pro-rating by area resulted in the coefficients used in the calculations. Tc (time of concentration) Five minutes is the minimum value used in the Rational Method. Some of the smaller sub-basins would calculate to less than 5 minutes. Peak Runoff Values (Q2 through Q100) Values were calculated using the Rational Method formula (Q = CiA) and the intensity formulas in the City’s design standards (Rainfall Intensity – Duration Curves) 3 Detention For the 10-year design storm, post-development peak flows and detention volumes are estimated using the Rational Method in accordance with City of Bozeman Design Standards. Sub-basins D2.1, D2.2 and D2.4 will drain to “StormTech” pre-fabricated underground storage and infiltration systems. The StormTech system will include an inlet manhole that doubles as access for cleaning the isolator (sediment accumulation) row of the system. Sub-basin D2.1 The detention facility for Sub-basin D2.1 will discharge through a 12” PVC pipe to a control structure housed in a manhole. The detention outlet control structure will consist of a vertical tee with a 1¼” diameter (or a 13/16” square) orifice on the bottom and a 15” diameter vertical riser to pass runoff exceeding the 10-year storage maximum water surface elevation into the piped storm drain system. The top of the overflow riser will be set at elevation level with the top of the 36” storage depth (top of stone backfill). Excess runoff from larger, less frequent storm events will overtop the vertical tee, to the 25-year maximum depth indicated in Table 1. Sub-basin D2.2 and D2.4 The detention facility for the combined sub-basins D2.2 and D2.4 will discharge through a 15-inch pipe. The control structure for this detention facility will consist of a 21” diameter vertical tee with a 1 ¾” diameter (or a 15/8” square) orifice cut into an end cap on the bottom of the tee; the orifice will limit 10-year peak runoff to the required maximum rate. Like Sub-Basin D.2, the top of the vertical tee will act as an overflow riser and will be cut horizontally to an elevation level with the top of the 36” storage depth (top of stone backfill). Page 4 of 5 The control structure and discharge piping for each facility will convey the 25-year peak runoff to the existing culvert that crosses north on Huffine. Detention volume and pipe sizing calculations are attached in Appendix B. Design details will be provided on the construction drawings. 4 Conveyance The storm drain piping system for the proposed development is designed to convey flows from a 25-year storm. See Appendix C for the conveyance calculations for the storm drain pipes and culverts within Phase 5. Huffine Culvert Almost all of Phase 5 along with other offsite flows mentioned in the existing conditions section of this report will drain to the culvert crossing Huffine to the north. If on-site detention effects are ignored in a 25-year storm event, the 25-year peak runoff to the Huffine culvert can be estimated by adding the flow from Basins 2.1, 2.2 and 2.4, direct flow from Phase 5, flow from the farmers canal and the offsite flows from Rosauers, Building F and the existing pond for Fowler Ave: Q25 (Basins 2.1, 2.2 and 2.4) = 3.33 + 6.14 + 1.66 = 11.13cfs Q25 (direct flow – Basins D2.3a + D2.3b + D2.3c) = 0.58 cfs Q25 (Farmers Canal) = 21.41cfs Q25 (offsite flows) = 9.21 + 12.26 + 4.36 + 3.12 = 28.95cfs Q25 (total to Huffine culvert) = 11.13 + 0.58 + 21.41 + 28.95 = 62.07cfs The calculations in Appendix C illustrate that the Huffine culvert can convey the 25-year peak runoff (62.07 cfs) without flooding the site. For the Huffine culvert, the equivalent pipe size of 42” diameter was used to model the 31”x51” arch pipe. In the case of a 100- year storm, stormwater would overtop Huffine Lane on the west side of the property. 5 Storm Water Treatment The City’s design standards require Low Impact Development (LID) practices that infiltrate, evapotranspire or capture runoff, to the extent feasible, for a specified design runoff event. This requirement is addressed using existing and proposed StormTech underground detention and storage facilities. These systems combine infiltration and runoff capture. The StormTech system is a widely accepted LID practice found to remove 80 percent of total suspended solids from municipal storm runoff. It meets LEED criteria for storm water treatment (SS6.2 water quality credit). The facilities for this project provide over 6 inches of capture depth for infiltration and runoff volume reduction, plus treatment of additional runoff by deposition as water slowly travels through the long, linear rows of chambers and gravel base. The system solves the problem of runoff “short-circuiting” from inlet to outlet that is inherent in surface detention ponds. Runoff from the first ½” of rainfall will percolate through and fill a gravel filter before finding its way to a perforated low-flow outlet pipe that discharges into the detention outlet structure. Additional runoff from larger storms can bypass this discharge route, but only after storage depth reaches 2 feet (this correlates to about 64 percent of the total available storage volume). Although the detention calculations assume zero infiltration, the existing alluvial (gravel/pit run) soils directly under the StormTech Page 5 of 5 systems provide excellent infiltration, which further improves treatment. We believe this type of treatment not only meets, but exceeds, the City’s current design standards. 6 Results Summary The proposed detention facilities will treat runoff from sub-basins D2.1, D2.2 and D2.4 under fully developed conditions. These three sub-basins include all of the proposed impervious area except the pedestrian trail along Fowler Avenue. The detention facilities also limit the 10-year maximum release rate from the site, to ensure that the total post-development peak runoff rate does not exceed the pre-development 10-year peak runoff rate in either basin (D1 draining east, or D2 draining north). In basin D1, the 10-year post-development peak runoff rate (sub-basin D1) is 0.03 cfs, which is less than the 0.14 cfs of existing Basin H1. In basin D2, the total 10-year post-development peak runoff from “direct runoff” sub-basins D2.3a, D2.3b and D2.3c (0.48 cfs see Appendix B), plus the total 10-year peak discharge from the two underground facilities (0.23 cfs, see Table 1 below) is 0.71 cfs; this equals the pre-development 10-year peak runoff rate of sub-basin H2. Therefore, the total post-development 10-year peak runoff rate does not exceed the pre-development rate. TABLE 1 - Detention Basin Data Description Detention Basin Name D2.1 D2.2+D2.4 Max. 10-yr Release Rate (cfs) 0.08 0.15 Min. Required Detention Volume (cu. ft.) 2,566 6,785 Sizes and Dimensions: vertical tee (riser) dia., inches 15 21 outlet pipe dia., inches 12 15 Orifice (two alternates): circular orifice dia., inches 11/4 13/4 rectangular (proposed replacement) 13/16 x 13/16 15/8 x 15/8 Elevations: 25-yr WSEL at control structure 38.50 39.75 top of riser (=10-yr max. WSEL) 38.08 39.16 discharge pipe invert at control structure 35.08 36.16 E E E E E FO FO FO FO H10.94 Ac.H24.48 Ac.4840484548364836483748374838483848394841484248434 8 4 448464847 48464847484848494846484 7 48474848 48 4 8306015300SCALE IN FEETFIGURE NUMBER©PROJECT NO.DRAWN BY:DSGN. BY:APPR. BY:DATE:COPYRIGHT MORRISON-MAIERLE, INC.,2020N:\3638\009\ACAD\Site Plans\Building-A\Exhibits\Strom Report Exhibits\3638009 Fig 03 Existing Drainage Basins.dwg Plotted by celine saucier onJun/15/2020engineers surveyors planners scientistsMorrisonMaierle2880 Technology Blvd WestBozeman, MT 59718406.587.0721www.m-m.net3638.009FIG 1BOZEMAN GATEWAY PUD - PHASE 5BOZEMANMONTANAPREDEVELOPMENT DRAINAGE MAPCMSJAUJAU06/2020PRECAST CONCRETEDIVERSION STRUCTUREINV IN = 4843.60INV OUT = 4843.60 (E)INV OUT = 4844.10 (N)6X8" PRECAST CONCRETEVAULT INV IN = 4841.22INV OUT = 4841.12108LF 48"ARCP ARCH PIPEINV IN = 4843.60INV OUT = 4841.22SLOPE 2.20%132 LF OF 72" ARCP W/FLARED END SECTIONSAND TRASH RACKSINV IN = 4844.94INV OUT = 4844.77SLOPE = 0.13%124 LF OF 15" RCP W/FLARED END SECTIONSBOTH SIDESINV IN = 4848.38INV OUT = 4847.15SLOPE = 1.0%180 LF 30" ARCPW/ FLARED END SECTIONWEST SIDEINV IN - 4835.54INV OUT = 4835.00SLOPE = 0.3%106 LF 15" RCPW/ FLARED END SECTIONWEST SIDEINV IN = 4836.31INV OUT = 4835.25SLOPE = 1.0%POND #3 VOL = 1213 CFWATER SURFACE EL = 4836.75TOP OF BANK EL 4837 TO 4837.25POND BOTTOM 4835.25SIDE SLOPE = 3:1EXISTING 31" X 51" ARCP@ 0.74% SLOPE SSSSSSSSSS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS W W W W W W W W W W W W W W W W W W W W W W W W W W W W SSSSSSSSWWWWWWWWWWWWSSSSSSSSSSSSSSSSSSSSSSSSE E E E E FO FO FO FO 12SD12SD12SD12SD12SD12SD 12SD12SD 12SD 12 S D 15SD 15SD 12 S D 12SD15SD 15SD 15SD12SD 12SD 12SD 12SD 12SD 12SDD2.22.04 Ac.D2.11.09 Ac.D2.3b0.81 Ac.D2.3c0.63 Ac.D2.40.54 Ac.D10.20 Ac.D2.3a0.14 Ac.48404845483848384839484148424843484448464847484848414 8 4 0 4 8 4 1 4841484148434844484548464847 4840 4837 4838 4839 4841 4835483448364837483848404838483948414842484348444842484348444845484548434846484448454846484748484 8 4 8484748 47 48 4 8 4848 4847 484948474848484948464847484848464847484848424844 4845 484 3306015300SCALE IN FEETFIGURE NUMBER©PROJECT NO.DRAWN BY:DSGN. BY:APPR. BY:DATE:COPYRIGHT MORRISON-MAIERLE, INC.,2020N:\3638\009\ACAD\Site Plans\Building-A\Exhibits\Strom Report Exhibits\3638009 Fig 04 Postdevelopment Drainage Areas.dwg Plotted by celine saucieron Jun/23/2020engineers surveyors planners scientistsMorrisonMaierle2880 Technology Blvd WestBozeman, MT 59718406.587.0721www.m-m.net3638.009FIG 2BOZEMAN GATEWAY PUD - PHASE 5BOZEMANMONTANAPOSTDEVELOPMENT BASINCMSJAUJAU06/202015" RCP W/ FLARED ENDSECTION WEST SIDEINV IN = 4836.31INV OUT = 4835.25SLOPE = 1.0%EXISTING PONDWATER SURFACE EL: 4836.25POND BOTTOM 4835.25EXISTING 22.5" X 36.25 ARCP79LF 24" CULVERT@ 0.5% SLOPEINV IN: 4843.45INV OUT: 4843.0679.9LF 36" CULVERT@ 2.0% SLOPEINV IN: 4845.93INV OUT: 4844.30CULVERT #155.4LF 30"@ 0.96% SLOPEINV IN: 4841.70INV OUT: 4841.17CULVERT #279.7LF 30"@ 0.60 % SLOPEINV IN: 4840.81INV OUT: 4840.33CULVERT #335.5LF 30"@ 1.27% SLOPEINV IN: 4838.51INV OUT: 4838.06EXISTING 31" X 51" ARCP@ 0.74% SLOPECULVERT #445LF 12"@ 1.82% SLOPEINV IN: 4835.82INV OUT: 4835.00PROPOSED STORM TECHDETENTION SYSTEMPROPOSED STORM TECHDETENTION SYSTEM N0°19'02"W 591.97'R =5 0.00' L=7 8.5 1 'Δ=89 °58'11"S0°00'00"E 267.01'SS S S S S S S SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSWWWWWWWWWWWWWWWWWWSSSSSSWW W W W W W W W W W W SS SS SS SS SS SS SS SS 12 S D 12 S D 12SD12SD12SD12SD 12SD 12SD15SD15SD15SD15SD15SD4838 4839 4841 4839 48414842484 4 48 4 3483948404841 48424841 4840 4841483648374838483948394838483748364835 4834 48364837483848394 8 3 8 4 8 3 9 39.25 38.85 39.67 39.70 39.02 -3 . 5 8% -3.26 % -1. 1 9 %-2.33% 39.60 -2.16 %-2.58%-1.26%-2.16% -1.0 7 % EX TBC 38.51 EX TBC 38.61 EX TBC 38.76 EX TBC 38.84 EX TBC 39.07 EX TBC 39.25 40.03 41.22 41.24 41.33 41.50 41.47 41.43 41.34 41.43 41.27 41.13 40.98 41.07 41.28 40.98 40.67 40.54 41.02 40.91 40.48 41.24 -1.00% -1.00% -1.00% -1.53% -1.69%-0.54%20 4010200 SCALE IN FEET  STORM TECH INFILTRATION DETENTION SYSTEM REQUIRED CHAMBERS: 40 STORAGE VOLUME: 2,716 CF ISOLATOR ROW INV: 35.08 © 2880 Technology Blvd. W. Bozeman, MT 59718 Phone: (406) 587-0721 Fax: (406) 922-6702 SHEET NUMBER PROJECT NUMBER DRAWING NUMBER DRAWN BY: CHK'D. BY: APPR. BY: DATE: Q.A. REVIEW DATE: BY: COPYRIGHT MORRISON-MAIERLE, INC.,2020 VERIFY SCALE! THESE PRINTS MAY BE REDUCED. LINE BELOW MEASURES ONE INCH ON ORIGINAL DRAWING. MODIFY SCALE ACCORDINGLY! REVISIONS DATEDESCRIPTIONNO.BY N:\3638\009\ACAD\Site Plans\Building-A\Sheets\3638.009 C600 Overall Grading Plan.dwg Plotted by celine saucier on Jun/23/2020 engineerssurveyorsplannersscientistsengineerssurveyorsplannersscientists 3638.009 C600 BOZEMAN MONTANA CMS JAU JAU 6/2020 HYATT HOTEL PRELIMINARY GRADING PLAN SITE "A" BOZEMAN GATEWAY PUD SDCB #1 RIM: 38.48 INV OUT (E): 35.48 41LF OF 12" PVC STORM PIPE @ 1.0% SLOPE SDCB #2 RIM: 38.65 INV OUT (SE): 35.65 SDMH #3 RIM: 40.22 INV IN (W): 35.07 INV OUT (N): 35.07 SDMH #1 RIM: 39.38 INV IN (SW): 35.07 INV OUT (E): 34.87 SDCB #3 RIM: 39.25 INV OUT (E): 35.25 SDMH #2 RIM: 4840.46 INV IN (SE): 35.07 INV OUT(W): 34.87 56LF OF 12" PVC STORM PIPE @ 1.0% SLOPE 28LF OF 12" PVC STORM PIPE @ 0.6% SLOPE STORM TECH INFILTRATION DETENTION SYSTEM REQUIRED CHAMBERS: 104 STORAGE VOLUME: 7,074 CF ISOLATOR ROW INV: 36.16' 116LF OF 12" PVC STORM PIPE @ 1.0% SLOPE INV OUT: 35.00' 62.7LF OF 12" PVC STORM PIPE @ 1.7% SLOPE CULVERT #3 35.5LF 30" @ 1.27% SLOPE INV IN: 4838.51 INV OUT: 4838.06 SDMH #5 RIM: 40.44 INV IN (S): 36.16 INV OUT(SE): 36.16 GENERAL NOTES 1.ALL STORM DRAIN MANHOLES SHALL BE 48-INCH DIAMETER, CONSTRUCTED PER CITY OF BOZEMAN STANDARD DETAILS. MANHOLES INDICATING “RIM=” SHALL HAVE SOLID COVERS, THOSE INDICATING “GRATE=” SHALL HAVE SLOTTED (GRATED) COVERS, AND THOSE INDICATING “TBC=” SHALL HAVE CURB INLET TYPE SLOTTED COVERS. 2.SPOT ELEVATIONS ALONG CURB LINES AND SIDEWALK EDGES ARE TOP BACK OF CURB (TBC) AND TOP OF SIDEWALK ELEVATIONS. SUBTRACT 0.50' (SPILL CURB) OR 0.37' (CATCH CURB) TO OBTAIN EDGE OF GUTTER (EG) ELEVATION AT THE ASPHALT/GUTTER LINE. 3.GRADE BREAK LINES (SEE LEGEND): USE STRAIGHT-LINE INTERPOLATION TO DETERMINE FINISHED GRADE ELEVATIONS BETWEEN INDICATED SPOT ELEVATIONS. T CATCH CURB SPILL CURB TRANSITION CURB (T) TOP BACK OF CURB ELEVATIONTBC EDGE OF GUTTER ELEVATIONEG LEGEND GRADE BREAK LINE (SEE NOTE 3) MATCH LINE C601 15" RCP W/ FLARED END SECTION WEST SIDE INV IN = 36.31 INV OUT = 35.25 SLOPE = 1.0% EXISTING POND TO BE RE-ESTABLISHED TOP: 37.25 WATER SURFACE EL: 36.25 POND BOTTOM 35.25 EXISTING 22.5" X 36.25 ARCP GRADING LIMITS GRADING LIMITS EXISTING 132LF OF 31" X 51" ARCP @ 0.74% SLOPE INV IN: 4832.99 INV OUT: 4832.01 CULVERT #4 45LF 12" @ 1.82% SLOPE INV IN: 4835.82 INV OUT: 4835.00 HYATT HOTEL FFE: 4841.5 S83°52'34"W 200.48'S0°18'43"E 196.42'S89°41'43"W 27.21' N0°00'00"E 26.91' N90°00'00"E 25.13' N76°44'45"E 7 0 . 6 0 ' S75°49'16"E 22.12' S52°55'58"W 14.64' S68°31'4 9 " W 5 7 . 9 3 ' N90°00'00"W 28.49'SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSWWWWWWWWWWWWWWWWWWWWWSS SS SS W W W W SS SS SS SS SS W W W W W W SSSSSSSSSSSSSSSSSSSSSSSSSSSSW W W W W W W W W W W W W W W W EEEEEEEFOFOFOFOFOFOFOSSWWWWWWWWWWWWWW W W W W W W W W W W W W W W W WSWSWS15SD 15SD 15SD 15SD 15SD 15SD 15SD 15SD 15SD 12SD15SD15SD15SD12SD12SD15SD 15SD 12SD12SD12SD12SD12SD12SD12SD12SD12SD12SDR=569.01' L=49.86'Δ=5°01'15" -1 .04% -1 .40% -1. 4 0 %-1.15%4842 4843 4844 4845 4846 4847 4848 484748484849 4846 4848 4847 4847 4846 4845 4844 4843 4846 484 8 484 7 4846 4845 48 4 4 484 3 48424842 -0.66%4846 4847 4848 4849 4 8 4 7 484748474847484 8 4846 48464847 4847 4848484848484849 4845 48 4 2 484 3 484 4 4 8 4 5 4 8 4 2 4 8 4 3 4 8 4 4 4 84 6 484 7 4841 4842 4843 4844 -2.31 %-2.47%-3.31%-3.61%-2.67 %-1.76%-2 .3 4%-2.43%-3.49%-3.35%-3.52%-3. 4 3 % -3.52% 40.83 41.66 41.96 42.35 42.66 42.93 45.39 45.63 48.09 47.90 48.44 48.83 47.91 48.29 47.38 47.36 47.17 46.06 45.81 46.39 46.27 46.69 46.79 47.17 46.26 45.95 44.83 45.37 43.40 43.3043.56 43.6944.03 43.75 43.8143.81 43.86 42.3042.31 42.50 42.47 © 2880 Technology Blvd. W. Bozeman, MT 59718 Phone: (406) 587-0721 Fax: (406) 922-6702 SHEET NUMBER PROJECT NUMBER DRAWING NUMBER DRAWN BY: CHK'D. BY: APPR. BY: DATE: Q.A. REVIEW DATE: BY: COPYRIGHT MORRISON-MAIERLE, INC.,2020 VERIFY SCALE! THESE PRINTS MAY BE REDUCED. LINE BELOW MEASURES ONE INCH ON ORIGINAL DRAWING. MODIFY SCALE ACCORDINGLY! REVISIONS DATEDESCRIPTIONNO.BY N:\3638\009\ACAD\Site Plans\Building-A\Sheets\3638.009 C600 Overall Grading Plan.dwg Plotted by celine saucier on Jun/23/2020 engineerssurveyorsplannersscientistsengineerssurveyorsplannersscientists 6421.001 C601 BOZEMAN MONTANA CMS JAU JAU 4/2020 20 4010200 SCALE IN FEET  HYATT HOTEL GRADING PLAN SITE "A" BOZEMAN GATEWAY PUD SDCB #4 RIM: 40.60 INV OUT (S): 38.00 SDCB #6 RIM: 41.93 INV OUT (E): 38.54 57.5LF OF 12" PVC STORM PIPE @ 1.15% SLOPE SDCB #5 RIM: 40.48 INV IN (W/S): 36.62 INV OUT (NE): 36.42 59LF OF 15" PVC STORM PIPE @ 1.15% SLOPE SDMH #7 RIM: 42.53 INV IN (W/E): 37.50 INV OUT (N): 37.30 79LF 24" CULVERT @ 0.5% SLOPE INV IN: 4843.45 INV OUT: 4843.06 SDCB #8 RIM: 4845.89 INV OUT (N): 4842.89 SDCB #9 RIM: 48445.89 INV IN (S): 4842.58 INV OUT (NE): 4842.38 31LF OF 12" RCP STORM PIPE @ 1% SLOPE 120LF OF 12" RCP STORM PIPE @ 1.15% SLOPE SDMH #4 RIM: 4841.63 INV IN (SW): 36.13 INV OUT(N): 35.93 25.5LF OF 15" HDPE STORM PIPE @ 1.15% SLOPE CULVERT #2 79.7LF 30" @ 0.60 % SLOPE INV IN: 4840.81 INV OUT: 4840.33 CULVERT #1 55.4LF 30" @ 0.96% SLOPE INV IN: 4841.70 INV OUT: 4841.17 10' CONCRETE PATH FARMERS CANAL SDCB #10 RIM: 4846.01 INV IN (SW): 4841.97 INV OUT (N): 4841.77 GENERAL NOTES 1.ALL STORM DRAIN MANHOLES SHALL BE 48-INCH DIAMETER, CONSTRUCTED PER CITY OF BOZEMAN STANDARD DETAILS. MANHOLES INDICATING “RIM=” SHALL HAVE SOLID COVERS, THOSE INDICATING “GRATE=” SHALL HAVE SLOTTED (GRATED) COVERS, AND THOSE INDICATING “TBC=” SHALL HAVE CURB INLET TYPE SLOTTED COVERS. 2.SPOT ELEVATIONS ALONG CURB LINES AND SIDEWALK EDGES ARE TOP BACK OF CURB (TBC) AND TOP OF SIDEWALK ELEVATIONS. SUBTRACT 0.50' (SPILL CURB) OR 0.37' (CATCH CURB) TO OBTAIN EDGE OF GUTTER (EG) ELEVATION AT THE ASPHALT/GUTTER LINE. 3.GRADE BREAK LINES (SEE LEGEND): USE STRAIGHT-LINE INTERPOLATION TO DETERMINE FINISHED GRADE ELEVATIONS BETWEEN INDICATED SPOT ELEVATIONS. T CATCH CURB SPILL CURB TRANSITION CURB (T) TOP BACK OF CURB ELEVATIONTBC EDGE OF GUTTER ELEVATIONEG LEGEND GRADE BREAK LINE (SEE NOTE 3) MATCH LINE C600 SDMH #8 RIM: 42.51 INV OUT (N): 38.16 57LF OF 12" PVC STORM PIPE @ 1.15% SLOPE 2'X3' CB RIM: 42.10 INV IN (W/E): 37.88 INV OUT (N): 37.68 16LF OF 12" PVC STORM PIPE @ 1.15% SLOPE PROPOSED DRAINAGE SWALE PROPOSED DRAINAGE SWALE 40.7 LF OF 12" HDPE STORM PIPE @ 1% SLOPE 192.5 LF OF 12" PVC STORM PIPE @ 2.2% SLOPE 79.9LF 36" CULVERT @ 2.0% SLOPE INV IN: 4845.93 INV OUT: 4844.30 GRADING LIMITS 1/4" BELOW TOP OF NEW PAVEMENT SURFACE 3'-0" (MIN) HEAVY DUTY MONUMENT BOX, SIMILAR TO CAIRD ENG. NO. 50608-1 PAVING & GRAVEL AS REQUIRED SEAL JOINT WITH RAM-NEK 8" x 3' ROUND CONCRETE SLAB SLIP HUB TO THREADED ADAPTER THREADED PLUGFROST EXPANSION SLEEVE CLEANOUT PIPE - 4" Ø PVC 45° BEND NON-SHRINK BACKFILL END OF TRENCH VERIFY PIPE SIZE PER PLAN DIMENSIONS END OF LINE CLEANOUT (IF REQUIRED) USE PLUG AS REQUIRED USINGVARIABLE LENGTH SECTIONSAS REQUIRED MANHOLE STEPS AT 16" ON CENTER 24" OPENING FLAT SLAB COVER CUTOUTS ASREQUIRED PRECAST OR POURED-IN-PLACE BASE. POURED-IN-PLACE BASE, MINIMUM CONCRETE THICKNESS BELOW PIPE IS EIGHT INCHES (8"). PRECAST BASE, MINIMUM THICKNESS TO BE SIX INCHES (6"). POURED-IN-PLACE BASE TO EXTEND BEYOND OUTER EDGE OF MANHOLE WALL. NOTES: 1.ALL JOINTS BETWEEN MANHOLE SECTIONS, ADJUSTING RINGS, MANHOLE RING & TOP SECTION, AND AROUND PIPE INTO MANHOLE SHALL BEWATERTIGHT. JOINTING MATERIAL SHALL BE "RAM-NEK" OR APPROVED EQUAL FOR ALL JOINTS EXCEPT BETWEEN PIPE AND MANHOLE WALL. 2.ADJUSTING RINGS AND CASTING SHALL BE CENTERED ON MANHOLE. 3.REMOVE SHIMS AND GROUT ANY GAPS BETWEEN THE CASTING, ADJUSTING RINGS, AND BARREL. REMOVE EXCESS GROUT.4.GROUT ALL LIFTING HOLES IN BARREL. 5.ALL LATERAL PIPES SHALL BE FINISHED FLUSH WITH INNER BARREL WALL. MATCH TOP OF CURB ELEVATION EJIW 7030 SERIES CURB INLET FRAME, GRATE, & CURB HOOD 9" SUMP SD MH #3 - SECTION SCALE: N.T.S. SD MH #5 - SECTION SCALE: N.T.S. © 2880 Technology Blvd. W. Bozeman, MT 59718 Phone: (406) 587-0721 Fax: (406) 922-6702 SHEET NUMBER PROJECT NUMBER DRAWING NUMBER DRAWN BY: CHK'D. BY: APPR. BY: DATE: Q.A. REVIEW DATE: BY: COPYRIGHT MORRISON-MAIERLE, INC.,2020 VERIFY SCALE! THESE PRINTS MAY BE REDUCED. LINE BELOW MEASURES ONE INCH ON ORIGINAL DRAWING. MODIFY SCALE ACCORDINGLY! REVISIONS DATEDESCRIPTIONNO.BY N:\3638\009\ACAD\Site Plans\Building-A\Sheets\3638.009 C700 Site Details.dwg Plotted by celine saucier on Jun/23/2020 engineerssurveyorsplannersscientistsengineerssurveyorsplannersscientists 3638.009 C701 BOZEMAN MONTANA CMS JAU JAU 4/2020 HYATT HOTEL SITE DETAILS SITE "A" BOZEMAN GATEWAY PUD . . . . COMBINATION MANHOLE AND CURB INLET SCALE: NTS 4 APPENDIX A Previously Approved Drainage Submittals Page 1 of 3 Storm Drainage Calculations Bozeman Gateway - Building F Site Plan June 19, 2014 1 Introduction This summary report provides hydrologic and hydraulic calculations for sizing of detention storage facilities and other storm drainage structures for development of the Building F site, including future development of the entire Bozeman Gateway Block 5 bordered by Fowler, Garfield, Technology Boulevard and Harmon Stream Boulevard. The storm drainage collection system will be phased in as development occurs, but all Block 5 detention and treatment facilities will be constructed in this first phase, along with Building F. The site is a retail development located south of the developed Bozeman Gateway, Block 2. Pre-development topography is gradual, about 2 to 3 percent slope from south to north. Existing ground cover is undeveloped, previously agricultural fields. 2 Approach Drainage calculations from the Bozeman Gateway Phase 1 application were used as a reference. Preliminary design has been completed for all of Block 5, and is the basis for post-development runoff calculations. Figure 2 shows the currently proposed site development. Conservatively high values for impervious area are assumed for these areas of future development. Pre-development sub-basin H1.1 (see Figure 1) corresponds to developed sub-basins D1.1 through D1.3, and pre-development sub-basin H2.2 corresponds to developed sub-basins D2.2A and D2.2B. Pre- and post-development drainage maps are attached as Figures 1 and 2. The 10-year peak runoff rates for D1.1 and D1.2 were calculated in the Bozeman Gateway Phase 1 application to be 1.05 and 0.84 cfs respectively; their total (1.89 cfs) was used in the detention calculations for sub-basin D1.3. Sub-basin D1.3 will drain to a proposed underground detention facility; this facility will discharge into the existing storm drain under Technology Boulevard and the Rosauers parking lot. Direct runoff from sub-basin D2.2A (stream “open space” area, primarily undeveloped), combined with discharge from a second underground detention facility proposed for sub-basin D2.2B, will drain to Harmon Stream. In each case, the post-development 10-year peak runoff rate will be limited to the pre-development rate. All storm drain pipes were sized to convey the 25-year peak runoff. 3 Detention Sub-basins D1.3 and D2.2B will drain to two separate “StormTech” pre-fabricated underground storage and infiltration systems. Each will include an inlet manhole that doubles as access for cleaning the isolator (sediment accumulation) row of the system. In a 10-year or smaller storm runoff event, all runoff will be routed through the StormTech system, and will discharge through a control structure. Detention volume and pipe sizing calculations are attached. Design details will be provided on the construction drawings. Page 2 of 3 Sub-Basin D1.3 Detention: Based on the maximum detention release rate of 0.34 cfs, the required minimum detention volume was calculated to be 1,735 cubic feet. The detention outlet control structure will consist of a vertical tee with a 2¾” diameter (or a 25/8” x 2¼” rectangular) orifice on the bottom, and an 18” diameter vertical riser to pass runoff exceeding the 10-year storage maximum water surface elevation into the piped storm drain system. The top of the overflow riser will be set at elevation 48.00, equal to the 10-year maximum water surface elevation of the detention storage facility. The head required to pass the 25-year peak runoff of 4.36 cfs over the riser is 0.47 feet, which is low enough to ensure piped conveyance of the 25-year peak runoff. A 12” PVC discharge pipe is required to convey the 25-year peak runoff to the existing Block 2 collection system. Sub-Basin D2.2B Detention: Based on the maximum detention release rate of 0.39 cfs, the required minimum detention volume was calculated to be 7,367 cubic feet. The detention outlet control structure will consist of a vertical tee with a 215/16” diameter (or a 211/16” x 2½” rectangular) orifice on the bottom, and a 24” diameter vertical riser to pass runoff exceeding the 10-year storage maximum water surface elevation into the piped storm drain system. The top of the overflow riser will be set at elevation 48.70, equal to the 10-year maximum water surface elevation of the detention storage facility. The head required to pass the 25-year peak runoff of 10.57 cfs over the riser is 0.70 feet, which is low enough to ensure piped conveyance of the 25-year peak runoff. An 18” PVC discharge pipe is required to convey the 25-year peak runoff to Harmon Stream. N:\3638\009\Design Docs\Drainage\Building S\Drainage Report.doc Page 3 of 3 Record Id: H1.1 Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Cultivated Soil w/ residue cover (s<=20%).: 0.06 150.00 ft 1.70% 0.0600 1.20 in 11.35 min Shallow Fallow or minimum tillage cultivation (n=0.04) 460.00 ft 1.60% 0.0400 7.55 min Channel (interm) Grassed (n=0.030) 160.00 ft 2.50% 0.0300 0.99 min Channel (interm) Grassed (n=0.030) 300.00 ft 0.30% 0.0300 5.37 min Pervious TC 25.27 min Record Id: H2.2 TC Calc Type Description Length Slope Coeff Misc TT Sheet Short prairie grass and lawns.: 0.15 60.00 ft 1.70% 0.1500 1.20 in 11.35 min Shallow Short grass, pasture and lawns (n=0.030) 230.00 ft 1.30% 0.0300 3.14 min Channel (interm) Grassed (n=0.030) 360.00 ft 1.70% 0.0300 2.71 min Channel (interm) Grassed (n=0.030) 440.00 ft 0.60% 0.0300 5.57 min Pervious TC 22.77 min Record Id: D2.2A TC Calc Type Description Length Slope Coeff Misc TT Sheet Short prairie grass and lawns.: 0.15 60.00 ft 1.80% 0.1500 1.20 in 11.09 min Shallow Short grass, pasture and lawns (n=0.030) 130.00 ft 1.90% 0.0300 1.47 min Channel (interm) Grassed (n=0.030) 680.00 ft 1.70% 0.0300 5.12 min Pervious TC 17.68 min Record Id: H2.2B TC Calc Type Description Length Slope Coeff Misc TT Sheet Short prairie grass and lawns.: 0.15 29.00 ft 8.70% 0.1500 1.20 in 3.30 min Shallow asphalt 100.00 ft 2.60% 0.0130 0.42 min Channel (interm) pipe 520.00 ft 0.90% 0.0110 1.97 min Pervious TC 5.69 min Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Roughness Coefficient 0.011 Channel Slope 1.20 % Diameter 12 in Discharge 4.21 ft³/s Results Normal Depth 0.75 ft Flow Area 0.63 ft² Wetted Perimeter 2.10 ft Hydraulic Radius 0.30 ft Top Width 0.86 ft Critical Depth 0.87 ft Percent Full 75.1 % Critical Slope 0.00919 ft/ft Velocity 6.66 ft/s Velocity Head 0.69 ft Specific Energy 1.44 ft Froude Number 1.37 Maximum Discharge 4.96 ft³/s Discharge Full 4.61 ft³/s Slope Full 0.01000 ft/ft Flow Type SuperCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 75.09 % Downstream Velocity Infinity ft/s D1.3, 25-yr discharge 6/19/2014 3:38:07 PM Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of1Page Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Roughness Coefficient 0.011 Channel Slope 0.80 % Diameter 18 in Discharge 10.57 ft³/s Results Normal Depth 1.17 ft Flow Area 1.48 ft² Wetted Perimeter 3.25 ft Hydraulic Radius 0.46 ft Top Width 1.24 ft Critical Depth 1.25 ft Percent Full 78.0 % Critical Slope 0.00705 ft/ft Velocity 7.15 ft/s Velocity Head 0.79 ft Specific Energy 1.96 ft Froude Number 1.16 Maximum Discharge 11.94 ft³/s Discharge Full 11.10 ft³/s Slope Full 0.00725 ft/ft Flow Type SuperCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 77.96 % Downstream Velocity Infinity ft/s D2.2B, 25-yr discharge 6/19/2014 3:40:58 PM Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of1Page PRE-DEVELOPMENT DRAINAGE MAPBOZEMAN GATEWAYBUILDING "F" SITE PLAN / BLOCK 5 BOZEMAN GATEWAYFIGURE NUMBERˆPROJECT NO.DRAWN BY:CHK'D. BY:APPR. BY:DATE:COPYRIGHT MORRISON-MAIERLE, INC.,20142880 Technology Blvd. W.Bozeman MT 59771Phone: (406) 587-0721Fax: (406) 922-6703N:\3638\009\ACAD\Exhibits\ROSAUERS STORM DRAIN DRAINAGE BASINS.dwg Plotted by cody farley on Jun/19/20143638.009FIG. 1BOZEMANMONTANACJFMGHMGH06/2014LEGEND POST-DEVELOPMENT DRAINAGE MAPFIGURE NUMBERˆPROJECT NO.DRAWN BY:CHK'D. BY:APPR. BY:DATE:COPYRIGHT MORRISON-MAIERLE, INC.,20142880 Technology Blvd. W.Bozeman MT 59771Phone: (406) 587-0721Fax: (406) 922-6703N:\3638\009\ACAD\Exhibits\ROSAUERS STORM DRAIN DRAINAGE BASINS.dwg Plotted by cody farley on Jun/19/20143638.009FIG. 2BOZEMANMONTANACJFMGHMGH06/2014BOZEMAN GATEWAY BUILDING "F" SITE PLAN / BLOCK 5 BOZEMAN GATEWAYLEGENDSD APPENDIX B Stormwater Calculations Site A - Hyatt Hotel Peak Runoff Calculations MODIFIED RATIONAL METHOD i = A * (Tc/60) B Qp = C i A Qp = peak runoff, cfs Design Coefficients C = runoff coefficient Storm A B i = A(Tc/60)B (Bozeman IDF curve)2-yr 0.36 -0.60 Tc = time of concentration, minutes 5-yr 0.52 -0.64 A = Area, acres 10-yr 0.64 -0.65 25-yr 0.78 -0.64 50-yr 0.92 -0.66 Retention Volume = 7,200*(C)*(i)*(A), where i = 0.41 in./hr 100-yr 1.01 -0.67 (Bozeman Design Standards, March 2004) Retention Sub-Basin Name Area C Tc Q2 Q5 Q10 Q25 Q50 Q100 Volume (ft.3) H1 0.94 0.20 50.00 0.08 0.11 0.14 0.17 0.20 0.22 H2 4.48 0.20 43.00 0.39 0.58 0.71 0.87 1.03 1.13 D1.1 (direct offsite) 0.20 0.20 50.00 0.02 0.02 0.03 0.04 0.04 0.05 D2.1 (det.) 1.09 0.80 5.00 1.39 2.22 2.80 3.33 4.13 4.64 2,568 D2.2 (det.) 2.04 0.79 5.00 2.57 4.10 5.17 6.14 7.62 8.57 4,740 D2.3a (direct) 0.14 0.29 9.22 0.04 0.07 0.09 0.11 0.13 0.14 120 D2.3b (direct) 0.81 0.28 11.50 0.22 0.34 0.43 0.51 0.62 0.70 673 D2.3c (direct) 0.63 0.29 16.60 0.14 0.21 0.26 0.32 0.38 0.43 527 D2.3a+D2.3b+D2.3c (direct) 1.57 0.28 26.90 0.26 0.39 0.48 0.58 0.70 0.77 1,321 D2.4 (det.) 0.54 0.80 5.00 0.69 1.11 1.40 1.66 2.06 2.32 1,281 D2.2 (det.) + D2.4 (det.) 2.59 0.79 5.00 3.26 5.20 6.56 7.80 9.67 10.89 6,021 Existing Pond Fowler 1.02 0.8 5 1.30467 2.08 2.63 3.12 3.87 4.36 2,409 Site A - Hyatt Hotel Sub-Basin 2.1 (ST1) Detention (10-yr storm) MODIFIED RATIONAL METHOD Qp = C i A POST-DEVELOPMENT PRE-DEVEL. 1.09 AC Qp (Basin H1) = 0.71 cfs Direct Runoff (Basin D2.3) = -0.48 cfs 0.80 0.23 5.0 MIN D2.1 release rate = 0.08 cfs 3.22 IN/HR TIME STEP 2.80 CFS DURATION = 5.0 min. Max. Volume, Max. Volume,Required Detention Triangle Rel. (cu. ft.) Constant Rel. (cu. ft.)Volume (cu. ft.) 3044.27 2088.66 2,566 Triangle Release Constant Release DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 4.75 3.33 2.89 802 779 9.75 2.09 1.81 1,026 991 14.75 1.59 1.39 1,179 1,133 19.75 1.32 1.15 1,299 1,241 ORIFICE CALCULATIONS 24.75 1.14 0.99 1,399 1,329 MATCHING Qp = 0.08 cfs 29.75 1.01 0.88 1,485 1,403 Max. Depth = 3.00 ft 34.75 0.91 0.79 1,560 1,467 39.75 0.84 0.73 1,628 1,523 44.75 0.77 0.67 1,689 1,573 49.75 0.72 0.63 1,746 1,617 CIRCULAR ORIFICE: 54.75 0.68 0.59 1,798 1,658 DIAMETER = 1.2500 inches 59.75 0.64 0.56 1,846 1,694 Area = 0.01 ft2 64.75 0.61 0.53 1,891 1,727 ORIFICE FLOW = 0.07 CFS 69.75 0.58 0.50 1,933 1,758 74.75 0.55 0.48 1,973 1,786 79.75 0.53 0.46 2,011 1,812 RECTANGULAR ORIFICE: 84.75 0.51 0.44 2,047 1,835 LENGTH = 1.188 inches 89.75 0.49 0.43 2,080 1,857 WIDTH = 1.188 inches 94.75 0.48 0.41 2,113 1,878 Area = 0.01 ft2 99.75 0.46 0.40 2,143 1,897 ORIFICE FLOW = 0.08 CFS 104.75 0.45 0.39 2,173 1,914 109.75 0.43 0.38 2,201 1,930 114.75 0.42 0.37 2,228 1,945 119.75 0.41 0.36 2,253 1,959 124.75 0.40 0.35 2,278 1,972 WEIR CALCULATIONS (not used) 129.75 0.39 0.34 2,302 1,984 Coefficient = 3.33 inches 134.75 0.38 0.33 2,325 1,996 Width = 0.1875 inches 139.75 0.37 0.32 2,347 2,006 WEIR FLOW = 0.27 CFS 144.75 0.36 0.31 2,369 2,015 POST-DEV Qp = POND VOLUME CALCULATIONS: BASIN AREA POST = POST-DEV Tc = POST-DEV C = STORM INTENSITY = Site A - Hyatt Hotel Sub-Basin 2.1 (ST1) Storage Calculations (10-yr storm) StormTech Sizing Calculations Required Storage Volume 2,566 ft3 StormTech Modules, Model No. SC740 (30" chamber height) Depth to top of gravel 36 in. installed storage volume 68.14 ft3 per chamber (see note 1) Number of chambers required 38 37.66 before rounding excess storage volume 0.9 % Number of chambers proposed 40 excess storage volume 5.8 % equal to (see note 2) 150 ft3 excess storage volume Installed chamber footprint (per chamber) = 5' x 7.12' Note: add 2' min. to each row, for end caps Storage Volume Provided = 2,716 ft3 Notes: 1. Storage volume assumes 6" of stone above and between chambers, and 40% stone porosity. Site A - Hyatt Hotel Sub-Basin D2.2+D2.4 (ST2) Detention (10-yr storm) MODIFIED RATIONAL METHOD Qp = C i A POST-DEVELOPMENT PRE-DEVEL. 2.59 AC Qp (Basin H2) = 0.71 cfs Direct Runoff (Basin D2.3) = -0.48 cfs 0.79 Release Rate (Basin 2.1) = -0.08 cfs 5.0 MIN D2.2 release rate = 0.15 cfs 3.22 IN/HR TIME STEP 6.56 CFS DURATION = 5.0 min. Max. Volume, Max. Volume,Required Detention Triangle Rel. (cu. ft.) Constant Rel. (cu. ft.)Volume (cu. ft.) 8044.62 5524.96 6,785 Triangle Release Constant Release DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 4.75 3.33 6.79 1,890 1,847 9.75 2.09 4.25 2,421 2,356 14.75 1.59 3.25 2,786 2,699 19.75 1.32 2.69 3,073 2,964 ORIFICE CALCULATIONS 24.75 1.14 2.32 3,312 3,181 MATCHING Qp = 0.15 cfs 29.75 1.01 2.06 3,519 3,366 Max. Depth = 3.00 ft 34.75 0.91 1.86 3,702 3,526 39.75 0.84 1.71 3,866 3,668 44.75 0.77 1.58 4,016 3,796 49.75 0.72 1.47 4,154 3,911 CIRCULAR ORIFICE: 54.75 0.68 1.39 4,281 4,016 DIAMETER = 1.750 inches 59.75 0.64 1.31 4,400 4,113 Area = 0.02 ft2 64.75 0.61 1.24 4,511 4,202 ORIFICE FLOW = 0.14 CFS 69.75 0.58 1.18 4,616 4,284 74.75 0.55 1.13 4,715 4,361 79.75 0.53 1.08 4,809 4,432 RECTANGULAR ORIFICE: 84.75 0.51 1.04 4,898 4,499 LENGTH = 1.625 inches 89.75 0.49 1.00 4,983 4,562 WIDTH = 1.625 inches 94.75 0.48 0.97 5,064 4,620 Area = 0.02 ft2 99.75 0.46 0.94 5,141 4,676 ORIFICE FLOW = 0.15 CFS 104.75 0.45 0.91 5,216 4,728 109.75 0.43 0.88 5,287 4,777 114.75 0.42 0.86 5,356 4,823 WEIR CALCULATIONS (not used) 119.75 0.41 0.83 5,422 4,867 Coefficient = 3.33 inches 124.75 0.40 0.81 5,485 4,908 Width = 0.5000 inches 129.75 0.39 0.79 5,547 4,947 WEIR FLOW = 0.72 CFS 134.75 0.38 0.77 5,606 4,984 POND VOLUME CALCULATIONS: BASIN AREA POST = POST-DEV C = POST-DEV Tc = STORM INTENSITY = POST-DEV Qp = Site A - Hyatt Hotel Sub-Basin D2.2+D2.4 (ST2) Storage Calculations (10-yr storm) StormTech Sizing Calculations Total required storage 6,785 ft3 Subtract surface retention 0 Required Storage Volume 6,785 ft3 StormTech Modules, Model No. SC740 (30" chamber height) Depth to top of gravel 36 in. installed storage volume 68.14 ft3 per chamber (see note 1) Number of chambers required 100 99.57 before rounding excess storage volume 0.4 % Number of chambers proposed 104 excess storage volume 4.3 % equal to (see note 2) 289 ft3 excess storage volume Installed chamber footprint (per chamber) = 5' x 7.12' Note: add 2' min. to each row, for end caps Storage Volume Provided = 7,074 ft3 Notes: 1. Storage volume assumes 6" of stone above and between chambers, and 40% stone porosity. APPENDIX C Conveyance Calculations Site A - Hyatt Hotel Conveyance Calculations (25-yr storm) MODIFIED RATIONAL METHOD Qp = C i A Qp = 25-yr peak runoff, cfs C = runoff coefficient i = 0.78(Tc/60)-0.64 (Bozeman IDF curve) Tc = time of concentration, minutes A = Area, acres Basin Name Area1 C Tc Qpipe-25 yr 2 Pipe Dia.3 Pipe Slope Capacity Pipe Flow D2.1 1.09 0.80 5.00 3.33 12"1.0% 4.145 D2.4 0.54 0.80 5.00 1.66 12"1.0% 4.145 D2.2 + D2.4 (det.) 2.59 0.79 5.00 7.80 15"1.15% 8.07 Basin Name Area1 C Tc Qpipe-25 yr 2 Pipe Dia.3 Pipe Slope Culvert Flow Famers Canal Flow 21.41 #4 D2.3a 0.14 0.29 9.22 0.11 12"0.50% D2.3c 0.63 0.29 16.60 0.32 #1/#2 D2.3c + Farmers Canal Flow 21.73 30"0.96% D2.3b 0.81 0.28 11.50 0.51 #3 D2.3c + D2.3b + Farmers Canal 22.24 30"0.60% Offsite Flow Rosauers and Building F 25.83 Existing Pond 3.12 Existing Huffine Culvert 62.07 42"0.74% FOOTNOTES: 1. Contributing drainage area (conservatively high in some cases) 2. Qpipe is the total 25-year peak runoff (direct surface runoff plus flows from upstream pipes) to the pipe draining the indicated structure/flow entry point. Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Tuesday, Jun 23 2020 Det 2.1 / D2.4 Circular Diameter (ft) = 1.00 Invert Elev (ft) = 100.00 Slope (%) = 1.00 N-Value = 0.012 Calculations Compute by: Q vs Depth No. Increments = 20 Highlighted Depth (ft) = 0.95 Q (cfs) = 4.145 Area (sqft) = 0.77 Velocity (ft/s) = 5.37 Wetted Perim (ft) = 2.70 Crit Depth, Yc (ft) = 0.86 Top Width (ft) = 0.43 EGL (ft) = 1.40 0 1 2 3 Elev (ft)Depth (ft)Section 99.50 -0.50 100.00 0.00 100.50 0.50 101.00 1.00 101.50 1.50 102.00 2.00 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Tuesday, Jun 23 2020 Det 2.2 + D2.4 Circular Diameter (ft) = 1.25 Invert Elev (ft) = 100.00 Slope (%) = 1.15 N-Value = 0.012 Calculations Compute by: Q vs Depth No. Increments = 50 Highlighted Depth (ft) = 1.17 Q (cfs) = 8.070 Area (sqft) = 1.20 Velocity (ft/s) = 6.74 Wetted Perim (ft) = 3.31 Crit Depth, Yc (ft) = 1.12 Top Width (ft) = 0.59 EGL (ft) = 1.88 0 1 2 3 Elev (ft)Section 99.50 100.00 100.50 101.00 101.50 102.00 Reach (ft) Culvert Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Friday, Jun 12 2020 Culvert #1 - 25 year storm Invert Elev Dn (ft) = 4841.17 Pipe Length (ft) = 55.40 Slope (%) = 0.96 Invert Elev Up (ft) = 4841.70 Rise (in) = 30.0 Shape = Circular Span (in) = 30.0 No. Barrels = 1 n-Value = 0.012 Culvert Type = Circular Concrete Culvert Entrance = Square edge w/headwall (C) Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 Embankment Top Elevation (ft) = 4846.19 Top Width (ft) = 10.00 Crest Width (ft) = 100.00 Calculations Qmin (cfs) = 0.00 Qmax (cfs) = 21.73 Tailwater Elev (ft) = (dc+D)/2 Highlighted Qtotal (cfs) = 21.73 Qpipe (cfs) = 21.73 Qovertop (cfs) = 0.00 Veloc Dn (ft/s) = 5.06 Veloc Up (ft/s) = 6.63 HGL Dn (ft) = 4843.21 HGL Up (ft) = 4843.28 Hw Elev (ft) = 4844.15 Hw/D (ft) = 0.98 Flow Regime = Inlet Control Culvert Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Friday, Jun 12 2020 Culvert #2 - 25 year storm Invert Elev Dn (ft) = 4840.33 Pipe Length (ft) = 79.70 Slope (%) = 0.60 Invert Elev Up (ft) = 4840.81 Rise (in) = 30.0 Shape = Circular Span (in) = 30.0 No. Barrels = 1 n-Value = 0.012 Culvert Type = Circular Concrete Culvert Entrance = Square edge w/headwall (C) Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 Embankment Top Elevation (ft) = 4845.45 Top Width (ft) = 35.00 Crest Width (ft) = 100.00 Calculations Qmin (cfs) = 0.00 Qmax (cfs) = 21.73 Tailwater Elev (ft) = (dc+D)/2 Highlighted Qtotal (cfs) = 21.73 Qpipe (cfs) = 21.73 Qovertop (cfs) = 0.00 Veloc Dn (ft/s) = 5.06 Veloc Up (ft/s) = 6.60 HGL Dn (ft) = 4842.37 HGL Up (ft) = 4842.40 Hw Elev (ft) = 4843.26 Hw/D (ft) = 0.98 Flow Regime = Inlet Control Culvert Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Friday, Jun 12 2020 Culvert #3 - 25 year storm Invert Elev Dn (ft) = 4838.06 Pipe Length (ft) = 35.50 Slope (%) = 1.27 Invert Elev Up (ft) = 4838.51 Rise (in) = 30.0 Shape = Circular Span (in) = 30.0 No. Barrels = 1 n-Value = 0.012 Culvert Type = Circular Concrete Culvert Entrance = Square edge w/headwall (C) Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 Embankment Top Elevation (ft) = 4842.06 Top Width (ft) = 10.00 Crest Width (ft) = 100.00 Calculations Qmin (cfs) = 0.00 Qmax (cfs) = 22.24 Tailwater Elev (ft) = (dc+D)/2 Highlighted Qtotal (cfs) = 22.24 Qpipe (cfs) = 22.24 Qovertop (cfs) = 0.00 Veloc Dn (ft/s) = 5.16 Veloc Up (ft/s) = 6.69 HGL Dn (ft) = 4840.11 HGL Up (ft) = 4840.11 Hw Elev (ft) = 4840.99 Hw/D (ft) = 0.99 Flow Regime = Inlet Control Culvert Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Friday, Jun 12 2020 Culvert #4 - 25 year storm Invert Elev Dn (ft) = 4835.00 Pipe Length (ft) = 45.00 Slope (%) = 1.82 Invert Elev Up (ft) = 4835.82 Rise (in) = 12.0 Shape = Circular Span (in) = 12.0 No. Barrels = 1 n-Value = 0.012 Culvert Type = Circular Concrete Culvert Entrance = Square edge w/headwall (C) Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 Embankment Top Elevation (ft) = 4839.05 Top Width (ft) = 10.00 Crest Width (ft) = 100.00 Calculations Qmin (cfs) = 0.00 Qmax (cfs) = 0.11 Tailwater Elev (ft) = (dc+D)/2 Highlighted Qtotal (cfs) = 0.11 Qpipe (cfs) = 0.11 Qovertop (cfs) = 0.00 Veloc Dn (ft/s) = 0.24 Veloc Up (ft/s) = 1.73 HGL Dn (ft) = 4835.57 HGL Up (ft) = 4835.96 Hw Elev (ft) = 4835.99 Hw/D (ft) = 0.17 Flow Regime = Inlet Control Culvert Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Monday, Jun 15 2020 Existing Huffine Culvert - 10yr Storm Invert Elev Dn (ft) = 4832.01 Pipe Length (ft) = 131.76 Slope (%) = 0.74 Invert Elev Up (ft) = 4832.99 Rise (in) = 42.0 Shape = Circular Span (in) = 42.0 No. Barrels = 1 n-Value = 0.012 Culvert Type = Circular Concrete Culvert Entrance = Square edge w/headwall (C) Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 Embankment Top Elevation (ft) = 4838.48 Top Width (ft) = 10.00 Crest Width (ft) = 100.00 Calculations Qmin (cfs) = 0.00 Qmax (cfs) = 42.69 Tailwater Elev (ft) = (dc+D)/2 Highlighted Qtotal (cfs) = 42.69 Qpipe (cfs) = 42.69 Qovertop (cfs) = 0.00 Veloc Dn (ft/s) = 5.23 Veloc Up (ft/s) = 7.36 HGL Dn (ft) = 4834.78 HGL Up (ft) = 4835.02 Hw Elev (ft) = 4836.05 Hw/D (ft) = 0.87 Flow Regime = Inlet Control Culvert Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Tuesday, Jun 23 2020 Existing Huffine Culvert - 25yr Storm Invert Elev Dn (ft) = 4832.01 Pipe Length (ft) = 131.76 Slope (%) = 0.74 Invert Elev Up (ft) = 4832.99 Rise (in) = 42.0 Shape = Circular Span (in) = 42.0 No. Barrels = 1 n-Value = 0.012 Culvert Type = Circular Concrete Culvert Entrance = Square edge w/headwall (C) Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 Embankment Top Elevation (ft) = 4838.48 Top Width (ft) = 10.00 Crest Width (ft) = 100.00 Calculations Qmin (cfs) = 0.00 Qmax (cfs) = 62.07 Tailwater Elev (ft) = (dc+D)/2 Highlighted Qtotal (cfs) = 62.07 Qpipe (cfs) = 62.07 Qovertop (cfs) = 0.00 Veloc Dn (ft/s) = 7.10 Veloc Up (ft/s) = 8.56 HGL Dn (ft) = 4834.99 HGL Up (ft) = 4835.46 Hw Elev (ft) = 4836.99 Hw/D (ft) = 1.14 Flow Regime = Inlet Control