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HomeMy WebLinkAbout207 Storm ReportNorton Ranch Lift Station – Stormwater Report Page 2 P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Stormwater\NortonRanch-StormMemo_20250206.docx conveyed to Basin D1.3C the Lakes at Valley West Phase 6 per the attached approved storm drainage report and its addendum (Attachments H and I). The Lakes Storm Reports indicates that treatment for the existing basin is provided using a Stormtech® underground detention storage facility (Facility D1.3C) prior to discharging into the East Lake, and that the facility was originally designed with 168 ft3 of excess storage volume. Proposed Lift Station Stormwater Discharge The lift station property is 0.157 acres in total area. As indicated previously, a large portion of storm drainage from this site is currently conveyed to Lakes at Valley West Phase 6 Stormwater Basin D1.3C based on the existing contours. The attached Lakes Storm Report Addendum indicates that the D1.3C basin is currently 1.95 acres with a rational coefficient of 0.51. Adding the Lift Station property to Basin D1.3C would increase its size to 2.11 acres. Since this total area is less than 5 acres, the modified rational method is applicable for stormwater calculations. Maps and figures showing the location of the lift station site, the proposed post-development surfacing, the proposed grading plan, and the redefined boundary of stormwater basin D1.3C can be found in Attachments A-E. Lift Station Rational Coefficient Calculation The proposed configuration of the lift station site includes the following cover breakdown: •36.2% Impervious Surfaces (Building and Access Driveway) o Area = 2,485.98 ft2 o Rational Coefficient = 0.95 •9.2% Gravel o Area = 630.26 ft2 o Rational Coefficient = 0.70 •54.6% Native Grass o Area = 3,733.86 ft2 o Rational Coefficient = 0.20 The combined rational coefficient for the lift station site is calculated as follows: CLiftStation = (0.95 * 2485.98) + (0.70 * 630.26) + (0.20 * 3733.86) / 6850.10 CLiftStation = 0.52 Norton Ranch Lift Station – Stormwater Report Page 3 P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Stormwater\NortonRanch-StormMemo_20250206.docx Updated Basin D1.3C Calculations To add the lift station site into Basin D1.3C, we need to re-calculate the combined coefficient. This is calculated as follows: CD1.3C-NEW = (1.95 * 0.51) + (0.157 * 0.52) / 2.11 CD1.3C-NEW = 0.511 The post-development time of concentration for this basin was maintained at 5 minutes to be conservative and estimate the highest flow rate and detention volume required. The detention calculations for treatment structure D1.3C in the Lakes Storm Report Addendum were performed using the modified Rational Method and considered a release rate of 0.59 cfs using a circular orifice of 3 9/16 inches (or rectangular orifice of 3 5/16 x 3 inches) based on the pre-development basin discharge. Since the pre-development basin was increased in size by adding the lift station site, the allowable release rate from the pre-development basin was revised to 0.63 cfs. To permit the release of 0.63 cfs, the existing outlet structure will need to be modified to provide a circular orifice with a diameter of 3 11/16 inches or a rectangular orifice of 3 9/16 x 3 inches. The detention calculations were updated using the updated peak flow calculations for both pre- and post-development using the values above. Based on the revised calculations, the excess storage of the existing facility is adequate to accommodate the additional design flow generated by the lift station site, while maintaining 19.3 cubic feet of excess storage volume (see Attachment F). The impacts to gutter flow and inlet capture were evaluated to ensure that no deleterious downstream effects would be created. Based on the updated calculations, the effect on gutter spread is minimal and falls within current limits (Attachment G). Norton Ranch Lift Station – Stormwater Report Page 4 P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Stormwater\NortonRanch-StormMemo_20250206.docx TABLE 1: DETENTION BASIN DATA Detention Basin Name Description DET 1.3C DET 1.3C (as-built)(proposed)* Area (acres) * 1.95 2.11 Rational Coefficient*0.51 0.511 Max. 10-yr Release Rate (cfs)*0.59 0.63 10-yr Detention Volume (cu. ft.)*984 1,071 Sizes and Dimensions: vertical tee (riser) dia., inches 15 15 outlet pipe dia., inches 12 12 overflow weir length, ft.-- Orifice (two alternates): circular orifice dia., inches*39/16 311/16 rectangular orifice, inches*3 x 35/16 3 x 39/16 Elevations: 25-yr WSEL at control structure 54.8 54.8 top of riser (=10-yr max. WSEL)54.4 54.4 discharge pipe invert at control structure 51.3 51.3 Notes: As-built conditions indicate those specified in the Addendum to the Lakes Storm Report (Attachment I). *The proposed revisions to Facility D1.3C are indicated in italics and are not as-built values. Replace or modify the existing 10-year orifice for each of these structures to one of the two indicated alternates. Conclusion Treatment of stormwater runoff from the Norton Ranch Lift Station site can be accommodated using the existing stormwater treatment structure D1.3C of the Lakes at Valley West by modifying the 10-yr orifice outlet as indicated above. Norton Ranch Lift Station – Stormwater Report Page 5 P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Stormwater\NortonRanch-StormMemo_20250206.docx Attachments Attachment A Vicinity Map Attachment B Lift Station Post-Development Map Attachment C Lift Station Grading Plan Attachment D Lakes at Valley West – Updated Basin 1.3C Drainage Basin Figure Attachment E Laurel Parkway Subbasin Additions Figure Attachment F Revised Peak Runoff and Detention Calculations Attachment G Revised Gutter Flow, Inlet, and Pipe Flow Calculations Attachment H Original Storm Drainage Report for the Lakes at Valley West, Phases 5 and 6 (Dated 5-25-18) Attachment I Addendum to Storm Drainage Report for the Lakes at Valley West, Phases 5 and 6 (Dated 4-9-21) A P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Stormwater\NortonRanch-StormMemo_20250206.docx ATTACHMENT A VICINITY MAP G IS S P SS E FM © PROJECT NO. FIGURE NUMBER COPYRIGHT MORRISON-MAIERLE,2025 P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\ACAD\Exhibits\VicinityMap\10678-001_VicinityMap-Storm.dwg Plotted by lee hageman on Feb/6/2025 DRAWN BY: DSGN. BY: APPR. BY: DATE:engineers surveyors planners scientists MorrisonMaierle 2880 Technology Blvd West Bozeman, MT 59718 406.587.0721 www.m-m.net 10678.001 FIG-1 NORTON RANCH LIFT STATION UPGRADES VICINITY MAP BOZEMAN MONTANA LRH LRH MEE 02/2025 500 1,0000 SCALE IN FEET LIFT STATION PROPERTY DURSTON RD N COTTONWOOD RDW BABCOCK STLAUREL PKWYHUFFINE LN W OAK ST LAKES AT VALLEY WEST (PH 6) B P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Stormwater\NortonRanch-StormMemo_20250206.docx ATTACHMENT B LIFT STATION POST-DEVELOPMENT MAP S2°11'57"W 54.99'S89°31'21"W 117.30' S87°48'03"E 120.00'N0°28'39"W 60.54'EEEE 8S15S 15S 15S 15S 15SSSE WWWW15S15S15SBPBPBPBPBPSSSSS S S S S S S S S S SSSS FM FMFMFM FMFM EE XXXXXXX BP BP FM FMFM FM FM FM FM -1 .91%-2.60%-1.79%-1.85%FIGURE NUMBER © PROJECT NO.DRAWN BY: DSGN. BY: APPR. BY: DATE: COPYRIGHT MORRISON-MAIERLE,2025 Plotted by lee hageman on Feb/6/2025 engineers surveyors planners scientists MorrisonMaierle 2880 Technology Blvd West Bozeman, MT 59718 406.587.0721 www.m-m.net P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\ACAD\Civil\DesignDevelopment\Stormwater-Calculations.dwg10678.001  FIG-2 LRH BOZEMAN MONTANA POST-DEVELOPMENT MAP LRH NORTON RANCH LIFT STATION UPGRADES LRH 02/2025 15 300 SCALE IN FEET VAUGHN DRIVE LAUREL PARKWAYLEGEND PROPOSED GRASS AREAS PROPOSED IMPERVIOUS AREAS PROPOSED GRAVEL AREAS LIFT STATION PROPERTY LOT 1 OF NORTON EAST RANCH PHASE 6 C P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Stormwater\NortonRanch-StormMemo_20250206.docx ATTACHMENT C LIFT STATION GRADING PLAN GIP NGNGNGNGNGNGNGNGNGNGNGN G NG NG NG NGSSSSSS XXXXS S S SBPBPBPBPBP BP BP BP BP BP BP BP BP BP BP BPS SS15S15S8S8S8SEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE8S8S8S8S8S8S8S8S15S15S15S15S15S15S15S15S15S15S15S15S15S15S15S15S15S15S15S15S15S15S15S15S15S15S15SSSSSSSSSSSSSSSSSE15S 15S 15S 15SBPBPBPBP BP BP BP BP BP BP BP BP BP BP BP BPS FMFMFMFMFMFMFMFMFMFMFMFM FM FM FMFMFMFMFMFMFM FMFMFMFMFMFMFMFM FM FM FM FM EEEEEEEEEEEEEEEEEEXXXXBPBPBPBPBPBPBPBP BP BP FMFMFMFMFMFMFMFM FM FM FM F M FMFMFMFMFMFMFMS2°11'57"W 54.99'S89°31'21"W 117.30 'S87°48'03"E 120.00'N0°28'39"W 60.54' 4782.50 4782.004783.004782.004782.5082.1282.2982.5782.5882.3181.9781.9782.8783.02MEG 83.0983.0882.93MEG 81.83MEG 81.81MEG 82.81MEG 82.3183.0483.0483.0483.04MEG 82.91MEG 81.82MEG 82.96MEG 82.45MEG 82.46MEG 82.09MEG 82.01MEG 81.87MEG 82.13MEG 82.81MEG 82.9082.6082.6082.6083.1482.6082.604783.00478 2 . 5 0 4782.00 4781.50 4781.504782.004782.504783.00 4782.004783.50 4781.50 4782.00-3.43%-1.11%-0.27%-1.78%-0.40%>> > >>>> > >>>> > > -2.00%-1.84%4782.50MEG 82.01GIP NGNGNGNGNGNGNGNGNGNGNGN G NG NG NG NGSSSSSS XXXXS S S SBPBPBPBPBP BP BP BP BP BP BP BP BP BP BP BPS SS-0.13%83.092025COPYRIGHT © MORRISON-MAIERLE,SHEET NUMBERPROJECT NUMBERDRAWING NUMBERDATEDESCRIPTIONNO.BYP:\10678-LAUREL PARKWAY LLC\001 - NORTON RANCH LIFT STATION\ACAD\SHEETS\1-CIVIL\C-5_SITEGRADINGPLAN.DWGREVISIONS DRAWN BY:DSGN. BY:APPR. BY:DATE:Q.C. REVIEWDATE:BY:2880 Technology Blvd WestBozeman, MT 59718406.587.0721www.m-m.netengineers surveyors planners scientistsMorrisonMaierleVERIFY SCALE AND COLOR!THIS SHEET MAY BE REDUCED AND ISINTENDED TO BE IN COLOR. THE BARBELOW WILL MEASURE ONE INCH ATORIGINAL DESIGN SCALE AND RED,GREEN, AND BLUE WILL BE VISIBLE IFREPRODUCED CORRECTLY.MODIFY SCALE ACCORDINGLY!PLOTTED BY:KARL SAND ON Feb/06/2025 NORTON RANCH LIFT STATION UPGRADES BOZEMANMONTANASITE GRADING PLAN10678.00112C-5KJSLRHLRH02/2025 612360SCALE IN FEETDRAFTFEBRUARY 202509/20/2024DRAFTNOT FORCONSTRUCION PROPERTY BOUNDARY (TYP.)LEGENDFLOW LINEPROPOSED MAJOR CONTOUR>>>>>>>>XXXXMATCH EXISTING GRADEPROPOSED SWALEPROPOSED FORCEMAIN. SEE SHEETSC-8 TO C-11.PROPOSED GRAVITYSEWER MAIN. SEESHEET C-7.PROPOSEDWET WELLFF ELEV. = 4783.14MEGPROPOSED MINOR CONTOUREXISTING MAJOR CONTOURXXXXEXISTING BUILDINGPROPOSED BUILDING EXPANSIONLAUREL PARKWAY EXISTING CONCRETE DRIVEWAYNEW 6" CONCRETEDRIVE ACCESSNEWTRANSFORMER PADNEW GRAVELACCESS D P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Stormwater\NortonRanch-StormMemo_20250206.docx ATTACHMENT D LAKES AT VALLEY WEST UPDATED BASIN 1.3C DRAINAGE BASIN FIGURE SDSDSDSDSDSDSDSDSDSDSDSD 15SD15SD15SD15SD18SD18SD12SD12SD010010020050HORIZ. SCALEIN FEETDURSTON ROADD1.1A0.82D1.2B3.51D1.3A10.98D1.3B64.30D1.1B114.16D2.13.94D2.21.62D1.4 A5.72LAUREL PARKWAYWESTMORLAND DRIVE1.500.500.800.800.500.701.75DURSTON ROADHUFFINE LANECOTTONWOOD ROADMATCH LINEMATCH LINEPHASE 1PHASE 2VICINITY MAPSCALE: 1"=1000'D1.1B114.16D1.3B61.93GOOCH HILL ROADAAJKER CREEKBAXTER CREEKEXISTING 2-3614" x 2212" ARCPEXISTING36" CMPEXISTINGCUTOFF DITCHSOUTH SITE BOUNDARYBAXTER CREEK WEST LAKEEAST LAKEEXISTING DRAINAGEEXISTINGDETENTIONSTORAGE D1.2LEGENDSUB-BASIN BOUNDARYX.XXX.XXPOST-DEVELOPMENTSUB-BASIN DESIGNATIONSUB-BASIN AREAPHASE BOUNDARYDITCH OR SWALED1.4 B7.26EXISTING 12" PVCEAST LAKE OUTLETEXISTINGDETENTIONBASIN 2.1EXISTINGDETENTIONSTORAGE D1.4EXISTING 12" PVCWEST LAKE OUTLET0.60EXISTINGCULVERTEXTENSIONEXISTING 88" x 44" ARCP CULVERTD1.1C1.24D1.2 A5.52EXISTING DETENTIONSTORAGE 1.4CFIGURE NUMBER©PROJECT NO.DRAWN BY:DSGN. BY:APPR. BY:DATE:COPYRIGHT MORRISON-MAIERLE, INC.,2018N:\5352\009\ACAD\Exhibits\PH 5 Post-Development.dwg Plotted by cooper krause on May/24/2018engineers surveyors planners scientistsMorrisonMaierle5352.009FIG. 2THE LAKES AT VALLEY WESTPHASES 5 AND 6BOZEMANMONTANAPOST-DEVELOPEMENT DRAINAGE MAPDSMGHJRN12/2017PHASE 3WESTGATE AVE.EXISTINGSTORM DRAINPHASE 4HERSTAL WAYPHASE 5PHASE 6D1.3D7.69D1.3C1.81D1.4C3.38D1.2C1.14HERSTAL WAYLEIDEN LANEVAHL WAYDEBOUR LANEVAUGHN DRIVEPROPOSED DETENTIONSTORAGE D1.3DHERSTAL WAYPROPOSED DETENTIONSTORAGE D1.3C E P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Stormwater\NortonRanch-StormMemo_20250206.docx ATTACHMENT E LAUREL PARKWAY SUBBASIN ADDITIONS FIGURE © PROJECT NO. FIGURE NUMBER COPYRIGHT MORRISON-MAIERLE, INC.,2021 N:\5352\009\ACAD\Exhibits\DRAINAGE-POST DEVELOPMENT OFFSITE.dwg Plotted by cody farley on Apr/8/2021 DRAWN BY: DSGN. BY: APPR. BY: DATE:engineers surveyors planners scientists MorrisonMaierle 2880 Technology Blvd West Bozeman, MT 59718 406.587.0721 www.m-m.net 5352.009 FIG.3 THE LAKES AT VALLEY WEST PHASES 5 AND 6 LAUREL PARKWAY - ADDITIONS TO SUB-BASINS D1.3C AND D1.4C BOZEMAN MONTANA CJF MGH MGH 04/2021 30 600 SCALE IN FEET NORTON RANCH LIFT STATION SITE (2025 ADDITION) 0.157 AC F P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Stormwater\NortonRanch-StormMemo_20250206.docx ATTACHMENT F REVISED PEAK RUNOFF AND DETENTION CALCULATIONS The Lakes at Valley West, Phases 5 & 6 Peak Runoff and Detention Calculations revised 2/6/25 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 -0.66 100-yr 1.01 -0.67 (Bozeman Design Standards, March 2004) = item modified for Norton Ranch Lift Station (February 6, 2025) Sub-Basin Name Area C Tc Q2 Q5 Q10 Q25 Q50 Q100 Basin 1 H1 218.30 0.20 90.6 12.27 17.44 21.38 26.16 30.60 33.46 D1.1 (A+B+C)116.22 0.20 97.6 6.25 8.85 10.84 13.28 15.51 16.95 D1.2A 5.52 0.48 5.0 4.24 6.76 8.53 10.14 12.57 14.14 D1.2B 3.51 0.50 5.0 2.81 4.48 5.65 6.72 8.32 9.37 D1.2C 1.14 0.50 5.0 0.91 1.45 1.83 2.18 2.70 3.04 D1.2 (A+B+C)10.17 0.49 6.3 6.92 10.94 13.78 16.42 20.26 22.74 D1.3A 10.98 0.50 5.0 8.78 14.00 17.67 21.01 26.04 29.31 D1.3B 64.30 0.50 90.6 9.04 12.84 15.74 19.26 22.53 24.64 H1.3C1 2.11 0.20 16.1 0.334 0.509 0.634 0.763 0.924 1.028 D1.3C 2.11 0.511 5.0 1.721 2.745 3.464 4.118 5.104 5.744 H1.3D1 7.69 0.20 12.8 1.40 2.15 2.69 3.22 3.92 4.37 D1.3D 7.69 0.50 7.5 4.82 7.57 9.51 11.35 13.95 15.64 West Lake outlet pipe2 88.67 0.50 -4.60 D1.4A 5.72 0.50 5.0 4.57 7.30 9.20 10.94 13.56 15.27 D1.4B 7.26 0.39 5.0 4.53 7.22 9.11 10.83 13.43 15.11 D1.4 (A+B)12.98 0.44 5.0 9.10 14.52 18.32 21.78 26.99 30.38 H1.4C1 3.59 0.20 9.9 0.76 1.18 1.48 1.77 2.17 2.43 D1.4C 3.59 0.51 9.4 2.00 3.12 3.91 4.68 5.72 6.40 D1.2+D1.4(A+B)23.15 0.46 6.3 14.85 23.47 29.54 35.20 43.43 48.77 FOOTNOTES: 1.The pre-development subbasin uses a pre-development C and Tc and an area matching the post-development area, for use in calculating detention volume. 2.Full retention of sub-basins draining into the East and West lakes (D1.3A, D1.3B, D1.3C, D1.3D and D1.4C) was assumed, in order to conservatively estimate the lakes' 25-year maximum water surface elevation and associated maximum discharge. Retention volume = (7,200)*(0.50)*(0.41)*(88.16) =130,124 cu. ft. Using the 5.14-acre combined surface area of the lakes, this correlates to a rise of 0.58 feet above the normal operating elevation of 44.50. An additional 0.5 feet was added to account for partial clogging of the 2' high fish screen. The result (WSEL=45.58) was used to calculate the 25-year peak discharge; see attached calculations for the West Lake Outfall. The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.3C Detention (10-yr storm) revised 2/6/25 MODIFIED RATIONAL METHOD Qp = C i A = item modified for Norton Ranch Lift Station POST-DEVELOPMENT PRE-DEVEL. 2.11 AC Qp (Basin H1.3C) = 0.63 cfs 0.51 5.0 MIN D1.3C release rate = 0.63 cfs 3.22 IN/HR TIME STEP 3.46 CFS DURATION = 5.0 min. Max. Volume, Max. Volume,Required Detention Triangle Rel. (cu. ft.) Constant Rel. (cu. ft.)Volume (cu. ft.) 1300.90 840.21 1071 Triangle Release Constant Release DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 4.75 3.33 3.58 836 685 9.75 2.09 2.24 1,034 808 14.75 1.59 1.71 1,144 840 19.75 1.32 1.42 1,213 829 ORIFICE CALCULATIONS 24.75 1.14 1.22 1,256 791 MATCHING Qp = 0.63 cfs 29.75 1.01 1.09 1,283 736 Max. Depth = 3.10 ft 34.75 0.91 0.98 1,297 667 39.75 0.84 0.90 1,301 587 44.75 0.77 0.83 1,297 500 CIRCULAR ORIFICE: 49.75 0.72 0.78 1,287 406 DIAMETER = 3.6875 inches 54.75 0.68 0.73 1,272 306 Area = 0.07 ft2 59.75 0.64 0.69 1,252 201 ORIFICE FLOW = 0.63 cfs 64.75 0.61 0.66 1,228 92 69.75 0.58 0.62 1,201 -21 74.75 0.55 0.60 1,170 -137 RECTANGULAR ORIFICE: 79.75 0.53 0.57 1,137 -256 LENGTH = 3.5625 84.75 0.51 0.55 1,102 -378 WIDTH = 3.0000 inches 89.75 0.49 0.53 1,064 -502 Area = 0.07 ft2 94.75 0.48 0.51 1,024 -629 ORIFICE FLOW = 0.63 cfs 99.75 0.46 0.49 982 -757 104.75 0.45 0.48 939 -887 109.75 0.43 0.47 894 -1,019 114.75 0.42 0.45 848 -1,152 POND VOLUME CALCULATIONS: BASIN AREA POST = POST-DEV C = POST-DEV Tc = STORM INTENSITY = POST-DEV Qp = DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 119.75 0.41 0.44 800 -1,287 WEIR CALCULATIONS 124.75 0.40 0.43 751 -1,423 Coefficient = 3.33 inches 129.75 0.39 0.42 701 -1,560 Width = 0.4150 inches 134.75 0.38 0.41 650 -1,699 WEIR FLOW = 0.63 cfs 139.75 0.37 0.40 598 -1,839 144.75 0.36 0.39 544 -1,980 149.75 0.35 0.38 490 -2,121 154.75 0.35 0.37 435 -2,264 159.75 0.34 0.36 379 -2,408 164.75 0.33 0.36 323 -2,552 169.75 0.33 0.35 265 -2,698 174.75 0.32 0.34 207 -2,844 179.75 0.31 0.34 148 -2,991 184.75 0.31 0.33 89 -3,138 189.75 0.30 0.33 29 -3,286 194.75 0.30 0.32 -31 -3,435 199.75 0.29 0.32 -93 -3,585 204.75 0.29 0.31 -154 -3,735 209.75 0.28 0.31 -216 -3,885 214.75 0.28 0.30 -279 -4,036 219.75 0.28 0.30 -342 -4,188 224.75 0.27 0.29 -406 -4,340 229.75 0.27 0.29 -470 -4,493 234.75 0.26 0.28 -534 -4,646 239.75 0.26 0.28 -599 -4,800 244.75 0.26 0.28 -665 -4,954 249.75 0.25 0.27 -730 -5,108 254.75 0.25 0.27 -796 -5,263 259.75 0.25 0.27 -863 -5,419 264.75 0.24 0.26 -930 -5,574 269.75 0.24 0.26 -997 -5,730 274.75 0.24 0.26 -1,064 -5,887 279.75 0.24 0.25 -1,132 -6,043 284.75 0.23 0.25 -1,200 -6,201 289.75 0.23 0.25 -1,268 -6,358 294.75 0.23 0.24 -1,337 -6,516 299.75 0.22 0.24 -1,406 -6,674 304.75 0.22 0.24 -1,475 -6,832 309.75 0.22 0.24 -1,545 -6,991 314.75 0.22 0.23 -1,614 -7,150 319.75 0.22 0.23 -1,684 -7,309 324.75 0.21 0.23 -1,755 -7,469 329.75 0.21 0.23 -1,825 -7,629 334.75 0.21 0.23 -1,896 -7,789 339.75 0.21 0.22 -1,967 -7,949 344.75 0.21 0.22 -2,038 -8,110 349.75 0.20 0.22 -2,109 -8,271 354.75 0.20 0.22 -2,181 -8,432 359.75 0.20 0.22 -2,253 -8,593 364.75 0.20 0.21 -2,325 -8,754 369.75 0.20 0.21 -2,397 -8,916 374.75 0.19 0.21 -2,470 -9,078 379.75 0.19 0.21 -2,542 -9,240 384.75 0.19 0.21 -2,615 -9,403 389.75 0.19 0.20 -2,688 -9,565 394.75 0.19 0.20 -2,761 -9,728 399.75 0.19 0.20 -2,834 -9,891 404.75 0.19 0.20 -2,908 -10,054 409.75 0.18 0.20 -2,982 -10,218 414.75 0.18 0.20 -3,055 -10,381 419.75 0.18 0.19 -3,129 -10,545 The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.3C revised 2/6/25 StormTech Sizing Calculations = item modified for Norton Ranch Lift Station (February 6, 2025) Required Storage Volume 1,071 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 16 15.71 before rounding excess storage volume 1.8 % Number of chambers proposed 16 (as-built) excess storage volume 1.8 % equal to 19.3 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 = 1,090 ft3 Notes: 1. Storage volume assumes 6" of stone above and between chambers, and 40% stone porosity. G P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Stormwater\NortonRanch-StormMemo_20250206.docx ATTACHMENT G REVISED GUTTER FLOW, INLET, AND PIPE FLOW CALCULATIONS Laurel south of Debour double inlet, east side (25-yr) Project Description EfficiencySolve For Input Data cfs4.12Discharge ft/ft0.013Slope ft1.50Gutter Width ft/ft0.063Gutter Cross Slope ft/ft0.030Road Cross Slope 0.013Roughness Coefficient in1.0Local Depression in18.0Local Depression Width ft1.50Grate Width ft6.0Grate Length 30˚ Tilt BarGrate Type %20.0Clogging ft6.0Curb Opening Length Options Use BothCalculation Option Exclude NoneGrate Flow Option Results %71.84Efficiency cfs2.96Intercepted Flow cfs1.16Bypass Flow ft8.1Spread in3.5Depth ft²1.0Flow Area in0.6Gutter Depression in1.6Total Depression ft/s3.99Velocity ft/s8.74Splash Over Velocity 1.000Frontal Flow Factor 0.379Side Flow Factor 0.464Grate Flow Ratio ft/ft0.071Equivalent Cross Slope ft4.8Active Grate Length 0.061Length Factor ft19.6Total Interception Length Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2/7/2025 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution Centeropen channels (rev 2-7-25).fm8 Laurel Sta. 8+00 gutter, east side (25-yr) Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.006Channel Slope cfs3.29Discharge Section Definitions Elevation (ft) Station (ft) 0.450+00 0.000+01 0.080+02 0.500+16 Roughness Segment Definitions Roughness CoefficientEnding StationStart Station 0.013(0+16, 0.50)(0+00, 0.45) Options Pavlovskii's Method Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Results in3.8Normal Depth 0.013Roughness Coefficient ft0.32Elevation 0.00 to 0.50 ftElevation Range ft²1.4Flow Area ft9.8Wetted Perimeter in1.7Hydraulic Radius ft9.54Top Width in3.8Normal Depth in4.0Critical Depth ft/ft0.005Critical Slope ft/s2.39Velocity ft0.09Velocity Head ft0.41Specific Energy 1.111Froude Number SupercriticalFlow Type Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2/7/2025 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution Centeropen channels (rev 2-7-25).fm8 Laurel Sta. 8+00 gutter, east side (25-yr) GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth Profile Description ft0.00Profile Headloss ft/sInfinityDownstream Velocity ft/sInfinityUpstream Velocity in3.8Normal Depth in4.0Critical Depth ft/ft0.006Channel Slope ft/ft0.005Critical Slope Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2/7/2025 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution Centeropen channels (rev 2-7-25).fm8 Laurel Sta. 8+00 double inlet, east side (25-yr) Project Description EfficiencySolve For Input Data cfs3.29Discharge ft/ft0.006Slope ft1.50Gutter Width ft/ft0.063Gutter Cross Slope ft/ft0.030Road Cross Slope 0.013Roughness Coefficient in1.0Local Depression in18.0Local Depression Width ft1.50Grate Width ft6.0Grate Length 30˚ Tilt BarGrate Type %20.0Clogging ft6.0Curb Opening Length Options Use BothCalculation Option Exclude NoneGrate Flow Option Results %79.33Efficiency cfs2.61Intercepted Flow cfs0.68Bypass Flow ft8.7Spread in3.7Depth ft²1.2Flow Area in0.6Gutter Depression in1.6Total Depression ft/s2.82Velocity ft/s8.74Splash Over Velocity 1.000Frontal Flow Factor 0.534Side Flow Factor 0.438Grate Flow Ratio ft/ft0.069Equivalent Cross Slope ft4.8Active Grate Length 0.083Length Factor ft14.4Total Interception Length Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2/7/2025 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution Centeropen channels (rev 2-7-25).fm8 Worksheet for Laurel Sta. 13+97.18 (at Durston), east side (25-yr) Project Description SpreadSolve For Input Data cfs2.96Discharge ft1.50Gutter Width ft/ft0.063Gutter Cross Slope ft/ft0.030Road Cross Slope in0.1Local Depression in18.0Local Depression Width ft1.50Grate Width ft3.0Grate Length 30˚ Tilt BarGrate Type %20.0Clogging ft3.0Curb Opening Length ft0.4Opening Height VerticalCurb Throat Type degrees0.00Throat Incline Angle Options Use BothCalculation Option Results ft9.0Spread in3.8Depth in0.6Gutter Depression in0.7Total Depression ft²1.2Open Grate Area ft5.4Active Grate Weir Length Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2/7/2025 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution Centeropen channels (rev 2-7-25).fm8 The Lakes at Valley West, Phases 5 & 6 Pipe Flow Calculations revised 2-6-25 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 = item modified for Norton Ranch Lift Station (2-6-2025) Sub-Basin Description Area1 Tc C Qdirect2 Qtotal3 Qint4 Qbypass Qpipe5 Pipe Dia.6 Notes Vaughn Drive West of Westgate, north side 0.78 5.00 0.50 1.49 1.49 1.49 0.00 1.49 12" West of Westgate, south side 0.34 5.00 0.50 0.65 0.65 0.65 0.00 2.14 12" East of Westgate, north side 0.09 5.00 0.50 0.17 0.17 0.17 0.00 0.17 12" East of Westgate, south side 0.67 5.00 0.50 1.28 1.28 1.28 0.00 1.45 12" Vaughn/Westgate manhole 3.60 15" Westgate Avenue South of Herstal, west side 0.42 5.00 0.50 0.80 0.80 0.72 0.08 0.72 12" South of Herstal, east side 0.43 5.00 0.50 0.82 0.82 0.73 0.09 5.05 15" North of Herstal, west side7 1.51 5.00 0.50 2.89 2.97 1.80 1.17 1.80 12" North of Herstal, east side7 0.16 5.00 0.50 0.31 0.40 0.38 0.02 2.17 18"as-built10 South of roundabout, west side park inlet7 1.19 5.00 0.50 2.28 2.28 2.28 0.00 2.28 12"as-built10 South of roundabout, west curb inlet7 0.53 5.00 0.50 1.01 2.18 1.44 0.74 3.72 15"as-built10 South of roundabout, east curb inlet7 0.78 5.00 0.50 1.49 1.51 1.10 0.41 7.00 24"as-built10 South quadrant of roundabout7 1.54 5.00 0.50 2.95 3.69 3.69 0.00 4.43 15"as-built10 Manhole at roundabout7 11.42 24"as-built10 Alleys7 Manhole at Leiden's NW dead end 1.30 5.00 0.50 2.49 2.49 2.49 0.00 7.54 18" Vahl, NW dead end 1.51 5.00 0.50 2.89 2.89 2.89 0.00 2.89 12" Manhole between Vahl & Leiden 0.71 5.00 0.50 1.36 1.36 1.36 0.00 4.25 15" Manhole at Leiden's NE dead end 1.27 5.00 0.50 2.43 2.43 2.43 0.00 6.68 18" Manhole 55' north of Leiden's NW dead end 0.17 5.00 0.50 0.33 0.33 0.33 0.00 11.35 24" South inlet pipe to Detention D1.3D 9 7.69 7.50 0.50 11.35 11.35 24" Laurel Parkway South of Debour, double inlet, east side 2.11 5.00 0.51 4.12 4.12 2.96 1.16 2.96 12" Sta. 8+00 existing double inlet, east side 1.67 9.40 0.50 2.13 3.29 2.61 0.68 3.77 12"as-built10 Sta. 13+97.18, 65' east (drop inlet)2.00 5.00 0.35 2.68 2.68 2.68 0.00 2.68 12"as-built10 Sta. 13+97.18, existing east inlet (low point)1.70 5.00 0.35 2.28 5.63 5.63 0.00 5.63 18"as-built10 Sta. 8+00 double inlet, west side 1.92 9.20 0.51 2.54 2.54 2.10 0.44 5.87 12"as-built10 Detention D1.4C discharge pipe9 3.59 9.40 0.51 4.68 4.68 15"as-built10 Sta. 13+97.18, existing west inlet (low point)1.41 5.00 0.50 2.70 3.14 3.14 0.00 9.21 18"as-built10 FOOTNOTES: 1 Contributing drainage area 2 Qdirect is direct surface runoff to the inlet, and does not include bypass flows from upstream inlets. 3 Qtotal is total peak surface runoff to the inlet (direct runoff plus bypass flows from upstream inlets). 4 Qint is surface runoff intercepted by the inlet. 5 Qpipe is total flow to outlet pipe (total pipe flow from upstream inlets plus surface runoff intercepted at the inlet). 6 Calculations are attached where "Pipe Dia." column uses bold text. Other pipe sizes are evident based on flow rates. 7 These subbasins were defined in previous phases of construction; refer to previous drainage reports. 8 Qpipe for alleys is the total runoff to the nearest downstream drop inlet or manhole. 9 Equal to values in the Peak Runoff and Detention calculations. 10 Pipes were sized and installed during previous phases of construction. The Lakes at Valley West, Phases 5 & 6 Gutter Flow, Direct (Surface) Runoff Calculations revised 2-6-25 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 = item modified for Norton Ranch Lift Station (February 6, 2025) Sub-Basin Description Area1 Tc C Qp Vaughn Drive West of Westgate, north side 0.78 5.00 0.50 1.49 West of Westgate, south side 0.34 5.00 0.50 0.65 East of Westgate, north side 0.09 5.00 0.50 0.17 East of Westgate, south side 0.67 5.00 0.50 1.28 Westgate Avenue South of Herstal, west side 0.42 5.00 0.50 0.80 South of Herstal, east side 0.43 5.00 0.50 0.82 North of Herstal, west side3 1.51 5.00 0.50 2.89 North of Herstal, east side3 0.16 5.00 0.50 0.31 South of roundabout, west side park inlet3 1.19 5.00 0.50 2.28 South of roundabout, west curb inlet3 0.53 5.00 0.50 1.01 South of roundabout, east curb inlet3 0.78 5.00 0.50 1.49 South quadrant of roundabout3 1.54 5.00 0.50 2.95 Alleys2 Manhole at Leiden's NW dead end 1.30 5.00 0.50 2.49 Manhole at Leiden's NE dead end 1.27 5.00 0.50 2.43 Vahl, NW dead end 1.51 5.00 0.50 2.89 Laurel Parkway South of Debour, double inlet, east side 2.11 5.00 0.51 4.12 Sta. 8+00 existing double inlet, east side 1.67 9.40 0.50 2.13 Sta. 13+97.18, existing east inlet (low point)1.70 5.00 0.35 2.28 Sta. 8+00 existing double inlet, west side 1.92 9.20 0.51 2.54 Sta. 13+97.18, existing west inlet (low point)1.41 5.00 0.50 2.70 FOOTNOTES: 1 Areas and flow rates are for direct runoff only and do not include inlet bypass. Inlet bypass flow is accounted for on the following page. 2 Typical section for alleys is an inverted crown with 2% slope toward the center. 3 These subbasins were defined in previous phases of construction; refer to previous drainage reports. The Lakes at Valley West, Phases 5 & 6 Gutter Spread Width Calculations revised 2-6-25 = item modified for Norton Ranch Lift Station (2-6-2025) 25-yr. Peak Runoff (cfs)Gutter Sub-Basin Description Direct1 Upstream2 Total Inlet Type Bypass Spread (ft.) Vaughn Drive West of Westgate, north side 1.49 0.00 1.49 sag 0.00 5.32 West of Westgate, south side 0.65 0.00 0.65 sag 0.00 3.10 East of Westgate, north side 0.17 0.00 0.17 sag 0.00 1.28 East of Westgate, south side 1.28 0.00 1.28 sag 0.00 4.84 Westgate Avenue South of Herstal, west side 0.80 0.00 0.80 on grade 0.08 4.14 South of Herstal, east side 0.82 0.00 0.82 on grade 0.09 4.19 North of Herstal, west side4 2.89 0.08 2.97 on grade 1.17 9.03 North of Herstal, east side4 0.31 0.09 0.40 on grade 0.02 4.04 South of roundabout, west side park inlet4 2.28 0.00 2.28 drop inlet 0.00 n/a South of roundabout, west curb inlet4 1.01 1.17 2.18 on grade 0.74 8.00 South of roundabout, east curb inlet4 1.49 0.02 1.51 on grade 0.41 6.93 South quadrant of roundabout4 2.95 0.74 3.69 sag 0.00 9.11 Alleys3 Manhole at Leiden's NW dead end 2.49 0.00 2.49 -0.00 13.62 Manhole at Leiden's NE dead end 2.43 0.00 2.43 -0.00 12.15 Vahl, NW dead end 2.89 0.00 2.89 -0.00 13.67 Laurel Parkway South of Debour, double inlet, east side 4.12 0.00 4.12 on grade 1.16 8.96 Sta. 8+00 existing double inlet, east side 2.13 1.16 3.29 on grade 0.68 9.54 Sta. 13+97.18, existing east inlet (low point)2.28 0.68 2.96 sag 0.00 9.00 Sta. 8+00 existing double inlet, west side 2.54 0.00 2.54 on grade 0.44 8.63 Sta. 13+97.18, existing west inlet (low point)2.70 0.44 3.14 sag 0.00 9.27 FOOTNOTES: 1 Direct runoff is from "Gutter Flow" calculations on the previous page, and does not include runoff from upstream inlets. 2 Upstream runoff is the bypass flow from contributing upstream inlets. 3 For alleys with inverted crown, minor submergence is acceptable. The maximum submergence at the wheels of a car straddling the inverted crown centerline would be less than 1.5 inches, which is considered acceptble for the short duration of peak runoff involved. 4 These subbasins were defined in previous phases of construction; refer to previous drainage reports. Laurel gutter south of Debour, east side (25-yr) Project Description Manning FormulaFriction Method Normal DepthSolve For Input Data ft/ft0.013Channel Slope cfs4.12Discharge Section Definitions Elevation (ft) Station (ft) 0.450+00 0.000+01 0.080+02 0.500+16 Roughness Segment Definitions Roughness CoefficientEnding StationStart Station 0.013(0+16, 0.50)(0+00, 0.45) Options Pavlovskii's Method Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Results in3.6Normal Depth 0.013Roughness Coefficient ft0.30Elevation 0.00 to 0.50 ftElevation Range ft²1.2Flow Area ft9.2Wetted Perimeter in1.6Hydraulic Radius ft8.96Top Width in3.6Normal Depth in4.3Critical Depth ft/ft0.005Critical Slope ft/s3.38Velocity ft0.18Velocity Head ft0.48Specific Energy 1.619Froude Number SupercriticalFlow Type Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2/7/2025 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution Centeropen channels (rev 2-7-25).fm8 Laurel gutter south of Debour, east side (25-yr) GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth Profile Description ft0.00Profile Headloss ft/sInfinityDownstream Velocity ft/sInfinityUpstream Velocity in3.6Normal Depth in4.3Critical Depth ft/ft0.013Channel Slope ft/ft0.005Critical Slope Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2/7/2025 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution Centeropen channels (rev 2-7-25).fm8 H P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Stormwater\NortonRanch-StormMemo_20250206.docx ATTACHMENT H ORIGINAL STORM DRAINAGE REPORT FOR THE LAKES AT VALLEY WEST, PHASES 5 AND 6 (DATED 5-25-18) Page 2 of 5 storm drain system to detention facility D1.2, and then will discharge through the existing pair of 36¼” x 22½” RCP arch pipes (double culvert) under Durston Road. Detention facility D1.2 was sized and constructed as part of Phase 3 (see Phase 3 Drainage Report), incorporating additional capacity for future phases. Refer to Part 3 below for additional discussion. Sub-basin D1.3: Sub-basin D1.3 encompasses all runoff into the East Lake and West Lake, which are hydraulically connected to a single, existing discharge structure. For the purposes of detention calculations, this report will utilize 4.60 cfs as the 10-year peak discharge rate out of Sub-basin D1.3, a conservative value that was calculated in the drainage report for Phases 1 and 2 and has been re-calculated in this report using current Phase 5 and Phase 6 drainage basins. This runoff flows to the existing pair of 36¼” x 22½” RCP arch pipes (double culvert) under Durston Road. Sub-basin D1.3 consists of the following: - D1.3A includes the West Lake, perimeter open space and adjacent back yards of residential lots. - D1.3B includes the East Lake, perimeter open space and adjacent back yards of residential lots, plus a large offsite area to the south (east of Laurel Parkway). Runoff from the offsite area is intercepted by an existing earth berm along the south property line and flows east around Phase 6 to existing constructed wetlands draining to the East Lake. - D1.3C covers part of Phase 6 and will drain to the East Lake (sub-basin D1.3B). - D1.3D covers a small part of Phase 4 and most of Phase 5, and will drain to a proposed underground (StormTech) detention and treatment facility discharging to the West Lake (sub-basin D1.3A). - D1.4C includes Laurel Parkway and adjacent parts of Phases 5 and 6, and will drain to an existing underground (StormTech) detention and treatment facility discharging to the West Lake (sub-basin D1.3A). Sub-basin D1.4: Sub-basin D1.4 consists of D1.4A (runoff from Phases 2 and 3) and D1.4B (runoff from Phases 1 and 2), both draining to existing underground (StormTech) detention and treatment facility D1.4, which discharges through the existing pair of 36¼” x 22½” RCP arch pipes (double culvert) under Durston Road. Sub-basin D1.4 is unaffected by the currently proposed Phases 5 and 6. Because sub-basin D1.4C drains to the West Lake, it is included in the discussion above for sub-basin D1.3. Part 3 Detention Basins Three underground detention and treatment facilities (D1.2, D1.4 and D1.4C) were constructed in earlier phases and sized to accommodate construction of all future phases including the last two (Phases 5 and 6), which are the subject of this report. The attached calculations confirm that with site runoff routed through the existing, “as-built” control structures, the existing storage volumes and release rates remain in compliance with City drainage policy through final buildout of all contributing phases of the Lakes at Valley West subdivision. The three existing detention facilities of interest, named to correspond to their respective sub-basins, are described below. Page 3 of 5 Sub-basins D1.2 and D1.4: The following quote, from the Phase 3 Drainage Report, applies to this report as well: “Two underground detention storage facilities, D1.2 and D1.4, are proposed [now existing] for storm water treatment and control of the 10-year peak runoff rate. Discharge from these two detention facilities will limit the total post-development 10-year peak discharge (sub-basins D1.1 through D1.4) to the pre-development peak rate (sub-basin H1).” Detention Facility D1.4 is unaffected by the currently proposed Phases 5 and 6 because the contributing drainage areas were fully defined prior to construction of the facility. For Detention Facility D1.2, calculations have been revised using the “as-built” storage and discharge parameters from Phase 3 construction. Results are summarized in Table 1. Sub-basin D1.4C: D1.4C detention was sized and constructed as part of Phases 1 and 2, incorporating additional capacity for future phases. Calculations have been revised for detention facility D1.4C using the “as-built” storage and discharge parameters from Phase 1 and 2 construction. Results are summarized in Table 1. In addition to the existing detention facilities described above, two additional detention facilities are proposed for construction during the final phases of development (Phases 5 and 6). Both will discharge to the onsite lakes, and offsite runoff rate is therefore unaffected due to onsite detention in the lakes. However, both will be constructed to provide treatment and to limit peak runoff to the pre-development rate, in accordance with City of Bozeman drainage policy. The two proposed detention basins, named to correspond to their respective sub-basins, are described below. Sub-basin D1.3D (Phase 5 construction): Detention facility D1.3D is proposed as an underground (StormTech) detention storage and treatment facility to be located north of Leiden Lane, discharging to the West Lake. Calculations are attached; results are summarized in Table 1. Sub-basin D1.3C (Phase 6 construction): Detention facility D1.3C is proposed as an underground (StormTech) detention storage and treatment facility to be located northeast of the Laurel Parkway/Debour Lane intersection, discharging to the East Lake. Calculations are attached; results are summarized in Table 1. Part 4 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 as follows: Detention Storage D1.2, D1.4, D1.4C, D1.3C and D1.3D: StormTech underground detention and storage facilities are existing (D1.2, D1.4 and D1.4C) and proposed (D1.3C and D1.3D). 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 Page 4 of 5 TABLE 1 - Detention Basin Data Description Detention Basin Name DET 1.4 (as-built) DET 1.2 (as-built) DET 1.3C (proposed) DET 1.3D (proposed) DET 1.4C (as-built) Max. 10-yr Release Rate (cfs) 2.30 3.63 0.57 2.69 1.36 10-yr Detention Volume (cu. ft.) 7,211 4,058 883 3,147 1,088 Sizes and Dimensions: vertical tee (riser) dia., inches 30 30 15 24 12 outlet pipe dia., inches 30 30 12 24 12 overflow weir length, ft. - - - - Orifice (two alternates): circular orifice dia., inches 63/4 81/2 33/8 75/8 5 rectangular orifice - - 3 x 3 7 x 61/2 - Elevations: 25-yr WSEL at control structure 43.47 43.43 54.80 50.31 52.40 top of riser (=10-yr max. WSEL) 42.50 42.50 54.40 49.70 51.80 discharge pipe invert at control structure 39.00 39.00 51.30 46.60 48.30 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. Although the detention calculations assume zero infiltration, the existing alluvial (gravel/pit run) soils directly under the StormTech 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. Part 5 Conveyance and Collection The proposed storm drain system is shown on Figure 2. Existing storm drain is utilized for runoff from sub-basins D1.2C and D1.4C; proposed, separate storm drain systems are proposed for sub-basins D1.3C and D1.3D. Pipes in both the existing (previous phase) and proposed systems were sized to convey the 25-year peak runoff. Calculations for the existing systems were provided in earlier reports; this report includes calculations for representative pipes as required to assure pipe size is adequate for all pipes. Drop inlets and curb inlets have been placed where needed to limit the spread of water in the street, such that an unobstructed (un-flooded) travel lane will be available during a 25-year storm, in accordance with City of Bozeman design standards. Provisions for overland flow of larger, less frequent storms up to the 100-year storm will be incorporated into the site grading. Calculations for gutter spread width, inlet intercept/bypass flows and pipe flows are attached. Bypass flows are accounted for at all existing and proposed on-grade inlets. Conveyance and collection for Phase 5 and 6 sub-basins is described below. Page 5 of 5 Sub-basin D1.2C (Phase 5 construction): Runoff will surface drain to existing curb inlets on Westgate Avenue, about 70 feet north of Herstal Way. Gutter spread width, inlet intercept/bypass and storm drain pipe flows have been re-calculated in this report, to show that the existing storm drain system remains in compliance with City requirements. Sub-basin D1.3C (Phase 6 construction): Runoff will surface drain to a proposed storm drain inlet on the east side of Laurel Parkway, south of its intersection with Debour Lane. The intercepted runoff will drain to a proposed underground (StormTech) detention facility. Sub-basin D1.3D (Phase 5 construction): Runoff will surface drain to a proposed storm drain with four curb inlets in Vaughn Drive, two in Westgate Avenue south of Herstal Way and several drop inlets near the West Lake’s south shore, discharging to a proposed underground (StormTech) detention basin. Runoff draining to Leiden Lane and Vahl Way (inverted crown sections) will surface drain on the asphalt and enter drop inlets at the dead ends. Sub-basin D1.4C (Phase 5 and 6 construction): Runoff will surface drain to existing curb inlets on Laurel Parkway, about 660 feet north of Vaughn Drive. Gutter spread width, inlet intercept/bypass and storm drain pipe flows have been re-calculated in this report, to show that the existing storm drain system remains in compliance with City requirements. Calculations are attached. Design details for Phase 5 and 6 improvements will be provided on the construction drawings. N:\5352\009\Design Docs\Reports\drainage\drainage report (text).docx (this page left blank intentionally)    PEAK RUNOFF AND DETENTION CALCULATIONS (this page left blank intentionally) The Lakes at Valley West, Phases 5 & 6 Peak Runoff and Detention Calculations MODIFIED RATIONAL METHOD i = A * (Tc/60) B Qp = C i A Qp = peak runoff, cfs Design Coefficients C = runoff coefficient Storm AB 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 -0.66 100-yr 1.01 -0.67 (Bozeman Design Standards, March 2004) Sub-Basin Name Area C Tc Q2 Q5 Q10 Q25 Q50 Q100 Basin 1 H1 218.30 0.20 90.6 12.27 17.44 21.38 26.16 30.60 33.46 D1.1 (A+B+C) 116.22 0.20 97.6 6.25 8.85 10.84 13.28 15.51 16.95 D1.2A 5.52 0.48 5.0 4.24 6.76 8.53 10.14 12.57 14.14 D1.2B 3.51 0.50 5.0 2.81 4.48 5.65 6.72 8.32 9.37 D1.2C 1.14 0.50 5.0 0.91 1.45 1.83 2.18 2.70 3.04 D1.2 (A+B+C) 10.17 0.49 6.3 6.92 10.94 13.78 16.42 20.26 22.74 D1.3A 10.98 0.50 5.0 8.78 14.00 17.67 21.01 26.04 29.31 D1.3B 64.30 0.50 90.6 9.04 12.84 15.74 19.26 22.53 24.64 H1.3C1 1.81 0.20 16.1 0.29 0.44 0.54 0.66 0.79 0.88 D1.3C 1.81 0.50 5.0 1.45 2.31 2.91 3.46 4.29 4.83 H1.3D1 7.69 0.20 12.8 1.40 2.15 2.69 3.22 3.92 4.37 D1.3D 7.69 0.50 7.5 4.82 7.57 9.51 11.35 13.95 15.64 West Lake outlet pipe2 88.16 0.50 - 4.60 D1.4A 5.72 0.50 5.0 4.57 7.30 9.20 10.94 13.56 15.27 D1.4B 7.26 0.39 5.0 4.53 7.22 9.11 10.83 13.43 15.11 D1.4 (A+B) 12.98 0.44 5.0 9.10 14.52 18.32 21.78 26.99 30.38 H1.4C1 3.38 0.20 9.9 0.72 1.11 1.40 1.67 2.04 2.28 D1.4C 3.38 0.50 9.4 1.85 2.88 3.61 4.32 5.28 5.91 D1.2+D1.4(A+B) 23.15 0.46 6.3 14.85 23.47 29.54 35.20 43.43 48.77 FOOTNOTES: 1. The pre-development subbasin uses a pre-development C and Tc and an area matching the post-development area, for use in calculating detention volume. 2. Full retention of sub-basins draining into the East and West lakes (D1.3A, D1.3B, D1.3C, D1.3D and D1.4C) was assumed, in order to conservatively estimate the lakes' 25-year maximum water surface elevation and associated maximum discharge. Retention volume = (7,200)*(0.50)*(0.41)*(88.16) =130,124 cu. ft. Using the 5.14-acre combined surface area of the lakes, this correlates to a rise of 0.58 feet above the normal operating elevation of 44.50. An additional 0.5 feet was added to account for partial clogging of the 2' high fish screen. The result (WSEL=45.58) was used to calculate the 25-year peak discharge; see attached calculations for the West Lake Outfall. Culvert Calculator Report West Lake outfall Title: The Lakes at Valley West n:\...\design docs\reports\drainage\old\pipes.cvm 03/15/18 04:35:16 PM Morrison Maierle Inc © Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1-203-755-1666 Project Engineer: mhickman CulvertMaster v3.3 [03.03.00.04] Page 1 of 1 Solve For: Discharge Culvert Summary Allowable HW Elevation 45.58 ft Headwater Depth/Height 4.08 Computed Headwater Eleva 45.58 ft Discharge 4.60 cfs Inlet Control HW Elev. 43.53 ft Tailwater Elevation 40.93 ft Outlet Control HW Elev. 45.58 ft Control Type Outlet Control Grades Upstream Invert 41.50 ft Downstream Invert 40.48 ft Length 280.00 ft Constructed Slope 0.3643 % Hydraulic Profile Profile CompositeM2PressureProfile Depth, Downstream 0.89 ft Slope Type Mild Normal Depth N/A ft Flow Regime Subcritical Critical Depth 0.89 ft Velocity Downstream 6.22 ft/s Critical Slope 1.0589 % Section Section Shape Circular Mannings Coefficient 0.011 Section MaterialCorrugated HDPE (Smooth Interior) Span 1.00 ft Section Size 12 inch Rise 1.00 ft Number Sections 1 Outlet Control Properties Outlet Control HW Elev. 45.58 ft Upstream Velocity Head 0.53 ft Ke 0.50 Entrance Loss 0.27 ft Inlet Control Properties Inlet Control HW Elev. 43.53 ft Flow Control Submerged Inlet Type Square edge w/headwall Area Full 0.8 ft² K 0.00980 HDS 5 Chart 1 M 2.00000 HDS 5 Scale 1 C 0.03980 Equation Form 1 Y 0.67000 Record Id: H1.3C Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Short prairie grass and lawns.: 0.15 50.00 ft 1.00% 0.1500 1.20 in 12.13 min Channel (interm) Grassed (n=0.030) 100.00 ft 1.00% 0.0300 0.98 min Channel (interm) Grassed (n=0.030) 330.00 ft 1.20% 0.0300 2.96 min Pervious TC 16.06 min Record Id: H1.3D Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Short prairie grass and lawns.: 0.15 50.00 ft 1.40% 0.1500 1.20 in 10.60 min Channel (interm) Grassed (n=0.030) 310.00 ft 2.06% 0.0300 2.12 min Channel (interm) Grassed (n=0.030) 30.00 ft 15.00% 0.0300 0.08 min Pervious TC 12.79 min Record Id: H1.4C Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Short prairie grass and lawns.: 0.15 50.00 ft 4.20% 0.1500 1.20 in 6.83 min Channel (interm) Grassed (n=0.030) 380.00 ft 1.50% 0.0300 3.04 min Pervious TC 9.87 min Record Id: D1.3D Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Short prairie grass and lawns.: 0.15 20.00 ft 2.00% 0.1500 1.20 in 4.42 min Shallow Paved and gravel areas (n=0.012) 15.00 ft 3.00% 0.0120 0.05 min Channel (interm) asphalt 180.00 ft 1.20% 0.0120 0.64 min Channel (interm) asphalt 80.00 ft 2.60% 0.0120 0.19 min Channel (interm) storm drain 470.00 ft 0.70% 0.0120 2.20 min Pervious TC 7.51 min Record Id: D1.4C (east) Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Short prairie grass and lawns.: 0.15 20.00 ft 1.00% 0.1500 1.20 in 5.83 min Shallow asphalt 15.00 ft 3.00% 0.0120 0.05 min Channel (interm) asphalt 480.00 ft 1.80% 0.0120 1.40 min Channel (interm) asphalt 420.00 ft 0.60% 0.0120 2.13 min Pervious TC 9.41 min Record Id: D1.4C (west) Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Short prairie grass and lawns.: 0.15 20.00 ft 1.00% 0.1500 1.20 in 5.83 min Shallow Paved and gravel areas (n=0.012) 15.00 ft 3.00% 0.0120 0.05 min Channel (interm) curb & gutter 170.00 ft 1.50% 0.0120 0.54 min Channel (interm) curb & gutter 170.00 ft 2.10% 0.0120 0.46 min Channel (interm) curb & gutter 75.00 ft 1.30% 0.0120 0.26 min Channel (interm) curb & gutter 400.00 ft 0.60% 0.0120 2.03 min Pervious TC 9.17 min The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.4 (A+B) Detention (10-yr storm) MODIFIED RATIONAL METHOD Qp = C i A POST-DEVELOPMENT PRE-DEVEL. 12.98 AC Qp (Basin H1) = 21.38 cfs Basins D1.1 + D1.3 = -15.44 cfs 0.44 Total, D1.2 det + D1.4 det = 5.93 cfs (combined release rate) 5.0 MIN D1.4 release rate = 2.30 cfs 3.22 IN/HR TIME STEP 18.32 CFS DURATION = 5.0 min. Max. Volume, Max. Volume,Required Detention Triangle Rel. (cu. ft.) Constant Rel. (cu. ft.)Volume (cu. ft.) 8664.83 5757.86 7,211 Triangle Release Constant Release DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 4.75 3.33 18.94 4,725 4,136 9.75 2.09 11.87 5,925 5,040 14.75 1.59 9.07 6,662 5,474 19.75 1.32 7.50 7,180 5,684 ORIFICE CALCULATIONS 24.75 1.14 6.48 7,566 5,758 MATCHING Qp = 2.30 cfs 29.75 1.01 5.75 7,860 5,739 Max. Depth = 3.50 ft 34.75 0.91 5.19 8,089 5,651 39.75 0.84 4.76 8,265 5,511 44.75 0.77 4.41 8,401 5,328 CIRCULAR ORIFICE (as-built): 49.75 0.72 4.11 8,503 5,111 DIAMETER = 6.750 inches 54.75 0.68 3.87 8,577 4,864 Area = 0.25 ft2 59.75 0.64 3.65 8,626 4,593 ORIFICE FLOW = 2.24 cfs 64.75 0.61 3.47 8,655 4,300 69.75 0.58 3.30 8,665 3,988 74.75 0.55 3.16 8,659 3,659 RECTANGULAR ORIFICE (not used): 79.75 0.53 3.03 8,638 3,315 LENGTH = 6.125 inches 84.75 0.51 2.91 8,605 2,958 WIDTH = 6.000 inches 89.75 0.49 2.80 8,560 2,588 Area = 0.26 ft2 94.75 0.48 2.71 8,504 2,208 ORIFICE FLOW = 2.30 cfs 99.75 0.46 2.62 8,439 1,817 104.75 0.45 2.54 8,364 1,417 109.75 0.43 2.46 8,281 1,009 114.75 0.42 2.39 8,191 592 119.75 0.41 2.32 8,093 168 WEIR CALCULATIONS (not used) 124.75 0.40 2.26 7,989 -262 Coefficient = 3.33 129.75 0.39 2.21 7,879 -700 Width = 1.250 inches 134.75 0.38 2.15 7,763 -1,143 WEIR FLOW = 2.27 cfs 139.75 0.37 2.10 7,641 -1,592 144.75 0.36 2.05 7,514 -2,046 149.75 0.35 2.01 7,383 -2,506 POND VOLUME CALCULATIONS: BASIN AREA POST = POST-DEV C = POST-DEV Tc = STORM INTENSITY = POST-DEV Qp = DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 154.75 0.35 1.97 7,246 -2,970 159.75 0.34 1.93 7,106 -3,438 164.75 0.33 1.89 6,961 -3,911 169.75 0.33 1.85 6,813 -4,389 174.75 0.32 1.82 6,660 -4,869 179.75 0.31 1.79 6,505 -5,354 184.75 0.31 1.75 6,345 -5,842 189.75 0.30 1.72 6,183 -6,334 194.75 0.30 1.69 6,017 -6,829 199.75 0.29 1.67 5,849 -7,327 204.75 0.29 1.64 5,677 -7,828 209.75 0.28 1.61 5,503 -8,332 214.75 0.28 1.59 5,326 -8,838 219.75 0.28 1.57 5,147 -9,348 224.75 0.27 1.54 4,965 -9,859 229.75 0.27 1.52 4,781 -10,374 234.75 0.26 1.50 4,595 -10,890 239.75 0.26 1.48 4,407 -11,409 244.75 0.26 1.46 4,216 -11,930 249.75 0.25 1.44 4,023 -12,453 254.75 0.25 1.42 3,829 -12,979 259.75 0.25 1.41 3,632 -13,506 264.75 0.24 1.39 3,434 -14,035 269.75 0.24 1.37 3,234 -14,567 274.75 0.24 1.35 3,032 -15,100 279.75 0.24 1.34 2,828 -15,634 284.75 0.23 1.32 2,623 -16,171 289.75 0.23 1.31 2,416 -16,709 294.75 0.23 1.29 2,208 -17,249 299.75 0.22 1.28 1,998 -17,790 304.75 0.22 1.27 1,787 -18,333 309.75 0.22 1.25 1,574 -18,877 314.75 0.22 1.24 1,360 -19,423 319.75 0.22 1.23 1,144 -19,971 324.75 0.21 1.22 928 -20,519 329.75 0.21 1.20 710 -21,069 334.75 0.21 1.19 490 -21,620 339.75 0.21 1.18 270 -22,173 344.75 0.21 1.17 48 -22,727 349.75 0.20 1.16 -175 -23,282 354.75 0.20 1.15 -398 -23,838 359.75 0.20 1.14 -624 -24,396 364.75 0.20 1.13 -850 -24,954 369.75 0.20 1.12 -1,077 -25,514 374.75 0.19 1.11 -1,305 -26,075 379.75 0.19 1.10 -1,534 -26,636 384.75 0.19 1.09 -1,765 -27,199 389.75 0.19 1.08 -1,996 -27,763 394.75 0.19 1.07 -2,228 -28,328 399.75 0.19 1.06 -2,461 -28,894 404.75 0.19 1.05 -2,695 -29,461 409.75 0.18 1.04 -2,930 -30,029 414.75 0.18 1.04 -3,165 -30,597 419.75 0.18 1.03 -3,402 -31,167 424.75 0.18 1.02 -3,639 -31,737 429.75 0.18 1.01 -3,878 -32,309 434.75 0.18 1.01 -4,117 -32,881 439.75 0.18 1.00 -4,357 -33,454 444.75 0.17 0.99 -4,597 -34,028 449.75 0.17 0.98 -4,839 -34,603 454.75 0.17 0.98 -5,081 -35,178 459.75 0.17 0.97 -5,323 -35,754 464.75 0.17 0.96 -5,567 -36,331 The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.4 (A+B) StormTech Sizing Calculations Required Storage Volume 7,211 ft3 StormTech Modules, Model No. SC740 (30" chamber height) Depth to top of gravel 36 in. installed storage volume 74.9 ft3 per chamber (see note 1) Number of chambers required 97 96.28 before rounding excess storage volume 0.7 % Number of chambers proposed 100 excess storage volume 3.7 % equal to 268 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 = 7,480 ft3 Notes: 1. Storage volume assumes 6" of stone above and below chambers, and 40% stone porosity. The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.2 Detention (10-yr storm) MODIFIED RATIONAL METHOD Qp = C i A POST-DEVELOPMENT PRE-DEVEL. 10.17 AC Qp (Basin H1) = 21.38 cfs Basins D1.1 + D1.3 +D1.4 = -17.74 cfs 0.49 D1.2 release rate = 3.63 cfs 6.3 MIN D1.2 release rate = 3.63 cfs 2.77 IN/HR TIME STEP 13.78 CFS DURATION = 5.0 min. Max. Volume, Max. Volume,Required Detention Triangle Rel. (cu. ft.) Constant Rel. (cu. ft.)Volume (cu. ft.) 5029.56 3086.80 4,058 Triangle Release Constant Release DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 5.99 2.86 14.24 3,776 2,787 12.29 1.79 8.93 4,553 3,087 18.59 1.37 6.82 4,893 2,912 24.89 1.13 5.64 5,024 2,509 ORIFICE CALCULATIONS 31.19 0.98 4.87 5,030 1,968 MATCHING Qp = 3.63 cfs 37.49 0.87 4.32 4,949 1,331 Max. Depth = 3.50 ft 43.79 0.79 3.91 4,806 624 50.09 0.72 3.58 4,614 -138 56.39 0.67 3.31 4,383 -945 62.69 0.62 3.09 4,119 -1,787 CIRCULAR ORIFICE (as-built): 68.99 0.58 2.91 3,829 -2,660 DIAMETER = 8.500 inches 75.29 0.55 2.75 3,517 -3,559 Area = 0.39 ft 2 81.59 0.52 2.61 3,184 -4,481 ORIFICE FLOW = 3.55 cfs 87.89 0.50 2.48 2,834 -5,423 94.19 0.48 2.37 2,468 -6,383 100.49 0.46 2.28 2,089 -7,358 RECTANGULAR ORIFICE (not used): 106.79 0.44 2.19 1,698 -8,348 LENGTH = 8.000 inches 113.09 0.42 2.11 1,296 -9,351 WIDTH = 7.825 inches 119.39 0.41 2.04 883 -10,365 Area = 0.43 ft 2 125.69 0.40 1.97 461 -11,390 ORIFICE FLOW = 3.92 cfs 131.99 0.38 1.91 31 -12,425 138.29 0.37 1.85 -407 -13,470 144.59 0.36 1.80 -853 -14,523 150.89 0.35 1.75 -1,305 -15,583 157.19 0.34 1.70 -1,763 -16,652 WEIR CALCULATIONS (not used) 163.49 0.33 1.66 -2,228 -17,727 Coefficient = 3.33 169.79 0.33 1.62 -2,697 -18,808 Width = 2.500 inches 176.09 0.32 1.58 -3,172 -19,896 WEIR FLOW = 4.54 cfs 182.39 0.31 1.55 -3,652 -20,990 188.69 0.30 1.51 -4,137 -22,089 194.99 0.30 1.48 -4,625 -23,193 POST-DEV Qp = POND VOLUME CALCULATIONS: BASIN AREA POST = POST-DEV Tc = POST-DEV C = STORM INTENSITY = DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 201.29 0.29 1.45 -5,118 -24,302 207.59 0.29 1.42 -5,615 -25,416 213.89 0.28 1.39 -6,116 -26,534 220.19 0.27 1.37 -6,620 -27,657 226.49 0.27 1.34 -7,127 -28,783 232.79 0.27 1.32 -7,638 -29,914 239.09 0.26 1.30 -8,151 -31,048 245.39 0.26 1.27 -8,668 -32,186 251.69 0.25 1.25 -9,188 -33,327 257.99 0.25 1.23 -9,710 -34,471 264.29 0.24 1.21 -10,234 -35,618 270.59 0.24 1.20 -10,762 -36,769 276.89 0.24 1.18 -11,291 -37,922 283.19 0.23 1.16 -11,823 -39,079 289.49 0.23 1.14 -12,357 -40,238 295.79 0.23 1.13 -12,894 -41,399 302.09 0.22 1.11 -13,432 -42,563 308.39 0.22 1.10 -13,972 -43,730 314.69 0.22 1.08 -14,515 -44,898 320.99 0.22 1.07 -15,059 -46,070 327.29 0.21 1.06 -15,605 -47,243 333.59 0.21 1.04 -16,152 -48,418 339.89 0.21 1.03 -16,702 -49,596 346.19 0.20 1.02 -17,253 -50,776 352.49 0.20 1.01 -17,806 -51,957 358.79 0.20 1.00 -18,360 -53,141 365.09 0.20 0.98 -18,915 -54,326 371.39 0.20 0.97 -19,473 -55,513 377.69 0.19 0.96 -20,031 -56,702 383.99 0.19 0.95 -20,591 -57,893 390.29 0.19 0.94 -21,152 -59,085 396.59 0.19 0.93 -21,715 -60,279 402.89 0.19 0.92 -22,279 -61,474 409.19 0.18 0.91 -22,844 -62,671 415.49 0.18 0.91 -23,410 -63,870 421.79 0.18 0.90 -23,978 -65,070 428.09 0.18 0.89 -24,547 -66,271 434.39 0.18 0.88 -25,116 -67,474 440.69 0.18 0.87 -25,687 -68,678 446.99 0.17 0.86 -26,259 -69,884 453.29 0.17 0.86 -26,832 -71,091 459.59 0.17 0.85 -27,406 -72,299 465.89 0.17 0.84 -27,981 -73,508 472.19 0.17 0.83 -28,557 -74,719 478.49 0.17 0.83 -29,134 -75,931 484.79 0.16 0.82 -29,712 -77,144 491.09 0.16 0.81 -30,291 -78,358 497.39 0.16 0.81 -30,871 -79,573 503.69 0.16 0.80 -31,451 -80,789 509.99 0.16 0.79 -32,033 -82,007 516.29 0.16 0.79 -32,615 -83,225 522.59 0.16 0.78 -33,198 -84,445 528.89 0.16 0.77 -33,782 -85,665 535.19 0.15 0.77 -34,367 -86,887 541.49 0.15 0.76 -34,952 -88,109 547.79 0.15 0.76 -35,538 -89,333 554.09 0.15 0.75 -36,125 -90,557 560.39 0.15 0.75 -36,713 -91,783 566.69 0.15 0.74 -37,302 -93,009 572.99 0.15 0.73 -37,891 -94,236 579.29 0.15 0.73 -38,481 -95,464 585.59 0.15 0.72 -39,071 -96,693 The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.2 StormTech Sizing Calculations Required Storage Volume 4,058 ft3 StormTech Modules, Model No. SC740 (30" chamber height) Depth to top of gravel 36 in. installed storage volume 74.90 ft3 per chamber (see note 1) Number of chambers required 55 54.18 before rounding excess storage volume 1.5 % Number of chambers proposed 77 (as-built) excess storage volume 29.6 % equal to (see note 2) 1,203 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 = 5,261 ft3 Notes: 1. Storage volume assumes 6" of stone above and between chambers, and 40% stone porosity. 2. 1,203 cubic feet equates to a maximum allowable groundwater elevation of about 3.6" above the bottom of the chambers, without infringing on the required detention. Groundwater will not reach this depth due to the free draining outfall (discharge elevation at bottom of chambers). The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.3C Detention (10-yr storm) MODIFIED RATIONAL METHOD Qp = C i A POST-DEVELOPMENT PRE-DEVEL. 1.81 AC Qp (Basin H1.3C) = 0.54 cfs 0.50 5.0 MIN D1.3C release rate = 0.54 cfs 3.22 IN/HR TIME STEP 2.91 CFS DURATION = 5.0 min. Max. Volume, Max. Volume,Required Detention Triangle Rel. (cu. ft.) Constant Rel. (cu. ft.)Volume (cu. ft.) 1073.87 692.17 883 Triangle Release Constant Release DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 4.75 3.33 3.01 699 569 9.75 2.09 1.89 863 669 14.75 1.59 1.44 953 692 19.75 1.32 1.19 1,009 679 ORIFICE CALCULATIONS 24.75 1.14 1.03 1,043 643 MATCHING Qp = 0.54 cfs 29.75 1.01 0.91 1,063 593 Max. Depth = 3.10 ft 34.75 0.91 0.83 1,073 531 39.75 0.84 0.76 1,074 460 44.75 0.77 0.70 1,069 383 CIRCULAR ORIFICE: 49.75 0.72 0.65 1,058 299 DIAMETER = 3.375 inches 54.75 0.68 0.61 1,043 211 Area = 0.06 ft2 59.75 0.64 0.58 1,024 119 ORIFICE FLOW = 0.53 cfs 64.75 0.61 0.55 1,001 23 69.75 0.58 0.53 976 -76 74.75 0.55 0.50 948 -178 RECTANGULAR ORIFICE: 79.75 0.53 0.48 918 -282 LENGTH = 3.000 84.75 0.51 0.46 886 -388 WIDTH = 3.000 inches 89.75 0.49 0.45 852 -497 Area = 0.06 ft2 94.75 0.48 0.43 816 -607 ORIFICE FLOW = 0.53 cfs 99.75 0.46 0.42 779 -719 104.75 0.45 0.40 740 -833 109.75 0.43 0.39 700 -948 114.75 0.42 0.38 659 -1,064 119.75 0.41 0.37 617 -1,181 WEIR CALCULATIONS 124.75 0.40 0.36 573 -1,300 Coefficient = 3.33 inches 129.75 0.39 0.35 529 -1,420 Width = 0.344 inches 134.75 0.38 0.34 484 -1,540 WEIR FLOW = 0.52 cfs 139.75 0.37 0.33 437 -1,662 144.75 0.36 0.33 390 -1,785 149.75 0.35 0.32 343 -1,908 POND VOLUME CALCULATIONS: BASIN AREA POST = POST-DEV C = POST-DEV Tc = STORM INTENSITY = POST-DEV Qp = DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 154.75 0.35 0.31 294 -2,032 159.75 0.34 0.31 245 -2,157 164.75 0.33 0.30 195 -2,283 169.75 0.33 0.29 144 -2,410 174.75 0.32 0.29 93 -2,537 179.75 0.31 0.28 42 -2,664 184.75 0.31 0.28 -10 -2,792 189.75 0.30 0.27 -63 -2,921 194.75 0.30 0.27 -116 -3,051 199.75 0.29 0.27 -170 -3,181 204.75 0.29 0.26 -224 -3,311 209.75 0.28 0.26 -279 -3,442 214.75 0.28 0.25 -334 -3,573 219.75 0.28 0.25 -389 -3,705 224.75 0.27 0.25 -445 -3,837 229.75 0.27 0.24 -501 -3,970 234.75 0.26 0.24 -557 -4,103 239.75 0.26 0.24 -614 -4,236 244.75 0.26 0.23 -671 -4,370 249.75 0.25 0.23 -729 -4,504 254.75 0.25 0.23 -787 -4,639 259.75 0.25 0.22 -845 -4,774 264.75 0.24 0.22 -903 -4,909 269.75 0.24 0.22 -962 -5,044 274.75 0.24 0.22 -1,021 -5,180 279.75 0.24 0.21 -1,080 -5,316 284.75 0.23 0.21 -1,140 -5,452 289.75 0.23 0.21 -1,199 -5,589 294.75 0.23 0.21 -1,259 -5,726 299.75 0.22 0.20 -1,320 -5,863 304.75 0.22 0.20 -1,380 -6,001 309.75 0.22 0.20 -1,441 -6,138 314.75 0.22 0.20 -1,502 -6,276 319.75 0.22 0.20 -1,563 -6,414 324.75 0.21 0.19 -1,624 -6,553 329.75 0.21 0.19 -1,686 -6,692 334.75 0.21 0.19 -1,747 -6,830 339.75 0.21 0.19 -1,809 -6,970 344.75 0.21 0.19 -1,871 -7,109 349.75 0.20 0.18 -1,934 -7,248 354.75 0.20 0.18 -1,996 -7,388 359.75 0.20 0.18 -2,059 -7,528 364.75 0.20 0.18 -2,122 -7,668 369.75 0.20 0.18 -2,185 -7,808 374.75 0.19 0.18 -2,248 -7,949 379.75 0.19 0.17 -2,311 -8,090 384.75 0.19 0.17 -2,375 -8,230 389.75 0.19 0.17 -2,438 -8,371 394.75 0.19 0.17 -2,502 -8,513 399.75 0.19 0.17 -2,566 -8,654 404.75 0.19 0.17 -2,630 -8,795 409.75 0.18 0.17 -2,694 -8,937 414.75 0.18 0.16 -2,759 -9,079 419.75 0.18 0.16 -2,823 -9,221 424.75 0.18 0.16 -2,888 -9,363 429.75 0.18 0.16 -2,952 -9,505 434.75 0.18 0.16 -3,017 -9,648 439.75 0.18 0.16 -3,082 -9,790 444.75 0.17 0.16 -3,147 -9,933 449.75 0.17 0.16 -3,213 -10,076 454.75 0.17 0.16 -3,278 -10,219 459.75 0.17 0.15 -3,343 -10,362 464.75 0.17 0.15 -3,409 -10,505 The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.3C StormTech Sizing Calculations Required Storage Volume 883 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 13 12.96 before rounding excess storage volume 0.3 % Number of chambers proposed 16 excess storage volume 19.0 % equal to 168 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 = 1,051 ft3 Notes: 1. Storage volume assumes 6" of stone above and between chambers, and 40% stone porosity. The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.3D Detention (10-yr storm) MODIFIED RATIONAL METHOD Qp = C i A POST-DEVELOPMENT PRE-DEVEL. 7.69 AC Qp (Basin H1.3D) = 2.69 cfs 0.50 7.5 MIN D1.3D release rate = 2.69 cfs 2.47 IN/HR TIME STEP 9.51 CFS DURATION = 5.0 min. Max. Volume, Max. Volume,Required Detention Triangle Rel. (cu. ft.) Constant Rel. (cu. ft.)Volume (cu. ft.) 3927.49 2365.75 3,147 Triangle Release Constant Release DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 7.13 2.56 9.83 3,024 2,175 14.63 1.60 6.16 3,622 2,366 22.13 1.22 4.71 3,860 2,162 29.63 1.01 3.89 3,927 1,769 ORIFICE CALCULATIONS 37.13 0.87 3.36 3,892 1,261 MATCHING Qp = 2.69 cfs 44.63 0.78 2.98 3,785 673 Max. Depth = 3.10 ft 52.13 0.70 2.70 3,627 26 59.63 0.64 2.47 3,429 -667 67.13 0.59 2.29 3,198 -1,397 CIRCULAR ORIFICE: 74.63 0.56 2.14 2,942 -2,157 DIAMETER = 7.625 inches 82.13 0.52 2.01 2,663 -2,942 Area = 0.32 ft2 89.63 0.49 1.90 2,366 -3,749 ORIFICE FLOW = 2.69 cfs 97.13 0.47 1.80 2,052 -4,576 104.63 0.45 1.71 1,724 -5,419 112.13 0.43 1.64 1,384 -6,277 RECTANGULAR ORIFICE: 119.63 0.41 1.57 1,032 -7,148 LENGTH = 7.000 127.13 0.39 1.51 670 -8,031 WIDTH = 6.500 inches 134.63 0.38 1.46 299 -8,925 Area = 0.32 ft2 142.13 0.37 1.40 -81 -9,829 ORIFICE FLOW = 2.68 cfs 149.63 0.35 1.36 -468 -10,742 157.13 0.34 1.32 -862 -11,663 164.63 0.33 1.28 -1,262 -12,592 172.13 0.32 1.24 -1,668 -13,528 179.63 0.31 1.21 -2,080 -14,471 WEIR CALCULATIONS 187.13 0.31 1.17 -2,497 -15,420 Coefficient = 3.33 194.63 0.30 1.15 -2,919 -16,375 Width = 1.7500 inches 202.13 0.29 1.12 -3,345 -17,335 WEIR FLOW = 2.65 cfs 209.63 0.28 1.09 -3,776 -18,301 217.13 0.28 1.07 -4,211 -19,271 224.63 0.27 1.04 -4,649 -20,246 POND VOLUME CALCULATIONS: BASIN AREA POST = POST-DEV C = POST-DEV Tc = STORM INTENSITY = POST-DEV Qp = DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 232.13 0.27 1.02 -5,091 -21,225 239.63 0.26 1.00 -5,536 -22,209 247.13 0.26 0.98 -5,985 -23,196 254.63 0.25 0.96 -6,437 -24,187 262.13 0.25 0.94 -6,891 -25,182 269.63 0.24 0.93 -7,348 -26,180 277.13 0.24 0.91 -7,808 -27,182 284.63 0.23 0.89 -8,271 -28,186 292.13 0.23 0.88 -8,736 -29,194 299.63 0.23 0.87 -9,203 -30,204 307.13 0.22 0.85 -9,672 -31,217 314.63 0.22 0.84 -10,144 -32,233 322.13 0.21 0.83 -10,617 -33,251 329.63 0.21 0.81 -11,093 -34,272 337.13 0.21 0.80 -11,570 -35,295 344.63 0.21 0.79 -12,049 -36,320 352.13 0.20 0.78 -12,530 -37,348 359.63 0.20 0.77 -13,013 -38,378 367.13 0.20 0.76 -13,497 -39,409 374.63 0.19 0.75 -13,983 -40,443 382.13 0.19 0.74 -14,471 -41,479 389.63 0.19 0.73 -14,960 -42,516 397.13 0.19 0.72 -15,450 -43,556 404.63 0.19 0.71 -15,942 -44,597 412.13 0.18 0.70 -16,435 -45,640 419.63 0.18 0.70 -16,929 -46,684 427.13 0.18 0.69 -17,425 -47,730 434.63 0.18 0.68 -17,922 -48,778 442.13 0.17 0.67 -18,420 -49,827 449.63 0.17 0.66 -18,920 -50,878 457.13 0.17 0.66 -19,420 -51,930 464.63 0.17 0.65 -19,922 -52,984 472.13 0.17 0.64 -20,424 -54,039 479.63 0.17 0.64 -20,928 -55,095 487.13 0.16 0.63 -21,433 -56,153 494.63 0.16 0.62 -21,938 -57,211 502.13 0.16 0.62 -22,445 -58,271 509.63 0.16 0.61 -22,952 -59,333 517.13 0.16 0.61 -23,461 -60,395 524.63 0.16 0.60 -23,970 -61,459 532.13 0.15 0.60 -24,481 -62,524 539.63 0.15 0.59 -24,992 -63,589 547.13 0.15 0.58 -25,504 -64,656 554.63 0.15 0.58 -26,017 -65,724 562.13 0.15 0.57 -26,530 -66,793 569.63 0.15 0.57 -27,045 -67,863 577.13 0.15 0.57 -27,560 -68,935 584.63 0.15 0.56 -28,076 -70,007 592.13 0.14 0.56 -28,593 -71,080 599.63 0.14 0.55 -29,110 -72,153 607.13 0.14 0.55 -29,628 -73,228 614.63 0.14 0.54 -30,147 -74,304 622.13 0.14 0.54 -30,666 -75,381 629.63 0.14 0.53 -31,186 -76,458 637.13 0.14 0.53 -31,707 -77,536 644.63 0.14 0.53 -32,229 -78,616 652.13 0.14 0.52 -32,751 -79,695 659.63 0.13 0.52 -33,273 -80,776 667.13 0.13 0.51 -33,797 -81,858 674.63 0.13 0.51 -34,320 -82,940 682.13 0.13 0.51 -34,845 -84,023 689.63 0.13 0.50 -35,370 -85,107 697.13 0.13 0.50 -35,895 -86,192 The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.3D StormTech Sizing Calculations Required Storage Volume 3,147 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 47 46.18 before rounding excess storage volume 1.7 % Number of chambers proposed 55 excess storage volume 16.0 % equal to 505 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 = 3,651 ft3 Notes: 1. Storage volume assumes 6" of stone above and between chambers, and 40% stone porosity. The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.4C Detention (10-yr storm) MODIFIED RATIONAL METHOD Qp = C i A POST-DEVELOPMENT PRE-DEVEL. 3.38 AC Qp (Basin H1) = 1.40 cfs 0.50 9.4 MIN D1.4 release rate = 1.40 cfs 2.14 IN/HR 3.3 3.61 CFS DURATION = 5.0 min. Max. Volume, Max. Volume,Required Detention Triangle Rel. (cu. ft.) Constant Rel. (cu. ft.)Volume (cu. ft.) 1417.44 758.56 1,088 1.2 Triangle Release Constant Release DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 8.93 2.21 3.73 1,232 759 18.33 1.38 2.34 1,410 719 27.73 1.06 1.79 1,417 478 37.13 0.87 1.48 1,344 139 ORIFICE CALCULATIONS 46.53 0.76 1.28 1,221 -260 MATCHING Qp = 1.40 cfs 55.93 0.67 1.13 1,064 -701 Max. Depth = 3.50 ft 65.33 0.61 1.02 883 -1,173 74.73 0.55 0.94 682 -1,669 84.13 0.51 0.87 467 -2,184 CIRCULAR ORIFICE (as-built): 93.53 0.48 0.81 239 -2,715 DIAMETER = 5.000 inches 102.93 0.45 0.76 0 -3,260 Area = 0.14 ft2 112.33 0.43 0.72 -247 -3,817 ORIFICE FLOW = 1.23 cfs 121.73 0.40 0.68 -502 -4,384 131.13 0.39 0.65 -764 -4,960 140.53 0.37 0.62 -1,032 -5,544 RECTANGULAR ORIFICE: 149.93 0.35 0.60 -1,306 -6,135 LENGTH = 5.000 inches 159.33 0.34 0.57 -1,584 -6,732 WIDTH = 4.375 inches 168.73 0.33 0.55 -1,866 -7,335 Area = 0.15 ft2 178.13 0.32 0.53 -2,153 -7,944 ORIFICE FLOW = 1.37 cfs 187.53 0.31 0.52 -2,443 -8,558 196.93 0.30 0.50 -2,736 -9,176 206.33 0.29 0.48 -3,033 -9,798 215.73 0.28 0.47 -3,332 -10,424 225.13 0.27 0.46 -3,634 -11,054 WEIR CALCULATIONS 234.53 0.26 0.45 -3,938 -11,688 Coefficient = 3.33 243.93 0.26 0.43 -4,245 -12,324 Width = 0.7500 inches 253.33 0.25 0.42 -4,554 -12,964 WEIR FLOW = 1.36 cfs 262.73 0.25 0.41 -4,865 -13,606 272.13 0.24 0.40 -5,177 -14,251 281.53 0.23 0.40 -5,492 -14,898 POND VOLUME CALCULATIONS: BASIN AREA POST = POST-DEV C = POST-DEV Tc = STORM INTENSITY = POST-DEV Qp = DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 290.93 0.23 0.39 -5,808 -15,548 300.33 0.22 0.38 -6,126 -16,201 309.73 0.22 0.37 -6,445 -16,855 319.13 0.22 0.36 -6,766 -17,511 328.53 0.21 0.36 -7,088 -18,170 337.93 0.21 0.35 -7,412 -18,830 347.33 0.20 0.35 -7,737 -19,492 356.73 0.20 0.34 -8,063 -20,156 366.13 0.20 0.33 -8,390 -20,822 375.53 0.19 0.33 -8,718 -21,489 384.93 0.19 0.32 -9,047 -22,157 394.33 0.19 0.32 -9,377 -22,827 403.73 0.19 0.31 -9,709 -23,499 413.13 0.18 0.31 -10,041 -24,172 422.53 0.18 0.30 -10,374 -24,846 431.93 0.18 0.30 -10,708 -25,521 441.33 0.17 0.30 -11,043 -26,198 450.73 0.17 0.29 -11,378 -26,876 460.13 0.17 0.29 -11,715 -27,555 469.53 0.17 0.28 -12,052 -28,235 478.93 0.17 0.28 -12,390 -28,917 488.33 0.16 0.28 -12,728 -29,599 497.73 0.16 0.27 -13,067 -30,282 507.13 0.16 0.27 -13,407 -30,967 516.53 0.16 0.27 -13,748 -31,652 525.93 0.16 0.26 -14,089 -32,338 535.33 0.15 0.26 -14,431 -33,025 544.73 0.15 0.26 -14,773 -33,713 554.13 0.15 0.25 -15,116 -34,402 563.53 0.15 0.25 -15,460 -35,092 572.93 0.15 0.25 -15,804 -35,782 582.33 0.15 0.25 -16,148 -36,474 591.73 0.14 0.24 -16,493 -37,166 601.13 0.14 0.24 -16,839 -37,858 610.53 0.14 0.24 -17,185 -38,552 619.93 0.14 0.24 -17,532 -39,246 629.33 0.14 0.23 -17,879 -39,941 638.73 0.14 0.23 -18,226 -40,637 648.13 0.14 0.23 -18,574 -41,333 657.53 0.13 0.23 -18,922 -42,030 666.93 0.13 0.23 -19,271 -42,728 676.33 0.13 0.22 -19,620 -43,426 685.73 0.13 0.22 -19,970 -44,125 695.13 0.13 0.22 -20,320 -44,825 704.53 0.13 0.22 -20,670 -45,525 713.93 0.13 0.22 -21,021 -46,226 723.33 0.13 0.21 -21,372 -46,927 732.73 0.13 0.21 -21,723 -47,629 742.13 0.12 0.21 -22,075 -48,331 751.53 0.12 0.21 -22,427 -49,034 760.93 0.12 0.21 -22,779 -49,737 770.33 0.12 0.21 -23,132 -50,441 779.73 0.12 0.20 -23,485 -51,146 789.13 0.12 0.20 -23,839 -51,850 798.53 0.12 0.20 -24,192 -52,556 807.93 0.12 0.20 -24,546 -53,262 817.33 0.12 0.20 -24,901 -53,968 826.73 0.12 0.20 -25,255 -54,675 836.13 0.12 0.20 -25,610 -55,382 845.53 0.11 0.19 -25,965 -56,090 854.93 0.11 0.19 -26,321 -56,798 864.33 0.11 0.19 -26,676 -57,506 873.73 0.11 0.19 -27,032 -58,215 The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.4C StormTech Sizing Calculations Required Storage Volume 1,088 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 16 15.97 before rounding excess storage volume 0.2 % Number of chambers proposed 18 (as-built) excess storage volume 11.3 % equal to 123 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 = 1,211 ft3 Notes: 1. Storage volume assumes 6" of stone above and between chambers, and 40% stone porosity.    (this page left blank intentionally)    GUTTER FLOW CALCULATIONS    (this page left blank intentionally) The Lakes at Valley West, Phases 5 & 6 Gutter Flow, Direct (Surface) Runoff Calculations 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 Sub-Basin Description Area1 Tc CQp Vaughn Drive West of Westgate, north side 0.78 5.00 0.50 1.49 West of Westgate, south side 0.34 5.00 0.50 0.65 East of Westgate, north side 0.09 5.00 0.50 0.17 East of Westgate, south side 0.67 5.00 0.50 1.28 Westgate Avenue South of Herstal, west side 0.42 5.00 0.50 0.80 South of Herstal, east side 0.43 5.00 0.50 0.82 North of Herstal, west side3 1.51 5.00 0.50 2.89 North of Herstal, east side3 0.16 5.00 0.50 0.31 South of roundabout, west side park inlet3 1.19 5.00 0.50 2.28 South of roundabout, west curb inlet3 0.53 5.00 0.50 1.01 South of roundabout, east curb inlet3 0.78 5.00 0.50 1.49 South quadrant of roundabout3 1.54 5.00 0.50 2.95 Alleys2 Manhole at Leiden's NW dead end 1.30 5.00 0.50 2.49 Manhole at Leiden's NE dead end 1.27 5.00 0.50 2.43 Vahl, NW dead end 1.51 5.00 0.50 2.89 Laurel Parkway South of Debour, double inlet, east side 1.81 5.00 0.50 3.46 Sta. 8+00 existing double inlet, east side 1.67 9.40 0.50 2.13 Sta. 13+97.18, existing east inlet (low point) 1.70 5.00 0.35 2.28 Sta. 8+00 existing double inlet, west side 1.71 9.20 0.50 2.21 Sta. 13+97.18, existing west inlet (low point) 1.41 5.00 0.50 2.70 FOOTNOTES: 1 Areas and flow rates are for direct runoff only and do not include inlet bypass. Inlet bypass flow is accounted for on the following page. 2 Typical section for alleys is an inverted crown with 2% slope toward the center. 3 These subbasins were defined in previous phases of construction; refer to previous drainage reports. The Lakes at Valley West, Phases 5 & 6 Gutter Spread Width Calculations 25-yr. Peak Runoff (cfs) Gutter Sub-Basin Description Direct1 Upstream2 Total Inlet Type Bypass Spread (ft.) Vaughn Drive West of Westgate, north side 1.49 0.00 1.49 sag 0.00 5.32 West of Westgate, south side 0.65 0.00 0.65 sag 0.00 3.10 East of Westgate, north side 0.17 0.00 0.17 sag 0.00 1.28 East of Westgate, south side 1.28 0.00 1.28 sag 0.00 4.84 Westgate Avenue South of Herstal, west side 0.80 0.00 0.80 on grade 0.08 4.14 South of Herstal, east side 0.82 0.00 0.82 on grade 0.09 4.19 North of Herstal, west side4 2.89 0.08 2.97 on grade 1.17 9.03 North of Herstal, east side4 0.31 0.09 0.40 on grade 0.02 4.04 South of roundabout, west side park inlet4 2.28 0.00 2.28 drop inlet 0.00 n/a South of roundabout, west curb inlet4 1.01 1.17 2.18 on grade 0.74 8.00 South of roundabout, east curb inlet4 1.49 0.02 1.51 on grade 0.41 6.93 South quadrant of roundabout4 2.95 0.74 3.69 sag 0.00 9.11 Alleys3 Manhole at Leiden's NW dead end 2.49 0.00 2.49 - 0.00 13.62 Manhole at Leiden's NE dead end 2.43 0.00 2.43 - 0.00 12.15 Vahl, NW dead end 2.89 0.00 2.89 - 0.00 13.67 Laurel Parkway South of Debour, double inlet, east side 3.46 0.00 3.46 on grade 0.88 8.38 Sta. 8+00 existing double inlet, east side 2.13 0.88 3.01 on grade 0.59 9.20 Sta. 13+97.18, existing east inlet (low point) 2.28 0.59 2.87 sag 0.00 8.83 Sta. 8+00 existing double inlet, west side 2.21 0.00 2.21 on grade 0.34 8.18 Sta. 13+97.18, existing west inlet (low point) 2.70 0.34 3.04 sag 0.00 9.12 FOOTNOTES: 1 Direct runoff is from "Gutter Flow" calculations on the previous page, and does not include runoff from upstream inlets. 2 Upstream runoff is the bypass flow from contributing upstream inlets. 3 For alleys with inverted crown, minor submergence is acceptable. The maximum submergence at the wheels of a car straddling the inverted crown centerline would be less than 1.5 inches, which is considered acceptble for the short duration of peak runoff involved. 4 These subbasins were defined in previous phases of construction; refer to previous drainage reports. Project Description Solve For Spread Input Data Discharge 1.49 ft³/s Gutter Width 1.50 ft Gutter Cross Slope 6.25 % Road Cross Slope 3.00 % Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 3.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 3.00 ft Opening Height 5.00 in Curb Throat Type Vertical Throat Incline Angle 0.00 degrees Options Calculation Option Use Both Results Spread 5.32 ft Depth 2.50 in Gutter Depression 0.05 ft Total Depression 0.13 ft Open Grate Area 1.22 ft² Active Grate Weir Length 5.40 ft Vaughn west of Westgate, north side (25-yr) 3/19/2018 3:31:26 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 1of1Page Project Description Solve For Spread Input Data Discharge 0.65 ft³/s Gutter Width 1.50 ft Gutter Cross Slope 6.25 % Road Cross Slope 3.00 % Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 3.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 3.00 ft Opening Height 5.00 in Curb Throat Type Vertical Throat Incline Angle 0.00 degrees Options Calculation Option Use Both Results Spread 3.10 ft Depth 1.70 in Gutter Depression 0.05 ft Total Depression 0.13 ft Open Grate Area 1.22 ft² Active Grate Weir Length 5.40 ft Vaughn west of Westgate, south side (25-yr) 3/19/2018 3:34:37 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 1of1Page Project Description Solve For Spread Input Data Discharge 0.17 ft³/s Gutter Width 1.50 ft Gutter Cross Slope 6.25 % Road Cross Slope 3.00 % Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 3.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 3.00 ft Opening Height 5.00 in Curb Throat Type Vertical Throat Incline Angle 0.00 degrees Options Calculation Option Use Both Results Spread 1.28 ft Depth 0.82 in Gutter Depression 0.05 ft Total Depression 0.13 ft Open Grate Area 1.22 ft² Active Grate Weir Length 5.40 ft Vaughn east of Westgate, north side (25-yr) 1/5/2018 9:17:58 AM 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 1of1Page Project Description Solve For Spread Input Data Discharge 1.28 ft³/s Gutter Width 1.50 ft Gutter Cross Slope 6.25 % Road Cross Slope 3.00 % Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 3.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 3.00 ft Opening Height 5.00 in Curb Throat Type Vertical Throat Incline Angle 0.00 degrees Options Calculation Option Use Both Results Spread 4.84 ft Depth 2.33 in Gutter Depression 0.05 ft Total Depression 0.13 ft Open Grate Area 1.22 ft² Active Grate Weir Length 5.40 ft Vaughn east of Westgate, south side (25-yr) 3/19/2018 3:35:51 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 1of1Page Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Channel Slope 2.30 % Discharge 0.80 ft³/s Section Definitions Station (ft)Elevation (ft) 0+00.33 0.45 0+00.50 0.00 0+02.00 0.08 0+16.00 0.50 Roughness Segment Definitions Start Station Ending Station Roughness Coefficient (0+00.33, 0.45) (0+16.00, 0.50) 0.013 Options Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Pavlovskii's Method Results Normal Depth 1.89 in Elevation Range 0.00 to 0.50 ft Flow Area 0.28 ft² Wetted Perimeter 4.26 ft Hydraulic Radius 0.79 in Top Width 4.14 ft Normal Depth 1.89 in Critical Depth 0.20 ft Critical Slope 0.00575 ft/ft Westgate gutter south of Herstal, west side (25-yr) 3/19/2018 3:40:02 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 Results Velocity 2.85 ft/s Velocity Head 0.13 ft Specific Energy 0.28 ft Froude Number 1.93 Flow Type Supercritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 1.89 in Critical Depth 0.20 ft Channel Slope 2.30 % Critical Slope 0.00575 ft/ft Westgate gutter south of Herstal, west side (25-yr) 3/19/2018 3:40:02 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 2of2Page Project Description Solve For Efficiency Input Data Discharge 0.80 ft³/s Slope 2.30 % Gutter Width 1.50 ft Gutter Cross Slope 6.30 % Road Cross Slope 3.00 % Roughness Coefficient 0.013 Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 3.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 3.00 ft Options Calculation Option Use Both Grate Flow Option Exclude None Results Efficiency 89.43 % Intercepted Flow 0.72 ft³/s Bypass Flow 0.08 ft³/s Spread 3.56 ft Depth 1.88 in Flow Area 0.23 ft² Gutter Depression 0.05 ft Total Depression 0.13 ft Velocity 3.51 ft/s Splash Over Velocity 5.18 ft/s Frontal Flow Factor 1.00 Side Flow Factor 0.13 Grate Flow Ratio 0.84 Equivalent Cross Slope 0.10418 ft/ft Active Grate Length 2.40 ft Length Factor 0.06 Total Interception Length 9.27 ft Westgate south of Herstal, west side (25-yr) 3/19/2018 3:43:03 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 Channel Slope 2.30 % Discharge 0.82 ft³/s Section Definitions Station (ft)Elevation (ft) 0+00.33 0.45 0+00.50 0.00 0+02.00 0.08 0+16.00 0.50 Roughness Segment Definitions Start Station Ending Station Roughness Coefficient (0+00.33, 0.45) (0+16.00, 0.50) 0.013 Options Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Pavlovskii's Method Results Normal Depth 1.91 in Elevation Range 0.00 to 0.50 ft Flow Area 0.29 ft² Wetted Perimeter 4.30 ft Hydraulic Radius 0.80 in Top Width 4.19 ft Normal Depth 1.91 in Critical Depth 0.20 ft Critical Slope 0.00574 ft/ft Westgate gutter south of Herstal, east side (25-yr) 3/19/2018 3:44:15 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 Results Velocity 2.86 ft/s Velocity Head 0.13 ft Specific Energy 0.29 ft Froude Number 1.93 Flow Type Supercritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 1.91 in Critical Depth 0.20 ft Channel Slope 2.30 % Critical Slope 0.00574 ft/ft Westgate gutter south of Herstal, east side (25-yr) 3/19/2018 3:44:15 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 2of2Page Project Description Solve For Efficiency Input Data Discharge 0.82 ft³/s Slope 2.30 % Gutter Width 1.50 ft Gutter Cross Slope 6.30 % Road Cross Slope 3.00 % Roughness Coefficient 0.013 Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 3.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 3.00 ft Options Calculation Option Use Both Grate Flow Option Exclude None Results Efficiency 89.01 % Intercepted Flow 0.73 ft³/s Bypass Flow 0.09 ft³/s Spread 3.61 ft Depth 1.89 in Flow Area 0.23 ft² Gutter Depression 0.05 ft Total Depression 0.13 ft Velocity 3.53 ft/s Splash Over Velocity 5.18 ft/s Frontal Flow Factor 1.00 Side Flow Factor 0.13 Grate Flow Ratio 0.83 Equivalent Cross Slope 0.10374 ft/ft Active Grate Length 2.40 ft Length Factor 0.06 Total Interception Length 9.39 ft Westgate south of Herstal, east side (25-yr) 3/19/2018 3:45:05 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 Channel Slope 0.65 % Discharge 2.97 ft³/s Section Definitions Station (ft)Elevation (ft) 0+00.33 0.45 0+00.50 0.00 0+02.00 0.08 0+16.00 0.50 Roughness Segment Definitions Start Station Ending Station Roughness Coefficient (0+00.33, 0.45) (0+16.00, 0.50) 0.013 Options Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Pavlovskii's Method Results Normal Depth 3.63 in Elevation Range 0.00 to 0.50 ft Flow Area 1.24 ft² Wetted Perimeter 9.24 ft Hydraulic Radius 1.60 in Top Width 9.03 ft Normal Depth 3.63 in Critical Depth 0.32 ft Critical Slope 0.00484 ft/ft Westgate gutter north of Herstal, west side (25-yr) 3/19/2018 3:47:21 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 Results Velocity 2.40 ft/s Velocity Head 0.09 ft Specific Energy 0.39 ft Froude Number 1.15 Flow Type Supercritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 3.63 in Critical Depth 0.32 ft Channel Slope 0.65 % Critical Slope 0.00484 ft/ft Westgate gutter north of Herstal, west side (25-yr) 3/19/2018 3:47:21 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 2of2Page Project Description Solve For Efficiency Input Data Discharge 2.97 ft³/s Slope 0.65 % Gutter Width 1.50 ft Gutter Cross Slope 6.30 % Road Cross Slope 3.00 % Roughness Coefficient 0.013 Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 3.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 3.00 ft Options Calculation Option Use Both Grate Flow Option Exclude None Results Efficiency 60.69 % Intercepted Flow 1.80 ft³/s Bypass Flow 1.17 ft³/s Spread 8.21 ft Depth 3.55 in Flow Area 1.05 ft² Gutter Depression 0.05 ft Total Depression 0.13 ft Velocity 2.84 ft/s Splash Over Velocity 5.18 ft/s Frontal Flow Factor 1.00 Side Flow Factor 0.19 Grate Flow Ratio 0.46 Equivalent Cross Slope 0.07077 ft/ft Active Grate Length 2.40 ft Length Factor 0.04 Total Interception Length 13.88 ft Westgate north of Herstal, west side (25-yr) 3/19/2018 3:48:40 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 Channel Slope 0.65 % Discharge 0.40 ft³/s Section Definitions Station (ft)Elevation (ft) 0+00.33 0.45 0+00.50 0.00 0+02.00 0.08 0+16.00 0.50 Roughness Segment Definitions Start Station Ending Station Roughness Coefficient (0+00.33, 0.45) (0+16.00, 0.50) 0.013 Options Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Pavlovskii's Method Results Normal Depth 1.85 in Elevation Range 0.00 to 0.50 ft Flow Area 0.27 ft² Wetted Perimeter 4.15 ft Hydraulic Radius 0.78 in Top Width 4.04 ft Normal Depth 1.85 in Critical Depth 0.16 ft Critical Slope 0.00629 ft/ft Westgate gutter north of Herstal, east side (25-yr) 3/19/2018 3:49:39 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 Results Velocity 1.49 ft/s Velocity Head 0.03 ft Specific Energy 0.19 ft Froude Number 1.02 Flow Type Supercritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 1.85 in Critical Depth 0.16 ft Channel Slope 0.65 % Critical Slope 0.00629 ft/ft Westgate gutter north of Herstal, east side (25-yr) 3/19/2018 3:49:39 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 2of2Page Project Description Solve For Efficiency Input Data Discharge 0.40 ft³/s Slope 0.65 % Gutter Width 1.50 ft Gutter Cross Slope 6.30 % Road Cross Slope 3.00 % Roughness Coefficient 0.013 Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 3.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 3.00 ft Options Calculation Option Use Both Grate Flow Option Exclude None Results Efficiency 94.72 % Intercepted Flow 0.38 ft³/s Bypass Flow 0.02 ft³/s Spread 3.46 ft Depth 1.84 in Flow Area 0.22 ft² Gutter Depression 0.05 ft Total Depression 0.13 ft Velocity 1.85 ft/s Splash Over Velocity 5.18 ft/s Frontal Flow Factor 1.00 Side Flow Factor 0.33 Grate Flow Ratio 0.85 Equivalent Cross Slope 0.10526 ft/ft Active Grate Length 2.40 ft Length Factor 0.13 Total Interception Length 4.71 ft Westgate north of Herstal, east side (25-yr) 3/19/2018 3:50:46 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 Channel Slope 0.65 % Discharge 2.18 ft³/s Section Definitions Station (ft)Elevation (ft) 0+00.33 0.45 0+00.50 0.00 0+02.00 0.08 0+16.00 0.50 Roughness Segment Definitions Start Station Ending Station Roughness Coefficient (0+00.33, 0.45) (0+16.00, 0.50) 0.013 Options Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Pavlovskii's Method Results Normal Depth 3.26 in Elevation Range 0.00 to 0.50 ft Flow Area 0.98 ft² Wetted Perimeter 8.19 ft Hydraulic Radius 1.43 in Top Width 8.00 ft Normal Depth 3.26 in Critical Depth 0.28 ft Critical Slope 0.00504 ft/ft Westgate gutter south of roundabout, west curb inlet (25-yr) 1/8/2018 11:54:29 AM 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 Results Velocity 2.23 ft/s Velocity Head 0.08 ft Specific Energy 0.35 ft Froude Number 1.13 Flow Type Supercritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 3.26 in Critical Depth 0.28 ft Channel Slope 0.65 % Critical Slope 0.00504 ft/ft Westgate gutter south of roundabout, west curb inlet (25-yr) 1/8/2018 11:54:29 AM 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 2of2Page Project Description Solve For Efficiency Input Data Discharge 2.18 ft³/s Slope 0.65 % Gutter Width 1.50 ft Gutter Cross Slope 6.30 % Road Cross Slope 3.00 % Roughness Coefficient 0.013 Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 3.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 3.00 ft Options Calculation Option Use Both Grate Flow Option Exclude None Results Efficiency 66.28 % Intercepted Flow 1.44 ft³/s Bypass Flow 0.74 ft³/s Spread 7.25 ft Depth 3.20 in Flow Area 0.83 ft² Gutter Depression 0.05 ft Total Depression 0.13 ft Velocity 2.64 ft/s Splash Over Velocity 5.18 ft/s Frontal Flow Factor 1.00 Side Flow Factor 0.21 Grate Flow Ratio 0.51 Equivalent Cross Slope 0.07535 ft/ft Active Grate Length 2.40 ft Length Factor 0.05 Total Interception Length 11.74 ft Westgate south of roundabout, west curb inlet (25-yr) 3/19/2018 3:54:20 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 Channel Slope 0.65 % Discharge 1.51 ft³/s Section Definitions Station (ft)Elevation (ft) 0+00.33 0.45 0+00.50 0.00 0+02.00 0.08 0+16.00 0.50 Roughness Segment Definitions Start Station Ending Station Roughness Coefficient (0+00.33, 0.45) (0+16.00, 0.50) 0.013 Options Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Pavlovskii's Method Results Normal Depth 2.88 in Elevation Range 0.00 to 0.50 ft Flow Area 0.74 ft² Wetted Perimeter 7.10 ft Hydraulic Radius 1.25 in Top Width 6.93 ft Normal Depth 2.88 in Critical Depth 0.25 ft Critical Slope 0.00530 ft/ft Westgate gutter south of roundabout, east side (25-yr) 1/8/2018 3:49:35 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 Results Velocity 2.04 ft/s Velocity Head 0.06 ft Specific Energy 0.31 ft Froude Number 1.10 Flow Type Supercritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 2.88 in Critical Depth 0.25 ft Channel Slope 0.65 % Critical Slope 0.00530 ft/ft Westgate gutter south of roundabout, east side (25-yr) 1/8/2018 3:49:35 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 2of2Page Project Description Solve For Efficiency Input Data Discharge 1.51 ft³/s Slope 0.65 % Gutter Width 1.50 ft Gutter Cross Slope 6.30 % Road Cross Slope 3.00 % Roughness Coefficient 0.013 Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 3.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 3.00 ft Options Calculation Option Use Both Grate Flow Option Exclude None Results Efficiency 73.06 % Intercepted Flow 1.10 ft³/s Bypass Flow 0.41 ft³/s Spread 6.24 ft Depth 2.84 in Flow Area 0.62 ft² Gutter Depression 0.05 ft Total Depression 0.13 ft Velocity 2.43 ft/s Splash Over Velocity 5.18 ft/s Frontal Flow Factor 1.00 Side Flow Factor 0.23 Grate Flow Ratio 0.58 Equivalent Cross Slope 0.08128 ft/ft Active Grate Length 2.40 ft Length Factor 0.06 Total Interception Length 9.61 ft Westgate south of roundabout, east side (25-yr) 1/8/2018 3:48:44 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 Solve For Spread Input Data Discharge 3.69 ft³/s Gutter Width 1.50 ft Gutter Cross Slope 6.25 % Road Cross Slope 3.00 % Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 3.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 3.00 ft Opening Height 5.00 in Curb Throat Type Vertical Throat Incline Angle 0.00 degrees Options Calculation Option Use Both Results Spread 9.11 ft Depth 3.87 in Gutter Depression 0.05 ft Total Depression 0.13 ft Open Grate Area 1.22 ft² Active Grate Weir Length 5.40 ft Westgate, south quadrant of roundabout (25-yr) 1/8/2018 4:01:52 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 1of1Page Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Roughness Coefficient 0.013 Channel Slope 2.00 % Left Side Slope 50.00 ft/ft (H:V) Right Side Slope 50.00 ft/ft (H:V) Discharge 2.49 ft³/s Results Normal Depth 1.63 in Flow Area 0.93 ft² Wetted Perimeter 13.62 ft Hydraulic Radius 0.82 in Top Width 13.62 ft Critical Depth 0.17 ft Critical Slope 0.00557 ft/ft Velocity 2.68 ft/s Velocity Head 0.11 ft Specific Energy 0.25 ft Froude Number 1.81 Flow Type Supercritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 1.63 in Critical Depth 0.17 ft Channel Slope 2.00 % Critical Slope 0.00557 ft/ft Leiden, NW dead end (25-yr) 3/23/2018 1:31:32 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 1of1Page Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Roughness Coefficient 0.013 Channel Slope 3.50 % Left Side Slope 50.00 ft/ft (H:V) Right Side Slope 50.00 ft/ft (H:V) Discharge 2.43 ft³/s Results Normal Depth 1.46 in Flow Area 0.74 ft² Wetted Perimeter 12.16 ft Hydraulic Radius 0.73 in Top Width 12.15 ft Critical Depth 0.17 ft Critical Slope 0.00559 ft/ft Velocity 3.29 ft/s Velocity Head 0.17 ft Specific Energy 0.29 ft Froude Number 2.35 Flow Type Supercritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 1.46 in Critical Depth 0.17 ft Channel Slope 3.50 % Critical Slope 0.00559 ft/ft Leiden, NE dead end (25-yr) 3/19/2018 3:58:24 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 1of1Page Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Roughness Coefficient 0.013 Channel Slope 2.60 % Left Side Slope 50.00 ft/ft (H:V) Right Side Slope 50.00 ft/ft (H:V) Discharge 2.89 ft³/s Results Normal Depth 1.64 in Flow Area 0.93 ft² Wetted Perimeter 13.67 ft Hydraulic Radius 0.82 in Top Width 13.67 ft Critical Depth 0.18 ft Critical Slope 0.00546 ft/ft Velocity 3.09 ft/s Velocity Head 0.15 ft Specific Energy 0.29 ft Froude Number 2.09 Flow Type Supercritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 1.64 in Critical Depth 0.18 ft Channel Slope 2.60 % Critical Slope 0.00546 ft/ft Vahl, NW dead end (25-yr) 3/23/2018 1:38:24 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 1of1Page Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Channel Slope 1.30 % Discharge 3.46 ft³/s Section Definitions Station (ft)Elevation (ft) 0+00.33 0.45 0+00.50 0.00 0+02.00 0.08 0+16.00 0.50 Roughness Segment Definitions Start Station Ending Station Roughness Coefficient (0+00.33, 0.45) (0+16.00, 0.50) 0.013 Options Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Pavlovskii's Method Results Normal Depth 3.40 in Elevation Range 0.00 to 0.50 ft Flow Area 1.07 ft² Wetted Perimeter 8.58 ft Hydraulic Radius 1.49 in Top Width 8.38 ft Normal Depth 3.40 in Critical Depth 0.34 ft Critical Slope 0.00474 ft/ft Laurel gutter south of Debour, east side (25-yr) 5/24/2018 2:34:56 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 Results Velocity 3.24 ft/s Velocity Head 0.16 ft Specific Energy 0.45 ft Froude Number 1.60 Flow Type Supercritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 3.40 in Critical Depth 0.34 ft Channel Slope 1.30 % Critical Slope 0.00474 ft/ft Laurel gutter south of Debour, east side (25-yr) 5/24/2018 2:34:56 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 2of2Page Project Description Solve For Efficiency Input Data Discharge 3.46 ft³/s Slope 1.30 % Gutter Width 1.50 ft Gutter Cross Slope 6.30 % Road Cross Slope 3.00 % Roughness Coefficient 0.013 Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 6.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 6.00 ft Options Calculation Option Use Both Grate Flow Option Exclude None Results Efficiency 74.67 % Intercepted Flow 2.58 ft³/s Bypass Flow 0.88 ft³/s Spread 7.60 ft Depth 3.33 in Flow Area 0.90 ft² Gutter Depression 0.05 ft Total Depression 0.13 ft Velocity 3.83 ft/s Splash Over Velocity 8.74 ft/s Frontal Flow Factor 1.00 Side Flow Factor 0.40 Grate Flow Ratio 0.49 Equivalent Cross Slope 0.07360 ft/ft Active Grate Length 4.80 ft Length Factor 0.07 Total Interception Length 17.79 ft Laurel south of Debour double inlet, east side (25-yr) 5/24/2018 2:47:12 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 Channel Slope 0.60 % Discharge 3.01 ft³/s Section Definitions Station (ft)Elevation (ft) 0+00.33 0.45 0+00.50 0.00 0+02.00 0.08 0+16.00 0.50 Roughness Segment Definitions Start Station Ending Station Roughness Coefficient (0+00.33, 0.45) (0+16.00, 0.50) 0.013 Options Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Pavlovskii's Method Results Normal Depth 3.69 in Elevation Range 0.00 to 0.50 ft Flow Area 1.28 ft² Wetted Perimeter 9.42 ft Hydraulic Radius 1.63 in Top Width 9.20 ft Normal Depth 3.69 in Critical Depth 0.32 ft Critical Slope 0.00483 ft/ft Laurel Sta. 8+00 gutter, east side (25-yr) 5/24/2018 2:26:40 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 Results Velocity 2.35 ft/s Velocity Head 0.09 ft Specific Energy 0.39 ft Froude Number 1.11 Flow Type Supercritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 3.69 in Critical Depth 0.32 ft Channel Slope 0.60 % Critical Slope 0.00483 ft/ft Laurel Sta. 8+00 gutter, east side (25-yr) 5/24/2018 2:26:40 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 2of2Page Project Description Solve For Efficiency Input Data Discharge 3.01 ft³/s Slope 0.60 % Gutter Width 1.50 ft Gutter Cross Slope 6.30 % Road Cross Slope 3.00 % Roughness Coefficient 0.013 Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 6.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 6.00 ft Options Calculation Option Use Both Grate Flow Option Exclude None Results Efficiency 80.55 % Intercepted Flow 2.42 ft³/s Bypass Flow 0.59 ft³/s Spread 8.38 ft Depth 3.61 in Flow Area 1.09 ft² Gutter Depression 0.05 ft Total Depression 0.13 ft Velocity 2.76 ft/s Splash Over Velocity 8.74 ft/s Frontal Flow Factor 1.00 Side Flow Factor 0.54 Grate Flow Ratio 0.45 Equivalent Cross Slope 0.07002 ft/ft Active Grate Length 4.80 ft Length Factor 0.09 Total Interception Length 13.71 ft Laurel Sta. 8+00 double inlet, east side (25-yr) 5/24/2018 2:28:19 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 Solve For Spread Input Data Discharge 2.87 ft³/s Gutter Width 1.50 ft Gutter Cross Slope 6.25 % Road Cross Slope 3.00 % Local Depression 0.08 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 3.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 3.00 ft Opening Height 5.00 in Curb Throat Type Vertical Throat Incline Angle 0.00 degrees Options Calculation Option Use Both Results Spread 8.83 ft Depth 3.76 in Gutter Depression 0.05 ft Total Depression 0.06 ft Open Grate Area 1.22 ft² Active Grate Weir Length 5.40 ft Laurel Sta. 13+97.18 (at Durston), east side (25-yr) 5/24/2018 2:56:40 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 1of1Page Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Channel Slope 0.60 % Discharge 2.21 ft³/s Section Definitions Station (ft)Elevation (ft) 0+00.33 0.45 0+00.50 0.00 0+02.00 0.08 0+16.00 0.50 Roughness Segment Definitions Start Station Ending Station Roughness Coefficient (0+00.33, 0.45) (0+16.00, 0.50) 0.013 Options Current Roughness Weighted Method Pavlovskii's Method Open Channel Weighting Method Pavlovskii's Method Closed Channel Weighting Method Pavlovskii's Method Results Normal Depth 3.33 in Elevation Range 0.00 to 0.50 ft Flow Area 1.02 ft² Wetted Perimeter 8.38 ft Hydraulic Radius 1.46 in Top Width 8.18 ft Normal Depth 3.33 in Critical Depth 0.29 ft Critical Slope 0.00504 ft/ft Laurel Sta. 8+00 gutter, west side (25-yr) 3/19/2018 4:12:26 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 Results Velocity 2.17 ft/s Velocity Head 0.07 ft Specific Energy 0.35 ft Froude Number 1.08 Flow Type Supercritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 3.33 in Critical Depth 0.29 ft Channel Slope 0.60 % Critical Slope 0.00504 ft/ft Laurel Sta. 8+00 gutter, west side (25-yr) 3/19/2018 4:12:26 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 2of2Page Project Description Solve For Efficiency Input Data Discharge 2.21 ft³/s Slope 0.60 % Gutter Width 1.50 ft Gutter Cross Slope 6.30 % Road Cross Slope 3.00 % Roughness Coefficient 0.013 Local Depression 1.00 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 6.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 6.00 ft Options Calculation Option Use Both Grate Flow Option Exclude None Results Efficiency 84.59 % Intercepted Flow 1.87 ft³/s Bypass Flow 0.34 ft³/s Spread 7.41 ft Depth 3.26 in Flow Area 0.86 ft² Gutter Depression 0.05 ft Total Depression 0.13 ft Velocity 2.57 ft/s Splash Over Velocity 8.74 ft/s Frontal Flow Factor 1.00 Side Flow Factor 0.57 Grate Flow Ratio 0.50 Equivalent Cross Slope 0.07453 ft/ft Active Grate Length 4.80 ft Length Factor 0.10 Total Interception Length 11.60 ft Laurel Sta. 8+00 double inlet, west side (25-yr) 3/19/2018 4:13:50 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 Solve For Spread Input Data Discharge 3.04 ft³/s Gutter Width 1.50 ft Gutter Cross Slope 6.25 % Road Cross Slope 3.00 % Local Depression 0.08 in Local Depression Width 1.50 ft Grate Width 1.50 ft Grate Length 3.00 ft Grate Type 30˚ Tilt Bar Clogging 20.00 % Curb Opening Length 3.00 ft Opening Height 5.00 in Curb Throat Type Vertical Throat Incline Angle 0.00 degrees Options Calculation Option Use Both Results Spread 9.12 ft Depth 3.87 in Gutter Depression 0.05 ft Total Depression 0.06 ft Open Grate Area 1.22 ft² Active Grate Weir Length 5.40 ft Laurel Sta. 13+97.18 (at Durston ), west side (25-yr) 3/19/2018 4:14:52 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 1of1Page (this page left blank intentionally)    PIPE FLOW CALCULATIONS    (this page left blank intentionally) The Lakes at Valley West, Phases 5 & 6 Pipe Flow Calculations 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 Sub-Basin Description Area1 Tc CQdirect2 Qtotal3 Qint4 Qbypass Qpipe5 Pipe Dia.6 Notes Vaughn Drive West of Westgate, north side 0.78 5.00 0.50 1.49 1.49 1.49 0.00 1.49 12" West of Westgate, south side 0.34 5.00 0.50 0.65 0.65 0.65 0.00 2.14 12" East of Westgate, north side 0.09 5.00 0.50 0.17 0.17 0.17 0.00 0.17 12" East of Westgate, south side 0.67 5.00 0.50 1.28 1.28 1.28 0.00 1.45 12" Vaughn/Westgate manhole 3.60 15" Westgate Avenue South of Herstal, west side 0.42 5.00 0.50 0.80 0.80 0.72 0.08 0.72 12" South of Herstal, east side 0.43 5.00 0.50 0.82 0.82 0.73 0.09 5.05 15" North of Herstal, west side7 1.51 5.00 0.50 2.89 2.97 1.80 1.17 1.80 12" North of Herstal, east side7 0.16 5.00 0.50 0.31 0.40 0.38 0.02 2.17 18" as-built10 South of roundabout, west side park inlet7 1.19 5.00 0.50 2.28 2.28 2.28 0.00 2.28 12" as-built10 South of roundabout, west curb inlet7 0.53 5.00 0.50 1.01 2.18 1.44 0.74 3.72 15" as-built10 South of roundabout, east curb inlet7 0.78 5.00 0.50 1.49 1.51 1.10 0.41 7.00 24" as-built10 South quadrant of roundabout7 1.54 5.00 0.50 2.95 3.69 3.69 0.00 4.43 15" as-built10 Manhole at roundabout7 11.42 24"as-built10 Alleys7 Manhole at Leiden's NW dead end 1.30 5.00 0.50 2.49 2.49 2.49 0.00 7.54 18" Vahl, NW dead end 1.51 5.00 0.50 2.89 2.89 2.89 0.00 2.89 12" Manhole between Vahl & Leiden 0.71 5.00 0.50 1.36 1.36 1.36 0.00 4.25 15" Manhole at Leiden's NE dead end 1.27 5.00 0.50 2.43 2.43 2.43 0.00 6.68 18" Manhole 55' north of Leiden's NW dead end 0.17 5.00 0.50 0.33 0.33 0.33 0.00 11.35 24" South inlet pipe to Detention D1.3D 9 7.69 7.50 0.50 11.35 11.35 24" Laurel Parkway South of Debour, double inlet, east side 1.81 5.00 0.50 3.46 3.46 2.58 0.88 2.58 12" Sta. 8+00 existing double inlet, east side 1.67 9.40 0.50 2.13 3.01 2.42 0.59 3.30 12"as-built10 Sta. 13+97.18, 65' east (drop inlet) 2.00 5.00 0.35 2.68 2.68 2.68 0.00 2.68 12" as-built10 Sta. 13+97.18, existing east inlet (low point) 1.70 5.00 0.35 2.28 2.87 2.87 0.00 6.13 18" as-built10 Sta. 8+00 double inlet, west side 1.71 9.20 0.50 2.21 2.21 1.87 0.34 5.18 12"as-built10 Detention D1.4C discharge pipe9 3.30 9.30 0.50 4.24 4.24 15" as-built10 Sta. 13+97.18, existing west inlet (low point) 1.41 5.00 0.50 2.70 3.04 3.04 0.00 9.51 18" as-built10 FOOTNOTES: 1 Contributing drainage area 2 Qdirect is direct surface runoff to the inlet, and does not include bypass flows from upstream inlets. 3 Qtotal is total peak surface runoff to the inlet (direct runoff plus bypass flows from upstream inlets). 4 Qint is surface runoff intercepted by the inlet. 5 Qpipe is total flow to outlet pipe (total pipe flow from upstream inlets plus surface runoff intercepted at the inlet). 6 Calculations are attached where "Pipe Dia." column uses bold text. Other pipe sizes are evident based on flow rates. 7 These subbasins were defined in previous phases of construction; refer to previous drainage reports. 8 Qpipe for alleys is the total runoff to the nearest downstream drop inlet or manhole. 9 Equal to values in the Peak Runoff and Detention calculations. 10 Pipes were sized and installed during previous phases of construction. Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Roughness Coefficient 0.013 Channel Slope 0.60 % Diameter 12.00 in Discharge 2.89 ft³/s Results Normal Depth 10.44 in Flow Area 0.73 ft² Wetted Perimeter 2.40 ft Hydraulic Radius 3.62 in Top Width 0.67 ft Critical Depth 0.73 ft Percent Full 87.0 % Critical Slope 0.00847 ft/ft Velocity 3.98 ft/s Velocity Head 0.25 ft Specific Energy 1.12 ft Froude Number 0.68 Maximum Discharge 2.97 ft³/s Discharge Full 2.76 ft³/s Slope Full 0.00658 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 87.02 % Downstream Velocity Infinity ft/s 12" pipe at 0.60% slope (25-yr) 3/23/2018 2:28:11 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 0.013 Channel Slope 0.60 % Diameter 15.00 in Discharge 5.05 ft³/s Results Normal Depth 12.42 in Flow Area 1.09 ft² Wetted Perimeter 2.86 ft Hydraulic Radius 4.56 in Top Width 0.94 ft Critical Depth 0.91 ft Percent Full 82.8 % Critical Slope 0.00787 ft/ft Velocity 4.65 ft/s Velocity Head 0.34 ft Specific Energy 1.37 ft Froude Number 0.76 Maximum Discharge 5.38 ft³/s Discharge Full 5.00 ft³/s Slope Full 0.00611 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 82.83 % Downstream Velocity Infinity ft/s 15" pipe at 0.60% slope (25-yr) 3/20/2018 9:46:58 AM 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 0.013 Channel Slope 0.60 % Diameter 18.00 in Discharge 7.54 ft³/s Results Normal Depth 13.69 in Flow Area 1.44 ft² Wetted Perimeter 3.18 ft Hydraulic Radius 5.44 in Top Width 1.28 ft Critical Depth 1.06 ft Percent Full 76.1 % Critical Slope 0.00710 ft/ft Velocity 5.23 ft/s Velocity Head 0.42 ft Specific Energy 1.57 ft Froude Number 0.87 Maximum Discharge 8.75 ft³/s Discharge Full 8.14 ft³/s Slope Full 0.00515 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 76.07 % Downstream Velocity Infinity ft/s 18" pipe at 0.60% slope (25-yr) 3/23/2018 2:27:18 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 0.013 Channel Slope 0.60 % Diameter 24.00 in Discharge 11.42 ft³/s Results Normal Depth 14.12 in Flow Area 1.92 ft² Wetted Perimeter 3.50 ft Hydraulic Radius 6.60 in Top Width 1.97 ft Critical Depth 1.21 ft Percent Full 58.8 % Critical Slope 0.00546 ft/ft Velocity 5.94 ft/s Velocity Head 0.55 ft Specific Energy 1.73 ft Froude Number 1.06 Maximum Discharge 18.85 ft³/s Discharge Full 17.52 ft³/s Slope Full 0.00255 ft/ft Flow Type SuperCritical GVF Input Data Downstream Depth 0.00 in Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 in Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 58.84 % Downstream Velocity Infinity ft/s 24" pipe at 0.60% slope (25-yr) 5/7/2018 9:18:37 AM 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 Culvert Calculator Report Laurel Sta. 8+00 east side, 12" pipe to west side (25-yr) Title: The Lakes at Valley West n:\5352\009\design docs\reports\drainage\pipes.cvm 05/24/18 03:13:17 PM Morrison Maierle Inc © Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1-203-755-1666 Project Engineer: mhickman CulvertMaster v3.3 [03.03.00.04] Page 1 of 1 Solve For: Headwater Elevation Culvert Summary Allowable HW Elevation 54.50 ft Headwater Depth/Height 3.86 Computed Headwater Eleva 53.96 ft Discharge 3.30 cfs Inlet Control HW Elev. 53.12 ft Tailwater Elevation 53.12 ft Outlet Control HW Elev. 53.96 ft Control Type Outlet Control Grades Upstream Invert 50.10 ft Downstream Invert 49.52 ft Length 58.00 ft Constructed Slope 1.0000 % Hydraulic Profile Profile PressureProfile Depth, Downstream 3.60 ft Slope Type N/A Normal Depth 0.71 ft Flow Regime N/A Critical Depth 0.78 ft Velocity Downstream 4.20 ft/s Critical Slope 0.8108 % Section Section Shape Circular Mannings Coefficient 0.012 Section MaterialCorrugated HDPE (Smooth Interior) Span 1.00 ft Section Size 12 inch Rise 1.00 ft Number Sections 1 Outlet Control Properties Outlet Control HW Elev. 53.96 ft Upstream Velocity Head 0.27 ft Ke 0.50 Entrance Loss 0.14 ft Inlet Control Properties Inlet Control HW Elev. 53.12 ft Flow Control Submerged Inlet Type Square edge w/headwall Area Full 0.8 ft² K 0.00980 HDS 5 Chart 1 M 2.00000 HDS 5 Scale 1 C 0.03980 Equation Form 1 Y 0.67000 Culvert Calculator Report Laurel Sta. 8+00 west side, 12" pipe to detention (25-yr) Title: The Lakes at Valley West n:\5352\009\design docs\reports\drainage\pipes.cvm 05/24/18 03:28:45 PM Morrison Maierle Inc © Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1-203-755-1666 Project Engineer: mhickman CulvertMaster v3.3 [03.03.00.04] Page 1 of 1 Solve For: Headwater Elevation Culvert Summary Allowable HW Elevation 54.50 ft Headwater Depth/Height 3.58 Computed Headwater Eleva 53.10 ft Discharge 5.18 cfs Inlet Control HW Elev. 51.91 ft Tailwater Elevation 51.80 ft Outlet Control HW Elev. 53.10 ft Control Type Outlet Control Grades Upstream Invert 49.52 ft Downstream Invert 49.20 ft Length 16.00 ft Constructed Slope 2.0000 % Hydraulic Profile Profile PressureProfile Depth, Downstream 2.60 ft Slope Type N/A Normal Depth 0.78 ft Flow Regime N/A Critical Depth 0.93 ft Velocity Downstream 6.60 ft/s Critical Slope 1.5602 % Section Section Shape Circular Mannings Coefficient 0.012 Section MaterialCorrugated HDPE (Smooth Interior) Span 1.00 ft Section Size 12 inch Rise 1.00 ft Number Sections 1 Outlet Control Properties Outlet Control HW Elev. 53.10 ft Upstream Velocity Head 0.68 ft Ke 0.50 Entrance Loss 0.34 ft Inlet Control Properties Inlet Control HW Elev. 51.91 ft Flow Control Submerged Inlet Type Square edge w/headwall Area Full 0.8 ft² K 0.00980 HDS 5 Chart 1 M 2.00000 HDS 5 Scale 1 C 0.03980 Equation Form 1 Y 0.67000    DRAINAGE MAPS    (this page left blank intentionally) HUFFINE LANE DURSTON ROAD COTTONWOOD ROADBABCOCK STREETGOOCH HILL ROADLAURELPARKWAYBAXTERAAJCKERCREEKCREEK© PROJECT NO. FIGURE NUMBER COPYRIGHT MORRISON-MAIERLE, INC.,2018 N:\5352\009\ACAD\Exhibits\PH 5 Pre-Development.dwg Plotted by cooper krause on Jan/9/2018 DRAWN BY: DSGN. BY: APPR. BY: DATE:engineers surveyors planners scientists MorrisonMaierle 5352.009 FIG. 1 THE LAKES AT VALLEY WEST PHASES 5 AND 6 PRE-DEVELOPMENT DRAINAGE BOZEMAN MONTANA CPK MGH JRN 01/2018 2880 Technology Blvd West Bozeman, MT 59718 Phone: 406.587.0721 Fax: 406.922.6702 (this page left blank intentionally) SDSDSDSDSDSDSDSDSDSDSDSD 15SD15SD15SD15SD18SD18SD12SD12SD010010020050HORIZ. SCALEIN FEETDURSTON ROADD1.1A0.82D1.2B3.51D1.3A10.98D1.3B64.30D1.1B114.16D2.13.94D2.21.62D1.4 A5.72LAUREL PARKWAYWESTMORLAND DRIVE1.500.500.800.800.500.701.75DURSTON ROADHUFFINE LANECOTTONWOOD ROADMATCH LINEMATCH LINEPHASE 1PHASE 2VICINITY MAPSCALE: 1"=1000'D1.1B114.16D1.3B61.93GOOCH HILL ROADAAJKER CREEKBAXTER CREEKEXISTING 2-3614" x 2212" ARCPEXISTING36" CMPEXISTINGCUTOFF DITCHSOUTH SITE BOUNDARYBAXTER CREEK WEST LAKEEAST LAKEEXISTING DRAINAGEEXISTINGDETENTIONSTORAGE D1.2LEGENDSUB-BASIN BOUNDARYX.XXX.XXPOST-DEVELOPMENTSUB-BASIN DESIGNATIONSUB-BASIN AREAPHASE BOUNDARYDITCH OR SWALED1.4 B7.26EXISTING 12" PVCEAST LAKE OUTLETEXISTINGDETENTIONBASIN 2.1EXISTINGDETENTIONSTORAGE D1.4EXISTING 12" PVCWEST LAKE OUTLET0.60EXISTINGCULVERTEXTENSIONEXISTING 88" x 44" ARCP CULVERTD1.1C1.24D1.2 A5.52EXISTING DETENTIONSTORAGE 1.4CFIGURE NUMBER©PROJECT NO.DRAWN BY:DSGN. BY:APPR. BY:DATE:COPYRIGHT MORRISON-MAIERLE, INC.,2018N:\5352\009\ACAD\Exhibits\PH 5 Post-Development.dwg Plotted by cooper krause on May/24/2018engineers surveyors planners scientistsMorrisonMaierle5352.009FIG. 2THE LAKES AT VALLEY WESTPHASES 5 AND 6BOZEMANMONTANAPOST-DEVELOPEMENT DRAINAGE MAPDSMGHJRN12/2017PHASE 3WESTGATE AVE.EXISTINGSTORM DRAINPHASE 4HERSTAL WAYPHASE 5PHASE 6D1.3D7.69D1.3C1.81D1.4C3.38D1.2C1.14HERSTAL WAYLEIDEN LANEVAHL WAYDEBOUR LANEVAUGHN DRIVEPROPOSED DETENTIONSTORAGE D1.3DHERSTAL WAYPROPOSED DETENTIONSTORAGE D1.3C             (this page left blank intentionally) I P:\10678-Laurel Parkway LLC\001 - Norton Ranch Lift Station\04 Design\Reports\Stormwater\NortonRanch-StormMemo_20250206.docx ATTACHMENT I ADDENDUM TO STORM DRAINAGE REPORT FOR THE LAKES AT VALLEY WEST, PHASES 5 AND 6 (DATED 4-9-21) Page 2 of 4 Phase 6 drainage basins. This runoff flows to the existing pair of 36¼” x 22½” RCP arch pipes (double culvert) under Durston Road. Sub-basin D1.3 consists of includes the following: - D1.3C covers part of Phase 6 and will drain to the East Lake (sub-basin D1.3B). With this addendum, sub-basin D1.3C also includes the additional 0.14 acres south of The Lakes and within the east half of the Laurel Parkway right-of-way. - D1.4C includes Laurel Parkway and adjacent parts of Phases 5 and 6, and will drain to an existing underground (StormTech) detention and treatment facility discharging to the West Lake (sub-basin D1.3A). With this addendum, sub-basin D1.4C also includes the additional 0.21 acres south of The Lakes and within the west half of the Laurel Parkway right-of-way. Sub-basin D1.4: Because sub-basin D1.4C drains to the West Lake, it is included in the discussion above for sub-basin D1.3. Part 3 Detention Basins Three underground detention and treatment facilities (D1.2, D1.4 and D1.4C) were constructed in earlier phases and sized to accommodate construction of all future phases including the last two (Phases 5 and 6), which are the subject of this report. The attached calculations confirm that with site runoff routed through the existing, “as-built” control structures, the existing storage volumes and release rates remain in compliance with City drainage policy through final buildout of all contributing phases of the Lakes at Valley West subdivision. The three existing detention facilities facility of interest, named to correspond to their respective sub-basins, are is described below. Sub-basin D1.4C: D1.4C detention was sized and constructed as part of Phases 1 and 2, incorporating additional capacity for future phases. Calculations have been revised for detention facility D1.4C using the “as-built” storage and discharge parameters from Phase 1 and 2 construction. Results are summarized in Table 1. This addendum incorporates the additional 0.21 acres south of The Lakes and within the west half of the Laurel Parkway right-of-way, which drains to detention facility D1.4C. This facility was designed and constructed with excess capacity as a contingency. The amended calculations confirm that adequate capacity exists for the proposed offsite addition, and that no changes to the existing structure are necessary except to modify the orifice size for the 10-year release rate. In addition to the existing detention facilities described above, two additional detention facilities are proposed for construction during the final phases of development (Phases 5 and 6). Both will discharge to the onsite lakes, and offsite runoff rate is therefore unaffected due to onsite detention in the lakes. However, both will be constructed to provide treatment and to limit peak runoff to the pre-development rate, in accordance with City of Bozeman drainage policy. The two proposed detention basins, named to correspond to their respective sub-basins sub-basin, are basin of interest is described below. Sub-basin D1.3C (Phase 6 construction): Detention facility D1.3C is proposed as an underground (StormTech) detention storage and treatment facility to be located northeast of the Laurel Parkway/Debour Lane intersection, discharging to the East Lake. Calculations are attached; results are summarized in Table 1. Page 3 of 4 This addendum incorporates the additional 0.14 acres south of The Lakes and within the east half of the Laurel Parkway right-of-way, which drains to detention facility D1.3C. This facility was designed and constructed with excess capacity as a contingency. The amended calculations confirm that adequate capacity exists for the proposed offsite addition, and that no changes to the existing structure are necessary except to modify the orifice size for the 10-year release rate. TABLE 1 - Detention Basin Data Description Detention Basin Name DET 1.4 (as-built) DET 1.2 (as-built) DET 1.3C (proposed)* DET 1.3D (proposed) DET 1.4C (as-built)* Max. 10-yr Release Rate (cfs)* 2.30 3.63 0.59 2.69 1.48 10-yr Detention Volume (cu. ft.)* 7,211 4,058 984 3,147 1,205 Sizes and Dimensions: vertical tee (riser) dia., inches 30 30 15 24 12 outlet pipe dia., inches 30 30 12 24 12 overflow weir length, ft. - - - - Orifice (two alternates): circular orifice dia., inches* 63/4 81/2 39/16 75/8 57/16 rectangular orifice, inches* - - 3 x 35/16 7 x 61/2 5 x 411/16 Elevations: 25-yr WSEL at control structure 43.47 43.43 54.80 50.31 52.40 top of riser (=10-yr max. WSEL) 42.50 42.50 54.40 49.70 51.80 discharge pipe invert at control structure 39.00 39.00 51.30 46.60 48.30 *Note: The proposed revisions to DET 1.3C and DET 1.4C are indicated in italics and are not as-built values. Replace or modify the existing 10-year orifice for each of these structures to one of the two indicated alternates. Part 4 Storm Water Treatment (No changes to this section) Part 5 Conveyance and Collection The proposed storm drain system is shown on Figure 2 and Figure 3. Existing storm drain is utilized for runoff from sub-basins D1.2C and D1.4C; proposed, separate storm drain systems are proposed for sub-basins D1.3C and D1.3D. Pipes in both the existing (previous phase) and proposed systems were sized to convey the 25-year peak runoff. Calculations for the existing systems were provided in earlier reports; this report includes calculations for representative pipes as required to assure pipe size is adequate for all pipes. The revised pipe calculations in this addendum include the additional offsite runoff from Laurel Parkway into sub-basins D1.3C and D1.4C. Page 4 of 4 Drop inlets and curb inlets have been placed where needed to limit the spread of water in the street, such that an unobstructed (un-flooded) travel lane will be available during a 25-year storm, in accordance with City of Bozeman design standards. Provisions for overland flow of larger, less frequent storms up to the 100-year storm will be incorporated into the site grading. Calculations for gutter spread width, inlet intercept/bypass flows and pipe flows are attached. Bypass flows are accounted for at all existing and proposed on-grade inlets. Conveyance and collection for the applicable Phase 5 and 6 sub-basins is described below. Sub-basin D1.3C (Phase 6 construction): Runoff will surface drain to a proposed storm drain inlet on the east side of Laurel Parkway, south of its intersection with Debour Lane. The intercepted runoff will drain to a proposed underground (StormTech) detention facility. The calculations for gutter spread width, inlet intercept/bypass flows and pipe flows in this addendum include the additional 0.14 acres of offsite runoff from Laurel Parkway into sub-basin D1.3C. Sub-basin D1.4C (Phase 5 and 6 construction): Runoff will surface drain to existing curb inlets on Laurel Parkway, about 660 feet north of Vaughn Drive. Gutter spread width, inlet intercept/bypass and storm drain pipe flows have been re-calculated in this report, to show that the existing storm drain system remains in compliance with City requirements. The calculations for gutter spread width, inlet intercept/bypass flows and pipe flows in this addendum include the additional 0.21 acres of offsite runoff from Laurel Parkway into sub-basin D1.4C. N:\5352\009\Design Docs\Reports\drainage\4-9-21 (Norton addition)\drainage report, Norton addition.docx    PEAK RUNOFF AND DETENTION CALCULATIONS    (this page left blank intentionally) The Lakes at Valley West, Phases 5 & 6 Peak Runoff and Detention Calculations revised 4/9/21 MODIFIED RATIONAL METHOD i = A * (Tc/60) B Qp = C i A Qp = peak runoff, cfs Design Coefficients C = runoff coefficient Storm AB 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 -0.66 100-yr 1.01 -0.67 (Bozeman Design Standards, March 2004) = revisions for 4/9/21 addendum (Norton addition) Sub-Basin Name Area C Tc Q2 Q5 Q10 Q25 Q50 Q100 Basin 1 H1 218.30 0.20 90.6 12.27 17.44 21.38 26.16 30.60 33.46 D1.1 (A+B+C) 116.22 0.20 97.6 6.25 8.85 10.84 13.28 15.51 16.95 D1.2A 5.52 0.48 5.0 4.24 6.76 8.53 10.14 12.57 14.14 D1.2B 3.51 0.50 5.0 2.81 4.48 5.65 6.72 8.32 9.37 D1.2C 1.14 0.50 5.0 0.91 1.45 1.83 2.18 2.70 3.04 D1.2 (A+B+C) 10.17 0.49 6.3 6.92 10.94 13.78 16.42 20.26 22.74 D1.3A 10.98 0.50 5.0 8.78 14.00 17.67 21.01 26.04 29.31 D1.3B 64.30 0.50 90.6 9.04 12.84 15.74 19.26 22.53 24.64 H1.3C1 1.95 0.20 16.1 0.31 0.47 0.59 0.71 0.85 0.95 D1.3C 1.95 0.51 5.0 1.59 2.54 3.20 3.81 4.72 5.31 H1.3D1 7.69 0.20 12.8 1.40 2.15 2.69 3.22 3.92 4.37 D1.3D 7.69 0.50 7.5 4.82 7.57 9.51 11.35 13.95 15.64 West Lake outlet pipe2 88.51 0.50 - 4.60 D1.4A 5.72 0.50 5.0 4.57 7.30 9.20 10.94 13.56 15.27 D1.4B 7.26 0.39 5.0 4.53 7.22 9.11 10.83 13.43 15.11 D1.4 (A+B) 12.98 0.44 5.0 9.10 14.52 18.32 21.78 26.99 30.38 H1.4C1 3.59 0.20 9.9 0.76 1.18 1.48 1.77 2.17 2.43 D1.4C 3.59 0.51 9.4 2.00 3.12 3.91 4.68 5.72 6.40 D1.2+D1.4(A+B) 23.15 0.46 6.3 14.85 23.47 29.54 35.20 43.43 48.77 FOOTNOTES: 1.The pre-development subbasin uses a pre-development C and Tc and an area matching the post-development area, for use in calculating detention volume. 2. Full retention of sub-basins draining into the East and West lakes (D1.3A, D1.3B, D1.3C, D1.3D and D1.4C) was assumed, in order to conservatively estimate the lakes' 25-year maximum water surface elevation and associated maximum discharge. Retention volume = (7,200)*(0.50)*(0.41)*(88.16) =130,124 cu. ft. Using the 5.14-acre combined surface area of the lakes, this correlates to a rise of 0.58 feet above the normal operating elevation of 44.50. An additional 0.5 feet was added to account for partial clogging of the 2' high fish screen. The result (WSEL=45.58) was used to calculate the 25-year peak discharge; see attached calculations for the West Lake Outfall. The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.3C Detention (10-yr storm) revised 4/9/21 MODIFIED RATIONAL METHOD Qp = C i A = revisions for 4/9/21 addendum (Norton addition) POST-DEVELOPMENT PRE-DEVEL. 1.95 AC Qp (Basin H1.3C) =0.59 cfs 0.51 5.0 MIN D1.3C release rate =0.59 cfs 3.22 IN/HR TIME STEP 3.20 CFS DURATION = 5.0 min. Max. Volume, Max. Volume,Required Detention Triangle Rel. (cu. ft.) Constant Rel. (cu. ft.)Volume (cu. ft.) 1195.83 771.89 984 Triangle Release Constant Release DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 4.75 3.33 3.31 771 631 9.75 2.09 2.07 953 743 14.75 1.59 1.58 1,054 772 19.75 1.32 1.31 1,117 760 ORIFICE CALCULATIONS 24.75 1.14 1.13 1,157 724 MATCHING Qp =0.59 cfs 29.75 1.01 1.00 1,181 672 Max. Depth = 3.10 ft 34.75 0.91 0.91 1,193 607 39.75 0.84 0.83 1,196 532 44.75 0.77 0.77 1,192 450 CIRCULAR ORIFICE: 49.75 0.72 0.72 1,182 362 DIAMETER =3.5625 inches 54.75 0.68 0.68 1,167 268 Area = 0.07 ft 2 59.75 0.64 0.64 1,148 170 ORIFICE FLOW = 0.59 cfs 64.75 0.61 0.61 1,125 67 69.75 0.58 0.58 1,099 -38 74.75 0.55 0.55 1,070 -147 RECTANGULAR ORIFICE: 79.75 0.53 0.53 1,039 -258 LENGTH =3.3125 84.75 0.51 0.51 1,005 -372 WIDTH =3.0000 inches 89.75 0.49 0.49 970 -488 Area = 0.07 ft 2 94.75 0.48 0.47 932 -606 ORIFICE FLOW = 0.59 cfs 99.75 0.46 0.46 893 -726 104.75 0.45 0.44 852 -847 109.75 0.43 0.43 810 -970 114.75 0.42 0.42 766 -1,095 119.75 0.41 0.41 722 -1,221 WEIR CALCULATIONS 124.75 0.40 0.40 676 -1,348 Coefficient = 3.33 inches 129.75 0.39 0.39 629 -1,476 Width =0.3750 inches 134.75 0.38 0.38 581 -1,606 WEIR FLOW = 0.57 cfs 139.75 0.37 0.37 532 -1,736 144.75 0.36 0.36 482 -1,867 149.75 0.35 0.35 431 -2,000 POND VOLUME CALCULATIONS: BASIN AREA POST = POST-DEV C = POST-DEV Tc = STORM INTENSITY = POST-DEV Qp = DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 154.75 0.35 0.34 379 -2,133 159.75 0.34 0.34 327 -2,267 164.75 0.33 0.33 274 -2,402 169.75 0.33 0.32 220 -2,538 174.75 0.32 0.32 166 -2,674 179.75 0.31 0.31 111 -2,811 184.75 0.31 0.31 55 -2,949 189.75 0.30 0.30 -1 -3,087 194.75 0.30 0.30 -58 -3,226 199.75 0.29 0.29 -115 -3,365 204.75 0.29 0.29 -172 -3,505 209.75 0.28 0.28 -231 -3,646 214.75 0.28 0.28 -289 -3,787 219.75 0.28 0.27 -348 -3,928 224.75 0.27 0.27 -408 -4,070 229.75 0.27 0.27 -468 -4,213 234.75 0.26 0.26 -528 -4,356 239.75 0.26 0.26 -589 -4,499 244.75 0.26 0.26 -650 -4,643 249.75 0.25 0.25 -711 -4,787 254.75 0.25 0.25 -773 -4,931 259.75 0.25 0.25 -835 -5,076 264.75 0.24 0.24 -898 -5,221 269.75 0.24 0.24 -960 -5,367 274.75 0.24 0.24 -1,023 -5,513 279.75 0.24 0.23 -1,087 -5,659 284.75 0.23 0.23 -1,150 -5,806 289.75 0.23 0.23 -1,214 -5,952 294.75 0.23 0.23 -1,278 -6,100 299.75 0.22 0.22 -1,343 -6,247 304.75 0.22 0.22 -1,407 -6,395 309.75 0.22 0.22 -1,472 -6,543 314.75 0.22 0.22 -1,538 -6,691 319.75 0.22 0.21 -1,603 -6,840 324.75 0.21 0.21 -1,669 -6,988 329.75 0.21 0.21 -1,734 -7,137 334.75 0.21 0.21 -1,801 -7,287 339.75 0.21 0.21 -1,867 -7,436 344.75 0.21 0.20 -1,933 -7,586 349.75 0.20 0.20 -2,000 -7,736 354.75 0.20 0.20 -2,067 -7,886 359.75 0.20 0.20 -2,134 -8,037 364.75 0.20 0.20 -2,201 -8,187 369.75 0.20 0.20 -2,269 -8,338 374.75 0.19 0.19 -2,336 -8,489 379.75 0.19 0.19 -2,404 -8,640 384.75 0.19 0.19 -2,472 -8,792 389.75 0.19 0.19 -2,540 -8,943 394.75 0.19 0.19 -2,609 -9,095 399.75 0.19 0.19 -2,677 -9,247 404.75 0.19 0.18 -2,746 -9,399 409.75 0.18 0.18 -2,815 -9,552 414.75 0.18 0.18 -2,884 -9,704 419.75 0.18 0.18 -2,953 -9,857 424.75 0.18 0.18 -3,022 -10,010 429.75 0.18 0.18 -3,091 -10,163 434.75 0.18 0.18 -3,161 -10,316 439.75 0.18 0.17 -3,230 -10,469 444.75 0.17 0.17 -3,300 -10,623 449.75 0.17 0.17 -3,370 -10,776 454.75 0.17 0.17 -3,440 -10,930 459.75 0.17 0.17 -3,510 -11,084 464.75 0.17 0.17 -3,581 -11,238 The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.3C revised 4/9/21 StormTech Sizing Calculations = revisions for 4/9/21 addendum (Norton addition) Required Storage Volume 984 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 15 14.44 before rounding excess storage volume 3.7 % Number of chambers proposed 16 (as-built) excess storage volume 9.8 % equal to 96 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 = 1,080 ft3 Notes: 1. Storage volume assumes 6" of stone above and between chambers, and 40% stone porosity. The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.4C Detention (10-yr storm) revised 4/9/21 MODIFIED RATIONAL METHOD Qp = C i A = revisions for 4/9/21 addendum (Norton addition) POST-DEVELOPMENT PRE-DEVEL. 3.59 AC Qp (Basin H1) =1.48 cfs 0.51 9.4 MIN D1.4 release rate =1.48 cfs 2.14 IN/HR TIME STEP 3.91 CFS DURATION = 5.0 min. Max. Volume, Max. Volume,Required Detention Triangle Rel. (cu. ft.) Constant Rel. (cu. ft.)Volume (cu. ft.) 1568.63 842.02 1,205 1.2 Triangle Release Constant Release DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 8.93 2.21 4.04 1,351 842 18.33 1.38 2.53 1,552 809 27.73 1.06 1.94 1,569 558 37.13 0.87 1.60 1,497 202 ORIFICE CALCULATIONS 46.53 0.76 1.38 1,372 -219 MATCHING Qp =1.48 cfs 55.93 0.67 1.23 1,211 -684 Max. Depth = 3.50 ft 65.33 0.61 1.11 1,023 -1,183 74.73 0.55 1.02 814 -1,707 84.13 0.51 0.94 589 -2,253 CIRCULAR ORIFICE (as-built): 93.53 0.48 0.88 350 -2,816 DIAMETER =5.4375 inches 102.93 0.45 0.83 100 -3,393 Area = 0.16 ft 2 112.33 0.43 0.78 -160 -3,983 ORIFICE FLOW = 1.45 cfs 121.73 0.40 0.74 -428 -4,584 131.13 0.39 0.70 -703 -5,194 140.53 0.37 0.67 -985 -5,813 RECTANGULAR ORIFICE: 149.93 0.35 0.65 -1,273 -6,440 LENGTH =5.0000 inches 159.33 0.34 0.62 -1,566 -7,074 WIDTH =4.6875 inches 168.73 0.33 0.60 -1,864 -7,714 Area = 0.16 ft 2 178.13 0.32 0.58 -2,166 -8,360 ORIFICE FLOW = 1.47 cfs 187.53 0.31 0.56 -2,471 -9,011 196.93 0.30 0.54 -2,781 -9,666 206.33 0.29 0.53 -3,094 -10,327 215.73 0.28 0.51 -3,410 -10,991 225.13 0.27 0.50 -3,728 -11,660 WEIR CALCULATIONS 234.53 0.26 0.48 -4,050 -12,332 Coefficient = 3.33 243.93 0.26 0.47 -4,374 -13,007 Width =0.8125 inches 253.33 0.25 0.46 -4,700 -13,686 WEIR FLOW = 1.48 cfs 262.73 0.25 0.45 -5,028 -14,368 272.13 0.24 0.44 -5,359 -15,052 281.53 0.23 0.43 -5,691 -15,740 POND VOLUME CALCULATIONS: BASIN AREA POST = POST-DEV C = POST-DEV Tc = STORM INTENSITY = POST-DEV Qp = DURATION INTENSITY Qp POND VOLUME POND VOLUME (MIN) (IN/HR) (CFS) (CF) (CF) 290.93 0.23 0.42 -6,025 -16,430 300.33 0.22 0.41 -6,361 -17,122 309.73 0.22 0.40 -6,699 -17,817 319.13 0.22 0.40 -7,038 -18,514 328.53 0.21 0.39 -7,379 -19,213 337.93 0.21 0.38 -7,721 -19,914 347.33 0.20 0.37 -8,064 -20,617 356.73 0.20 0.37 -8,409 -21,321 366.13 0.20 0.36 -8,755 -22,028 375.53 0.19 0.36 -9,102 -22,736 384.93 0.19 0.35 -9,451 -23,446 394.33 0.19 0.34 -9,800 -24,158 403.73 0.19 0.34 -10,151 -24,871 413.13 0.18 0.33 -10,502 -25,585 422.53 0.18 0.33 -10,855 -26,301 431.93 0.18 0.32 -11,208 -27,018 441.33 0.17 0.32 -11,562 -27,737 450.73 0.17 0.32 -11,918 -28,457 460.13 0.17 0.31 -12,274 -29,178 469.53 0.17 0.31 -12,631 -29,900 478.93 0.17 0.30 -12,988 -30,624 488.33 0.16 0.30 -13,347 -31,348 497.73 0.16 0.30 -13,706 -32,074 507.13 0.16 0.29 -14,066 -32,801 516.53 0.16 0.29 -14,426 -33,528 525.93 0.16 0.29 -14,788 -34,257 535.33 0.15 0.28 -15,150 -34,987 544.73 0.15 0.28 -15,512 -35,717 554.13 0.15 0.28 -15,875 -36,449 563.53 0.15 0.27 -16,239 -37,182 572.93 0.15 0.27 -16,603 -37,915 582.33 0.15 0.27 -16,968 -38,649 591.73 0.14 0.26 -17,334 -39,384 601.13 0.14 0.26 -17,700 -40,120 610.53 0.14 0.26 -18,066 -40,857 619.93 0.14 0.26 -18,433 -41,594 629.33 0.14 0.25 -18,801 -42,332 638.73 0.14 0.25 -19,169 -43,071 648.13 0.14 0.25 -19,538 -43,811 657.53 0.13 0.25 -19,907 -44,551 666.93 0.13 0.24 -20,276 -45,292 676.33 0.13 0.24 -20,646 -46,033 685.73 0.13 0.24 -21,016 -46,776 695.13 0.13 0.24 -21,387 -47,519 704.53 0.13 0.24 -21,758 -48,262 713.93 0.13 0.23 -22,130 -49,007 723.33 0.13 0.23 -22,502 -49,751 732.73 0.13 0.23 -22,874 -50,497 742.13 0.12 0.23 -23,247 -51,243 751.53 0.12 0.23 -23,620 -51,989 760.93 0.12 0.22 -23,993 -52,736 770.33 0.12 0.22 -24,367 -53,484 779.73 0.12 0.22 -24,741 -54,232 789.13 0.12 0.22 -25,116 -54,981 798.53 0.12 0.22 -25,491 -55,730 807.93 0.12 0.22 -25,866 -56,480 817.33 0.12 0.21 -26,241 -57,230 826.73 0.12 0.21 -26,617 -57,981 836.13 0.12 0.21 -26,993 -58,732 845.53 0.11 0.21 -27,370 -59,484 854.93 0.11 0.21 -27,746 -60,236 864.33 0.11 0.21 -28,123 -60,989 873.73 0.11 0.21 -28,501 -61,742 The Lakes at Valley West, Phases 5 & 6 Sub-Basin D1.4C revised 4/9/21 StormTech Sizing Calculations = revisions for 4/9/21 addendum (Norton addition) Required Storage Volume 1,205 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 18 17.69 before rounding excess storage volume 1.7 % Number of chambers proposed 18 (as-built) excess storage volume 1.7 % equal to 21 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 = 1,226 ft3 Notes: 1. Storage volume assumes 6" of stone above and between chambers, and 40% stone porosity. (this page left blank intentionally)    GUTTER FLOW CALCULATIONS    (this page left blank intentionally) The Lakes at Valley West, Phases 5 & 6 Gutter Flow, Direct (Surface) Runoff Calculations revised 4-9-21 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 = revisions for 4/9/21 addendum (Norton addition) Sub-Basin Description Area1 Tc C Qp Vaughn Drive West of Westgate, north side 0.78 5.00 0.50 1.49 West of Westgate, south side 0.34 5.00 0.50 0.65 East of Westgate, north side 0.09 5.00 0.50 0.17 East of Westgate, south side 0.67 5.00 0.50 1.28 Westgate Avenue South of Herstal, west side 0.42 5.00 0.50 0.80 South of Herstal, east side 0.43 5.00 0.50 0.82 North of Herstal, west side3 1.51 5.00 0.50 2.89 North of Herstal, east side3 0.16 5.00 0.50 0.31 South of roundabout, west side park inlet3 1.19 5.00 0.50 2.28 South of roundabout, west curb inlet3 0.53 5.00 0.50 1.01 South of roundabout, east curb inlet3 0.78 5.00 0.50 1.49 South quadrant of roundabout3 1.54 5.00 0.50 2.95 Alleys2 Manhole at Leiden's NW dead end 1.30 5.00 0.50 2.49 Manhole at Leiden's NE dead end 1.27 5.00 0.50 2.43 Vahl, NW dead end 1.51 5.00 0.50 2.89 Laurel Parkway South of Debour, double inlet, east side 1.95 5.00 0.51 3.81 Sta. 8+00 existing double inlet, east side 1.67 9.40 0.50 2.13 Sta. 13+97.18, existing east inlet (low point) 1.70 5.00 0.35 2.28 Sta. 8+00 existing double inlet, west side 1.92 9.20 0.51 2.54 Sta. 13+97.18, existing west inlet (low point) 1.41 5.00 0.50 2.70 FOOTNOTES: 1 Areas and flow rates are for direct runoff only and do not include inlet bypass. Inlet bypass flow is accounted for on the following page. 2 Typical section for alleys is an inverted crown with 2% slope toward the center. 3 These subbasins were defined in previous phases of construction; refer to previous drainage reports. The Lakes at Valley West, Phases 5 & 6 Gutter Spread Width Calculations revised 4-9-21 = revisions for 4/9/21 addendum (Norton addition) 25-yr. Peak Runoff (cfs) Gutter Sub-Basin Description Direct 1 Upstream2 Total Inlet Type Bypass Spread (ft.) Vaughn Drive West of Westgate, north side 1.49 0.00 1.49 sag 0.00 5.32 West of Westgate, south side 0.65 0.00 0.65 sag 0.00 3.10 East of Westgate, north side 0.17 0.00 0.17 sag 0.00 1.28 East of Westgate, south side 1.28 0.00 1.28 sag 0.00 4.84 Westgate Avenue South of Herstal, west side 0.80 0.00 0.80 on grade 0.08 4.14 South of Herstal, east side 0.82 0.00 0.82 on grade 0.09 4.19 North of Herstal, west side4 2.89 0.08 2.97 on grade 1.17 9.03 North of Herstal, east side4 0.31 0.09 0.40 on grade 0.02 4.04 South of roundabout, west side park inlet4 2.28 0.00 2.28 drop inlet 0.00 n/a South of roundabout, west curb inlet4 1.01 1.17 2.18 on grade 0.74 8.00 South of roundabout, east curb inlet4 1.49 0.02 1.51 on grade 0.41 6.93 South quadrant of roundabout4 2.95 0.74 3.69 sag 0.00 9.11 Alleys3 Manhole at Leiden's NW dead end 2.49 0.00 2.49 - 0.00 13.62 Manhole at Leiden's NE dead end 2.43 0.00 2.43 - 0.00 12.15 Vahl, NW dead end 2.89 0.00 2.89 - 0.00 13.67 Laurel Parkway South of Debour, double inlet, east side 3.81 0.00 3.81 on grade 1.02 8.68 Sta. 8+00 existing double inlet, east side 2.13 1.02 3.15 on grade 0.63 9.37 Sta. 13+97.18, existing east inlet (low point) 2.28 0.63 2.91 sag 0.00 8.90 Sta. 8+00 existing double inlet, west side 2.54 0.00 2.54 on grade 0.44 8.63 Sta. 13+97.18, existing west inlet (low point) 2.70 0.44 3.14 sag 0.00 9.27 FOOTNOTES: 1 Direct runoff is from "Gutter Flow" calculations on the previous page, and does not include runoff from upstream inlets. 2 Upstream runoff is the bypass flow from contributing upstream inlets. 3 For alleys with inverted crown, minor submergence is acceptable. 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6LHPRQV&RPSDQ\'ULYH6XLWH::DWHUWRZQ&786$ RI3DJH Revised for 4/9/21 Addendum 5HVXOWV 9HORFLW\  IWV 9HORFLW\+HDG  IW 6SHFLILF(QHUJ\  IW )URXGH1XPEHU  )ORZ7\SH 6XSHUFULWLFDO *9),QSXW'DWD 'RZQVWUHDP'HSWK LQ /HQJWK IW 1XPEHU2I6WHSV  *9)2XWSXW'DWD 8SVWUHDP'HSWK  LQ 3URILOH'HVFULSWLRQ 3URILOH+HDGORVV  IW 'RZQVWUHDP9HORFLW\ ,QILQLW\ IWV 8SVWUHDP9HORFLW\ ,QILQLW\ IWV 1RUPDO'HSWK  LQ &ULWLFDO'HSWK  IW &KDQQHO6ORSH   &ULWLFDO6ORSH  IWIW Laurel Sta. 8+00 gutter, west side (25-yr) $0 %HQWOH\6\VWHPV,QF+DHVWDG0HWKRGV6ROXWLRQ&HQWHU%HQWOH\)ORZ0DVWHU9L 6(/(&7VHULHV  >@ 6LHPRQV&RPSDQ\'ULYH6XLWH::DWHUWRZQ&786$ RI3DJH Revised for 4/9/21 Addendum 3URMHFW'HVFULSWLRQ 6ROYH)RU (IILFLHQF\ ,QSXW'DWD 'LVFKDUJH IWñV 6ORSH  *XWWHU:LGWK IW *XWWHU&URVV6ORSH  5RDG&URVV6ORSH  5RXJKQHVV&RHIILFLHQW  /RFDO'HSUHVVLRQ LQ /RFDO'HSUHVVLRQ:LGWK IW *UDWH:LGWK IW *UDWH/HQJWK IW *UDWH7\SH Û7LOW%DU &ORJJLQJ  &XUE2SHQLQJ/HQJWK IW 2SWLRQV &DOFXODWLRQ2SWLRQ 8VH%RWK *UDWH)ORZ2SWLRQ ([FOXGH1RQH 5HVXOWV (IILFLHQF\ ,QWHUFHSWHG)ORZ IWñV 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%HQWOH\6\VWHPV,QF+DHVWDG0HWKRGV6ROXWLRQ&HQWHU%HQWOH\)ORZ0DVWHU9L 6(/(&7VHULHV  >@ 6LHPRQV&RPSDQ\'ULYH6XLWH::DWHUWRZQ&786$ RI3DJH Revised for 4/9/21 Addendum (this page left blank intentionally)    PIPE FLOW CALCULATIONS    (this page left blank intentionally) The Lakes at Valley West, Phases 5 & 6 Pipe Flow Calculations revised 4-9-21 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 = revisions for 4/9/21 addendum (Norton addition) Sub-Basin Description Area1 Tc C Qdirect2 Qtotal3 Qint4 Qbypass Qpipe5 Pipe Dia.6 Notes Vaughn Drive West of Westgate, north side 0.78 5.00 0.50 1.49 1.49 1.49 0.00 1.49 12" West of Westgate, south side 0.34 5.00 0.50 0.65 0.65 0.65 0.00 2.14 12" East of Westgate, north side 0.09 5.00 0.50 0.17 0.17 0.17 0.00 0.17 12" East of Westgate, south side 0.67 5.00 0.50 1.28 1.28 1.28 0.00 1.45 12" Vaughn/Westgate manhole 3.60 15" Westgate Avenue South of Herstal, west side 0.42 5.00 0.50 0.80 0.80 0.72 0.08 0.72 12" South of Herstal, east side 0.43 5.00 0.50 0.82 0.82 0.73 0.09 5.05 15" North of Herstal, west side7 1.51 5.00 0.50 2.89 2.97 1.80 1.17 1.80 12" North of Herstal, east side7 0.16 5.00 0.50 0.31 0.40 0.38 0.02 2.17 18"as-built10 South of roundabout, west side park inlet7 1.19 5.00 0.50 2.28 2.28 2.28 0.00 2.28 12"as-built10 South of roundabout, west curb inlet7 0.53 5.00 0.50 1.01 2.18 1.44 0.74 3.72 15"as-built10 South of roundabout, east curb inlet7 0.78 5.00 0.50 1.49 1.51 1.10 0.41 7.00 24"as-built10 South quadrant of roundabout7 1.54 5.00 0.50 2.95 3.69 3.69 0.00 4.43 15"as-built10 Manhole at roundabout7 11.42 24"as-built10 Alleys7 Manhole at Leiden's NW dead end 1.30 5.00 0.50 2.49 2.49 2.49 0.00 7.54 18" Vahl, NW dead end 1.51 5.00 0.50 2.89 2.89 2.89 0.00 2.89 12" Manhole between Vahl & Leiden 0.71 5.00 0.50 1.36 1.36 1.36 0.00 4.25 15" Manhole at Leiden's NE dead end 1.27 5.00 0.50 2.43 2.43 2.43 0.00 6.68 18" Manhole 55' north of Leiden's NW dead end 0.17 5.00 0.50 0.33 0.33 0.33 0.00 11.35 24" South inlet pipe to Detention D1.3D 9 7.69 7.50 0.50 11.35 11.35 24" Laurel Parkway South of Debour, double inlet, east side 1.95 5.00 0.51 3.81 3.81 2.79 1.02 2.79 12" Sta. 8+00 existing double inlet, east side 1.67 9.40 0.50 2.13 3.15 2.52 0.63 3.54 12"as-built10 Sta. 13+97.18, 65' east (drop inlet) 2.00 5.00 0.35 2.68 2.68 2.68 0.00 2.68 12"as-built10 Sta. 13+97.18, existing east inlet (low point) 1.70 5.00 0.35 2.28 5.58 5.58 0.00 5.58 18"as-built10 Sta. 8+00 double inlet, west side 1.92 9.20 0.51 2.54 2.54 2.10 0.44 5.64 12"as-built10 Detention D1.4C discharge pipe9 3.59 9.40 0.51 4.68 4.68 15"as-built10 Sta. 13+97.18, existing west inlet (low point) 1.41 5.00 0.50 2.70 3.14 3.14 0.00 9.16 18"as-built10 FOOTNOTES: 1 Contributing drainage area 2 Qdirect is direct surface runoff to the inlet, and does not include bypass flows from upstream inlets. 3 Qtotal is total peak surface runoff to the inlet (direct runoff plus bypass flows from upstream inlets). 4Qint is surface runoff intercepted by the inlet. 5Qpipe is total flow to outlet pipe (total pipe flow from upstream inlets plus surface runoff intercepted at the inlet). 6 Calculations are attached where "Pipe Dia." column uses bold text. Other pipe sizes are evident based on flow rates. 7 These subbasins were defined in previous phases of construction; refer to previous drainage reports. 8Qpipe for alleys is the total runoff to the nearest downstream drop inlet or manhole. 9 Equal to values in the Peak Runoff and Detention calculations. 10 Pipes were sized and installed during previous phases of construction. &XOYHUW&DOFXODWRU5HSRUW /DXUHO6WDHDVWVLGHSLSHWRZHVWVLGH \U 7LWOH7KH/DNHVDW9DOOH\:HVW Q?? 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SCALEIN FEETDURSTON ROADD1.1A0.82D1.2B3.51D1.3A10.98D1.3B64.30D1.1B114.16D2.13.94D2.21.62D1.4 A5.72LAUREL PARKWAYWESTMORLAND DRIVE1.500.500.800.800.500.701.75DURSTON ROADHUFFINE LANECOTTONWOOD ROADMATCH LINEMATCH LINEPHASE 1PHASE 2VICINITY MAPSCALE: 1"=1000'D1.1B114.16D1.3B61.93GOOCH HILL ROADAAJKER CREEKBAXTER CREEKEXISTING 2-3614" x 2212" ARCPEXISTING36" CMPEXISTINGCUTOFF DITCHSOUTH SITE BOUNDARYBAXTER CREEK WEST LAKEEAST LAKEEXISTING DRAINAGEEXISTINGDETENTIONSTORAGE D1.2LEGENDSUB-BASIN BOUNDARYX.XXX.XXPOST-DEVELOPMENTSUB-BASIN DESIGNATIONSUB-BASIN AREAPHASE BOUNDARYDITCH OR SWALED1.4 B7.26EXISTING 12" PVCEAST LAKE OUTLETEXISTINGDETENTIONBASIN 2.1EXISTINGDETENTIONSTORAGE D1.4EXISTING 12" PVCWEST LAKE OUTLET0.60EXISTINGCULVERTEXTENSIONEXISTING 88" x 44" ARCP CULVERTD1.1C1.24D1.2 A5.52EXISTING DETENTIONSTORAGE 1.4CFIGURE NUMBER©PROJECT NO.DRAWN BY:DSGN. BY:APPR. BY:DATE:COPYRIGHT MORRISON-MAIERLE, INC.,2018N:\5352\009\ACAD\Exhibits\PH 5 Post-Development.dwg Plotted by cooper krause on May/24/2018engineers surveyors planners scientistsMorrisonMaierle5352.009FIG. 2THE LAKES AT VALLEY WESTPHASES 5 AND 6BOZEMANMONTANAPOST-DEVELOPEMENT DRAINAGE MAPDSMGHJRN12/2017PHASE 3WESTGATE AVE.EXISTINGSTORM DRAINPHASE 4HERSTAL WAYPHASE 5PHASE 6D1.3D7.69D1.3C1.81D1.4C3.38D1.2C1.14HERSTAL WAYLEIDEN LANEVAHL WAYDEBOUR LANEVAUGHN DRIVEPROPOSED DETENTIONSTORAGE D1.3DHERSTAL WAYPROPOSED DETENTIONSTORAGE D1.3C             (this page left blank intentionally) © PROJECT NO. FIGURE NUMBER COPYRIGHT MORRISON-MAIERLE, INC.,2021 N:\5352\009\ACAD\Exhibits\DRAINAGE-POST DEVELOPMENT OFFSITE.dwg Plotted by cody farley on Apr/8/2021 DRAWN BY: DSGN. BY: APPR. BY: DATE:engineers surveyors planners scientists MorrisonMaierle 2880 Technology Blvd West Bozeman, MT 59718 406.587.0721 www.m-m.net 5352.009 FIG.3 THE LAKES AT VALLEY WEST PHASES 5 AND 6 LAUREL PARKWAY - ADDITIONS TO SUB-BASINS D1.3C AND D1.4C BOZEMAN MONTANA CJF MGH MGH 04/2021 30 600 SCALE IN FEET (this page left blank intentionally)