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HomeMy WebLinkAboutPZ - Preliminary Stormwater Management Report ESE CONSULTAN T S ESE Consultants, Inc. 3103 W. Sheryl Drive ENGINEERING - PLANNING • SURVEYING • ENVIRONMENTAL Meridian, Idaho 83642 TEL: 208-424-0020 PRELIMINARY STORMWATER MANAGEMENT REPORT FOR DAYSPRING SUBDIVISION LEGEVfi 77 �S NAL EN 12449 s� �a 9/e OF E.ao2°y� 3lrgl24r Justin E. Bozovich Professional Engineer Idaho License No. 12449 December 2024 LHT Revised March 2025 LOCATEDIN: CITY OF MERIDIAN ADA COUNTY, IDAHO TABLE OF CONTENTS SUBJECT SECTION Project Overview 1 Stormwater Management Design 2 Stormwater Equations 3 Intensity-Duration-Frequency Curve 4 Drainage Basin Map 5 SECTION 1 - Project Overview Dayspring is a multi-phase residential development located in the City of Meridian, Ada County, Idaho.The development consisting of 143 Acres and 540 single-family residential lots, is situated between Black Cat Rd and McDermott Rd, and south of W Ustick Rd. The applicant proposes for the overall subdivision development to include the construction of homes and infrastructure and will include roads, sidewalks, stormwater management facilities, utilities, and other improvements typical of residential construction. This report presents the preliminary stormwater plan for the Dayspring Subdivision that will be included with the preliminary plat submittal. Included in this report are all the calculations to verify that the stormwater management plan meets Ada County Highway District Policy Manual Existing Conditions The project site is currently bounded by a Hawkeye Landscaping to the east, McDermott Rd to the west, residential properties to the south. The project site itself is comprised single-family homes with associated barns. Geotechnical Characteristics A Geotechnical Report was prepared by GeoTek, Inc. for Dayspring Subdivision, dated May lot" 2024. The surface soils were generally described as layers of silt loam and silty clay loam underlain by very gravelly sand to loam. Groundwater Groundwater monitoring of the project site was conducted by GeoTek in August 2024 through September 2024 with groundwater ranging from 4' to 10' below the existing ground at several of the test pit locations. Soil Infiltration Geo Tek, Inc. has performed soil infiltration testing at thirty (30) locations within the project site and presented their results in Appendix C of the Geotechnical Engineering Report. Soil infiltration rates noted in the report range from 2.7 in/hr to 8.9 in/hr. An infiltration rate of 1 in/hr was conservatively used in the calculations. SECTION 2 - Stormwater Management Design Design Criteria The Preliminary Stormwater Management Plan described herein has been designed according to the Ada County Highway District Policy Manual to determine the stormwater facility storage volumes that will be required for the project.The proposed Stormwater Management Design has been prepared to meet the following requirements and guidelines: ♦ The Rational Method (Q=CiA) has been utilized to calculate 100-year storage volumes. Runoff coefficient of 0.50 was used per the ACHD Policy Manual for residential subdivisions. Rainfall intensity of 0.96 in/hr was used using the ACHD adopted Intensity- Duration-Frequency Curve located in Section 5 of this report. ♦ An infiltration rate of 1 inch per hour has been used for the design of the stormwater swales. SECTION 3 - Stormwater Equations Coefficient of Runoff(ACHD Policy Manual 8011.2.1) Estimated Runoff Coefficients for Various Surfaces Type-of Surface RuriofF Coefficients"C" Business Downtuwfi areas 0.70.0.95 Urbannelghborhoods 0.50.0.70 Resldentkal SI ngle Faml ly 0.35.0.50 Multi family 0.60.0.75 Resldentkal rural} 0.2".40 ApartmentDwelll rig Areas 0.70 Industrial and[ommerclal Light areas 0.80 Heavy areas 0.90 Parks,Cemeterles 0.10.0.25 Playgrounds 0.20.0.35 Rallroad yard areas 0.20.0.40 UnlmpFaved areas 0,10.0.30 StFB@tS Asphalt 0.95 CaficFete 0.95 Brick D.95 Roofs D.45 GraM D.75 4elds:Sandy sail Soll Type Slope A b t U. Flat 0.2% 0.D4 0.07 0.11 0.15 Average,2.6% 0.09 0.12 0.15 0.20 Steep:,6g. 0.13 0.18 0.23 0.28 Adapted from AS[E Design Storm Runoff Volume (ACHD Policy Manual 8011.3.2) V— C1A(3600) V: Design storm runoff volume required for storage C: Coefficient of Runoff is Rainfall Intensity per IDF Curve 1-hour 100-year storm event, i=0.96 1-hour 2-year storm event, i=0.26 A: Total catchment area(acres) SECTION 4 Primary Stormwater Facility Calculations BASIN CATCHMENT AREA 2 BASIN CHARACTERISTICS Basin Area,A: 0.55 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 257 90 3 5.5 157 531 688 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft) (in/hr) (ft) (ft) (hrs) 950 90 5.5 70 863 1.0 34 967 25.34 BASIN CATCHMENT AREA 3 BASIN CHARACTERISTICS Basin Area,A: 1.03 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft) (ft) (ft') (ft') (ft') 482 60 4 5.5 104 486 591 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft) (in/hr) (ft) (ft) (hrs) 1,780 60 5.5 46 1,763 1.0 68 1,877 23.73 BASIN CATCHMENT AREA 4 BASIN CHARACTERISTICS Basin Area,A: 1.04 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 487 80 3 5 140 424 564 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft) (hrs) 1,797 80 11 5 62 1,735 1.0 73 1,871 22.06 BASIN CATCHMENT AREA 5 BASIN CHARACTERISTICS Basin Area,A: 1.43 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft) (ft) (ft') (ft') (ft') 669 90 3 5.5 157 531 688 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 2,471 90 5.5 70 2,348 1.0 90 2,508 24.71 BASIN CATCHMENT AREA 6 BASIN CHARACTERISTICS Basin Area,A: 1.51 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 707 70 6 4.5 122 707 829 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft') (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft) (hrs) 2,609 70 ,'U.5 4.5 54 2,561 1.0 120 2,735 19.64 BASIN CATCHMENT AREA 6B BASIN CHARACTERISTICS Basin Area,A: 2.33 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft) (ft) (ft') (ft') (ft') 1,090 90 6 7.5 157 1,557 1,714 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 4,026 90 7.5 70 4,022 1.0 113 4,204 32.21 BASIN CATCHMENT AREA 7 BASIN CHARACTERISTICS Basin Area,A: 0.70 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 328 50 4 5 87 365 452 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft) (in/hr) (ft) (ft) (hrs) 1,210 50 5 38 1,135 1.0 48 1,221 22.72 BASIN CATCHMENT AREA 8 BASIN CHARACTERISTICS Basin Area,A: 0.98 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 459 50 4.5 5 87 415 502 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft') (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft) (hrs) 1,693 50 5 38 1,635 1.0 69 1,742 22.17 BASIN CATCHMENT AREA 9 BASIN CHARACTERISTICS Basin Area,A: 0.38 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft) (ft) (ft') (ft') (ft') 178 60 4 5 104 438 543 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 657 60 5 46 641 1.0 28 715 21.49 BASIN CATCHMENT AREA 10 BASIN CHARACTERISTICS Basin Area,A: 1.88 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, 2 YR d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft') (ft') (ft') 880 150 3 5.5 263 885 1,148 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft) (in/hr) (ft) (ft) (hrs) 3,249 150 5.5 117 3,253 1.0 125 3,495 23.39 BASIN CATCHMENT AREA 11 BASIN CHARACTERISTICS Basin Area,A: 3.62 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft') (ft') (ft')1,694 2-YR 110 7 5.5 193 1,617 1,810 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft) (hrs) 6,255 110 5.5 86 6,016 1.0 229 6,331 24.57 BASIN CATCHMENT AREA 12 BASIN CHARACTERISTICS Basin Area,A: 1.75 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, 2-YR d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft') (ft') (ft') 819 110 4 5.5 193 891 1,084 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft) (hrs) 3,024 110 5.5 86 2,870 1.0 110 3,065 24.74 BASIN CATCHMENT AREA 12B BASIN CHARACTERISTICS Basin Area,A: 0.99 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 463 85 4 5 148 621 769 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft') (in/hr) (ft) (ft) (hrs) 1,711 85 5 66 1,589 1.0 67 1,722 22.88 BASIN CATCHMENT AREA 13 BASIN CHARACTERISTICS Basin Area,A: 0.98 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft) (ft) (ft') (ft') (ft') 459 60 4 5.5 104 486 591 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 1,693 60 5.5 46 1,697 1.0 65 1,809 23.45 BASIN CATCHMENT AREA 14 BASIN CHARACTERISTICS Basin Area,A: 1.10 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 515 50 5 5.5 87 515 602 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft') (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft) (hrs) 1,901 50 5.5 38 1,965 1.0 75 2,078 22.81 BASIN CATCHMENT AREA 15 BASIN CHARACTERISTICS Basin Area,A: 0.48 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 225 30 5 5 51 280 331 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft') (hrs) 829 30 5 23 891 1.0 38 951 19.91 BASIN CATCHMENT AREA 16 BASIN CHARACTERISTICS Basin Area,A: 1.25 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 585 50 6 5.5 87 625 712 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft') (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft) (hrs) 2,160 50 5.5 38 2,515 1.0 96 2,649 20.29 BASIN CATCHMENT AREA 17 BASIN CHARACTERISTICS Basin Area,A: 4.05 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, 2_ d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft') (ft') (ft') 1,895 180 4 6.5 316 1,746 2,062 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft) (hrs) 6,998 180 6.5 141 6,730 1.0 218 7,088 28.96 BASIN CATCHMENT AREA 18 BASIN CHARACTERISTICS Basin Area,A: 2.93 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft) (ft) (ft') (ft') (ft') 1,371 80 8.5 5 140 1,304 1,444 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft') (in/hr) (ft) (ft) (hrs) 5,063 80 5 62 4,935 1.0 207 5,204 22.05 BASIN CATCHMENT AREA 19 BASIN CHARACTERISTICS Basin Area,A: 1.56 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 730 80 4.5 5 140 664 804 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft') (in/hr) (ft) (ft) (hrs) 2,696 80 5 62 2,695 1.0 113 2,871 21.41 BASIN CATCHMENT AREA 20 BASIN CHARACTERISTICS Basin Area,A: 1.57 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 735 65 5.5 5 113 670 783 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 2,713 65 5 50 2,580 1.0 108 2,738 22.54 BASIN CATCHMENT AREA 21 BASIN CHARACTERISTICS Basin Area,A: 1.03 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft) (ft) (ft') (ft') (ft') 482 50 5.5 5 87 515 602 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 1,780 50 5 38 1,785 1.0 75 1,898 21.36 BASIN CATCHMENT AREA 22 BASIN CHARACTERISTICS Basin Area,A: 3.13 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, 2_ d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft') (ft') (ft') 1,465 100 6 6 175 1,370 1,545 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft) (hrs) 5,409 100 6 78 5,249 1.0 183 5,510 26.55 BASIN CATCHMENT AREA 23 BASIN CHARACTERISTICS Basin Area,A: 1.97 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft) (ft) (ft') (ft') (ft') 922 70 4 8 122 847 969 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft) (in/hr) (ft) (ft) (hrs) 3,404 70 8 54 3,338 1.0 88 3,480 35.01 BASIN CATCHMENT AREA 24 BASIN CHARACTERISTICS Basin Area,A: 2.87 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, 2-Y d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft') (ft') (ft') 1,343 120 4.5 6 210 1,212 1,422 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 4,959 120 6 93 4,859 1.0 170 5,122 26.26 BASIN CATCHMENT AREA 25 BASIN CHARACTERISTICS Basin Area,A: 1.17 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 548 40 6 6.5 69 596 665 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft') (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 2,022 40 6.5 31 2,068 1.0 67 2,165 27.29 BASIN CATCHMENT AREA 26 BASIN CHARACTERISTICS Basin Area,A: 1.70 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 796 60 5 6.5 104 738 843 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft) (hrs) 2,938 60 6.5 46 2,945 1.0 95 3,087 27.83 BASIN CATCHMENT AREA 27 BASIN CHARACTERISTICS Basin Area,A: 2.20 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 1,030 80 5 6.5 140 984 1,124 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft') (in/hr) (ft) (ft) (hrs) 3,802 80 6.5 62 3,719 1.0 120 3,901 28.51 BASIN CATCHMENT AREA 28 BASIN CHARACTERISTICS Basin Area,A: 1.77 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, 2-Y d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft') (ft') (ft') 828 170 2 8 298 969 1,267 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft') (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft) (hrs) 3,059 170 8 133 2,939 1.0 78 3,150 35.33 BASIN CATCHMENT AREA 29 BASIN CHARACTERISTICS Basin Area,A: 2.39 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft) (ft) (ft') (ft') (ft') 1,119 80 5.5 6 140 1,000 1,140 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft') (in/hr) (ft) (ft) (hrs) 4,130 80 6 62 4,007 1.0 140 4,209 26.55 BASIN CATCHMENT AREA 30 BASIN CHARACTERISTICS Basin Area,A: 0.57 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft) (ft) (ft') (ft') (ft') 267 80 2 8 140 456 596 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft') (in/hr) (ft) (ft) (hrs) 985 80 4 8 62 999 1.0 27 1,088 33.24 BASIN CATCHMENT AREA 31 BASIN CHARACTERISTICS Basin Area,A: 3.82 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft') (ft') (ft')1,788 2-YR 110 9 5 193 1,903 2,096 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft) (hrs) 6,601 110 5 86 6,346 1.0 266 6,697 22.35 BASIN CATCHMENT AREA 32 BASIN CHARACTERISTICS Basin Area,A: 2.88 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft') (ft') (ft')1,348 2-YR 110 6 5 193 1,243 1,436 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft') (in/hr) (ft) (ft) (hrs) 4,977 110 5 86 4,806 1.0 202 5,093 22.21 BASIN CATCHMENT AREA 33 BASIN CHARACTERISTICS Basin Area,A: 1.04 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, 2_ d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft') (ft') (ft') 487 100 2 5 175 330 505 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 1,797 100 5 78 1,669 1.0 71 1,817 22.83 BASIN CATCHMENT AREA 34 BASIN CHARACTERISTICS Basin Area,A: 1.41 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, 2_ d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft') (ft') (ft') 660 100 2 8 175 570 745 3 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 2,436 100 8 78 2,369 1.0 63 2,509 35.09 BASIN CATCHMENT AREA 35 BASIN CHARACTERISTICS Basin Area,A: 2.85 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, 2_ d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft') (ft') (ft') 1,334 100 4 8 175 1,210 1,385 3 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 4,925 100 8 78 4,769 1.0 125 4,972 35.46 BASIN CATCHMENT AREA 36 BASIN CHARACTERISTICS Basin Area,A: 1.74 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, 2-Y d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft') (ft') (ft') 814 175 2 7.5 307 927 1,234 3 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft) (in/hr) (ft) (ft) (hrs) 3,007 175 7.5 137 2,833 1.0 80 3,050 33.74 BASIN CATCHMENT AREA 37 BASIN CHARACTERISTICS Basin Area,A: 1.65 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft) (ft) (ft') (ft') (ft') 772 75 5 6 131 848 978 3 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 2,851 75 6 58 2,767 1.0 97 2,922 26.49 BASIN CATCHMENT AREA 38 BASIN CHARACTERISTICS Basin Area,A: 2.04 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, 2 Y d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft') (ft') (ft') 955 200 2.5 7 351 1,259 1,611 3 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft') (in/hr) (ft) (ft) (hrs) 3,525 200 7 156 3,298 1.0 100 3,554 31.73 BASIN CATCHMENT AREA 39 BASIN CHARACTERISTICS Basin Area,A: 0.66 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, 2_ t13.5 d1 Pipe Volume,VP1 VR1 Vl (ft) (ft) (ft') (ft') (ft')309 100 6 175 770 945 3 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 1,140 100 5 6 78 1,169 1.0 42 1,288 24.63 BASIN CATCHMENT AREA 40 BASIN CHARACTERISTICS Basin Area,A: 1.75 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, 2-Y d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft') (ft') (ft') 819 175 2 7.5 307 927 1,234 3 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft') (ft) (hrs) 3,024 175 7.5 137 2,833 1.0 80 3,050 33.93 BASIN CATCHMENT AREA 41 BASIN CHARACTERISTICS Basin Area,A: 0.68 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 318 55 3 5.5 95 325 420 3 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft) (ft) (in/hr) (ft) (ft) (hrs) 1,175 55 5.5 42 1,193 1.0 46 1,281 23.07 BASIN CATCHMENT AREA 42 BASIN CHARACTERISTICS Basin Area,A: 0.50 ac Runoff Coefficient,C: 0.5 25 YR Rainfaill Intensity,is 0.26 in/hr 100 YR Rainfaill Intensity,is 0.96 in/hr Infiltration Rate,r: 1.0 in/hr STORAGE VOLUMES Chamber 1 Rock Void Volume, Storage Volume, Req'd Volume, V2-YR L1 W1 d1 Pipe Volume,VP1 VR1 Vl (ft') (ft) (ft) (ft) (ft') (ft') (ft') 234 70 3 5.5 122 413 535 3 Chamber 2 Design Rock Void Volume, Infiltration Rate, Bed Infiltration Storage Time to Req'd Volume,V100-YR L2 W2 d2 Pipe Volume,VP2 VR2 I Volume,V2i Volume,V2 Drain 90% (ft) (ft) (ft) (ft) (ft') (ft') (in/hr) (ft) (ft) (hrs) 864 70 5.5 54 825 1.0 32 912 24.24 SECTION 5 Intensity-Duration-Frequency Curve ACHD Intensity-Duration-Frequency Intensity(inches per hour) Design Storm 2 5 10 25 50 100 Tc(hr) Tc(min) 0.17 10 0.69 1.15 1.48 1.85 2.20 2.58 0.25 15 0.59 0.97 1.22 1.56 1.86 2.18 0.33 20 0.49 0.81 1.01 1.30 1.54 1.81 0.42 25 0.43 0.71 0.89 1.14 1.35 1.58 0.50 30 0.41 0.67 0.85 1.08 1.29 1.51 0.58 35 0.34 0.56 0.70 0.90 1.07 1.25 0.67 40 0.31 0.51 0.64 0.82 0.98 1.15 0.75 45 0.29 0.48 0.60 0.77 0.91 1.07 0.83 50 0.27 0.45 0.56 0.72 0.85 1.00 0.92 55 0.26 0.43 0.54 0.69 0.82 0.96 1 60 0.26 0.43 0.54 0.69 0.82 0.96 2 120 0.16 0.25 0.31 0.39 0.46 0.54 3 180 0.13 0.19 0.23 0.29 0.34 0.40 6 360 0.09 0.12 0.14 0.18 0.21 0.25 12 720 0.06 0.08 0.10 0.12 0.14 0.16 24 1440 1 0.04 0.06 1 0.06 0.08 1 0.09 0.10 Intensity Duration Frequency ------ 2 3 -)K-5 -x-10 2.5 25 t 50 2 ---0-100 L H u 1.5 c c c �X�X X----X_X\X_X- --~-- \X-_)K X- �X-X 0.5 ------ ---------X-X-X- \ _ 0 - - ---- 10 15 20 25 30 35 40 45 50 55 60 120 180 360 720 1440 Duration(minutes) SECTION 6 Drainage Basin Map LEGEND DRAINAGE BASIN ass w DRAINAGE BASIN AREA B o a 8 3 4 .03 w ' i } 55 x 1.04 w 5 6 0 .4J w 1.51 w 6B 7 JJ w 7a w 9a w 9 O.Je ac 23 .92 w ° 24 22 2.12 w 11J w • 34 • 35 .1—. . .e533 ® 1.04 w 37 36 /.65 w .74 w 26 25 1.70 w 1.17 w , Ffl 32 ee w • 28 27 38 .nw .2ow 04 w 0 s 29 31 .J9 w 62 w 1.66 w 162 w SD 20 age w 1.57 w . 12B a99 w , 40 7.5 w 12 13 9e w 14 17 1.fo w 405 w _ 16 .25 w 21 1.0J ae 18 •9j°O 39 19 i .56 w FEET 300 0 150 300 GRAPHIC SCALE 1 inch=300ft. Horizontal CESCE COMSML4LaHM DAYSPRING Toll Brothers ENGINEERING • PLANNING • SURVEYING • ENVIRONMENTAL DRAINAGE BASIN M A P ESE Consultants,Inc. AMERICA'S LUXURY HOME BUILDER* 3103 W.Sheryl DrT:208-2400•Meridian,ID83642 November 2024 - Meridian, Idaho T:208-424-0020