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HomeMy WebLinkAboutDrainage Reports - 08/15/2019City of Fort Collins Approved Plans Approved by: Date: Wes Lamarque 08/15/2019 Forebay 1 Tributary Area/Total Area = .80ac/2.12ac = 38% 38% * WQCV = .38 * 1655.3ft3 = 629.0ft3 = WQCV-1 V1 = 2% * WQCV-1 = 0.02 * 629.0ft3 = 12.6ft3 H1 = V1/A1 = 12.6ft3 / 16ft2 = .786ft = 9.43in >>Round up to get H1 = 10" Forebay 2 62% * WQCV = .62 * 1655.3ft3 = 1026.3ft3 = WQCV-2 V2 = 2% * WQCV-2 = 0.02 * 1026.3ft3 = 20.5ft3 H2 = V2/A2 = 20.5ft3 / 20ft2 = 1.026ft3 = 12.31in >>Round up to get H2 = 13" Runoff Chapter 6 6-8 Urban Drainage and Flood Control District January 2016 Urban Storm Drainage Criteria Manual Volume 1 Table 6-3. Recommended percentage imperviousness values Land Use or Percentage Imperviousness (%)Surface Characteristics Business: Downtown Areas 95 Suburban Areas 75 Residential: Single-family 2.5 acres or larger 12 0.75 – 2.5 acres 20 0.25 – 0.75 acres 30 0.25 acres or less 45 Apartments 75 Industrial: Light areas 80 Heavy areas 90 Parks, cemeteries 10 Playgrounds 25 Schools 55 Railroad yard areas 50 Undeveloped Areas: Historic flow analysis 2 Greenbelts, agricultural 2 Off-site flow analysis (when land use not defined)45 Streets: Paved 100 Gravel (packed) 40 Drive and walks 90 Roofs 90 Lawns, sandy soil 2 Lawns, clayey soil 2 REVISIONS NO. REV.DATE REVISIONS DESCRIPTION www.olsson.com TEL 970.461.7733 Suite 200 Loveland, CO 80538 1880 Fall River Drive, DRAINAGE BASIN MAP FORT COLLINS, CO2019 SPIRIT AT THE RIVER HOTEL PRELIMINARY DESIGN PLANS