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<br />Table IL2,6-l <br /> <br />Runoff Coefficients for Rational :1er:hod <br />(From: American Soc. of Civil Engineers and ',-later <br />Pollution Control Fed. [1970J and ~;eelye [1960]) <br /> <br />Character of surface <br /> <br />Pavement--asphalt or concrl=te <br /> <br />Gravel, from clean and ~oose <br />to clayey and compact <br /> <br />Roofs <br /> <br />Lawns (irrigated) sandy so11 <br />Flat, 2 percent <br />Average, 2 to 7 percent <br />Steep, 7 percent or more <br /> <br />Lawns (irrigated) heavy soil <br />Flat, 2 percent <br />Average, 2 to 7 percent <br />Steep, 7 percent <br /> <br />Pasture and non-irrigated la.~s <br />Sand <br />Bare <br />Light vegetation <br />Loam <br />Bare <br />Light vegetation <br /> <br />Clay <br />Bare <br />Light vegetation <br /> <br />Composite areas <br />Urban <br />Single-family, 4-6 unitslacre <br />Multi-family, >6 units/acre <br />Rural (mostly non-irrigated lawn area) <br /><1/2 acre - I acre <br />1 acre - 3 acres <br />Industrial <br />Light <br />Heavy <br />Business <br />Do;mtown <br />Neighborhood <br />Parks <br />Rural open space <br /> <br />LCS-WM I'lSnual <br /> <br />4.2---4 <br /> <br />Runoff coefficients <br />----.- <br />llange Reco~ended <br /> <br />0.;'0-0.95 0.90 <br />0.25-0.'/0 0.50 <br />0.:'0-0.95 0.90 <br />0.05-0.15 0.10 <br />o .l5-0.:1O 0.17 <br />0.20-0.:30 0.25 <br />0.:,3-0.17 0.15 <br />O. :.8-0.:12 0.20 <br />0.25-0.35 0.30 <br /> <br />0.:.5-0.';0 <br />0.:_0-0.,\0 <br /> <br />0.30 <br />0.25 <br /> <br />0.20-0.60 <br />o. :,0-0. ,,5 <br /> <br />0.40 <br />0.30 <br /> <br />0.30-0.15 <br />0.20-0.60 <br /> <br />0.50 <br />0.40 <br /> <br />0.25-0.,';0 <br />0.';0-0.15 <br /> <br />0.40 <br />0.60 <br /> <br />0.20-0.';0 <br />0.15-0.';0 <br /> <br />0.35 <br />0.30 <br /> <br />0.';0-0.130 <br />0.60-0.90 <br /> <br />0.65 <br />0.75 <br /> <br />0.70-0.95 <br />0.50-0.10 <br />0.:.0-0./,0 <br /> <br />0.85 <br />0.60 <br />~ 0.20 <br /> <br />April 1979 <br />