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<br />Page 13 <br /> <br /> TABLE III. RUNOFF COEFFICIENTS FOR RATIONAL METHOD <br /> RUNOFF COEFFICIENTS <br /> PERCENT FREQUENCY <br />SURFACE CHARACTERISTICS IMPERVIOUS 2 5 10 100 <br />Business: <br />Commercial Areas 95 .87 .88 .90 .93 <br />Neighborhood Areas 65 .60 .65 .70 .80 <br />Residential: <br />Single-Family 40 .40 .45 .50 .70 <br />Multi-Unit (detached) 50 .50 .55 .60 .75 <br />Multi-Unit (attached) 70 .65 .70 .70 .80 <br />1/2 Acre Lots or Larger 30 .30 .40 .45 .65 <br />Apartments 70 .65 .70 .70 .80 <br />Industrial: <br />Light Areas 80 .75 .80 .80 .85 <br />Heavy Areas 90 .80 .80 .85 .90 <br />Parks, Cemeteries 7 .15 .25 .35 .60 <br />Playgrounds 13 .20 .30 .40 .70 <br />Schools 50 .50 .55 .60 .75 <br />Railroad Yard Areas 40 .40 .45 .50 .70 <br />Undeveloped Areas: <br />Historic Flow Analysis, <br />Greenbelts, Agricultural <br />Natural Vegetation, <br />Clayey Soils, 2 .10 .20 .30 .60 <br />Sandy Soils .00 .05 .15 .35 <br />Offsite Flow Analysis 45 .45 .50 .55 .72 <br />(when land use not defined <br />Streets: <br />Paved 100 .87 .88 .90 .93 <br />Gravel 7 .15 .25 .35 .65 <br />Drives and Walks 96 .85 .87 .90 .92 <br />Roofs 90 .80 .85 .90 .90 <br />Lawns, Sandy So il 0 .00 .10 .20 .50 <br />Lawns , Clayey Soil 0 .10 .20 .30 .60 <br />