Simplified Table of Rational Method Runoff Coefficients (see references below) Ground CoverRunoff Coefficient, c Lawns0.05 - 0.35 Forest0.05 - 0.25 Cultivated land0.08-0.41 Meadow0.1 - 0.5 Parks, cemeteries0.1 - 0.25 Unimproved areas0.1 - 0.3 ...
Version 2 is used in the United States, and was developed to estimate runoff volumes and hydrographs, using the same input data and coefficients as Rational Method along with the further assumption that the duration of peak-producing rainfall is also the entire storm duration (Akan, 2002; ...