Estimating infiltration for erratic rainfall

摘要

To estimate cheaply the infiltration/runoff of typically unsteady rainfall events for purposes of watershed modeling, a method known as ‘time compression’ has been tested against hysteretic Darcy computations. This method assumes that for a given soil the maximum infiltration rate is simply a function of the cumulative infiltration, regardless of the rainfall versus time history. Hysteretic characteristics from soils measured by Topp (1971) were employed in the Darcian calculations. The appraisal proved generally encouraging for application of this approximation to watershed modeling. The maximum infiltration rate was uniformly underestimated to a moderate degree in the early minutes of a downpour commencing late in an unsteady ev