Drainage Coefficients for Heavy Land

Abstract

Due to the impeding nature of the subsoil, drainage discharge from heavy land predominantly takes the forms of lateral interflow through the more permeable toplayer and of overland flow. Evidence is presented that this type of “shallow drainage” discharge can be described by the linear reservoir type rainfall‐discharge model. Procedures and guidelines are given, detailing how this model can be used to derive drainage coefficients for heavy land. Results are evaluated by comparison with other methods of deriving drainage coefficients and with commonly used design standards. It is concluded that the presented method is reliable and universally applicable.