A sedimentation model for small watersheds

Abstract

The digital computer model presented here is designed to predict sediment yields from individual storms occurring on small watersheds. It is also designed to use minimal amounts of actual storm data. In the model, rainfall, runoff and the erosion process are represented by three component models which can also function as separate entities. Rainfall and runoff are treated similarly in that both are simulated by probability density functions of the Erlang distribution which are fitted to their total amounts and maximum rates. The erosion process is partitioned into several of its component processes, and each of these components is then represented by a single mathematical function. When tested, the model showed some deficiencies, particularly in its representation of the actual regimen of rainfall and runoff. Despite these deficiencies, however, it accurately predicted the observed sediment yields from 17 of the 29 storms on which it was tested. It appears that correction of these deficiencies will result in an improved success rate,