A SPATIALLY RESPONSIVE HYDROLOGIC MODEL TO PREDICT EROSION AND SEDIMENT TRANSPORT¹

Abstract

A finite element numerical model has been developed by the authors which routes overland and channel flows in a watershed, given soils, land use, topographic descriptors, and rainfall as input. Such processes as infiltration, canopy interception, seasonal growth of vegetation, and depression storage are described in the hydrologic context of the model. These capabilities, along with the spatial detail and responsiveness of the model, allow a ready adaptation of the model to provide for the prediction of sediment transport and yield. It is assumed that the best results can be obtained by a technique which utilizes the following procedures. Sediment yield to the channel is described by functions describing soil detachment by rainfall and overland flow and transport by overland flow. Since the model description of the channel flow processes involves a more realistic representation of the physical drainage system, an attempt was made to define sediment transport in the channel by erosion and sedimentation mechanics. A conceptual framework is provided whereby the integrated effects of various land use activities on sediment transport and yield can be evaluated. Inherent in this provision of the model is the capability of determining the effects of any control measures to be implemented on a watershed.

Agroforestry for Sustainable Production

“…There is also a growing number of mathematical models based on sediment budgets, hydrological principles and shear resistance. Models that have been tested include: a watershed planning model, ANSWERS (Park et al 1982); an hydrological sediment transport model, FESHM (Ross et al, 1980); and a field scale model, CREAMS (Knisel, 1980). While the future of erosion prediction clearly lies in the further development of models based on the actual physical processes, none so far is workable in practice.…”