A unified approach for erosion and sediment transport studies

Most of the approaches used in the estimation of soil erosion rates, such as the "Universal Soil Loss Equation," arc empirical in nature. The empirical parameters used depend on local conditions. The application of this type of equation to geographic areas where conditions are different from conditions in the area where the parameters were derived is questionable, Most sediment transport equations are derived from simplified assumptions that the sediment transport rate can be determined from a hydraulic parameter, such as shear stress, water discharge, or flow velocity. Comparisons among computed results from equations based on different assumptions often differ significantly from each other and from measurements. The application of theories of unit stream power and minimum energy dissipation rate can provide a unified approach for the determination of soil erosion rates for watersheds, rills, and gullies and sediment transport rates in rivers. Laboratory and field data will be used to demonstrate the applicability and reliability of this process-based approach.