Sediment Yield Computed with Universal Equation

Sediment yield from watersheds is predicted by modifying the Universal Soil Loss Equation and using a delivery ratio. All factors of the equation except the rainfall factor are modified to increase computational efficiency. In addition, the erosion-control-practice factor is expanded to include the separate effect of grassed waterways. Delivery ratios are computed for five small blackland watersheds and related to watershed characteristics. Step-wise multiple regression was used to develop equations for predicting delivery ratios. The regression analysis showed that the most important watershed characteristic, slope of the main stem channel, explains about 99% of the variation in delivery ratios. The modified Universal Soil Loss Equation and the equation for predicting delivery ratios form a sediment yield model that should be useful in reservoir design and water quality studies.