Estimating erosion and sediment yield on field-sized areas
ABSTRACT A model for field-sized areas was developed to evaluate sediment yield under various management practices. The model provides a tool for evaluating sediment yield on a storm-by-storm basis for control of erosion and sedi-ment yield from farm fields. The model incorporates fun-damental principles of erosion, deposition, and sediment transport. The procedures allow parameter values to change along complex overland flow profiles and along waterways to represent both spatial variability and varia-tions that occur from storm to storm. Many of the model parameter values are obtained from topographic maps or directly from the Universal Soil-Loss Equation (USLE). Thus we feel that the model has immediate applications without extensive calibration. Individual components of the model were tested using experimental data from studies of overland flow, erodi-ble channels, and small impoundments. These results suggest that the model produces reasonable estimates of erosion, sediment transport, and deposition under a variety of conditions common to field-sized areas. The procedures developed here can be used to evaluate alter-native management practices such as conservation tillage, terracing, and contouring.