Predicting runoff from Rangeland Catchments: A comparison of two models

This is a comparison of two very different hydrology models, both designed to predict runoff from ungaged rural catchments. One is the commonly used and conceptually simple Soil Conservation Service curve number method. The other is a process oriented model based on the Green and Ampt equation. The Green and Ampt model employs newly developed techniques for parameterizing the Green and Ampt equation based on readily available soil and vegetation information. Annual, monthly and daily predicted runoff were compared to observed on six uncalibrated rangeland catchments located in Texas, Oklahoma, Arizona, Nebraska and Idaho. Model parameterization was based strictly on individual catchment characteristics. No model calibration was performed. Results indicate that the Green and Ampt model is a potentially useful tool for predicting runoff. These results are important because they demonstrate the utility of complex physically based models as management tools for predicting land use impacts to runoff and infiltration.

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