Predicting runoff from Rangeland Catchments: A comparison of two models

TLDR

This study compares two hydrology models—the Soil Conservation Service curve number method and a Green‑and‑Ampt process‑oriented model with new soil‑vegetation parameterization—for predicting runoff from ungaged rural catchments. The authors evaluated annual, monthly, and daily runoff predictions from both models against observed data from six uncalibrated rangeland catchments across Texas, Oklahoma, Arizona, Nebraska, and Idaho, using catchment‑specific parameterization without any calibration. The Green‑and‑Ampt model proved to be a potentially useful tool, illustrating that complex physically based models can serve as management tools for assessing land‑use impacts on runoff and infiltration.

Abstract

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.