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Curve number, runoff, hydrologic models, land use and land cover, water quality, water quantity


The Curve Number (CN) method has been widely used to estimate runoff from rainfall runoff events. In this study, experimental plots in Roorkee, India have been used to measure natural rainfall-driven rates of runoff under the main crops found in the region and derive associated CN values from the measured data using five different statistical methods. CNs obtained from the standard United States Department of Agriculture - Natural Resources Conservation Service (USDA-NRCS) table were suitable to estimate runoff for bare soil, soybeans and sugarcane. However, we propose a new method to estimate CN values from measured rainfall-runoff data (CN calibrated) from fallow lands, finger millet and maize. The new CN values provide better runoff estimates than the values from the standard USDA-NRCS table. The results of this study can be used in hydrologic models to evaluate impacts of land use and land cover (LULC) changes on water quality and water quantity over the years in the region.