Runoff estimation by using optimized hydrological parameters with special reference to semi-arid agriculture watershed

Abstract

GIS technology is used to estimate the spatial heterogeneity of the hydrological parameters of a watershed. Hydrological models help to overcome the spatial variability and parameter uncertainties. Runoff is important parameter of hydrological cycle. Soil and Water Assessment Tool (SWAT) which is a physical distributed model developed to forecast runoff, sediment, erosion and nutrient transport from agricultural watershed helps to understand the hydrology of a watershed with rainfall, temperature, solar radiation, wind speed and relative humidity. SWAT simulates better results in both gauged and ungauged watersheds. In the present paper, Krishna river catchment area known as Jurala watershed in Mahabubnagar district, Telangana state of South India is taken to study surface runoff from agricultural areas as this area receives less annual rainfall and agriculture is mostly dependent on seasonal rainfall. Soil has less water infiltration capacity and bottom layer calcium carbonate deposits make soil alkaline due to bore well irrigation. To suggest proper water conservation methods, understanding hydrology of this watershed is important. To simulate runoff from this agriculture watershed SWAT model is used for 11 years from 2000 to 2010. The results are calibrated with observed values.