Effect of Spatial Resolution on Watershed Characteristics and the AGNPS Model Hydrologic Simulations

Abstract

The distributed parameter hydrologic and non point source (NPS) pollution models consider the spatial variability of watershed characteristics and simulate the distributed watershed processes by dividing the watershed into small elements called ‘cells’. Arbitrary selection of cell size for these models yields ambiguous results. Automatic extraction of watershed drainage characteristics from digital elevation model (DEM) is an effective alternative to the tedious manual mapping from topographic maps. Geographical information systems(GIS), DEM and remote sensing techniques provide faster, more efficient and accurate ways to extract parameters of distributed parameter models for each cell. In India, very limited applications of these advanced techniques have been made in NPS pollution modelling. The present aims to study the effect of cell size variation on hydrological simulations of the distributed parameter Agricultural Non Point Source (AGNPS) pollution model version 5.00 for a 16.13 km2 small watershed of the eastern India using DEM, GIS and remote sensing techniques for automatic extraction of the model input parameters.