Impact of Total and Effective Imperviousness on Runoff Prediction

Abstract

Urbanization in a broad sense means increase in imperviousness and thus putting more obstruction to free flow of water into the ground surface. The most commonly used measure of imperviousness is total impervious area (TIA), which is a measure of the area that resists the rain water to infiltrate the down soil, whereas effective impervious area (EIA) is that fraction of TIA that has a direct hydraulic connection to the downstream drainage. Imperviousness being an important parameter in most of the hydrologic models has brought considerable attention in recent years among the researchers community. Hence, the need arises to evaluate the degree of accuracy of using TIA or EIA in hydrologic modeling. Toward this end, the current study presents a comparison between the predicted runoff of an Indian catchment using TIA and EIA in a hydrologic model and hence the better predictor has been found out.