Indirect Determination of Effective Impervious Area (EIA) of an Urban City of North East India

Abstract

Rapid urbanization and industrialization results in drastic changes in land use and land cover, which is reflected by the change in impervious area. Information regarding imperviousness is very much essential for urban hydrology and watershed management. Impervious area can further be classified into total impervious area (TIA) or effective impervious area (EIA). The most commonly used measure of imperviousness is TIA which is a measure of the area that seals water to infiltrate the down soil. Whereas EIA is that fraction of TIA that has a direct hydraulic connection to the downstream drainage. From hydrology prospective, EIA gives more accurate result than TIA and is considered as a better predictor of urbanization impact. However determination of EIA is difficult and needs high resolution satellite imageries. In the present study an attempt has been made to determine EIA of an urban city in a developing country like India making use of the space technology output. The urbanization growth pattern for 30 years has been identified from analysis of the low resolution satellite imageries employing remote sensing technique. EIA was then indirectly determined based on the land cover classification result.