Study of Ground Water Recharge-Ability in the Context of Urbanization, Using Remote Sensing and Gis, Ernakulam District, Kerala

Abstract

Growth of urban areas results in significant changes in the physical properties of the land surface. The consequence is increase in area of impervious surface resulting in enhanced surface runoff and reduced infiltration which declines the ground water reduction and quality. In order to facilitate a sustainable urban ground water management practise, an understanding of long term spatial and temporal hydrologic variations is essential. This study is an attempt to quantify the impact of long term land use changes due to urbanization on surface runoff and groundwater table in Greater Cochin, comprises of Cochin as well as the major towns surrounding Cochin within Ernakulum district. The available satellite data is integrated in a GIS platform to quantify the impact of changing land use pattern on prevailing hydrology. Effective impervious area, runoff for peak rainfall and water depth contour map was calculated and generated using previous and present ground water data which indicates that overall ground water depth is getting deeper from previous years. Runoff to recharge ratio was calculated and the results were used to generate graphs plotted between effective impervious area (EIA) and runoff to recharge ratio of the study area. These plotes clearly indicate the linear increase in runoff to recharge ratio with EIA. Thus, the present study clearly shows that the increase in urbanization have negatively impacted the ground water hydrology of the study area.