Impact of urbanisation on lakes-a study of Bengaluru lakes through water quality index (WQI) and overall index of pollution (OIP).

Abstract

Bengaluru, widely known for its pleasant climate and IT activities, is one of the fastest growing cities of the world. It houses more than 200 lakes. Lakes are important in a city like Bengaluru which does not have a perennial river, thus is dependent on many lakes for both water supply and recreation. Water quality of these lakes is essential, as they are open spaces as well as interact with groundwater. In this study, ten lakes of three different subwatersheds-rural, semi-urban and urban were studied. Physicochemical analysis of the lakes was carried out. The water quality index was then computed using the weighted arithmetic method and overall index of pollution method. It is found that in the city of Bengaluru, urban subwatersheds host lakes of very poor water quality and need immediate attention. Also, the lakes in semi-urban watersheds must be protected to avoid further deterioration and protection of water bodies. The current study presents the lake water quality of three different types of subwatersheds and hence will be useful in understanding the effect of land use on water quality. It will be helpful for decision makers to take further action in protecting not only the land but also the water quality present in the lakes.