33-The influence of catchment modifications on two fresh water lakes of Udaipur

Abstract

The present research is an effort to invesitigate the effects of catchment modifications on chemical and biological characteristics of two freshwater tropical lakes of Udaipur, Rajasthan. The lakes, Fateh sagar and Bari, considered in this study, differ wih respect to the catchment characteristics and level of human interference. The chosen determinants were pH, chloride, sulphate, dissolved organic-C, nitrate-N, phosphate-P, phytoplankton density, chlorophyll biomass and primary productivity. Changes in water chemistry were related with the nature of catchment flushing and trophic status of both the lakes. The study indicated that the catchment characteristics and the extent of human modifications have influenced the water chemistry and ecosystem functioning of both the lakes considered in this study. Lake Bari although situated away from direct human interference, supported good phytoplankton density and productivity due to input of nutrients as atmospheric deposition from aerial catchment in addition to the drainage through the terrestrial catchments. The study demonstrated that the modifications in terrestrial catchment when combined with atmospheric deposition accelerate eutrophication of freshwater lakes.