SEDIMENT ACCUMULATION RATE IN THE LAKES OF KUMAUN HIMALAYA, INDIA USING PB-210 AND RA-226

The rate of sedimentation and the source of sediments in the lake basins of Nainital region, Kumaun Himalaya, have been estimated employing Pb-210 and 226Ra methods. This has yielded a rate of sedimentation of 11.5, 4.70, 3.72, and 3.00 mm/yr in Nainital, Bhimtal, Naukuchiyatal, and Sattal lakes, respectively. The higher rate of sedimentation in Nainital lake, compared to other lakes, is related to faster erosion in the catchment aided by greater anthropogenic activity, while the slowest rate in Sattal lake is due to less erosion and more input of soil-derived material involving a slow rate of accumulation.