Sedimentation rate and pattern of a Himalayan foothill lake using 137Cs and 210Pb

Abstract

An attempt has been made to determine the sedimentation rate and pattern of Mansar Lake, a natural lake located in the Himalayan Foothills of Jammu and Kashmir India. Five core samples were collected from different locations in the lake and analysed for 137Cs and 210Pb. The results show that the rate of sedimentation in the lake varies between 1.4 and 3.7 mm year-1 with the mean rate of 2.3 ± 0.02 mm year-1. The spatial variation of sedimentation rate provides evidence on the existence of three depositional zones in the lake. The higher sedimentation rates at two sites located near the periphery of the lake show the effects of human activities in the catchment area, such as agriculture and construction. The sediment accumulation rate of Mansar Lake is compared with that of four Lesser Himalayan lakes and it is found that Mansar Lake is receiving sediment at the rate of 892.8 m3 km-2 year-1, which is higher than for all the Lesser Himalayan lakes. This higher rate reveals that the Siwalik terrain of the Himalayan Foothills, consisting of sandstone, mudstone, siltstone and clay, is eroding out at a faster rate than the Lesser Himalaya terrain. Copyright © 2007 IAHS Press.