Improved prediction of life expectancy for a Himalayan lake: Nainital, UP., India

An attempt has been made to predict the life of Lake Nainital, a natural la ke located in the Kumaun Himalaya with a fairly large human settlement arou nd it. Sediment accumulation rates estimated by dating the lake sediment co res employing Pb-210 and Cs-137 dating techniques have been used for the pu rpose, The sediment accumulation rates estimated by radioisotope techniques are comparable to the rates obtained by the sediment balance method using suspended sediment data. The estimated useful life of the lake is about 2,2 00 years, which is much higher than the results obtained by earlier investi gators who used short-term bathymetric data. In the present study, long-ter m (46 years) annual lake sounding data have also been analysed. Large bi-di rectional variations in the annual bathymetry imply that major errors are a ssociated with the lake sounding data that led to the under-estimation of t he life span of Lake Nainital by earlier investigators.