LAUSR

Investigations have been carried out on Sukhna Lake catchment in the north-western Siwalik Hills in the Himalayas, to estimate recent erosion rates and to assess the impact of conservation measures on the erosion rate. The RUSLE model has been used using data for the period of 2011–2014 and its suitability has been evaluated by comparing its estimates with the observed bathymetric data. The model was found to estimate the erosion rate with fair degree of accuracy. The average recent erosion rate for the catchment comes out to be 34.27 t ha-1 y-1. The slope and steepness factor is found to have a major effect on the erosion process in the catchment. About 56% of the catchment area is observed to have high to very severe soil erosion rates. It is, however, observed that the recent erosion rates in the catchment are significantly reduced compared to the erosion rates in the initial years after the construction of the lake. This significant reduction is observed to be less due to the support practices of construction of silt detention dams and terracing etc., and more due to the cover management practices like extensive reforestation and plantation undertaken in the catchment.