Impact of Check Dams on Runoff and Sedimentation in Data-scarce Fatehsagar Lake Catchment, Rajasthan, India

Check dams built in the catchment of a reservoir intercept the reservoir inflow and act as sediment traps and thus maintain storage capacity of the reservoir. This study aimed at evaluating the impact of check dams on runoff, sediment deposition and storage capacity of the Fatehsagar lake in Udaipur district of Rajasthan, India. A lake water balance model was developed considering soils, hydrologic soil group, land use pattern and hydrologic parameters like rainfall, evaporation and groundwater levels in the catchment area. Furthermore, field investigations were undertaken to gather information about the hydrological and sediment deposition parameters of the check dams. The dams’ water storages were calculated for 11-year period (1995 to 2005) based on the rainfall-weighted siltation pattern. The results indicated that interception of the lake inflow by check dams varied from 2.5% in an average rainfall year to 22.4% in the driest monsoon year. The overall interception of the lake inflow capacity by the check dams was estimated to be 5.3% for the study period. Moreover, sediment interception through check dams enhanced the life of the lake by 10 years during the study period. Findings of the study are useful to water resources managers and policy makers in formulating appropriate strategies to deal with the problems of reduced lake inflows and sedimentation of the lake. Also, the outcomes of this study would be useful in other regions in assessing the significance of check dams constructed in catchment area of a reservoir.