Assessment of Trap Efficiency of Sedimentation in KrishnagiriReservoir, South India

Reservoir sedimentation is inevitable, but need to be managed to ensure the continued beneficial water uses to the society. Estimation of trap efficiency and lifeexpectancy are key tools in assessing sediment accumulation and help plan desilting operations. This paper reports the results of sedimentation of Krishnagiri Reservoir across Ponnaiyar river in Tamil Nadu, South India. Investigations on soil erosion, nutrient loss, reservoir eutrophication conducted earlier and sedimentation reports available for 1985 and 2004 provided data to study the trap efficiency of the krishnagiri reservoir. Four methods, Brune, Churchill, Gill and Brown methods were applied to the data. The churchill method over estimated the trap efficiency while Brown method predicted the lowest estimates. The trap efficiency varied from 75.69 to 97.28 % by the Gill method which is found closer to the actual values that were observed during four occasions from 1957 to 2008.

Keywords:

Krishnagiri Reservoir , Sedimentation , trap efficiencies