ESTIMATION OF DELTA-PROFILE IN THE INDRAVATI RESERVOIR

In case of the Upper Indravati Hydro Electric Project in the Orissa st ate of India, the topography of the reservoir area governed the locati on of the water intake, which is situated about; 6.6 km from the upstr eam edge of the water spread. The total length of the reservoir is 43 km. When the delta arrives at the intake, the water draws a heavy char ge of sand and coarser sediment that will damage the turbines. seasona bly accurate prediction of the period required for the sediment delta to travel down to the intake position therefore achieved crucial impor tance. Three different methods were used to predict the time rate of d elta development: (1) a mathematical model; (2) the empirical procedur e developed by the U.S. Bureau of Reclamation (USER), based on the obs ervations about the topset slope, foreset slope, and pivot point, made when the reservoir is in operation; and (3) a procedure based on sedi ment distribution following the empirical area reduction method. Resul ts achieved by each of the three methods compared well, indicating tha t such comparative analysis increases confidence in quantitative predi ctions and improves the predictive methods for delta profile.