(3rd International Conference on Silting Problems in Hydropower Projects, 27-28 February 2008, New Delhi, India, pp. 93-101)
The 775 MW Luhri HEP is a run of the river scheme located on river Satluj between Rampur HEP (412 MW) on the u/s and Kol dam (800 MW) on the dIs. Since river Satluj carries heavy sediment load during snowmelt and monsoons, attention has been given to address the problem of sediment management during OPR stage itself. A novel method of using part of the reservoir for desilting has been evolved which is largely possible on account of the favourable topography available in dam/reservoir area. Two no diversion tunnels have also been provided to divert surplus discharge during high flow from 2 kms u/s of dam axis so that tranquil flow conditions can be maintained in the section of reservoir close to intakes. Periodic flushing of the reservoir would be carried out twice in a year. This concept was evolved on the basis of hydraulic model studies carried out for improving seltling efficiency on reservoir of NJHPs (1500 MW) which showed encouraging results in removal of silt. Numerical modeling, to be followed by hydraulic modeling, has been carried out for Luhri HEP to study the effectiveness of the system & to optimize the arrangement for settling of sediments and their flushing. The results of the studies indicate that particles greater than 0,1 mm can be removed and the velocities are reduced to 0.1 m/sec in lower reservoir.
