Sustainable Reservoir Operation: The Submerged Weir Flushing System

Where suitable conditions are present, reservoir flushing can be an economical and effective approach to maintaining existing storage capacity, thus extending the useful life of reservoirs. A flushing system known as the Submerged Labyrinth Weir Closed Conduit system (SLWCC) which has already been successfully tested at the University of Bristol is introduced. The new flushing system may overcome the main constraints of conventional flushing operation such as significant loss of impounded water and the impact of reservoir operation during flushing. The submerged weir acts to block the advancement of deposited delta into the reservoir hence ensuring intakes are kept clear and is capable to flush sediment downstream, thus fully preserving the storage capacity between the submerged weir and the marn dam. This paper describes some results ot a physical model study of the proposed SLWCC system and discusses some of Halcrow sedimentation projects highlighting the main constraints in tackling reservoir sedimentation by sediment flushing. From the physical modeling results, it can been demonstrated that the use of the SLWCC system for the mitigation of reservoir sedimentation shows great promise in many cases and merits further research.