ABSTRACT
ABSTRACT: Many of the reservoirs in Southern California are subject to relatively high sediment accumulation rates. In an effort to provide a cost effective and environmentally acceptable method of removing sediment from these reservoirs a series of operational experiments were conducted on three of the major reservoirs in this area. In two of the reservoirs an approach that might be best described as a version of hydraulic flushing, involving carefully managed Flow Assisted Sediment Transport (FAST), was employed to convey sediment out of the reservoirs. In the third reservoir a more conventional method of draining the reservoir followed by sediment removal using mechanical extraction and trucking was employed. The volume of sediment removed in these operations ranged from approximately 350,000 m3, to in excess of 3,000,000 m3. In total in excess of 5,000,000 m3 were removed as part of these projects. The results of both an initial pilot study and the more extensive larger scale operational experiments, summarized in this paper, suggest the use of the carefully managed FAST approach, in appropriate situations, can be employed at a fraction of the cost of conventional removal methods such as trucking or dredging along with the added benefit of significantly lower environmental impacts.
