Time Variations of Sediment Floc Size and Density by using Settling Column Data

The investigation of settling process and cohesive sediments consolidation in dam reservoirs and beaches is one of the most important issues playing an effective role in different descaling and sediment controlling designs, including dredging projects and hydraulic sediment removal operations. The superfine cohesive sediments even settle in the canals in which the existing standard criteria of design have been observed. They have also settled in dam reservoir and resulted in trapping efficiency near 100%. In addition to reducing the service life of reservoir, this problem has also changed the limpidity of the water released from the existing reservoir, ecology and morphology of the downstream river. In the beaches and seaports, the cohesive sediments settlement has caused an increase in dredging costs. In many cases it is impossible to overcome this phenomenon in practice [1].