EXPERIMENTAL STUDY ON DESIGN OF SEDIMENT SETTLING BASINS

摘要

In the design of sediment settling basins for irrigation, it is important to determine the basin length. According to normal methods, the design length of a settling basin used to deposit sediment is very long. In this paper, some measures are suggested to decrease the length of a basin by the aid of sediment physical model experiment on the settling basin of Pokhara Irrigation Project in the Kingdom of Nepal. From the experimental results, the basic principles for design of sediment settling basin are presented and two methods are suggested. The first is to extend the storage capacity of skimming zone and prolong the length of weir adequately to reduce the overflow depth. The second is to open the sluice gate partially to release a part of heavily loaded current in the lower layer in settling period. Then, an optimum measure to increase the settling efficiency and prolong the operation period of a sediment basin is recommended. Though the measures are obtained from a specific project, the same techniques could be applied to solve other sedimentation problems in settling basin engineering.