Abstract:
River flows carry considerable sediment load which creates problems in operation of irrigation and hydroelectric projects. Canals get silted up, turbine's blade / buckets 'are subjected to abrasive action of sediment and require frequent repaire.
The problem of sediment management is complicated and it is tackled in each case in one or in combination of several of the following ways.
(i) Water Shed Management
(ii) Stabilization of river course by training and channel improvements
(iii) Sediment exclusion devices at the diversion and head works
(iv) Sediment ejection devices in the canals
The sediment exclusion and ejection devices remove coarse fractions of sediment which move as bed load. Desilting basins are commonly used for removal of the sediment from the water conductor system of the Hydro Electric Projects.. These basins are designed to exclude particles larger than certain size depending upon the head on the turbine and experience of the designer. The performance of the desilting basin depends upon the reduction in the velocity and turbulence, provision of adequate length of basin, which in turn mainly depends upon diffuser, for achieving the desired settlement and the skimming arrangements at the outlet.
