EFEKTIVITAS BANGUNAN PENANGKAP SEDIMEN PADA JARINGAN IRIGASI STUD! KASUS DI BEND UNG PUCANGGADING (DAERAH IRIGASI PENGGARON KANAN)

Abstract

For preventing the excessive sedimentation in irrigation system, it requires a sedimentation basin. The basin has a certain dimension so that it be able to trap sediment economically by knowing the trap efficiency. Construction of the sedimentation basin spends high cost, often has less effective function. More maintenance cost is needed to overcome the sedimentation that still happened in the irrigation channel. This study discusses and evaluates trap efficiency of the existing sedimentation basin. Through the computation and measurement of hydraulic geometry, sediment characteristics, sediment inflow and outflow around sedimentation basin the trap efficiency rate could be estimated. Decreasing efficiency may reduce the effectively of sedimentation basin. A total of 40 measurement data of hydraulic geometries and 38 laboratories test of sediment material where conducted. Using empirical equation, Camp Graph, Vetter equation and Modification of Ackers and White's sediment transport equation, 16 data sets were analysed to obtain trap efficiency rate. Based on the result of present study, it is found that the trap efficiency of sedimentation basin is less than the design rate. Trap efficiency determined based on the Camp Graph method by using the design data and the measured data are 68,00 % and 52,00 % respectively. According to the Sedimentation method, Vetter and empirical equation by using this study data, the values are 47,51 %, 42,43 % and 48,40 % respectively. It is concluded that the existing sedimentation basin is ineffective. The effectively may be improved by modifying the operation manual of sedimentation basin.