Perencanaan Pengendalian Erosi dan Sedimentasi di DAS Waduk Nawangan Kabupaten Wonogiri Jawa Tengah

Abstract

awangan Reservoir accommodates flow of water that is useful for irrigation, resulting in sediment carried by the water flow causing dead storage to be filled with sediment, indicating the reservoir's useful life has been exceeded. This studyoaims to calculate the rate ofoerosion and sedimentation, level ofoerosionohazard and land criticality in an effort to increase the usefulilifeiofithe reservoir that has been exceeded. Also propose handling in the Nawangan watershed that is predicted as a way to manage the troubles. The erosion rate became calculatedousingotheoUSLE. The data needed are rainfall for erosivity (R), soil type for erodibility value (K), slope for LS value, and land use for CP coefficient. The result erosion rate before handling is 70.445.74 tons/ha/year, the SDR calculation it is estimated the sediment is 6.298.19 tons/year. Knowing of the erosion rate, the proposed conservation management uses 2 methods, namely the vegetation and mechanical strategy. The calculation after handling obtained erosion rate is 7.547.03 tons/ha/year with a sediment of 674.74 tons/year. TBE analysis results obtained very light 59,20%, mild 15,77%, moderate 5,72%, subtantial 13,41%, very subtantial 5,91%. The estimation results obtained the useful life of the reservoir by 5 years.