Impact of Land Clearance on sedimentation at Balambano Dam, East Luwu Samsuar1, M. Achmad1 H. Mubarak1 and M. Lanuru2
1 Agricultural Engineering Study Program, Faculty of Agriculture, Universitas Hasanuddin, Makassar, Indonesia
2 Marine Science Study Program, Faculty of Marine Science and Fisheries, Universitas Hasanuddin, Makassar, Indonesia
Abstract
Land degradation in the Pongkeru watershed has resulted in increased sediment being captured in dams in the watershed area. There are three dams built in the Pongkeru river basin with a cascade system, namely the Larona, Balambano and Karebbe dams. The balambano dam has a water catchment area of 24,989 ha and receives water runoff from the Larona dam. Sedimentation analysis in the Balambano dam was carried out using the USLE modification method based on spatial data. The results of the study indicate that there has been a change in land use in Balambano sub watershed. The type of land use that has experienced changes is dry land forest which has decreased by 760 ha which has been converted into dry land agricultural areas and open land which is suspected to be illegal mining land. This condition resulted in an increase in the area of the area which was included in the category of Heavy and Medium Erosion Hazard (EH). The results of the spatial analysis show that the increase in EH values generally occurs in areas where community activity is quite high (settlement and agriculture area). The land area with medium category EH was increasing from 254 ha in 2009 to 2,026 ha in 2015, while the land with the high category EH increased from 383 ha in 2009 to 2,198 ha in 2015. The Sediment Delivery Ratio (SDR) 0.1865 was obtained, which means that there was an increase in the amount of sediment held in the dam from 36,736 tonnes / year in 2009 to 179,073 in 2015.
Keywords: Dam, Land Degradation, USLE, Sediment Delivery Ratio
