Sedimentation at the Rokan River Estuary Bagansiapiapi Riau Province Indonesia

The aim of this study was to analyze the characteristics of sediments and estimate the accumulatin rate of sediment at the Rokan River estuary. The results showed that the bottom estuary of the Rokan River are dominated by the mud sediment fraction. This type of mud sediment occupies almost the entire bottom of the estuary. This type of mud consists of a classification of coarse, medium, fine and very fine mud. Skewness of sediment are only very skewed and very fine skewed classification. The majority of sediment sorting goes into poorly sorted classification. Generally, sediments include into the classification of extremely leptokurtic. The sedimentation area for 72 years reaches 27, 441.9 ha with accumulation rate of 343, 0 ha/year. The highest sedimentation occurred in the coastal of Bagansiapiapi, sediment accumulation rate of 144.5 ha/year, the lowest in Halang Island 5.1 ha/year. On the right of the estuary of the Rokan River formed 3 islands namely Berkey Island, Serusa Islan, and Baru Island. Berkey Island estimated formed 1943 accumulated sediment rate of 114.2 ha/year. Serusa Island estimated formed 1966. Baru Island estimated formed 1997. Sedimentation of the right side of the estuary is greater than the left estuary.