THE EFFECT OF LAND USE CHANGE TO LAND EROSION AND SEDIMENT TRANSPORTED ON THE CACTHMENT AREA OF MRICA RESERVOIR

The problem of flooding, drought, erosion and sedimentation, has always been a topic of conversation that is always related with land conversion of natural forests into agricultural cultivation. The phenomenon of land conversion is an event in nature that must be understood to determine action in the future. SWAT Hydrological models that have been validated on a very good level based on the Nash-Sutcliffe Efficiency (NSE), is used to simulate in land use changes, based on land cover index changes (IPL) permanent and production scenarious, on soil erosion SYLD and sediment transported Sed-out , in 101,027.250 ha the cacthment area of Mrica reservoir upstream zone. SWAT simulation model results indicate that quantitatively, the increase IPL permanent followed by a decrease in IPL production has the potential to lowering the value of land erosion (ton /ha/yr) of approximately 5.77 to 82.37% and from 5.15 to 75.12% of sedimentary transported (mm/yr). Qualitevely, extreme positive scenario, can increase the value of land erosion in some subbasin and the cacthment area of Mrica reservoir upstream zone, from heavy quality on the existing condition become moderate to light. Watershed management efforts to reduce the rate of soil-land erosion and sediment transported on the river, withland use changes should be followed by soil and water conservation techniques that others such as bench terraces,countering