L.O. Hadini, J. Sartohadi, M.A. Setiawan and D. Mardiatno
Abstract
The upper watershed of the volcanic landscape in Indonesia commonly has very thick soil depth and land use of agroforestry. Landuse and geophysical characteristics influence the characteristics of sediment flow and soil loss. Very view studies focus on sediment flow and soil loss of agroforestry in the upper watershed of volcanic landscapes. In this study, quantitative investigations were carried out to examine the sediment rate, soil loss rate, material type of sediment and the relationship of one into another. Outlet of the gully was selected to measure the flow discharge and sediment sampling for each rainfall event. The results showed that the sediment rate (Qs) could be predicted based on discharge (Q) and water level (h) with the following rating curves, Q = 0.8809 (h-0.0019)1.2454 and Qs = 0.0274Q1,8623. The soil loss value at catchment area was 0.836 ton/ha/year and 0.207 tons/ha/year of which was in the form of suspension and bed load. The contribution of suspension and bed load in the total sediment was 91% and 9% respectively.