Estimation of soil erosion by USLE model using GIS technique (A case study of upper Citarum Watershed)

Abstract

Citarum Watershed is categorized as a critical watershed due to erosion and environmental damage. Erosion is a continuing long-term problem because of its impact to the economic use and environment. The purpose of this study is to determine the distribution of annual soil erosion by USLE model using Geographic Information System (GIS). The four major input parameters affecting to soil erosion are rainfall erosivity factor (R), length slope factor (LS), soil erodibility factor (K), and land use factor (CP). The result showed that the average annual soil erosion was 122,76 ton/ha/year. The erosion hazard categorized into four classes which are low, moderate, high and very high. The low level of erosion is <15 ton/ha/year has about 2,47% area of low level and located in the north of Upper Citarum Watershed. The moderate level of erosion is 15 - 60 ton/ha/year has about 11,13% area of moderate level and located in the north, east, southeast and south of Upper Citarum Watershed. The high level of erosion is 61 - 180 ton/ha/year has about 78,53% of high level which dominates Upper Citarum Watershed. The very high level of erosion is >180 ton/ha/year has about 7,87% of very high level and located in south and southwest of Upper Citarum Watershed. The result can be used as a consideration for soil erosion prevention measures by local people and government to reduce soil loss.