| Summary: | ABSTRAK
A methodology is developed to estimate upland erosion at the land parcel scale by implementing The Universal Soil Loss Equation (USLE) in a Geographic Information System (GIS) environment. Widely accepted, simple and straightforward properties of the USLE's method of estimation are paired with the ARC/INFO GIS capabilities in building spatial database to perform spatial and statistical analysis upon several different layers of information with geographic location as the common link.
As a case study, a spatial database was .built firstly for Ngrancah catchment area at Kulonprogo Regency of Yogyakarta Special Province, but the modeling approach should be compatible for any land area where the prerequisite-topographic, hydrologic, soil and land use data is available.
Statistical analysis performed successfully estimated 150,998 tons/ha of average annual erosion, whereas previously manual estimation resulted 151,609 tons/ha. Spatial analysis of this model showed whether most area of the case study was experiencing moderate soil loss (60 - 180 tons/ha/year). High and very high soil loss areas (/80 - 480 tons/ha/year and greater than 480 tons/ha/year) that must receive greater attention due to the management practices were also identified.
Key words: Universal Soil Loss Equation (USLE), Geographic Information System (GIS), spatial database.
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