Determination of the Spatial Spread of Erosion in the Keyang Sub-Watershed Ponorogo Regency, Indonesia

The 24,173-ha Keyang sub-watershed is located within the Madiun watershed in Ponorogo Regency, East Java, Indonesia. Erosion and sedimentation within the sub-watershed have resulted in frequent flooding. Using a digital elevation model in a geographic information system, slope length was determined and a modified form of the Universal Soil Loss Equation was used to evaluate the spatial variability of erosion. Results showed that erosion rates in the Keyang sub-watershed were dominated by values less than 5 metric tons /ha/yr.