Assessment of soil erosion risk within the Maasin Watershed Forest Reserve, Iloilo, Philippines using the Revised Universal Soil Loss Equation (RUSLE) and Geographical Information System (GIS)

FRANCE MATTHEW T. AGUILOS, FAYE ANDREA V. ENCANTO, GHELAI MARIE F. TOLENTINO, and MARIA DEANNA B. JOLITO

Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHSWVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines

Abstract

Soil erosion is the leading cause of watershed degradation. It affects the Maasin Watershed Forest Reserve (MWFR), the main source of domestic water to Iloilo, as evidenced by reports of sedimentation that degrade the water supply of receiving communities. Hence, this study aims to assess the soil erosion risk within the MWFR using the Revised Universal Soil Loss Equation (RUSLE) and Geographical Information System (GIS) data. Geospatial data were processed to calculate the RUSLE factors using ArcGIS. The soil loss rates were determined by multiplying the factors, and were classified into erosion risk classes whose area covered was also measured. It was estimated that the erosion rate in the watershed is 40.7 tons/ha/yr. High to very severe soil erosion risks occur in 63.6% of the MWFR which accounts for the watershed degradation The erosion map can be used in monitoring the soil erosion within the MWFR.

Keywords: watershed, erosion mapping, RUSLE, GIS,soil erosion

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