Analisis Spasial Pendugaan Erosi dan Pemilihan Strategi Mitigasi di Daerah Aliran Sungai (DAS) Belumai Provinsi Sumatera Utara

Abstract

Information on erosion estimation in watersheds is very important for watershed management. One of the determinants of land criticality is the occurrence of high erosion. Erosion causes the top layer of fertile soil needed for plant growth to decrease and the soil's ability to absorb and retain water to decrease. One of the watersheds that is categorized as critical and has not been studied is the Belumai watershed in North Sumatra Province. This study aims to analyze the level of soil erosion and erosion disaster mitigation strategies that are appropriate to the conditions in the Belumai watershed. This research uses the USLE method with factors that affect the amount of erosion, namely rainfall erosivity (R), soil erodibility (K), slope (LS), land cover and management (CP). The results showed that the dominating erosion hazard class in the Belumai watershed was very light erosion covering 30,583.8 Ha in 2015, followed by light erosion covering 27,243.7 Ha in 2015, then moderate erosion covering 30,042.3 Ha in 2010, then heavy erosion covering 5,451.9 Ha in 2020 and very heavy erosion covering 6293.6 Ha in 2010. Very heavy erosion is mainly found in the upper watershed. Mitigation to prevent erosion is important, especially in very heavy, heavy and moderate erosion classes to minimize disaster risk. The most appropriate mitigation strategy to overcome erosion that occurs in the Belumai watershed is based on land cover, which is done vegetatively such as implementing a good agroforestry system and planting ground cover plants such as grass, leguminous plants and woody trees.