EVALUASI PERUBAHAN TUTUPAN LAHAN TERHADAP FLUKTUASI DEBIT ALIRAN RENDAH DI DAS JUANA

Abstract

Land cover changes in the Juana Watershed continue to occur as the demand for building, residential, and industries increases. Today, Juana Watershed is experiencing a decline in water discharge due to prolonged drought, with the water level of the Silugonggo River dropping by up to 50 cm per day. Land cover changes within a watershed significantly affect hydrological balance, particularly low-flow. This research investigates the impact of land cover changes on low-flow fluctuations in Juana Watershed from 2017 to 2023. Land cover changes analysis utilizes secondary data by verifying shapefile data through digitization satellite image-based from Google Earth and classified into five categories: forest, agricultural, built area, crop land, and water bodies using ArcGIS software. The low-flow analysis uses FJ. Mock method. The evaluation of land cover changes on low-flow fluctuations is conducted by comparing the land cover changes with the maximum low-flow for each period. The results of this study indicate that land cover in Juana Watershed from 2017 to 2023 was predominantly agricultural area, 51%. During this period, 8,3% of forest was converted into built area and crop land, with 3,4% and 4,9% respectively. Where FJ. Mock model is considered reliable in predicting low-flow in Juana Watershed, with R² = 0,93 and NSE = 0,79 and the maximum low-flow values 162,50 m³/s, 146,01 m³/s, 74,93 m³/s, 107,33 m³/s, 117,96 m³/s, 139,08 m³/s, and 172,69 m³/s, respectively.