The Impact of Land Use Land Cover Change (LULCC) On Runoff Coefficient at Upper Bengawan Solo Watershed, Central Java (Jawa Tengah) Province

Land use land cover change (LULCC) can cause hydrological impact. LULCC for economic activities can provide social and economic benefits, however, these changes often have an impact on decreasing environmental quality. This study aims to determine LULCC in the impact on hydrological conditions, especially on the runoff coefficient. The research location is in the Upper Solo Watershed which has an outlet in Jurug, which has an area of approximately 368,792.43 ha. Water discharge from 2013 to 2021 was obtained from the Bengawan Solo Water Resources Management Office, Ministry of Public Works and Public Housing (PUPR). LULCC data were analyzed from Landsat 8 Operational Land Imager (OLI) satellite imagery recorded in 2013, 2018 and 2021. Based on Landsat 8 OLI satellite imagery results, land cover/use has changed in 2013, 2018 and 2021. Some types of land use that have changed significantly are forest area, dry land agriculture, built-up areas and paddy fields. In the period 2013 - 2018, there was a reduction in the forest area of 0.22% of the watershed area, a reduction in the area of dry land agriculture by 7.16% and addition of a built-up area of 7.16% of the watershed area, an increase in the area of paddy fields by 2.87%. In the period 2018 - 2021, there was a reduction in a forest area of 2.82% of the watershed area, a reduction in water bodies of 0.47% addition of dry land agriculture of 1.51%, and addition of paddy fields of 1.45%. In 2013 the runoff coefficient was 0.41. In 2018, with the addition of a built-up area of 7.16% of the watershed area, the runoff coefficient increased to 0.54. In 2021 the runoff coefficient was decreased to 0.46. LULCC from 2013 to 2021 causes the runoff coefficient value to increase from 0.41 to 0.46.