Land use planning for floods mitigation in Kelara Watershed, South Sulawesi Province, Indonesia

Abstract

Indonesia has a tropical climate with high rainfall. The high rain will affect the state of hydrology until the peak discharge is a flood. Other factors that influence flooding are morphometry, topography, soil type, and land cover conditions. The Kelara watershed in South Sulawesi has been flooded. Then a flood effort in the disaster mitigation disaster watershed is needed in the form of land use planning. So, this study conducted a mapping of watershed morphometry analysis, flood vulnerability areas, and hydrological modeling to obtain debit data using the Geographic Information System method. Based on flood mapping, the land use planning for mitigation will be formulated based on flood vulnerability areas, actual land use, district space patterns, and land suitability. The results showed that the morphometry of the Kelara watershed was not identified as vulnerable to flooding, namely the watershed shape, river density, and river gradient. While the mapping of flood vulnerability areas resulting from overlapping parameters of land cover, slope, elevation, and type of soil, indicates that there are flood vulnerability areas in Kelara watershed. The flood vulnerability areas to float in flat to gentle areas (0-15%) with a height of 0-50 meters above sea level and land that have a low infiltration rate. The peak of January in a maximum discharge of 1.7268 m3 / second Kelara river. Land use planning with the forest area and development of agroforestry patterns. The reduced land use planning of the maximum discharge on the Kelara River by 0.05 m3 / sec. But land use planning has not been optimal in decreasing peak discharge. So, it needs faster effort, namely other technical activities such as dam construction and river normalization.