Drought Vulnerability Mapping with Geomorphological Approach in Yogyakarta Special Region (DIY) and Central Java

Abstract

This study aims to determine the level of vulnerability of the geomorphologic drought that occurred in Central Java and Yogyakarta Special Region. This study examines geomorphologic drought. Parameters used were slope, drainage, Available Water Capacity (AWC), permeability, landform, and land use. Landsat 8 and SRTM data were used for the extraction of physical parameters, such as slope, drainage, landform, and land use. The method used in this study is scoring and weighting. Query results were used for data classification by overlaying drought geomorphologic parameters. The expected outcome of this research is to map the geomorphologic drought vulnerability on Central Java and Yogyakarta Special Region. Drought vulnerability was divided into wet, normal and dry classes. Distribution of the dry class is frequent. Some of the dry classes are distributed on the steep till extremely steep slope region and on the structural and karsts landform. This was related to AWC value where region with high AWC contributed to the poor drainage of the soil, such as at Kulonprogo, Purworejo, Kebumen, Blora, Wonogiri, Purbalingga, Pekalongan, Jepara and Kudus regency. Normal classes are distributed on the sloping till steep slope, have moderate till well-drained soil and low AWC, such as at Gunung Kidul, Pati, Temanggung regency, and Magelang city. Wet classes are distributed on the flat or almost flat and sloping region. Most of the wet classes are distributed on volcanic hills and coastal area. Those regions are well-drained and the land uses are mostly for settlement and farming, such as at Sleman, Yogyakarta city, Klaten, Bantul, and Wonosobo regency.