Flood vulnerability assessment trough overlay-scoring data method based on Geographical Information System (GIS) in Giriwoyo, Wonogiri, Indonesia

Abstract

The Sub-District of Giriwoyo, located on the southern edge of Wonogiri District, is classified as an agricultural land. This subdistrict is located in the Keduang sub-watershed. This geographical condition makes this subdistrict extremely vulnerable to flooding. This research seeks to determine the distribution of flood-prone areas and categorize the level of flood vulnerability in the Wonogiri Regency, with Giriwoyo as a research site. Quantitative descriptive research employs a scoring procedure based on environmental conditions-related scoring parameters. These variables include slope, soil type, rainfall, altitude, land use, and buffers for river flow. The measured parameters are then layered in a geographic information system (GIS) application to generate a flood vulnerability map. The data analysis procedure employed a descriptive approach. The results indicate that the dispersed, areas of Giriwoyo are classified into 4 vulnerability catogeries such as not vulnerable, vulnerable enough, vulnerable and very vulnerable. Areas with vulnerable categories are scattered throughout the giriwoyo area which is dominated by rice fields and settlements with a flat slope. The very vulnerable area dominates the western part of the giriwoyo which has a lower elevation and flat slope. The parts of giriwoyo that are not prone to flooding are in Selomarto, Tukulrejo, and Girikikis.