Identification of flood risk zones in the region of Yogyakarta

Abstract

There are three rivers that cross the center of the Yogyakarta region and through Sleman Regency, Yogyakarta City and Bantul District, namely Code River, Gajah Wong River and Winongo River. The contribution of these three rivers to flood events in Yogyakarta is considered significantly high because the river passes through urban areas, settlements, agricultural land, and densely populated areas. In this study a hazard level map and the level of vulnerability of floods are created in those three watersheds. Map making starts with a study of hazards and vulnerabilities using the Analytical Hierarchy Process (AHP) method, weighting, scoring, and continued with a map depiction using Geographic Information Systems (GIS). Map of research results in the form of hazard level maps and flood vulnerability levels for Code watershed, Gajah Wong and Winongo. From the map, it can be concluded that most watershed areas of the Code are included in the level of moderate danger and low level of vulnerability. The entire Gajah Wong watershed is included in a moderate level of danger and most of them are at a high level of vulnerability, while most of the Winongo watershed has a high level of danger and vulnerability.