Spatial Analysis of Water Infiltration Areas and Flood Risk in Yogyakarta City

Yogyakarta City faces environmental problems due to the reduction of water catchment areas resulting from urbanization and changes in land use. This reduction can disrupt the hydrological cycle, leading to groundwater depletion and an increased risk of flooding and inundation. Using a Geographic Information System (GIS) approach, this research will map the water catchment potential. The data analysed included soil type, rainfall, land slope, land use, and soil infiltration rate. Scoring and overlay methods were used to create a thematic map depicting the condition of water infiltration in Yogyakarta City. The results show that Yogyakarta City is dominated by regosol soil type (99.87%), residential land (61.08%), and slope <8% (45.16%). The highest infiltration zone is classified as “Very Large” (24.55%), while the lowest is “Very Small” (0.06%). Most areas have a “natural normal” condition (16.23%). Further analysis showed a relationship between infiltration ability and flood risk. This research is expected to serve as a basis for BPBD Yogyakarta City in formulating groundwater conservation and flood mitigation policies that support more adaptive decision-making in response to climate change and urban growth.