Study of groundwater vulnerability to contamination using the DRANTHVP method in wates groundwater Basin, Indonesia

Department of Environmental Geography, Faculty of Geography, Universitas Gadjah Mada, Indonesia

^* Corresponding author: mwiwik@ugm.ac.id

Abstract

Wates Groundwater Basin in Kulon Progo Regency, the Special Region of Yogyakarta, covers an area of 152.67 sq.m. With human occupations continuously growing in the regency, the groundwater in this basin is subject to change. This research was intended to identify the spatial distribution of groundwater vulnerability of Wates Groundwater Basin using the DRANTHVP method, which factors in Depth to Water Table (D), Recharge (R), Aquifer Thickness (A), Nitrate Attenuation Intensity (N), Topography (T), Groundwater Velocity (V), and Pollutant Input Intensity (P). The data were analyzed quantitatively using a weighted tiered approach―the rating was based on to what degree each of these factors contributes to the calculated vulnerability, then overlaid to produce a groundwater vulnerability map. From the analysis, the index values were clustered into three classes of groundwater vulnerability: low 4.48-6.35, medium 6.35-7.39, and high 7.39-7.97. A large proportion of the basin had medium groundwater vulnerability (109.16 sq.m), and less than half of it had low (39.63 sq.m) and high groundwater vulnerability (3.88 sq.m); these severity levels vary depending on the hydrogeological characteristics and land use of a study area.