Groundwater vulnerability and drinking water sustainability under compound hydroclimatic extremes: a spatial analysis of the Magelang volcanic catchment, Indonesia

ABSTRACT

Graphical abstract showing a GIS-based assessment of groundwater sustainability for drinking-water supply in the Magelang Volcanic Catchment, Indonesia. The framework integrates topography, hydro-meteorological data, land use, geology, and groundwater quality to assess groundwater availability, water quality, abstraction pressure, and hydroclimatic stress. It identifies upstream volcanic uplands as more sustainable and downstream zones as more vulnerable, resulting in high, moderate, and low groundwater sustainability zones.

Groundwater is a critical source of drinking water in tropical volcanic regions, where water security is increasingly affected by compound hydroclimatic extremes. This study evaluates groundwater vulnerability and drinking-water sustainability in the Magelang Volcanic Catchment, Central Java, Indonesia, using a GIS-based spatial framework integrating DEMNAS, hydro-meteorological records, land use, geology, hazard maps, and groundwater quality observations. The novelty of this study lies in integrating groundwater availability, groundwater quality, and drought–flood stress within a unified catchment-scale assessment of drinking-water sustainability. Five major catchment units were identified, extending from recharge-dominated volcanic uplands to flood-prone alluvial lowlands, and four drinking-water sustainability classes were delineated. The results reveal a clear upstream–downstream gradient, with upland areas showing greater resilience, while downstream zones experience higher hydroclimatic stress, poorer groundwater conditions, and lower reliability. These findings provide a spatial basis for adaptive drinking-water management and groundwater source protection in volcanic catchments.