Identification of groundwater potential zones in the Southern Mountains, Yogyakarta Special Region

Abstract

Southern Mountains, Yogyakarta Special Region is a zone that extends from the south-eastern part of Yogyakarta Special Region to the east along the southern coast of East Java. From the hydrogeological map, it is known that the area is an area of scarce groundwater. This study aims to determine the potential for groundwater in these areas. The identification of groundwater potential is carried out using the Groundwater Potentiality Index (GPI) method by referring to 5 determining parameters: lineaments, lithology, drainage, topography, and rainfall. Lineament, drainage, and topography data were obtained from the Indonesia Geospatial Portal and the Digital Elevation Model (DEM) belonging to the Indonesian Geospatial Information Agency. The lithological data is obtained from data from the Geological Survey Centre, Geological Agency, Ministry of Energy, and Mineral Resources in the form of Geological Maps of Remote Sensing Image Interpretation Results. Rainfall data were obtained from reports from the Serayu Opak River Basin Office and the Public Works, Housing, and Energy Department of Mineral Resources Yogyakarta Special Region. The evaluation of parameters reveals that even in the scarce groundwater zones, estimation of area with possible of groundwater can be classified into five classes of groundwater potential index, namely: very low (<56.25), low (56.25-90), medium (90-123.75), high (123.75-157.5), and very high (> 157.5). In the next step of research the validation may be conducted on a high and very high GPI value whether their are really is associated with the presence of springs and wells. If it is correlated, future exploration of groundwater in this area will be focused and successful.