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.

Mapping groundwater potential zone using groundwater potentiality index in Sulamu, Central Fatuleu and West Fatuleu, Kupang, East Nusa Tenggara

“…In addition, secondary data was also collected, including the Topographical Map of Indonesia (RBI) obtained from the Geospatial Information Agency's geoportal, Digital Elevation Model (DEM) obtained from DEMNAS with a spatial resolution of 0.27-arcsecond vertical datum EGM 2008, DEM SRTM, hydrogeology map scale 1: 250,000 [9], geological map scale 1: 250,000 [10], geological map of remote sensing imagery scale 1: 50,000 [16], and annual rainfall data. Processing of the thematic maps for each parameter up to the delineation of the groundwater potential zone map is using the Geographic Information System (GIS) technique integrated with Remote Sensing (RS) and other primary and secondary data [3,6,7,8,11,13,14,17]. Processing of the GPI thematic parameter map is as follows:…”

“…Fractures are void spaces within massive rocks that serve as potential spaces for the movement and occupancy of water [5,6,8,14]. The presence of fractures or joints can increase the permeability and function as secondary porosity [3,5,6,8,17]. Aperture, spacing, interconnection, and fracture plane orientation play an important role in the presence and movement of groundwater in fractured aquifers [14].…”

“…Zones with open, dense, and interconnected fractures are more likely to contain groundwater [3,6,8,14]. Fractures that occur structurally in rocks with linear or curved features are referred to as lineaments [6,8,17,19]. Lineaments represent fracture systems, discontinuity planes, and rock faults [17].…”

“…Fractures that occur structurally in rocks with linear or curved features are referred to as lineaments [6,8,17,19]. Lineaments represent fracture systems, discontinuity planes, and rock faults [17].…”

“…Lithology affects the presence of groundwater in an area [3,17]. Lithology influences the permeability of rocks and the distribution of fracture patterns [3,8,14,17].…”