Delineation of groundwater potential zones using remote sensing, GIS, and AHP techniques in southern region of Banjarnegara, Central Java, Indonesia

Abstract

Southern region of Banjarnegara Regency, Central Java, Indonesia have been experiencing water scarcity throughout dry season every year due to meteorological and geological condition. Meteorological drought in dry season have been recorded since 1984. About 85,000 people are affected. Local authorities were forced to send clean water aid routinely. This study aim to delineate groundwater potential zones using remote sensing, Geographical Information System (GIS), and Analytic Hierarchy Process (AHP). This study evaluate groundwater potential zones using 5 factors involving lineament, lithology, slope, drainage, and rainfall. Digital Elevation Model (DEM) from DEMNAS (published by Indonesian Geospatial Agency) was used to generate lineament delineation and slope map. Hydrography data provided by Indonesian Geospatial Agency was used to generate drainage density. Geological maps which were generated from remote sensing interpretation were provided from Geological Survey Center of Indonesia. Rainfall data were provided by BPS-Statistics of Banjarnegara. 52 springs and 2 bore wells data were used for result validation. All 5 thematic layers were prepared in GIS. All factors and its classes were assigned weights using AHP techniques and normalization of weights was conducted through the AHP. Groundwater potential zones map were generated, the results was classified into five zones as very high, high, moderate, low, and very low. The zones covered of 1.02 km2 (1.18%), 14.49 km2 (16.80%), 33.65 km2 (38.99%), 37.12 km2 (43.02%), and 1529 m2 (0.00%) of study area respectively. Result validation by comparing the AHP map values with discharge of springs and bore wells showed promising result.