Freshwater Potential Based on Identification of Aquifer Layer in Balangan County, Indonesia

Abstract

Groundwater is a reservoir of fresh water located beneath the ground surface in soil pore spaces and the fractures of lithology formations. Groundwater contained in the aquifer layer has a certain depth. Aquifer layer measurement was conducted with five tracks using the AGI Super Sting R1 IP tool with a spacing of 25 m and a track length of 675 m in Balangan County. This study aims to determine the 2D cross-sectional model, analyze lithology types, and determine the depth, thickness, and aquifer type in the study area based on the resistivity value. The results showed that the study area includes two rock formations – the Dahor and Warukin formations. The Dahor formation is clay with a resistivity value of 1–28.284 m, sandy clay 28.284–99.055 m, and sand 99.055–800 m. The Warukin formation is clay with a resistivity value of 1–10 m, sandy clay 10–31.623 m, and sand 31.623–100 m. Aquifer layer estimation shows that track 1 has a free aquifer and contains aquitard rock. Next, track 2 has a confined aquifer and contains rocks that are both aquifer and aquitard. Then, track 3 has a free aquifer type and contains rocks that are aquifer and aquitard. Track 4 has two measurements with a depressed aquifer and contains rocks that are aquifer. Finally, Track 5 has a depressed aquifer and contains aquitard rock. This study shows the existence of groundwater deposits in the thickness of the aquifer layer in Balangan County, Indonesia.