Groundwater Potential in Unconfined Aquifers Using a Landform Approach in Gorontalo City

Abstract

This research aimed to determine the potential of the unconfined aquifer in Gorontalo City based on the landform approach. The landforms in Gorontalo City consist of alluvial plains of lake deposits, floodplains of river deposits, alluvial fans of lake deposits, hills of structural fractures of reef limestones, hills of structural fractures of pinogu volcanic rocks, and hills of intrusive bone diorite. The method used consisted of a meteorological approach in the southern hills of Gorontalo City and a dynamic approach on the plains of Gorontalo City. The calculation of groundwater availability using a meteorological approach is 421.561,67 m3/year in the structural limestone reef fractures hill, 1.198.975,33 m3/year in the structural pinogu volcanic fractures hill, and 373.062,86 m3/year in the intrusive bone diorite hill, with a total of groundwater availability using the meteorological approach, is 1.993.599,87 m3/year. Groundwater availability using a dynamic approach was 2.621.535,19 m3/year or a discharge of 49,26 lt/sec (large) in the alluvial plain of lake sediment, discharge of 17,19 lt/sec (large) in the floodplain of river sediment, and discharge of 16,65 lt/sec (large) in the alluvial fan of lake sediment. The potential value of groundwater using the dynamic method is greater than the meteorological approach because of the amount of evapotranspiration, surface runoff, and crop coefficient.