Limestone Potential on the Bone Bolango Coast as a Groundwater Reservoir Based on Porosity Quality Analysis

Abstract

The research area, which includes five villages, namely Botubarani, Huangobotu, Biluango, Modelomo, and Botutonuo, is located on the south coast of Bone Bolango Regency. People in the coastal area still use shallow well water as a clean and drinking water source. The primary constituent lithology on the coast is limestone, so research on limestone is very important to support community expectations in the environmental field. For this reason, this research aims to assess the potential of limestone in the five villages as a groundwater reservoir rock based on the type and quality of porosity. This research will create a geological conservation area as a groundwater recharge area. The research methods to achieve the objectives consisted of field surveys and laboratory analyses. The laboratory analysis method includes the petrographic and specific gravity and water absorption test methods of coarse aggregate. Based on the research results, the site comprises four types of limestone: wackestone, packstone, rudstone, and boundstone. The four types of limestone have different porosities. The fabric selective porosity type is intercrystalline and moldic, while the non fabrnonfabricve porosity type is vuggy and channel. The porosity quality at the research location is divided into two levels, namely large porosity and medium porosity. These two levels of porosity quality make the potential of limestone in the study area as a groundwater reservoir rock very large. With the potential of limestone as a reservoir rock, the distribution of limestone can be used as a geological conservation area for groundwater recharge, so it must be preserved.