Proposed a survey system to clarify the distribution and flow model of high-salinity groundwater by resistivity exploration and geological survey

Abstract

The distribution and flow model of high-salinity groundwater is an important tool for use in various applications, such as determination of geological disposals, CO2 geological storages, and hot spring resources. In particular, the boundary between high salinity groundwater and freshwater is important information for assessing the geochemical impact on underground facilities. In order to ascertain the distribution of high-salinity groundwater over a wide area, there are electrical and electromagnetic exploration methods that can non-destructively visualize the resistivity profile from the ground surface; these methods have mainly been used to visualize the freshwater–saltwater interface near the coast. On the other hand, it is known that high-salinity inland groundwater is also distributed. As yet, there are few studies on the inland distribution and flow model of high-salinity groundwater; most hybrid studies using geophysical exploration have been conducted based on the geological information of the flow field and the groundwater itself. In this study, the distribution and flow model of high-salinity groundwater is based on the results of groundwater, electromagnetic, and geological surveys at three sites (Tokusa, Higashi-kubiki, and Yuda). Based on the results of these studies, we propose a survey system to clarify the distribution and flow model of high-salinity groundwater. Using this system, the research results at the three sites will contribute to groundwater flow modeling by enabling a bird's-eye view of the entire region, providing us with important basic information for underground use.