Scope 28: 104B State Water Resources Research Institute Program 2016 - 2021: In-situ 3D Electrical Resistivity Method for Understanding Water Dynamics in Shall Karst Features

Understanding how water infiltrates and recharges subsurface aquifers is important in protecting groundwater resources. The water infiltration process, however, is very complex, especially in karst areas where many surface karst features, such as sinkholes and sinking streams, provide different pathways connecting surface water to groundwater. In this project, we propose to use a novel electrical resistivity method to monitor water movement in different types of surface karst features. Using a newly modified AGI SuperSting resistivity meter, we will conduct in-situ 3D time-lapse electrical resistivity surveys to accurately measure temporal changes of electrical resistivity beneath karst features. These temporal changes in resistivity will allow us to analyze the infiltration rates of water into the subsurface as well as detect fast and slow flows within these features in responding to hydrologic events of varying magnitude and duration. We will conduct this study in the Royal Spring groundwater basin which provides sources of drinking water for Georgetown. The collected data will also be incorporated into a numerical modeling study to understand hydrologic and morphologic processes in the groundwater basin.