Measurement of Ground‐Water Parameters Using Salt‐Water Injection and Surface Resistivity

Abstract

1. ABSTRACT A method of determining the direction and velocity of ground‐water flow by injecting a salt‐water slug into an aquifer, and tracing its movement with surface resistivity measurements is described. Aquifer hydraulic conductivity can be derived from the measured velocity, the hydraulic gradient, and the aquifer porosity. The method is examined using theoretical considerations and New Zealand field examples. This method of measuring ground‐water velocities has several advantages over conventional well‐to‐well tracer experiments. Only a single access to the aquifer is required. Velocity estimates are more representative of true ground‐water velocities. The method is inexpensive and straightforward to perform. It is applicable to investigating freshwater aquifers within 20 m of the ground surface and when highly conductive materials do not occur above the aquifer.