DEVELOPMENT AND TESTING AN AUTOMATED, IN-SITU GROUNDWATER SEEPAGE METER

Groundwater–surface water exchange is an important aspect of maintaining the water level in aquifers and in surficial bodies. In order to measure the flux between groundwater systems and surficial bodies, a seepage meter based on Lee (1977) is a commonly used method. While the traditional Lee-style seepage meter is a relatively simple design, there are a number of shortcomings such as its long sampling time, limited ability of use in a number of environments, and lack of automation. The purpose of this study was to build a seepage meter based upon two previous designs that aims to be fully automated, be more accurate than traditional methods, be able to measure small fluxes, and be able to measure both positive and negative groundwater fluxes. The seepage meter is built around a 4-inch diameter PVC tube, inserted into a lake bottom. The water level within the tube is varied using a pump, and the recovery curve is captured by a magnetic float along a magnetostrictive linear position sensor with a 16-bit analog to digital converter, providing extremely high-resolution results. A small, artificial lake was built using buckets to test the seepage meter in a lab setting and peristaltic pumps are used to simulate groundwater seepage. This device and data analysis showed promising results that the device may provide accurate results in measuring extremely small seepage rates within water bodies.