SELF-POTENTIAL MEASUREMENTS: AN EMERGING TECHNIQUE FOR EVALUATING GROUNDWATER FLOW IN FRAGILE ENVIRONMENTS

Research in fragile environments, such as those preserved in our National Parks, requires innovative techniques to minimize disturbance. Accurate quantification of groundwater flow patterns, both in magnitude and direction, is a necessary component of evaluating hydrologic systems. Groundwater flow patterns often are determined using a dense network of wells or piezometers, which can be difficult to install and maintain due to logistical or regulatory constraints. The self-potential method, a passive geophysical technique that relies on currents generated by water movement through porous materials, is an emerging alternative to dense piezometer networks. Additionally, the method is well suited for remote locations, because it requires only a handheld voltmeter and two non-polarizing electrodes. Here we present the results of a series of self-potential measurements collected at Andrews Meadow, an alpine meadow located in a federally-designated wilderness area of Rocky Mountain National Park. Long-term records of climate and stream chemistry at Andrews Creek, adjacent to the meadow, and from the surrounding catchment, have been used to analyze source-water contributions to the stream. Despite a good understanding of surface-water components, groundwater dynamics of the system remain poorly constrained. Repeat self-potential measurements, collected seven times during the snow-free season, are used to evaluate seasonal patterns of subsurface flow within the meadow.