USING THE SELF-POTENTIAL METHOD TO ANALYZE THE TEMPORAL AND SPATIAL VARIATION OF SHALLOW GROUNDWATER FLOW THROUGH MEADOWS WITHIN THE BOULDER CREEK CRITICAL ZONE OBSERVATORY IN BOULDER, COLORADO

Previous studies have examined the potential impacts that a shift in climate can have on the surface water. However, little research has been done on the implications that climate change can have on the water flow in the subsurface. A less explored focus is the measurement of shallow groundwater flow in meadows because of their ability to exist in a fragile environment, making them susceptible to climate change. In the Boulder Creek Critical Zone Observatory outside of Boulder, Colorado, a shift in climate could lead to a dramatic alteration in precipitation from snow to rain and earlier snowmelt within the watershed. In the past, groundwater was measured by the installation and monitoring of groundwater wells, which only provide information on the groundwater flow of a single location. Self-potential is a geophysical method that measures the small voltage that occurs when water passes through the sand or soil in the ground. The goal of this project is to measure, through self-potential, the groundwater flow in the upper Gordon Gulch watershed in the Boulder Critical Zone and examine how the groundwater flows in a meadow. We can create models to understand how fragile ecosystems are impacted by climate change. Data collected during 10 Jun and 24 Jun 2015 show a significant decrease in self-potential values indicating a change in groundwater flow between the two dates. Based on our results we can show that the self-potential method is effective in understanding and mapping the spatial and temporal patterns of groundwater in the subsurface.