Natural Resources Management and Environmental Sciences Department
BS in Soil Science
The city of Los Osos sits on top of a coastal groundwater aquifer which is the sole supplier of all its residential, agricultural, and industrial water needs. Lacking a sewer system, the upper aquifer became progressively contaminated with nitrates over several decades. Groundwater pumping eventually shifted to the lower aquifer, however seawater intrusion of the lower aquifer caused by over-pumping has further degraded water quality. The Los Osos groundwater basin provides an excellent field region to examine the utility of geophysical methods for characterizing aquifer structure. In this study shallow (<20 >m) electrical resistivity imaging methods were performed at two locations in Los Osos to assess depth to water table. The goals of the electrical resistivity surveys were to assess the depth to the water table in each area and compare with water table depths from nearby well data. If accurate and sufficient data are found, the resistivity surveys might be a plausible way to monitor the areas of contamination in a non-invasive manner.