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Full-Text Articles in Physical Sciences and Mathematics

Investigation Of Pervasive Clay Layers And Their Effect On Groundwater Flow Using Electrical Resistivity Tomography In The San Antonio Groundwater Basin, James M. Carlson Jun 2019

Investigation Of Pervasive Clay Layers And Their Effect On Groundwater Flow Using Electrical Resistivity Tomography In The San Antonio Groundwater Basin, James M. Carlson

Natural Resources Management and Environmental Sciences

The United States Geological Survey is developing an integrated hydrologic model of the San Antonio Creek Groundwater Basin to better understand and simulate the integrated surface water and groundwater system. An abrupt 60 meter offset in groundwater depth over a distance of less than one kilometer is observed in well readings within the Cañada De Las Flores region of the groundwater basin. Abrupt changes in groundwater levels are often explained by the presence of a fault in the subsurface vertically offsetting sedimentary units. However, observations of the structural geology of this region indicates that faulting is unlikely and suggests an …


Geoelectrical Detection Of Water Table Depth At Two Locations In The Los Osos Groundwater Basin, Hallie A. Douglas Dec 2013

Geoelectrical Detection Of Water Table Depth At Two Locations In The Los Osos Groundwater Basin, Hallie A. Douglas

Natural Resources Management and Environmental Sciences

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 …