Meredith Goebel – Stanford University

Statement of Purpose:

Electrical resistivity profiles created using the geophysical method of electrical resistivity tomography (ERT) were used to image coastal aquifers. Because resistivity data is highly sensitive to changes in pore fluid salinity, these data are ideally suited to mapping out the distribution of fresh and salt water in coastal aquifers suffering from saltwater intrusion. Saltwater intrusion, the process by which saltwater migrates into portions of a groundwater aquifer that once contained freshwater, has (and continues to) resulted in significant ecological and economic costs around the world. Traditionally this process had been mapped and monitored using measurements made in wells, which are costly to install and may fail to capture spatial complexity in the subsurface. By utilizing new innovations in the acquisition of data, ERT now has the potential to fill in the gaps in these well-based monitoring systems, mapping saltwater intrusion at the basin scale. This information would allow water managers to understand the extent of intrusion at a level of detail previously unattainable, information which can then be used to make targeted management decisions, sight new wells, and possibly calibrate flow models.


Description of Data Sets:

The primary data sets used are those from Stanford’s 2014 ERT data acquisition along the coast of Monterey Bay. These data were collected for Additional data include publicly available groundwater basin boundaries, fault maps, and geologic information.