Characterizing aquifer structure with a towed time-domain EM (tTEM) system

The Remote Sensing Hydrology lab is fortunate to have one of the few tTEM systems in the United States. The tTEM is a towed Time-domain ElectroMagnetic system that is capable of imaging the subsurface resistivity to a depth of ~80 m. The resistivity values can then be related to sand, clay, bedrock, groundwater salinity, and in some cases water table data to improve the spatial characterization of the aquifer. The tTEM can acquire roughly 100 km of data per day, making it an excellent tool for groundwater studies in most water management districts.

Currently, we are using tTEM data to improve characterization of the Kansas River Alluvial Aquifer in Kansas, and the Parowan Valley aquifer in southwest Utah. These data will be used to estimate spatial variation in hydraulic conductivity, the presence of confining layers, and the volume of clay that could increase the risk of land subsidence.

3D visualization of tTEM-derived subsurface resistivity in Kansas. Red colors indicate sands/gravels, blue colors indicate clays. Click here for an interactive plot.