NGWOS AEMs For Illinois - Aerially Mapping the Illinois River Basin (AD)

The USGS is bringing expertise in the use of airborne electromagnetic (AEM) surveys to support groundwater studies. Like medical imaging allows us to non-invasively measure inside the human body, AEM surveys help to investigate Earth's subsurface without the need for expensive drilling. Surveys are conducted with specialized geophysical instruments towed beneath a helicopter, allowing large areas to be covered over a short period of time. AEM provides consistent data to about 1,000 ft. belowground that help to identify the configuration of subsurface aquifers and surrounding geologic units over large areas with high spatial resolution. In early 2023, the USGS acquired about 2,300 miles of AEM data along flight lines spaced across the Illinois River Basin.

The purpose of this investigation was to provide a regional picture of the subsurface to improve understanding of aquifers and their potential connection with surface water. After final processing is completed, the AEM data will all be made publicly available. Geophysicists, hydrologists, and geologists will work together to generate interpretations of the AEM data that will be used to improve understanding of groundwater resources in the region.