Airborne electromagnetic and magnetic survey of Illinois River Basin, 2023

Airborne electromagnetic (AEM) and magnetic survey data were collected during January and February 2023 over a distance of 3,799.3 line kilometers covering the Illinois River Basin and surrounding regions in Illinois and Indiana. Data were collected as part of the USGS Illinois River Basin Next Generation Water Observing Systems (NGWOS) project to improve understanding of depth to bedrock and groundwater systems near Illinois River Basin. The survey was funded by the USGS, and was carried out in collaboration with the Illinois State Geological Survey (ISGS) and Illinois State Water Survey (ISWS). Data were acquired by SkyTEM Canada Inc. with the SkyTEM 304 time-domain helicopter-borne electromagnetic system together with a Geometrics G822A cesium vapor magnetometer. The survey was acquired at a nominal flight height of 30 - 40 m above terrain along parallel flight lines primarily oriented northwest - southeast and with nominal line spacing of 20 km. Several irregular flightlines were acquired along rivers.