Joint EGLE-USGS airborne electromagnetic survey collecting data on region's geologic makeup, creating more accurate models of groundwater systems
It’s a bird - it’s a plane - no it's … airborne electromagnetic surveying! Over the next few weeks, if you see a helicopter flying relatively low with a large, hexagonal-shaped hoop hanging below it, don’t be alarmed. It is all part of a special survey being conducted by the U.S. Geological Survey (USGS) with support from the Michigan Department of Environment, Great Lakes, and Energy (EGLE). This effort is collecting geophysical measurements to create high-resolution, three-dimensional models of the region's aquifers and geology. The data will improve USGS bedrock maps and inform groundwater management efforts.
Although the joint EGLE-USGS effort is scanning portions of 15 counties across the southwest portion of the state, USGS will be paying special attention to Ottawa County. The County’s Department of Strategic Impact requested USGS conduct denser and more detailed scans of the central portion of the County - areas where residents and businesses are facing major groundwater quality and quantity issues.
"These denser passes by the USGS helicopter will provide us with higher resolution scans of the Marshall aquifer. With better data, we better understand the situation underground, supplementing our groundwater monitoring and management efforts," said Land Use Coordinator Matt Chappuies.
Map provided by EGLE
How it Works
This scanning system will catch people's attention - a helicopter flies approximately 200 feet overhead with a 60-foot-wide Airborne Electromagnetic (AEM) transmitter hoop suspended by cables horizontally about 100 feet below the aircraft. As the chopper passes over an area, a weak magnetic field penetrates the ground, measuring how well the ground conducts electricity. The resulting scans provides high-resolution data used to create three-dimensional models of the earth's subsurface to a depth of more than 1,000 feet.
Is it Safe?
The USGS says the AEM hoop does not pose health or safety risks. The low level of magnetic field exposure given off by the transmitter is less than one-one hundredth (1/100th) of the accepted general exposure level, or about the same as standing a foot from a toaster in operation.
During data collection, the helicopter pilot will not fly within 500 feet of buildings, and will make every effort to avoid people, livestock, or large equipment. It’s important to note the helicopter is flying a pre-determined grid based on study locations, so it will pass through the same area several times.
Track the Flights
The public can track the path of the USGS helicopter by visiting the Flight Tracker map. For more details on the project, visit USGS-EGLE AEM Surveys for Southwest Michigan website. See the scanning system in action by watching this video.
Have Questions?
For general project questions, please contact either:
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