Low-level flights to image geology and aquifers in Southwest Michigan

Survey flights starting this month and continuing through the summer will cover all or part of Allegan, Barry, Berrien, Branch, Calhoun, Cass, Eaton, Hillsdale, Ingham, Ionia, Jackson, Kalamazoo, Kent, Ottawa, St. Joseph, and Van Buren counties.

Flying at about 200 feet, the helicopters will suspend a large hoop-like horizontal frame on a cable about 100 feet below the aircraft carrying instruments to measure differences in Earth’s electrical properties and magnetic field created by different rock types across the survey area. Understanding the subsurface composition will shed light on the amount and movement of groundwater.

The daylight-only flights completed by specially trained pilots will avoid densely populated areas and will not pass over buildings at low altitude. The work poses no risk to humans, animals, or plant life and does not collect photos or videos.

The cooperative study is expected to provide a better understanding of bedrock depth and give us additional data about aquifer systems in southwest Michigan, which will result in better informed decisions about managing Michigan’s groundwater resources.

Groundwater in Michigan

Michiganders rely on rivers, streams, lakes, and groundwater for everything from drinking water to irrigation to recreation. Much of Michigan’s drinking water comes from groundwater sources. Between private wells and public water systems, Michiganders use about 700 million gallons of groundwater a day. Michigan agriculture draws more than 100 million gallons a day for irrigation, while Michigan industries pump another 180 million gallons a day from onsite wells.

The volume of Michigan’s groundwater reserve is comparable to a sixth Great Lake: huge, but not limitless. To avoid adverse impacts, the Water Use Assessment Unit in EGLE’s Geologic Resources Management Division regulates large-quantity groundwater and surface water withdrawals, which are usually for agricultural irrigation. The unit also administers a dispute resolution program for private groundwater wells impacted by nonagricultural high-capacity wells.

Meanwhile, EGLE’s Groundwater Data Unit provides technical support on groundwater issues in Michigan, including modeling, geographic information systems, and project management.

Michigan’s Water Use Advisory Council determined the state needed additional data to better characterize water resources across the state.

About the survey

The USGS survey uses airborne electromagnetic technology to develop three-dimensional imaging of the subsurface geology to better predict how water moves through those layers and how groundwater and surface water are connected. The data will create 3-D maps to a depth of more than 1,000 feet underground.

“The 3-D models and maps are important for improving our understanding of water resources,” said Burke Minsley, the USGS research geophysicist in charge of the airborne survey. “This type of airborne survey allows us to cover large areas very effectively.”

The helicopter will fly pre-planned fight paths spaced about one mile apart, with denser data collected over the Dowagiac River watershed and around the tribal lands of the Pokagon Band of Potawatomi and the Match-E-Be-Nash-She-Wish Band of Potawatomi (Gun Lake Tribe). The river corridors of the Kalamazoo, Thornapple, St. Joseph, Paw Paw, and Rocky rivers will also be overflown to improve understanding of connections to subsurface geology along these corridors.

Southwest Michigan was selected as the survey area due to the number of large-quantity water withdrawals, fast population growth, and groundwater availability issues that have been identified in that part of the state.

Local officials and conservation contacts are informed of the activities, and a flight tracker will map the daily progress of the study.

Survey data will be combined with information from groundwater wells. The results will:

• Create a better understanding of aquifer properties.
• Address groundwater supply questions.
• Improve understanding of groundwater-surface water connections.

More information is available on a USGS webpage. Data collected will be publicly available on the USGS ScienceBase data website once the survey is complete.