Joliet will be getting its water from Lake Michigan in the coming years. It is estimated that the groundwater beneath the city will be depleted by 2030.

Faced with dire conditions 90 miles southeast of Belvidere, the Boone County Board in May hired Dan Kane as part-time water resources coordinator. Kline has returned from retirement after serving for 23 years as executive director of the Boone County Conservation District.

He said recent studies have shown that groundwater levels have dropped by between 30 and 45 metres over the past 40 years.

He said the circumstances were not crisis-like but required attention.

“It says, ‘You have to be alert and prepare carefully and anticipate the impact of this (situation), and that is done through careful planning and implementation of those plans,'” Kane said.

He said Boone County’s water supply comes from several aquifers, including one shared with Joliet.

“So it’s not just Joliet that’s drawing water,” he said. “They’re the ones using the most because you can see they’re the center.”

He refers to a groundwater map with orange-red circles around Joliet, indicating the very shallow depth of its water source.

To better understand Boone County’s water supply, Kane recommends that the board approve the creation of a 3D map of the county’s geology and aquifers.

He said such a map would help the community answer questions such as:

“Where does the water get recharged? How does precipitation and snow melt and all the other things that happen on the surface?” Kane said. “Only some of that water seeps in and becomes groundwater. So where is that most likely to happen? And do we need to do something to protect it?”

The mapping would be conducted by the Illinois State Geological Survey, part of the University of Illinois, and would cost the county $491,917.

A helicopter is used for 3D mapping, flying over most of the county.

“They’ll fly back and forth between the north and south ends of the district 100 times,” he said. “They’ll have data covering the entire area and look at a scan that goes about 300 meters down into the earth.”

Belvidere and other urban areas of the county would not be included in the mapping.

“The geophysical instrument does not penetrate the buildings and streets,” Kane said, explaining that their construction interferes with the mapping instrument’s sensors.

Once completed, the 3D mapping will enable a detailed assessment of the subsurface layers and the materials that make them up, providing a better understanding of how water is absorbed and moves into the aquifer.

The county already has a map showing likely recharge areas, or places where water seeps into the ground. The map was drawn in 2019 and is based on data collected in the 1980s. Kane said the 3D mapping will provide more detailed and accurate information.

“It will close so many data gaps,” he said.

And Kline added that 3D mapping provides necessary data – especially as development increases in the community.

“Having a solid understanding of where our water supply comes from and how we can make it sustainable in the future is an absolutely cost-effective tool because it tells you up front: you can do this, this and that without negatively affecting your water supply.”

Earlier this month, Kane presented the board with a number of recommendations to consider in its water conservation efforts, including 3D mapping.

The board members were positive about the project, but also raised questions about the costs.

“I think I’m thinking about funding,” says Tom Walberg, a member of the Boone County Board, “and in that regard, working with our neighboring counties – Rockford, Winnebago County and McHenry, which are all around us.”

The Boone County Board is expected to decide whether to approve funding for three-dimensional geologic mapping at its next financial meeting on August 15.