The Illinois State Geological Survey’s Three-dimensional Mapping Effort

Note: I am still researching and writing EA each week, but other people will be voicing the spots until April 17, 2007. I'm running for a seat on the Park District board in Champaign, so my voice can't be on the radio without opening up the same amount of time for other candidates.

Dee Breeding from WILL-AM 580 narrates this week's installment.

--Rob

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Can you describe the landscape of Illinois in a single word? Most people just call it flat. But don’t be fooled by the smooth, relatively featureless surface of our state. We live atop many complex layers of geological material, deposited here over the underlying bedrock as glaciers advanced and retreated in the past million and a half years.

While most of us don’t give it a second thought, the Illinois State Geological Survey, which is based in Champaign on the U of I campus, is working to create three-dimensional maps that depict these subsurface layers in cross-section. [Click to visit ISGS mapping pages.] At the lowest levels the slices on these maps show layers of bedrock. Moving up toward the surface, they display the thickness and location of various layers of sand, gravel, clay and silt.

Now, you may think that three-dimensional maps of what’s underground have little to do with everyday life. But to understand their importance, you need look no further than some of the natural resources that enable us to live as we do.

Take water, for example. About a third of Illinois households, farms, businesses, and industries obtain this necessity from groundwater aquifers, a point that is being driven home for many people as water-guzzling ethanol plants seek to tap into them. We can’t begin to make reasonable calculations about how much water is available from aquifers without an accurate understanding of the geology that defines them.

In addition to providing important information about natural resources, the State Geological Survey’s three-dimensional maps will provide information about potential hazards as well. In southern Illinois, geologic maps can help identify areas where sinkholes and mines would make development dangerous. Along the shores of Lake Michigan and the Mississippi River, geologic maps can help identify areas prone to landslides. And throughout the state, geologic maps can help minimize the impacts of waste disposal by providing information about how well potential landfill sites are suited to contain pollution.

As you might imagine, mapping the subsurface geology of the state at a scale detailed enough to facilitate planning decisions is expensive, and at the current rate of funding we’re looking at another hundred years or more before the job is finished. But making decisions without good geological information can be even more costly. When wetlands mitigation projects are located on sites that don’t hold water, or test wells for water supplies are drilled in the wrong places, we wind up spending more than we would have needed to invest for good information up front.

While the geologic mapping project is a high priority for the Illinois State Geological Survey, it is but one of many current programs there. You’re invited to learn more about everything the Survey does at its annual open house this Friday and Saturday, March 9th and 10th. The open house takes place in the Natural Resources Building on the U of I campus in Champaign. It features information and exhibits that appeal to children of all ages, as well as adults. Click here [http://www.isgs.uiuc.edu/isgshome/openhouse/openhouse-2007.htm] for more information about the open house..