The Importance of Ground Water in the Great Lakes Region

Water Resources Investigations Report 00 - 4008

By N.G. Grannemann, R.J. Hunt, J.R. Nicholas, T.E. Reilly, and T.C. Winter

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Contents

Why do we need to know more about ground-water conditions in the Great Lakes Region?

What are the major ground-water issues in the Great Lakes Region?

Geology establishes the framework for aquifers

How does ground water move in the Great Lakes Region?

How is ground water replenished?

How much ground water is pumped in the Great Lakes Region?

Some areas where the effects of ground-water pumping have been evaluated:

Chicago - Milwaukee | Green Bay | Toledo, Ohio

Ground-water and surface-water interactions

Ground-water flow into the Great Lakes

Ground water, wetlands, and stream ecology

Summary and conclusions

References

Figures

1. Map showing surficial geology of the Great Lakes Basin
2. Maps showing
   1. Bedrock aquifers of the Great Lakes Basin
   2. Approximate extent of the freshwater bearing carbonate aquifer in Ohio, Indiana, Illinois, and parts of Michigan and Wisconsin
   3. Approximate extent of the sandstone aquifer west of Lake Michigan
3. Geologic section showing generalized local and regional ground-water flow systems in the Great Lakes Region
4. Map showing estimated ground-water withdrawal rates for some major U.S. metropolitan areas
5. Diagram showing generalized ground-water flow
   1. Under natural conditions
   2. Affected by pumping
6. Map showing decline in water levels in water levels in the sandstone confined aquifer, Chicago and Milwaukee areas, 1864-1980
7. Generalized section showing aquifers, confining unit, and direction of ground-water flow near Green Bay, Wisconsin
8. Maps showing simulated potentiometric surfaces in the sandstone aquifer, northeastern Wisconsin
1. In 1957
2. In 1990
9. Map showing potentiometric surface for the carbonate aquifer near Toledo, Ohio, July 1986
10. Schematic diagram showing approximate average water budget for Lake Michigan
11. Map showing average ground-water and surface-runoff components of selected watersheds in the U.S. portion of the Great Lakes Basin