Lake Michigan, the second largest Great Lake by volume with 1,180 cubic miles of water, is the only Great Lake entirely within the United States. Approximately 118 miles wide and 307 miles long, Lake Michigan has more than 1,600 miles of shoreline. Averaging 279 feet in depth, the lake reaches 925 feet at its deepest point. It is the fourth largest freshwater lake in the world in terms of area, and the fifth largest in terms of volume. The drainage basin, approximately twice as large as the 22,300 square mile surface area of the Lake, includes portions of Illinois, Indiana, Michigan and Wisconsin.

Because of the large size of the watershed, physical characteristics such as climate, soils and topography vary considerably across the basin. Average annual precipitation in the basin ranges from 28 to 40 inches. Average annual runoff ranges from 8 to 15 inches in the basin. The lake's northern tier is in the colder, less developed upper Great Lakes region which is sparsely populated, except for the Fox River Valley, and is dominated by conifer forests. The climate of the southern areas of the basin is much warmer, the soils are deeper with layers or mixtures of clays, silts, sands, gravels and boulders deposited as glacial drift or as glacial lake and river sediments. These lands are usually fertile and can be readily drained for agriculture. The original deciduous forests have given way to agriculture and sprawling urban development. About 37% of the southern basin is in agriculture, mostly in the St Joseph river basin of Michigan and Indiana.

Census data for 1990 indicate a basin population of over 10 million, most located in the densely populated southern portion of the basin which contains the Milwaukee and Chicago metropolitan areas. The predominant development trend is continued low-density sprawl which consumes vast amounts of agricultural lands and open space. Reductions in farmland acreage in some Counties in southern parts of the basin exceeded 15% for the 10 year period ending in 1992. Two of the top twenty areas of the country noted for most productive agriculture land combined with most development pressure are in the southern Lake Michigan basin.

Aquifers in the basin range from shallow glacial deposits to deep bedrock aquifers. Bedrock aquifers generally dip from northwest to southeast in the basin. Bedrock outcrops include (from west to east): Crystalline rock aquifers of Precambrian age; Cambrian-Ordivician era sandstones and dolomites; Silurian-Devonian dolomites and limestones; Mississippian era shales and sandstones; and Pennsylvanian sandstones.

Unconfined glacial meltwater aquifers (Plesitocene) occur throughout the basin These aquifers are generally copmprised of sand and gravel and readily receive, store, transmit and discharge water and are a primary source of water from wells and supply much of the base flow for streams. Water withdrawals from aquifers in the basin range from less than 5 mg/day to as much as 800 mg/day. About 37% of the water withdrawn from wells in the basin is for public supply, another 35% for agricultural uses, another 17% for commercial use and 11% for industrial use. For the Western side of the basin, however, about 95% of the water use is from surface water not ground water sources. Ground water contributions to base flow of streams and as an indirect discharge to Lake Michigan varies from about 20% to as much as 80% of streamflow. Indirect GW discharge to Lake Michigan has been estimated at about 35% of total basin water supply.

Water quality of GW in the basin is primarily a Calcium-Magnesium-Bicarbonate type but varies in portions of some aquifers to Sodium-Bicarbonate, Sodium-Chloride, and Sodium-Sulfate-Chloride water types. Dissolved solids in the surficial glacial deposit aquifers are typically in the 200 to 500 mg/L range. Dissolved soilids concentrations in the bedrock aquifers varies from less than 500 mg/L to greater than 150,000 mg/L. Much of the waater in the deeper aquifers is classified as marginally potable. Aquifer contaminat susceptibility ranges from less than moderately susceptible to severely susceptible.

The demand for high quality, relevant data concerning the health of the groundwater in the Lake Michigan basin has been escalating rapidly for about the past decade. Environmental management agencies are being asked to demonstrate that past programs have been successful and that the success of future or continuing programs will be commensurate with the resources expended. The demand for high quality data, while operating with limited resources, is forcing environmental and natural resource agencies to be more selective and more efficient in the collection and analysis of data.

The most efficient data collection efforts will be those that are cost-effective and relevant to multiple users. Numerous agencies at the Federal and State level are involved in groundwater studies in the Lake Michigan basin. An integrated monitoring and investigations network for groundwater in the Lake Michigan should be based on land use and other factors that influence water quality gradients and provide information sufficient to characterize Lake Michigan basin groundwater health across scales and disciplines. The network should provide information that links sources, with processors and receptors and when linked with retrospective data provide trends information.

Develop and implement a Lake Michigan groundwater monitoring and investigations network that addresses the objectives of investigations currently being funded and proposed for funding by Federal, State, and Local agencies. The network should include: 1) chemical, physical, and microbiological components; 2) address how water quality changes propogate with depth and along flow paths; 3) help to define the sources and sinks of contaminants as well as relevant processes; 4) and be capable of providing reasonable estimates of water quality in unmonitored portions of aquifers in the basin based on land use and other environmental characteristics. The parameters measured should be based on agency objectives and should utilize comparable protocols. The resultant data from the monitoring and investigations network should be stored in an easily accessible user friendly database that provides a minimum set of metadata elements.

The groundwater monitoring and investigations network developed and implemented according to this proposal will help to reduce the costs of current efforts by ensuring similar data quality and comparability and a reduction in duplication of effort. The development of an integrated network will also provide a mechanism for developing a coordinated response to issues of mutual interest.

Approach

1. Organize a small group of individuals from Federal, State, and Local agencies, and acedemic and non-profit institutions to implement the proposal;
2. Conduct a retrospective analyses of existing programs and data;
3. Develop a summary of findings based on retrospective data, agency needs and environmental factors;
4. Develop a list of monitoring and investigation gaps and a strategy to address basin needs;
5. Determine a mechanism to allow data collected from the network to be available to stakeholders;
6. Develop or utilize an existing approach for determining water quality for unmonitored portions of aquifers in the basin;
7. Develop a coordinated funding approach.

 

The approach employed should address: ground water/surface water interactions and impacts on water quality; water use and drinking water; important national and regional issues relevant to legislation and government initiatives (305b, CWAP, GLWQI, LaMP, INATURES, source water protection, etc) and provide appropriate links with ongoing investigations (SWRPC, NAWQA, RASA2, BRASS, Grand Traverse land use, etc).

 

Products

1. An organized workgroup, comprised of individuals from the primary groundwater monitoring and investigation programs in the Lake Michigan Basin, to work together to develop a monitoring network and investigative studies in response to current and future Lake Michigan groundwater resource issues. (FY99, FY00)
2. A retrospective report that describes existing and past groundwater monitoring and investigations and describes important results of those efforts (including trends), gaps in those data sets and availability of the data sets. (FY00, FY01)
3. The design of a database to allow coordinated access to the data produced from the network, and the approach proposed to provide the resources required to maintain the network. A pilot effort to develop and test a coordinated database design (including information on minimum meta data requirements) that is available on the internet in a user friendly format. (FY01)
4. A report describing the results of a model used to determine water quality in unmonitored portions of basin aquifers and to produce a lake-wide water and chemical budget. (FY03, FY04)

 

Resources

To implement this proposal resources will be required from a number of sources. In the near term, many of these resources must be supplied voluntarily, with the hope that in the long term efficiency gains from coordination will pay dividends. Additionally, the USEPA has provided some grant funding to the Great Lakes Commission for executive secretarial support to the Council.

Currently resources are being supplied for a number of ongoing projects in the basin, a listing that includes some of the ongoing projects and some past projects can be found below (4 States and USGS,WRD only). It is hoped that the funding needed for several of these projects can be reduced due to the coordination effort. It is also hoped that the coordination effort will provide additional impetus for committing available resources to the Lake Michigan Basin. The specifics of how the resource needs will be met will be developed as a part of the proposed study.

 

Partial list of ongoing ground water studies

• Western Lake Michigan Drainages NAWQA Study
• Land Use Study – 60 wells
• Study Unit Survey – 30 wells
• Flow Path Study – 19 wells
• Southeast Wisconsin Regional Aquifer Performance Simulation
• Regional flow and transport modeling
• Wisconsin Ground Water Level Network
• About 75 wells
• Crandon Ground Water Study
• Localized flow and transport modeling
• Brownfield Contaminated Land Recycling Study
• Field support in urban areas
• Superfund Remedial Response Support
• Field support at Superfund sites
• Michigan Ground Water Level Network
• About 20 wells
• Grand Traverse Land use effects
• GW/SW interaction modeling
• Battle Creek Well field
• About 10 wells and localized flow modeling
• Kalamazoo MDOT study
• About 15 wells and localized flow and transport modeling
• Kalamazoo County Assessment
• Source Area Delineation Lansing
• Ground Water – Surface Water Interaction Studies
• Base flow separation studies
• Bedrock Aquifer System
• Niagara Escarpment flow
• Effects of Road Salt on Ground Water Quality

Partial list of past ground water studies

• Ground Water – Surface Water Interactions near Indiana Harbor Canal
• Saline Ground Water – Valporaiso, IN
• Characterization of Fill Deposits – NE Illinois and NW Indiana
• Galena-Platteville Deposits Hydrogeology
• Ground Water Resources of the Chicago Region
• Water Quality of Cambrian Ordivician in NE Illinois
• Ground Water Quality Evaluation of Calumet Region
• Ground Water Quality of Wisconsin’s Aquifers
• Herbicides in Ground Water – 11 state area study
• Ground Water Age in Northwest Indiana
• Hydrogeology and Ground Water Use –Fox Cities Area
• Flow modeling
• Illinois Ground Water Protection Program
• Ground Water Flow and Quality of Indiana Dunes
• Geohydrology and Water Quality of the Calumet Aquifer
• Water Levels in the Calumet Aquifer
• Geohydrology of Lake County
• Ground Water Resources of LaPorte County
• Delineation of Wellhead protection Areas in Wisconsin
• Water Resources of Racine and Kenosha Counties
• Wisconsin Ground Water Coordinating Council –Summary 1998
• Status of Ground Water Quantity in Wisconsin 1997
• Regional Aquifer Study
• Northern Midwest Regional Aquifer Study
• Ground Water in Door County
• Directory of Ground Water Databases in Wisconsin 1998

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