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Basin Water Availability and Use A study of the National Assessment of Water Availability and Use Program

At the request of Congress, the U.S. Basin contains so many communities, Water Availability and Use assessment Geological Survey (USGS) is assessing industries, and ecosystems that depend will provide information to fill this need the availability and use of the Nation’s on present sources of water, and because for the U.S. part of the Great Lakes, their water resources to gain a clearer under- competition for available water is inten- tributary streams, and the ground-water standing of the status of our water sifying, there is a need to quantify the system that feeds the Great Lakes and its resources and the land-use, water-use, region’s water resources and the trends tributaries. and natural climatic trends that affect affecting them so that the potential for them. The goal of the National Assess- possible future water-use conflicts can be Great Lakes Basin Study ment of Water Availability and Use Pro- reduced or avoided. Water availability is a function of gram is to improve our ability to forecast In recent years, numerous govern- water availability for future economic ment agencies, commerce, industry, and many factors, including the quantity and and environmental uses. Simply put, the the general public all have expressed quality of water and the laws, regula- assessment will help characterize how concern about potential large withdrawals tions, economics, and environmental much water we have now, how water of water within the Great Lakes Basin. factors that control its use. The focus availability is changing, and how much In response, the Great Lakes States and of the Great Lakes Basin study is on water we can expect to have in the future. Canadian Provinces signed an Annex improving fundamental knowledge of the Currently (2005), the assessment to the Great Lakes Charter in 2001. The water balance of the basin, including the is focused on the Great Lakes Basin Annex commits the States and Provinces flows, storage, and water use by humans. (fig.1) to determine the best methods to to science-based water-resources manage- An improved quantitative understand- evaluate water resources and to develop ment. This commitment requires a more ing of the basin’s water balance not only strategies for delivering information detailed understanding of the region’s provides key information about water about water availability and use. Other water resources and a synthesis of avail- quantity but also is a fundamental basis water-resources regions will be added able data and information. The USGS

to the assessment as evaluation methods 0 0 90 80 improve and as funding permits. JAMES BAY

Water-Resources Issues in O N T A R I O the Great Lakes Basin EXPLANATION

0 GREAT LAKES BASIN The Great Lakes Basin, which 50 encompasses Lakes Superior, Michi-

CA gan, Huron, Erie, and (fig. 1), U. NA S. DA ERIOR A. SUP Q U E B E C KE contains 95 percent of the fresh surface LA St. Marys water in North America and 18 percent River Straits of of the fresh surface water in the world. Mackinac St. Lawrence Ground water underlying the basin River

LAKE constitutes another large volume of N HURON A

G I freshwater. Humans, animals, and plants H C LAKE I

0 M ONTARIO have adapted to this abundance in water 45 E K St. Clair A River Niagra L River NEW resources. Yet, even in this water-rich Lake St. Clair YORK DA CANA A. area, water withdrawals, diversions, and U. S. River LAKE use sometimes conflict with the needs of ERIE other users and ecosystems in the basin.

For example, pumping of large water- supply wells in Wisconsin and Illinois has lowered ground-water levels in other wells in the area, reducing the yield Base from ESRI, 2001; U.S. Army Corps of Engineers,1998; and Environment ,1995. 0 50 100 150 200 MILES of water to those wells and increasing 0 50 100 150 200 KILOMETERS pumping costs. Because the Great Lakes Figure 1. Location of the Great Lakes Basin in the and Canada.

U.S. Department of the Interior Fact Sheet 2005–3113 U.S. Geological Survey Printed on recycled paper November 2005 USGS stream gage during 2001 spring flood (photograph by Eric S. Wakeman, U.S. Geological Survey).

for many analyses of water quality and characterized in a variety of ways. For of these streamflow changes could be ecosystem health. many uses, an appropriate measure of far greater. Another aspect of quantify- streamflow is the “minimum daily flow,” ing future water availability is to quan- Water Levels of the Great Lakes which is especially important during tify trends—especially those related to The water-level elevations of Lakes droughts. For municipal wastes, a mea- floods, droughts, and seasonal timing. Michigan, Huron, Erie, and Ontario have sure of the low flow of a stream quanti- If significant trends are detected, subse- varied about 6 feet since 1860, when fies water available for effluent dilution quent investigations may determine the accurate records of lake levels were first or “assimilative capacity” for which a cause. That information will help inform recorded. Water levels in Lake Supe- treatment plant is designed. Other statis- plans for future water use or watershed rior varied about 3 feet during the same tics characterize the seasonal distribution development and will help water-resource interval. Prehistoric variations were much or persistence of streamflow. As a first managers determine an appropriate greater and were strongly correlated with step toward quantifying water availability, network for monitoring streamflow in the climate change. Changes in water levels this project will assemble published sta- basin. of the Great Lakes constitute the largest tistics and compute relevant new statistics Unmeasured streamflow. —The USGS changes in the amount of water in the for streams now or previously gaged. currently measures streamflow for only Trends in Streamflow.— region. The Great Lakes Basin study will Streamflow about 70 percent of the U.S. part of summarize what is known about lake is affected by climatic factors (primarily the Great Lakes Basin. Streamflow for levels over the past 4,700 years. This precipitation) and watershed charac- the remaining ungaged tributaries will analysis of lake levels will help put recent teristics including human factors such be estimated for this study by means low lake levels into perspective, espe- as urbanization, stream regulation, and of regional regression and correlation cially given the prospect of future global water diversions. Changes among these techniques to determine the contribution warming. factors have altered the timing and of those areas to the water balance. This rates of streamflow and, in some places method will allow USGS scientists to (especially urban areas), have affected Streamflow make monthly estimates of total tributary the magnitude and frequency of floods streamflow to the Great Lakes, which Streamflow maintains the water levels and low flows. In the past, these effects will be provided online by way of USGS of the Great Lakes, nourishes ecosystem were either unrecognized or dispersed Web sites. habitats, furnishes an essential raw mate- through a sparse, rural population and rial for a variety of industries, and carries economy. Today, the economic, envi- away municipal wastes. Corresponding ronmental, and political consequences to these uses, streamflow availability is Golf-course irrigation well and water distribution system (photograph by N. Grannemann, U.S. Geological Survey).

Ground-Water Flow and Storage from aquifers or if natural changes take computed recharge rates. The recharge place in the ground-water system. The component of this assessment will evalu- Ground water is a major natural Great Lakes Water Availability and Use ate new and existing methods to deter- resource in the Great Lakes Basin assessment will delineate ground-water mine spatial recharge rates and trends in because it is, in effect, a large subsur- divides for most aquifers in the Great recharge over time. face reservoir. Ground water discharges Lakes hydrologic system. This delin- Great Lakes Basin Hydrogeologic naturally to streams, lakes, and wetlands. eation will be a synthesis of data and Summary. —Previous hydrogeologic It is also tapped for drinking water by information from previous and current studies in the Great Lakes Basin consist many water suppliers and residents of regional and local studies. Where pos- of a variety of regional and subregional the basin who do not use water directly sible, areas where divides have shifted as investigations that were appropriate for from the lakes. Two major ground-water a result of ground-water withdrawals or a specific purpose but are difficult to resource issues in the Great Lakes Basin natural causes will be delineated. synthesize into a broader view of water are the amount of ground water available Recharge. —Areal recharge is the pri- availability and use basinwide. As part of at a given location and the interaction mary source of water to the ground-water the hydrogeologic summary effort, results of ground water with surface water. The system; however, regional estimates of from published studies will be com- Great Lakes Basin Water Availability ground-water recharge in the Great Lakes piled, evaluated, and synthesized. Where and Use assessment will address various Basin can differ substantially depend- possible, the amount of ground water in aspects of these ground-water issues. ing on the methods used. Consistent and storage will be determined, and changes Ground-water divides. —Ground- accurate estimates are needed to under- in ground-water storage through time will water divides are like watershed (land- stand how recharge to the ground-water be assessed. In addition, water levels in surface) divides in that their location system relates to water availability and observation wells with several decades of determines whether ground water will use. Locally, areal recharge rates range record will be analyzed for trends related flow toward or away from one of the from less than 1 inch per year to more to climatic factors. An analysis of avail- Great Lakes. Locations of ground-water than 20 inches per year on the basis of able data will be done to determine if cur- divides in the uppermost aquifers under- hydrograph analysis for large water- rent monitoring of ground-water levels in lying the basin commonly coincide with sheds. The rates depend on precipitation the basin is adequate to support regional watershed divides. In deeper aquifers, and other climatic factors, in addition and national decisionmaking for effective however, ground-water divides may not to watershed characteristics such as water management. Analysis of ground- coincide with watershed divides. Addi- soil type. Seasonal, year-to-year, and water monitoring programs will include tionally, the location of ground-water decade-to-decade changes all can affect divides can change if water is pumped data networks operated by Federal, state, from bedrock and glacial-deposit aqui- ment efforts and to test compilation and local agencies in the United States. fers, both of which are important aquifer approaches that may have nationwide systems throughout the Great Lakes applicability. Preliminary discussions Ground-Water-Flow Models Basin; (3) important issues related to with state agencies have indicated that Application of ground-water-flow ground-water and surface-water interac- refinement of consumptive-use factors models is one of the most comprehensive tion can be simulated with the model; (4) for all types of water use is the area of ways to synthesize ground-water data and ground-water withdrawals in the Lake greatest interest and value to water-sup- to analyze the response of a ground-water Michigan subbasin may affect the loca- ply managers. Initial plans are to conduct system to changes in the system, such tions of ground-water divides with Lakes a focused study on either (1) a small as increased pumping rates, changes in Superior, Huron, and Erie; and (5) prob- geographic area for a comprehensive pumping locations, changes in recharge, lems caused by large-scale ground-water understanding of consumptive use or (2) and climate variations. Regional models withdrawals have been documented in the selected water-use categories (fig. 2) to that simulate ground-water flow will subbasin. In addition, one or more sepa- refine the understanding of consumptive greatly improve the overall understand- rate models within the use for those categories basinwide. As ing of ground-water conditions in the subbasin will be developed specifically to an initial assessment of consumptive-use Great Lakes Basin and provide a quanti- simulate ground-water and surface-water factors, the USGS has begun work on an tative framework to help manage water interaction in smaller watersheds because annotated bibliography for consumptive- resources in ways consistent with the this is an important component of the use coefficients in the Great Lakes and Great Lakes Charter Annex. Compre- water balance not only here but elsewhere climatically similar regions. hensive ground-water-flow models are in the Great Lakes Basin. These models complex and time consuming to develop; will be used to test new techniques for —Norman G. Grannemann and therefore, the entire Great Lakes Basin simulating the interactions of ground Howard W. Reeves could not be modeled for this study. water and surface water at the appropriate Instead, a ground-water-flow model of scale. For additional information about the the Lake Michigan subbasin is being USGS National Assessment of Water developed because (1) the entire water- Water Use Availability and Use in the Great Lakes shed is in the United States, and many The USGS plans to compile water-use Basin, please contact: datasets already are available within the data (fig. 2) to assist Great Lakes Basin USGS; (2) ground water is withdrawn stakeholders in water-supply manage- Howard W. Reeves, Project Chief USGS Michigan Water Science Center 6520 Mercantile Way, Suite 5 Lansing, MI 48911 [email protected]

Surface Ground References Cited Water Water Public Baedke, S.J., and Thomas, T.A., 2000, 31,160 1,507 3,830 Supply 585 A 4,700-year record of lake level and 4,415 isostasy for Lake Michigan; Journal of Great Lakes Research, v. 26, no. 4, p. 416–426.

1.0 354 108 44 3,900 270 Council of Great Lakes Govenors, 2001, The Great Lakes Charter 355 152 4,170 Domestic Commercial Industrial Annex, accessed October 27, 2005, at http://www.cglg.org/projects/water/ Annex2001.pdf

National Oceanic and Atmospheric 22,800 0 356 34 20 50 145 170 Administration, Great Lakes Water 315 22,800 390 70 Levels, accessed October 27, 2005, at Irrigation Thermoelectric Mining Livestock http://www.glerl.noaa.gov/data/now/ wlevels/levels.html TOTAL WATER SUPPLY OR USE FOR CATEGORY, IN MILLION GALLONS PER DAY Solley, W.B., Pierce, R.R., and Perlman, H.A., 1998, Estimated use of water in 31,160 Surface-water source 4,415 Public-water-supply use 1,507 Ground-water source 22,800 Self-supplied water use the United States in 1995: U.S. Geo- logical Survey Circular 1200, 71 p.

Figure 2. Pipe diagram of the source and use of the estimated 32,667 million gallons per day of freshwater withdrawals in the Great Lakes Basin in 1995 (Solley and others, 1998).