Monday, February 7, 2011

USGS Warns Of Local Water Shortages In Great Lakes Basin

Feb 7: A new basin-wide water availability assessment by the U.S. Geological Survey (USGS) indicates that although the Great Lakes are the largest freshwater system on Earth, the basin has the potential for local shortages. For example, though groundwater pumping has had relatively little effect on water in the basin as a whole, pumping in the Chicago and Milwaukee areas has caused local groundwater levels to decline as much as 1,000 feet. Moreover, if pumping were to increase as anticipated in the region, water levels in these areas are estimated to decline an additional 100 feet by 2040.

    Howard Reeves, USGS scientist and lead author on the assessment said, "While there is an abundance of water in the region, we may see local shortages or conflicts because water is not distributed evenly. In some areas, the physical quantity of water may be limiting, and water availability in most of the Great Lakes Basin will be determined by social decisions about impacts of new uses on existing users and the environment." Water availability in the Great Lakes Basin is a balance between storage of surface water and groundwater in the system, flows of water through the system, and existing, sometimes competing, human and ecological uses of water.  

    Water use has a relatively minor effect on regional water availability, because of the large volume of water in storage, large annual flows and abundant, high quality groundwater. Development in the Great Lakes region also has had relatively little effect on basin-wide water availability, though surface-water diversions and pumping of groundwater have affected some flow patterns over large areas of the basin. Tim Eder, Great Lakes Commission Executive Director said, "This Great Lakes Basin study on water availability and use provides important information for restoration and protection of regional water resources and for guiding appropriate economic development of these resources. USGS information on consumptive water use also will be useful to the Great Lakes states and provinces to understand and estimate the cumulative impact of water use on regional water resources."

    Understanding the impact of climate variation on water use, lake levels, streamflow and groundwater levels was part of this five-year investigation. Results of the study will improve the ability to forecast the balance between water supply and demand for future economic and environmental uses. Reeves said, "The Great Lakes are a dynamic system responding primarily to short- and long-term variations in climate. Understanding the potential for local shortages or conflicts within this dynamic system is important for sound decision making.

    USGS water availability studies like this one examine water flow and storage in surface-water and groundwater systems and compile water-use information for the region. Studies are designed to quantify the effects of past development and examine the effects of future growth on flows and storage in the system. This type of comprehensive analysis shows how competing uses and demands interact over time across a region. Because most water-management decisions are made at the local level, this information is valuable for managers at state and local levels in making informed decisions regarding the potential effects of future water use on existing water users, aquatic ecosystems and the public.

    Access a release from USGS and link to a podcast, reports associated with the project, additional information on USGS water availability studies in the Great Lakes Basin,  and the USGS Groundwater Resources Program (click here).

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