Water regionally abundant in Great Lakes Basin, but not always when and where it’s needed

US Geological Survey: Though the Great Lakes are the largest freshwater system on Earth, the basin has the potential for local shortages, according to a new basin-wide water availability assessment by the U.S. Geological Survey.

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.

“While there is an abundance of water in the region, we may see local shortages or conflicts because water is not distributed evenly,” said Howard Reeves, USGS scientist and lead author on this assessment. “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.

…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….

Lake Huron, facing east on Mackinac Island, shot by Hgjudd, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license