In Great Lakes Basin, Water is not always Available – Even when it’s Abundant
It is possible to have plenty of water but still experience water shortages, as the U.S. government’s most recent water availability assessment found.
In the area surrounding the Great Lakes, water has traditionally been in abundant supply. The area is known as “the largest freshwater system on Earth,” according to the U.S. Geological Survey (USGS), and the total amount of water in the Great Lakes – 6 quadrillion gallons – would be enough to spread a foot-deep layer across North America, South America and Africa.
Yet according to a five-year USGS study, water pumped for municipal supplies in the Chicago-Milwaukee region has caused levels of groundwater beneath the earth’s surface to decrease about 1,000 feet. Over the next 30 years, groundwater levels could fall an additional 100 feet if the region withdraws groundwater at increasingly higher rates, as is expected to occur. A greater demand for water and climate changes could lead to water shortages, even in this water-rich region.
Meanwhile, surface water is also declining. Chicago diverts 2.1 billion gallons from Lake Michigan each day, and this withdrawal has lowered Lakes Michigan and Huron by about 2.5 inches, according to the USGS report.
The USGS study’s insights serve as an important reminder that water use must be managed effectively, even in areas where water appears to be readily available. All water resources are subject to depletion if not properly managed, regardless of their size.