The Great Lakes region, the world's largest freshwater system, could face local water shortages in the Chicago and Milwaukee areas due to increased demand and environmental changes, the U.S. Geological Survey said on Monday.
The Great Lakes are a unique and precious resource, providing freshwater for 33 million people who live within the basin and supporting the region's ecosystem and economy. The Great Lakes basin contains nearly 20 percent of the earth's fresh surface water. It is the only freshwater system of its kind in size and ecological diversity and is essential to humans and wildlife alike, providing homes, food, recreation, and economic sustainability. The Great Lakes are critically important to the region. Nearly 11,000 miles of coastline surround the Great Lakes and their connecting channels and islands.
The Great Lakes constitute a vast resource, but each year rainfall and snowmelt replenish only about one percent of the water in the basin, making them vulnerable to depletion and degradation. The other 99 percent is finite and nonrenewable. That fact, coupled with a growing demand for water by domestic users--including utilities, agriculture, manufacturers, and housing--and proposals to export water to other parts of the U.S. and to foreign countries jeopardize the Great Lakes’ future.
Water levels in Chicago and Milwaukee could drop by an additional 100 feet over the next 30 years due to increased demand from pumping of groundwater that has already reduced groundwater levels as much as 1,000 feet, the report found.
"In some areas, the physical quantity of water may be limiting"," said Howard Reeves, USGS scientist and lead author on this assessment.
The Great Lakes water basin has seen relatively little overall impact from groundwater pumping, but water is not distributed evenly throughout the region. This could lead to potential local shortages, according to the assessment, conducted over five years.
The five Great Lakes make up 84 percent of the fresh surface water in North America overall. The study will be used to improve forecasting water supply and demand.
"The Great Lakes are a dynamic system responding primarily to short- and long-term variations in climate," Reeves said. "Understanding the potential for local shortages or conflicts within this dynamic system is important for sound decision making."
Reuters, "Milwaukee, Chicago areas may face water shortages: report", accessed February 7, 2011
Indiana Wildlife, "Great Lakes Restoration", accessed February 7, 2011