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CGLI Explores the Potential for Water Scarcity in the Great Lakes Region

The Great Lakes system is commonly referred to as the largest system of freshwater in the world, accounting for roughly 20% by volume of the world’s supply. While only 1% of the water in the system is renewed each year by snowmelt and rain, the sheer magnitude of the system suggests that those who withdraw and use water in the Great Lakes watershed for residential, commercial, or industrial purposes will have a never ending supply.

The abundance of water in the system as a whole does not mean necessarily that water is available exactly when and where required. Various factors influence whether water in groundwater systems and in rivers, streams, and inland lakes is readily available to water users. At local scales, there have been and will be water scarcity issues in the Great Lakes region for many industrial and other large water users. Climate scientists warn that climate variability may further complicate water availability and planning for continued industrial water use.

CGLI’s Water Use and Quality Work Group met on August 13, 2015 for a webinar entitled Abundance or Scarcity: Evaluating the Potential for Water Scarcity in the Great Lakes Region. In this webinar, Howard Reeves of USGS provided an overview of the factors that influence whether water is readily available to Great Lakes water users. Dr. Reeves started from the general principle that water is “locally available” when it is available (1) at the location, (2) at the time, and (3) of a quality that is responsive to human and ecosystem needs. He identified four factors that can limit local water availability in the Great Lakes region:

  • Location: While an abundant volume of water is uniformly available in the Great Lakes themselves, neither surface nor groundwater elsewhere in the region is uniformly distributed.
  • Timing: Seasonal and annual variations in surface and groundwater levels can influence the availability of water at a particular location. For example, more water is withdrawn for use by industry, public water utilities, and irrigation in summer months than in winter months, which can impact the availability of water for other uses.
  • Quality: Some areas within the Great Lakes region have water quality limitations due to natural or manmade conditions that influence the usefulness of water for particular purposes. Dr. Reeves also noted that unique water characteristics may provide opportunity as well as limitation. Dow was sited in Midland, MI in the late 1800s to take commercial advantage of briny groundwater in that area, which was an important source of bromine, chlorine, sodium, calcium, magnesium, and other minerals.
  • Other users and ecosystem services: Local water availability may become limited if competing uses impact the system’s ability to provide a consistent supply. As an example, Dr. Reeves recounted a situation in Jasper County, Indiana where irrigation wells significantly impacted the availability of groundwater for residential use.

Watch for an upcoming webinar in which CGLI will focus on groundwater in the Great Lakes region. In that webinar, we will highlight the importance of groundwater as a source of water for commercial and residential uses, provide an overview of factors that influence the quality and availability of groundwater, and discuss the increasing call for policies and programs that would restore and protect groundwater resources.