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2024 ICM
Problem D: Great Lakes Water Problem
Background
The Great Lakes of the United States and Canada are the largest group of freshwater lakes in the
world. The five lakes and connecting waterways constitute a massive drainage basin that
contains many large urban areas in these two countries, with varied climate and localized
weather conditions.
The lakes’ water is used for many purposes (fishing, recreation, power generation, drinking,
shipping, animal and fish habitat, construction, irrigation, etc.). Consequently, a vast variety of
stakeholders have an interest in the management of the water that flows into and out of the lakes.
In particular, if too little water is drained or evaporates from the lakes, then flooding may occur
and homes and businesses along the shore suffer; if too much water is drained, then large ships
cannot travel through the waterways to bring supplies and support the local economy. The main
problem is regulating the water levels such that all stakeholders can benefit.
The water level in each lake is determined by how much water enters and leaves the lake. These
levels are the result of complex interactions among temperature, wind, tides, precipitation,
evaporation, bathymetry (the shape of the lake bottom), river flows and runoff, reservoir policies,
seasonal cycles, and long-term climate changes. There are two primary control mechanisms
within the flow of water in the Great Lakes system – Compensating Works of the Soo Locks at
Sault Ste. Marie (three hydropower plants, five navigation locks, and a gated dam at the head of
the rapids) and the Moses-Saunders Dam at Cornwall as indicated in the Addendum.
While the two control dams, many channels and canals, and the drainage basin reservoirs may be
controlled by humans, the rates of rain, evaporation, erosion, ice jams, and other water-flow
phenomena are beyond human manipulation. The policies of local jurisdictions may have
different effects than expected, as can seasonal and environmental changes in the water basin.
These changes in turn affect the ecosystem of the area, which impacts the health of the flora and
fauna found in and around the lakes and the residents that live in the water basin. Even though
the Great Lakes seem to have a regular annual pattern, a variance from normal of two to three
feet of water level can dramatically affect some of the stakeholders.
This dynamic network flow problem is “wicked” – exceptionally challenging to solve because of
interdependencies, complicated requirements, and inherent uncertainties. For the lake’s
problems, we have ever-changing dynamics and the conflicting interests of stakeholders.
See Problem D Addendum for Additional Information.
