1. The Great Lakes are the largest system of fresh surface water on earth.
2. The Great lakes contain 18 percent of the world’s fresh water.
3. This makes many of the 35 million people living in areas around the Great Lakes think that they will NEVER experience a shortage of water. THIS IS NOT TRUE!
4. The water inflow to the great lakes is small. It takes many years to replace the water volume within the Great Lakes as follows:
Superior 173 years
Michigan 62 years
Huron 21 years
Erie 2.7 years
Ontario 6 years
5. Water refills the Great lakes from precipitation directly onto the lake, direct surface water runoff, ground water discharge into streams leading into the lakes, direct ground water discharge into the lakes, and the returns of water from user (people and their industries).
6. Residents in area around the Great Lakes use water as follows:
Supply to homes 25%
Irrigation 25%
Livestock 25%
Mining and Manufacturing 15%
Power Generation* 10%
* Power generation requires huge withdrawals from the great lakes but 10% is the amount
lost by evaporation through power generation.
7. We are already withdrawing water equal to or slightly greater than the rate of replenishment into the lakes.
8. In our homes we typically use water as follows**:
Toilets 28%
Clothes Washing 21%
Showers 17%
Faucets 15%
Leaks 14%
Baths 2%
Dishwashers 2%
Other 1%
9. Conserve water even if you live near the Great Lakes. See our blog on conserving water for some useful tips and ideas.
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** Sources include American Water Works Association publications
