The Great Lakes: Trends and Impact.

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The modern history of the Great Lakes region can be viewed as a progression of intensifying use of a vast natural resource.   At first it was a matter of making use of the natural resources while avoiding its dangers.

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The first Europeans found a stable ecosystem, which had evolved during the 10,000 years since the retreat of the last glacier.  

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The Great Lakes system had been only moderately disturbed by the hunting and agricultural activities of the native peoples, and the first Europens also had a modest impact on the system, limited to the exploitation of some fur-bearing animals.

The following waves of immigrants, however, logged, farmed and fished commercially in the region, bringing about profound ecological changes.

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The mature forests were clear-cut from the watersheds, soil was laid bare by the plow, and the undisturbed fish populations were harvested indiscriminately by an awesome new predator – humans with nets. Logging removed protective shade from streams and left them blocked with debris. Sawmills left streams and embayments clogged with sawdust. When the land was plowed for farming the exposed soils washed away more readily, burying valuable stream and river mouth habitats. Exploitive fishing began to reduce the seemingly endless abundance of fish stocks, and whole populations of fish began to disappear.

Source:  The Great Lakes Environmental Atlas and Resource Book

And this was just the beginning.  Industrialization followed close behind agrarian settlement, and the virtually untreated wastes of early industrialization degraded one river after another.

PhotobucketIndustrialization of the Great Lakes basin followed early settlement and the growth in agriculture.

The growing urbanization that accompanied industrial development added to the degradation of water quality, creating nuisance conditions such as bacterial contamination, putrescence and floating debris in rivers and nearshore areas. In some situations, the resulting contaminated drinking water and polluted beaches contributed to fatal human epidemics of waterborne diseases such as typhoid fever. Nonetheless, the problems were perceived as being local in nature.

As industrialization progressed and as agriculture intensified after the turn of the 20th century, new chemical substances came into use, such as PCBs (1920s) and DDT (1940s).

Non-organic fertilizers were used to enrich the already fertile soils to enhance production. The combination of synthetic fertilizers, existing sources of nutrient-rich organic pollutants, such as untreated human wastes from cities, and phosphate detergents caused an acceleration of biological production (eutrophiction) in the lakes. In the 1950s, Lake Erie showed the first evidence of lake-wide eutrophic imbalance with massive algal blooms and the depletion of oxygen.

Source:  The Great Lakes Environmental Atlas and Resource Book

Trends and Impact

PhotobucketThe International Joint Commission developed tentative projections into trends in water use and their impact on potential future water demands. These projections were derived from a simple extension of trends established over the previous decade.

Results, presented below, extend to the years 2020-21. The Commission cautions that projections beyond two decades are highly speculative.

Thermoelectric Power Use – In the United States, Great Lakes withdrawals have remained relatively constant since 1985 and are expected to remain near their current levels for the next few decades. In Canada, modest increases are expected to continue along with population and economic growth.

Industrial and Commercial Use  – In the United States, industrial and commercial Great Lakes water use has declined. A similar trend is evident in Ontario. Expected use to gradually decline through 2020.

Domestic and Public Use  – In the United States, Great Lakes water use for domestic and public purposes generally increased from 1960 to 1995 and is expected to climb gradually through 2020. Because of aggressive water-conservation efforts in Ontario, a modest downward trend established in recent years is expected to continue.

Agriculture  – In the United States, Great Lakes water used for agriculture increased fairly steadily from 1960 to 1995. In Canada, the rate of increase was somewhat larger. Combined projections indicate a significant increase by 2020.

Total Water Use  

If current trends continue, total water use in the Canadian portion of the basin is expected to increase by close to 20 percent between 1996 and 2021.

A decrease of about 2 percent is expected in the United States portion of the basin between 1995 and 2020, although the United States use is expected to begin rising again after that time.

The combined projections indicate a modest increase of about 5 percent for the entire Great Lakes Basin between 1995-96 and 2020-21.

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    • dkmich on October 5, 2008 at 11:11 pm
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