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St. Lawrence Seaway: Western Great Lakes Basin

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Document pages: 20 pages

Abstract: The St. Lawrence Seaway connects Lake Superior, Lake Huron, Lake Michigan, Lake Erie and Lake Ontario to the Atlantic Ocean. The lakes and connecting rivers, St. Mary’s, St. Claire, Detroit, Niagara and St. Lawrence, have been a major artery for transportation, migration and trade. The Menominee River flows into Green Bay and Lake Michigan and connects to the St. Lawrence Seaway. The Great Lakes have been sailed for trading and commercial purposes since at least the 17th century. Approximately 6000 ships have sunk killing more than 30,000 sailors and passengers. Cold Canadian winds over the three Western Great Lakes pick up moisture when the lakes are not yet frozen and create snow belts in the states of Wisconsin, Michigan and in Ontario, Canada. The Western Great Lakes moderate the seasonal temperatures as they absorb heat and cool the air in the summer. The lakes radiate heat in the fall. This temperature buffering creates fruit belts further north of where the fruit is traditionally grown. During the 1950s and 1960s all of the Agent Blue, the arsenic containing herbicide used in Vietnam War, was manufactured on the banks of the Menominee River by the Ansul Company at Marinette, Wisconsin. The groundwater and the river bottom are now heavily contaminated with arsenic compounds that were released from 1957 to 1977 by Ansul as a result of the manufacture of the herbicide. The linkage of Lake Michigan to the Mississippi River has allowed Chicago’s wastewater to be disposed of into the tributaries of the Illinois River and Mississippi River to avoid contaminating Lake Michigan the source of Chicago’s drinking water. An unintended consequence of linking the Western Great Lakes basin with the Mississippi River basin was the creation of the wet pathway (Chicago Sanitary and Ship Canal) through which the flying Asian carp is trying to use to get into the Great Lakes. An electric fish barrier was constructed on the Chicago Sanitary and Ship Canal in an attempt to prevent the carp from migrating into Lake Michigan, the Great Lakes basin and the St. Lawrence Seaway. The Western Great Lakes shorelines are actively eroding partly as a consequence of the high surface water levels. In June of 2020 Lake Michigan, Lake St. Claire and Lake Huron experienced the highest water level ever recorded since the 1800s. The high risk erosion areas are retreating at the average rate of 30 cm per year for the last 15 years. Planned urban development in a high risk area helps to prevent the loss of buildings. Locating structures back from lake bluffs promotes natural shorelines and reduces the need for engineered shore protection. Erosion of the sediment under the Mackinac Bridge and pipeline has occurred. The pipeline which carries 87 million liters of oil per day between Sarnia, Ontario and Superior, Wisconsin is at risk.

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