Great Lakes Hydrology 101

A recent presentation at Crossroads at Big Creek by Dr. Eugene Stakhiv of the Institute for Water Resources and U.S. Army Corps of Engineers focused on the activities of the International Upper Great Lakes Study Group (IUGLSG). This group explored and defined the extent that water level variation affects resource groups and the environment throughout the Great Lakes basin.

In their study, specific issues were addressed supported by knowledge of the natural hydraulic processes occurring in the Great Lakes, the effect of climate change, and the need to update Plan 1977A which is the old obsolete Corps of Engineers control document that is still operating under new and entirely different conditions.

In Stakhiv’s report, titled “Hydrology 101,” the water losses for the Great Lakes were specifically enumerated:

• Chicago River/Sewage Canal = 2 billion gallons/day

• St Clair River = 121 billion gallons/day

• Evaporation on Michigan and Huron = 56 billion gallons/day

• Loss by bottling water (beer and soda included) = 250 million gallons/day

• All Great Lakes losses = 116 billion gallons/day.

Stakhiv also addressed both the natural and man-made causes for water losses on the Great Lakes, and touched upon the water gains in the system.

Causes of natural losses:

• Lack of ice cover causes more evaporation.

• Warm winters mean less ice cover and less restriction of flow in rivers (St. Clair River).

• Landscape is morphing south of 45th meridian (land levels are slowly rising).

Causes by man-made effect (from the Baird Report – Georgian Bay Foundation):

• Primary cause is dredging/river bed erosion – St Clair River was dredged 24 feet.

• Recommended water flow control weirs were not installed because of cost measures.

• More use of all lake waters for industry and municipal supplies (increases exponentially each year).

Water gains in the Great Lakes:

• Water is being returned to the Great Lakes from wastewater sources at a rate of 3.53 billion gallons a day.

• The amount of natural flow from rivers and tributaries is unknown and variable by years and seasons.

Dr. Stakhiv said he believes water level fluctuations are part of a long-term cycle, which he demonstrated by comparing water levels with those of the dust bowl years. Rises and falls compare in detail with 1920/30 cycles where there was a rebound late in the 1930s; however, the graph also shows that the current trend does not rebound but continues at the same level at the end of the 10-year cycle, which is drastically different from the 1930’s cycle.

The IUGLSG study will be completed in 2009, and the results will be utilized by the International Joint Commission on Waterways (US and Canada) in formulating future use and control policy for the Great Lakes waters. Unfortunately, according to Stakhiv, there is no anticipated result with any real impact or action before 2015 involving the US and Canadian government political committees.