Water Levels and Flows

by Jim Nies, FLOW’s Wisconsin Coordinator

Of all the problems facing the Great Lakes, loss of water is perhaps the most serious. The water is not, as many believe, a renewable resource; rather it is a gift of the glaciers, with only one percent replaced annually.

The water levels on Lakes Ontario and Erie, while down, seem to have been behaving normally over the past decade. Lake Superior has been trending downward and has been below the long-term average since 2005. Michigan and Huron – which are really one body of water and the only unregulated Great Lakes — have experienced great loss.

2012 marks the fourteenth year of unprecedented sustained low water, and by winter of 2013 the water level of Michigan/Huron may reach the lowest level in recorded history. Throughout history, the water levels of the Lakes have followed cyclical patterns. At about the turn of the century the pattern broke down, at least in Superior and Michigan/Huron, and while declines have continued, the normal, historic rebounds, have not.

The big Michigan/Huron drop started after July, 1997, when the level was at 581.40 feet, above average, but well below the record of 582.42. In October of 1998 the level dropped below the long-term average, and it has remained there ever since, at times falling below 576.5 feet. Over the past fourteen years Michigan/Huron has experienced a vertical decline of nearly 5 feet. The effects in bays and channels, and around much of the shoreline have been dramatic.

It is possible that North America experienced a climatic tipping point right about the turn of the century. According to the 2003 Union of Concerned Scientists/ Ecological Society of America report, very abrupt climate changes are not uncommon, and when they occur “human and natural systems have difficulty adapting.” The report suggests that future declines in water levels are likely.

What is certain is that the water in the Lakes is much warmer than it has ever been, there is about 70% less ice cover in winter, and evaporation is greater. Precipitation patterns have altered, with drought more common in the north central part of the continent. A panel of climate scientists report in the July 29, 2012 Nature Geoscience that “towards the latter half of the 21st century the precipitation regime associated with the turn of the century drought will represent an outlier of extreme wetness. These long-term trends are consistent with a 21st century “megadrought.”

Some forecasts indicate increased precipitation events such as the Duluth flood of summer 2012. This “flashiness” may counterbalance drought to some degree, but most forecasts anticipate continued water level decline. The IJC’s Upper Great Lakes Study board reports that even with increased flashiness and extreme storm events, there is an 85% likelihood of increased dryness and continuing water decline.

Dramatic and powerful as climate change appears to be, it is not, however, the greatest cause of the low level in Michigan/Huron. That honor goes to dredging, diversion, and extraction.

The largest unnecessary drain of Michigan/Huron water is the St. Clair River, where at Port Huron, water flows out of Lake Huron and through the St. Clair and Detroit Rivers into Lake Erie. Before European settlement, the St. Clair was a relatively slow-moving stream of shallows and meanders and with sandbars extending out into the Lake.

Dredging efforts date back to 1852 on the St. Clair River and to 1872 on the Detroit River, when specific obstacles to navigation were removed. Major dredging efforts to facilitate commercial navigation throughout the St. Clair/Detroit River system occurred from 1910-1923 (the 22-foot project), from 1933-1936 (the 25-foot project) and from 1958-1962 (the 27-foot project). Significant sand and gravel dredging has also taken place. Both the Canadian and U.S. governments committed to the building of compensating structures as a precondition to dredging of the St. Clair River in the 50s and 60s, but this was never done.

The dredging from in the 1910’s, 20’s, 30’s and 60’s caused a water level drop of about 16 inches. The later dredgings dropped the level more. An engineering report prepared by W.F. Baird & Associates in 2005 says that 40 years of erosion in the St. Clair may have dropped the level by an additional foot or more. Thus, engineering work and erosion have combined to lower the Lakes by more that three feet, and currently, something like 121 billion gallons a day drains out of Huron/Michigan down the St. Clair, much of it unnecessary for navigation or any other purpose.

The Chicago diversion is a second significant cause of reduced water levels. The canal built in the early 20th century reversed the flow of the Chicago River in order to flush sewage down the Mississippi. Today approximately 2.1 billion gallons a day of drinkable fresh water is used for this purpose, and the level of the Lakes has been further reduced.

Other factors contributing to declining water include:

  • high capacity wells,
  • water mining and the bottling of drinking water,
  • consumptive uses, in which about 2 billions gallons are “consumed” every day (not returned to the watershed) for things like grain, grapes, wine, beer, milk, fruits, vegetables and livestock.

According to David Dempsey, “the remorseless tapping of groundwater resources to support agriculture and industry is drying up aquifers alarmingly fast,” and drying aquifers fail to recharge the Great Lakes, and in fact can contribute to drawing them down. (Dave Dempsey, On the Brink, East Lansing: Michigan State University Press, 2004)

Continued water loss in Lakes Huron-Michigan will have profound consequences for the millions of people who rely upon them. Billions of dollars are at risk through declining property values, reduced fishing opportunities, inaccessible marinas, lower tourism, smaller shipping revenues and less hydro power. Wetlands and aquatic ecosystems face annihilation. Traditional lifestyles will certainly be lost. Even the supply of drinking water relied upon by millions of Canadians and Americans may be threatened.

Low levels also concentrate pollution, increase the likelihood of bacterial contamination and algal blooms, and generally exacerbate the suite of problems facing the lakes.

Having been unequivocally altered by human activity, the Great Lakes now need unstinting human care—the best science and the best engineering applied across the entire basin, with the interests of everyone carefully considered—to assist nature regain its natural balance.

Examples of what can happen to great bodies of water that do not get the necessary care include the Aral Sea, formerly one of the four largest lakes in the world which has lost 75% of its surface area and 90 percent of its volume; and Lake Chad, once the world’s sixth largest lake and the water supply of 30 million people which has shrunk by 90 per cent and will likely disappear altogether by 2030.