County commissioners learn about Great Lakes water levels

Mark Breederland, MSU Extension Sea Grant educator, explains causes and impacts of low lake levels to county commissioners in Northern Lower Michigan.

The water levels in the Great Lakes is a topic that has been on the minds of many in Michigan in recent years. Levels in Lakes Michigan, Superior, and Huron have remained mostly below the long-term averages since late 1998. The Great Lakes Water Level Dashboard is an interactive tool which shows measured water levels since the early 1900s.

The impacts of low water levels make this an important issue for local government officials in many parts of Michigan. Mark Breederland, Michigan State University Extension Sea Grant educator based in Traverse City, recently spoke to county commissioners at the Michigan Northern Counties Association (MNCA), about this issue. MNCA is a group of 33 counties in northern lower Michigan that meet monthly for educational programs coordinated by MSU Extension.

Breederland explained that lake levels are constantly changing. Water enters a lake mostly through precipitation and runoff from adjacent land. Water leaves a lake through outflows to other lakes and rivers and through evaporation. Evaporation is something we don’t often think about. Just as puddles in our yard dry up on windy days (both warm and cold ones), the wind is also responsible for evaporation losses from lakes. For example, one night of evaporation from a winter blast of cold Arctic air across 45000 square miles of surface area of the Great Lakes can take more water out of the lake than 100 years of bottling water to drink.

Lake levels are lower now due to less than normal inflows, largely due to lower precipitation in recent years, and higher than normal evaporation. While the current low levels have lasted for over a decade, there have been periods of low or high water over the years. Lakes Michigan and Huron had a similar period of low levels in the 1930s and early 1940s, and a long stretch of above normal levels from 1969 through most of 1988 with only a brief dip below average in early 1977.

So is this important, or merely interesting? Low lake levels have real impacts on the people of Michigan and our economy. Additional dredging, which costs money, needs to be done to allow boats access to ports. Until the dredging is completed, freight boats are limited in the amount they can haul so they remain afloat. Recreational boating is also affected, especially sailboats which use daggerboards or keels below the bottom of the boat for stability and thus need deeper water to operate. Some boat slips become unusable with lower lake levels, and loss of coastal wetlands can disrupt habitat.

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