Association of State Wetland Managers - Protecting the Nation's Wetlands.

Salameander: The flow of time at the water’s edge

SalameanderWe recently spent a few days at the summer home of a family member along northern Lake Huron.  A long quiet walk on the beach is perfect for contemplation – or to avoid thinking while listening to the slow rhythm of the waves and occasional announcements from the gulls.   One unavoidable thought this year is that the lake level is low.

Really low.

Again.

Low enough to see obvious changes in the shape of the shoreline, with the exposure of flats previously covered by water.

Low enough to expose more fossil coral, remnants of the salt seas that existed here some 350 million years ago, and that were exposed by glaciers 10 thousand years ago.  Low enough for woody vegetation to begin to colonize the narrow strip of sand and cobble between the woods and the water’s edge that supported only sparse vegetation 15 years ago.

For those of you not familiar with the Great Lakes – it is expected that water levels will fluctuate over a period of 10 to 20 years or so.   Annual differences depend on the amount of winter snow in the watershed, extent of ice cover that limits evaporation contrasted with warmer temperatures that encourage it, and of course precipitation and runoff during the rest of the year.  There are other, human, factors as well related to maintenance of shipping channels, and those are still being sorted out.  And so we all ask, are current lows “normal”?

Long term records maintained by the U.S. Army Corps of Engineers show that the level of Lake Huron reached an all-time low in January of 2013 based on records maintained since 1918.  Levels well below average have persisted since about 1999. There are those who say this is part of the normal fluctuation.  There are others who say this is climate change.  Just to add to uncertainty, while early climate change models inevitably predicted lower Great Lakes water levels (less snow pack and ice cover, warmer water) – there are now others that predict moderately increased levels (increased annual precipitation).   Meanwhile, harbor towns struggle to maintain deep water for boats, and commercial freighters are forced to lighten their loads.

As I walk along the shore, it feels as if I am observing a climate shift, in spite of my knowledge of uncertainty.  Every few feet, I can see the seeps where groundwater now enters the lake from above the water line. The vegetation is thicker, dryer.  Occasional small conifers from the woods appear in the sand.  During all the days at the beach, I never see a frog along the water’s edge in the drier, shrubbier vegetation.  The water is warmer, too, and a bloom of algae drifts along the shore, obscuring the cobble below.  If this is climate change, it was supposed to happen slowly.  I am used to thinking of the Great Lakes as a constant – even as the surface changes from calm to storm-tossed and back again – or at least as a system in tune with geologic time frames, with glaciation and fossilization.  I did not expect to see these changes in my relatively short human acquaintance with the lakeshore.  I think of the consternation of those facing the alarming problem of sea level rise on the saltwater coasts.  It feels as if we are facing not only a climate shift, but somehow a shift in time and in the rate of change in the world.

To review the Detroit District Corps of Engineers July 2013 water elevation bulletin for the Lake Huron, click here.

For an interactive NOAA dashboard of Great Lakes elevations, including multiple long term projections, click here.

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