Lake Michigan Coastal Dunes
Calvin College Home

Lake Michigan Coastal Dune Home
Introduction to Lake Michigan Coastal Dunes
Features and Types of Dunes
Wind, Sand and Coastal Dunes
Climate, Dune, Lake and Seasonal Factors
Methods, Results and Research Students
References and Links to More Information


 

Environment - Lake level


The level of Lake Michigan rises and falls as amounts of precipitation and evaporation change within the lake basin and drainage area. The historic record for Lake Michigan shows approximately 1.5 m (5 ft) variation over time. Currently, lake levels are low.

Changes in lake level affect the width of the subaerial beach (the above-water part of the beach which in turn affects dune processes.


Data source: US Army Corps of Engineers (2005). More information on Great Lakes water levels is available at their website.
Lake levels refer to the International Great Lakes Datum of 1985 (IGLD 1985) which is a reference zero point for the Great Lakes established near the mouth of the St. Lawrence River in 1985.
A wide beach (at low lake levels) represents a larger supply of sand that can be moved by the wind to inland dunes. During low lake levels, coastal foredunes grow. As a beach narrows (when lake levels rise), the supply of sand decreases and foredune growth slows down.

Approximately 10 m (33 feet) of subaerial beach is visible.
(Hoffmaster State Park in September 2005.)
When waves come right up to the foredune (there is no subaerial beach), vegetation and sand are eroded from the dune. The waves move dune sand to the underwater part of the beach. Wind can also move sand inland from areas of the dune no longer protected by vegetation.

No subaerial beach and waves come right up to foredune.
(Hoffmaster State Park in August 2004.)

Environment: previous page / next page /Return to Environment home page

 

Questions or Comments? Contact the webmaster.
Last updated 03/23/10.