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Cherokee Marsh Restoration
The
City of Madison has lost over 640 acres of wetland in Cherokee Marsh, along
the Yahara River, since 1849. These
wetlands "floated up" and were lost when the water level of Lake Mendota
was raised about 4 feet in 1849 with the construction of a dam at nearby
Tenney Park. A new dam built shortly after 1900 raised the lake level
another 3 feet. Many times
these floating sedge mats, or bogs, will break off and float away. Recently,
the Madison Parks Division received a $10,000 Lake Protection Grant to fund
experimental wetland restoration techniques.
Earlier this year the city
analyzed some historic 1937 air photos of the upper Yahara River.
By comparing to current air photos of the area, it was determined
that approximately 275 acres of high quality wetlands have been destroyed
since 1937. The Parks Division Staff then did additional research
using the 1834 Public Land Survey Records for Wisconsin. These records documented the width of the Yahara River at
several points where section lines crossed the river.
This information enabled the staff to calculate wetland losses prior
to 1937. The combined wetland
losses since the first dam was installed in 1849 are more than 640 acres (1
square mile). With such a large loss, the importance of this project is
obvious, and this is where the city volunteers come into play.
Volunteers will be involved in
experimental techniques that involve establishing submergent and emergent
wetland plants in the Yahara River to help protect the fragile "floating
shoreline". By establishing
these plants in front of the "floating shoreline" they will help buffer
the effects of erosion and in effect will create a vegetation breakwater.
Wind generated waves and foraging carp are the two most destructive
erosive forces working against these fragile wetlands.
Various types of wire fence enclosures will be installed to protect
the plants from carp, muskrats, and geese.
The citizens of Madison have shown
that they are willing to get dirty and wet in trying to save this lost
marshland. Not only will this
project help protect and enhance wildlife habitat, but will also trap
nutrients before they reach Lake Mendota.
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