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Waterways are often deepened for boat access or drainage, but the
marsh and its abundant life is destroyed in the process. Not only
are large areas of shallows filled with dredgings, but the actual
shoreline becomes abrupt.
The results of
ditch-dredging in the wetlands are:
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Little
change in land or water area as water levels change, providing no
shallows for marsh plant establishment (cattails, smartweeds) nor
for feeding by birds (ducks, shorebirds, herons).
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No habitat
for much of the abundant small forms of life of the shallows, from
frogs down to microscopic plants and animals.
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Wave and
ice action that perpetuate the abrupt drop-off through erosion,
until the bottom is filled and the dredging is repeated. Erosion
and animal action perpetuates muddy water. Bare soilbank and
erosion faces may become colonized by weed pests including
nettles and
shrubs and trees, which may not stop erosion, while they can stop
waterfowl use.
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Eutrophication of the water as a result of oxidation of any
organic spoils dumped above the water level, because of the rapid
release of soluble minerals from decaying peat.
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