U.S. Water News Online
DAVENPORT, Iowa -- Mississippi River flooding may be a
natural disaster for people that populate the river's banks, but
naturalists say the river is simply doing what it has done for
thousands of years -- cleansing and rejuvenating itself and its
``When the floodwaters spread out over an area, it provides
spawning areas for fish, it helps filter water, it improves water
quality,'' said Bob Clevenstine, a river biologist with the U.S. Fish
and Wildlife Service, based in Rock Island. ``It tends to tie up
pollutants in soil and plant material, breaking them down before they
are pulled into the food chain.''
That ecological perspective might meet with skepticism, given the
flooded river's muddy, stinky appearance and the fat, dead carp and
birds it is expelling as it retreats from Quad-City region streets
and parking lots.
Flooding happens more frequently because wetlands that once helped
absorb, retain and filter excess water have been replaced by
buildings, roads, parking lots and drainage systems that move water
much more quickly out of the way and into the river.
``Man has so altered the natural pulse of the Mississippi through
agriculture, levees, the lock and dam system,'' said Norm Emerick, a
wildlife biologist with the Illinois Natural Resources in Galesburg,
Manmade alterations to the flood plain, however, can't stop the
rivers essential rhythms.
``The river reclaims its flood plain where it's able to, and that
includes what's behind the levees,'' said Mike Griffin, a Mississippi
River wildlife biologist with the Iowa Department of Natural
``As the flood plain enlarges ... the native fish and wildlife are
adapted to expand into that new habitat. This may be a disaster for
us, but it is not at all a disaster for the critters,'' said Dan
Sallee, a Mississippi River biologist with the Illinois Department of
Natural Resources in Aledo, Ill.
``Actually, you may see fewer animals because the habitat has
expanded so much that they aren't as concentrated as they would be in
low water conditions. The herons need water less than thigh deep that
they can stand in and fish. If you provide that on River Drive,
they'll use it,'' he said.
``In nature, the river connects with its flood plain during
periods of high flow and rejuvenates those area, restocks those areas
with fish, wildlife, and re-colonizes those areas and makes them more
productive as far as ecosystems go,'' Griffin said. It's less
productive for farmland, and yet the silt it deposits in its wake
provides fertile material for growing, he said.
``We try to control the river from getting into the flood plain.
It wouldn't get to the magnitude it has gotten in recent years if the
river could spread without the constraint of levees,'' Griffin said.
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