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Dredge
Placement Impacts
On Fish
 Environmental
impacts that may be caused by the dredging needed to
maintain a minimum nine-foot navigation channel along
the Upper Mississippi River has long been a concern
of river resource managers. Under the terms of a recent
Clean Water Act-Section 404 permit to fill wetland habitats,
the U.S. Army Corps of Engineers (USACOE) agreed to
 begin
addressing dredge disposal concerns along the Upper
Mississippi River. To accomplish this, plans were developed
to evaluate impacts that may result from dredging. Representatives
of several resource agencies agreed that the best approach
would be to separately evaluate several key components
(i.e. fish, invertebrates, mussels, etc.) over a period
of several years at two sites, one which would have
dredge material placed on it (reference site) and the
other which would not (control site).
The fisheries
study in Pool 12 near Bellevue, Iowa called for an evaluation
of the bottom material and aquatic habitat at each site
and monthly water quality and fish sampling. The bottom
material at both sites was primarily made up of sand.
Root wads and fallen trees were more prevalent at the
control site, but the majority of this habitat was in
shallow water for most of the sampling season. Aquatic
plant beds were sparse at both sites. Three methods
were used to collect fish, electrofishing, hoop netting,
and mini-fyke nets.
 Funding
for this project was provided by the Corps of Engineers,
Rock Island District and the Fish and Wildlife Service.
The point
of contact for this project is:
Scott Yess Scott_Yess@fws.gov
(608) 783-8432
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