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Learning River Language

Bald_eagles_on_iceStanBousson

Bald eagles know where to find food on the river refuge.
Photo courtesy Stan Bousson.

  • River Pool

    Lock and Dam 4 upstream pool 4

     The river is often referred to as pools, defined by the locks and dams.  The pool number is determined by the Lock and Dam.  If you look upstream from Lock and Dam 4 the pool is 4, downstream the pool is 5.

  • Wing Dam

    Wing_Dam150x118

    Spotting a wing dam.
    They are pretty easy to locate visually just look for ripples on the river.

    What is a wing dam?
    The Mississippi River has thousands of wing dams, manmade rockpiles extending out into the river from the shoreline, deflecting the current to the main navigation channel. These were originally constructed in the early 1800s to reduce the amount of dredging required to maintain the 41⁄2 foot navigation channel. In the early 1930s the U.S. Army Corps of Engineers built locks and dams to aid in river navigation. Today the navigation channel maintained at a minimum of 9 feet deep. The wing dams still serve their purpose, but to a lesser extent than before.

    Fishing the wing dam.
    The scour hole is on the upstream side of a wing dam where the water hits the rock, this is where the fish sit and wait for their next meal. This is a classic walleye holding spot. The backside or downstream side is where they rest.
    Local anglers know to fish the wing dams for walleyes. A common way to fish the wing dam is to anchor your boat on the front side, tip or back side of a wing dam. Jigs and bottom bumping lures are cast into the scour holes. It has been said that wing dams that hold the most fish are the ones that have the deep scour hole behind them and they are usually located on the outside bend of the river or a straight stretch.
     

  • Navigation Channel

    Navigation_Channel150x118

    The Mississippi River is a working river; moving 70-85 million tons of cargo each year. In the 1930s Locks and Dams were authorized and today the 9-foot navigation channel is maintained. The 29 locks and dams on the Mississippi replaced rapids and falls with a stairway of water for commercial and recreational traffic.

  • Side Channels and Sloughs

    backwater_lake

    The Mississippi River is not just a large navigational channel but also a complex mosaic of side channels, backwaters, lakes and sloughs.  These off-channel areas provide critical habitat. Side channels are important fish habitats.

  • Braided Stream Zone

    Upper Pool 8

    The braided stream zone is found in the upper portion of each pool, where narrow cuts and channels snake between islands of floodplain forests. This zone resembles the river prior to lock and dam construction. Here you might see wood ducks, woodpeckers or an elusive river otter.   Purchased copyright photo used with permission Robert J. Hurt

  • Backwater Marsh Zone

    Backwater Marsh Zone

     The backwater marsh zone, in the middle of each pool, is where shallow water lies over old hay meadows. This zone supports the best marsh habitat and is the haunt of dabbling ducks, muskrats, bass and panfish.

  • Open Water Zone

    Open Water Zone150x118

     The open water zone, just upstream of each lock and dam, is where old tree stumps lurk, a reminder this was once a forest prior to the construction of the dams. Diving ducks prefer this open water area.
    Great flocks or rafts of canvasbacks find food in Pool 9 near Ferryville, Wisconsin.  They feed on beds of wild celery diving  among the trailing leaves feasting on starchy tubers, fueling them for their fall migration.

  • Restoring River Habitat

    Sunfish_Lake150x118

     Over time, these navigation pools have aged, and habitats have changed. Sediment is filling valuable backwaters; islands are eroding; and vegetation is disappearing from the river. The U.S. Fish and Wildlife Service, along with the public and other state and federal agencies explore ways to restore river habitats.


    One method of restoring river habitats is through the Environmental Management Program (EMP), a partnership between the U.S. Fish and Wildlife Service, the U.S. Army Corps of Engineers, state natural resource departments and others. Thousands of acres of fish and wildlife habitat have already been restored by rebuilding and protecting islands from erosion and constructing dikes to control water levels. Water level management also includes drawdowns. This is a temporary water level reduction of 1-2 feet during summer months which stimulates aquatic plant growth.
     

Last Updated: Apr 10, 2013
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