Rivers Make Wetlands, And Wetlands Make a River
Rivers and streams create, maintain and transform wetlands over time. But the influence of riverine wetlands on their flowing architects is equally powerful and important. Wetlands provide critical water quality, water quantity and habitat functions that support the health of stream and river ecosystems. In short, riverine wetlands are a big part of what gives a river life and character. The Upper Mississippi River along Wisconsin’s western border is one of the best examples of this. Touring the Mississippi
Riverine Wetlands
Dynamic by nature, a river is said to be made up of both a river of water and a river of sediment. These twin rivers are constantly working together under every day "baseflow" conditions to shape the riverbed, in-channel wetlands and shoreline wetlands through daily imperceptible amounts of erosion and deposition of sediment. During occasional overbank flood events, a river’s influence on associated wetlands can be noticeable and extend far into wet forests and sloughs of the floodplain. Large floods can even change the course of a river, cutting off oxbows that become new wetland basins. Once formed, riverine wetlands provide critical connections, as wildlife, water and more move through these habitats in both directions. Wisconsin Wetlands Association will continue to celebrate and explore riverine wetlands through future programs and events. Read about our upcoming Wetland Science Forum, Riverine Wetlands: Connections, Corridors and Catchments. Aerial photos by Great Lakes Indian Fish and Wildlife Commission.
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We grow up hearing so often that a straight line is the shortest distance between two points that we end up thinking it is also the best way to get there. A river knows better - in its bends, the sediment deposited soon turns into marshes and swampy islands, harboring all manner of interesting life, imparting charm and character to the whole waterway.
Jeff Janvrin, Mississippi River Habitat Specialist for Wisconsin DNR, provided a historical perspective. The Upper Mississippi is a substantially
altered river system due to decades of changes including construction of locks, dams and levees; navigation channel dredging; and expansion of watershed
land uses. Thanks to tremendous restoration efforts, the river is recovering an intricate mosaic of habitats ranging from deep flowing water to shallow
wetlands. Janvrin explained how his agency works through the Environmental Management Program, a partnership with the U.S. Army Corps of Engineers,
the U.S. Fish and Wildlife Service and other state agencies, to restore swampy islands, marshy coves, sloughs, side channels, and other backwater habitats
of the Upper Mississippi.
Consider a river corridor for a moment- not a straightened, ditch-like watercourse suppressed by channelization - these rivers usually suffer from a lack of wetlands and are bordered by dry, upland habitat types nearly up to the water’s edge. Imagine instead a sinuous, natural channel with all the complexity and diversity that tens of thousands of years of water’s work on the land can create. Natural rivers, especially large rivers, are
typically rich with wetland habitats both within their channels and in bordering floodplain corridors.