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Introduction How Rivers Run Stories Value Of A River What We Can Do
Connections of a River - Connectivity
Lateral disconnects (pg 2 of 2)

Separation of the stream and floodplain (by the construction of levees, for example) denies organisms such as fish, amphibians, and reptiles access to backwaters and floodplain lakes-spawning areas for some species, feeding areas for others, slow-current refuges for still others. A floodplain provides storage for floodwaters. By constraining the channel, rivers will reach higher stages, exacerbating flooding downstream.

Construction of levees tends to lower the water table adjacent to the river. Lower water tables can stress existing vegetation and reduce the potential for regeneration. Levees increase stream energy within the channel, which increases streambed erosion and destabilizes banks. The overall effect is impaired water quality, decreased productivity, degraded habitats and loss of biodiversity (Fitch and Ambrose, 2003).

Without periodic flooding, river bottom forests will degrade. Nutrient and energy cycles (in both floodplain and river) will be disrupted due to lack of exchange between river channel and floodplain. The floodplain is usually a net importer of dissolved inorganic material and a net exporter of particulate organic matter (Ward and Stanford, 1995). The diversity of species, ages and successional stages of floodplain forests depends on seasonal fluxes of water.


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