Life Depends on Water how streams work

How Streams Work

intro-watershed

Natural Stream Ecology		Altered Stream Ecology
			Urban Stream Dynamics
				Channelized Streams
				Dams

			Channelized Streams
			Channelized streams are ones that have been reconstructed in order to accommodate specific land uses and to protect nearby property from flooding or stream bank erosion. Streams are also straightened and deepened for navigational or shipping purposes, too. In agricultural areas, streams have been straightened so that there is more land available to be farmed. The negative impacts of channelization are great. Wetlands and other riparian areas are lost or severely altered.Wetlands and riparian areas lose their ability to filter pollutants before they reach the stream.

Loss of habitat with losing wetlands and riparian areas is also great. As streams are straightened, their flow rate increases.

This also increases the amount of soil erosion scoured from stream banks and stream bottoms. Channelization also funnels more water through the stream system faster allowing it to reach downstream areas quicker often resulting in flooding of these downstream areas. Armoring or lining stream banks with bulkheads of steel, concrete, or riprap often accompanies channelization.

Problems with this include loss of stream bank habitat and increased erosion downstream.

To read about how bulkheads are being changed in order to better support plant and animal life, see the Cuyahoga River Bulkhead Habitat Summary (pdf)

Finally, another negative outcome of channelization isthat these modified streams will need maintenance over time (fixing berms or walls, dredging, removal of vegetation) which is often expensive and impractical.



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