River facts in the US

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[#800000]River facts[/#800000][size 2][#800000] [/#800000] [left][/left] [left][#800000]American Rivers was founded in 1973 and is North America's leading river conservation organization. Our mission is to protect and restore America's river systems and to foster a river stewardship ethic. [/#800000][/left] [left][#800000]Rivers of the United States:[/#800000][/left] [left][#800000]The United States has over 250,000 rivers. That’s 3.5 million miles of rivers. [/#800000][/left] [left][#800000]The largest river is the Mississippi, which has a flow volume of 593,000 cubic feet per second at its mouth.[/#800000][/left] [left][#800000]The longest river is the Missouri, which flows for approximately 2,500 miles. [/#800000][/left][size 2]
[center][b][#800000]Primary threats to rivers[/#800000][/center]
[#800000]Dams
* Reduce river levels
* Alter river flow patterns
* Block fish passage
* Slow current
* Change water temperature
* Decrease oxygen levels important for healthy fish and vegetation
* Hold back silt, debris and nutrients
* Cut up fish in turbines
* Increase predator risk
Channelization
* Cuts off river from floodplains
* Eliminates nutrients from rivers
* Robs rivers of the ability to build new sand bars, islands, and side channels
* Increases river depth and velocity, forcing fish to use more energy
Urban sprawl
* Polluted runoff
* Loss of habitat
* Impermeable surfaces (which increase flooding and waterway pollution)
Agriculture
* Farm chemical pollution
* Animal waste pollution
* Livestock grazing can damage streamside habitat
Resource Extraction
* Logging
* Mining
Water Diversions
* Irrigation
* Municipal and industrial use
* Hydropower [/#800000] [left][/left] [left][#800000]Rivers are threatened:[/#800000][/left] [left][#800000]More than 235,000 river miles in the United States have been channelized.[/#800000][/left] [left][#800000]More than 600,000 river miles are impounded behind dams.[/#800000][/left] [left][#800000]More than 25,000 river miles have been dredged for navigation.[/#800000][/left] [left][#800000]More than 50% of wetlands have been lost or destroyed nationwide in the past century.[/#800000][/left] [left][#800000]Nearly 40% of the rivers and streams in the U.S. are too polluted for fishing and swimming.[/#800000][/left] [left][#800000]Thirty percent of the native freshwater fish species in North America are threatened, endangered, or of special concern.[/#800000][/left] [left][#800000]Why protect rivers? [/#800000][url "http://www.americanrivers.org/site/PhotoAlbumUser?AlbumID=5051&view=UserAlbum"][#800000]Click here for some reasons[/#800000][/url][#800000].[/#800000][/left] [left][#800000][/#800000][/left] [left][#800000]Longest rivers in the United States:[/#800000][/left] [left][#800000]Missouri: 2,540 miles [/#800000][/left] [left][#800000]Mississippi: 2,340 miles[/#800000][/left] [left][#800000]Yukon: 1,980 miles[/#800000][/left] [left][#800000]Rio Grande: 1,900 miles[/#800000][/left] [left][#800000]St. Lawrence: 1,900 miles[/#800000][/left] [left][#800000]Arkansas: 1,460 miles[/#800000][/left] [left][#800000]Colorado: 1,450 miles[/#800000][/left] [left][#800000]Atchafalaya: 1,420 miles[/#800000][/left] [left][#800000]Ohio: 1,310 miles[/#800000][/left] [left][#800000]Red: 1,290 miles[/#800000][/left] [left][#800000]Brazos: 1,280 miles[/#800000][/left] [left][#800000]Columbia: 1,240 miles[/#800000][/left] [left][#800000]Snake: 1,040 miles[/#800000][/left][/b][/size][/size]
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