Dams, over-consumption and pollution threaten US rivers and wildlife

Dams, over-abstraction and poor water quality are wiping out wildlife species in North America's rivers at a rate comparable to that occurring in rainforests, according to a report listing the US' most endangered rivers.

The Most Endangered Rivers report from conservation group, American Rivers, shows that dams, levees and stabilised riverbanks have destroyed river habitat and are contributing to the extinction of native fish and wildlife across the US.

The five most endangered rivers are the Lower Snake River, the Missouri, the Ventura, the Copper River and the Tri-State River Basin. Of these, the Lower Snake, the Missouri and the Ventura are threatened by dams; the Copper by a proposed logging road and the Tri-State Basin by a combination of dam work, over-consumption of water and pollution. The first two have not improved since American Rivers’ last report (see related story).

Dams block fish migrations, disrupt the transport of sediment and nutrients

The report draws on research published recently in the journal, Conservation Biology. This shows that US freshwater fish, snails, amphibians and mussels are disappearing five times faster than animals that live on land, according to recent research published in. The research compares the extinction rate to that of species living in tropical rainforests.

Seventeen freshwater fish species and one in ten of America’s native mussel species are extinct. Two-thirds of US mussels and one-third of America’s amphibians are threatened, the research shows.

” We are entering a new era of restoration,” said Rebecca Wodder, president of American Rivers. “We must learn from the mistakes of the past and act now to restore the life that should be teeming in our rivers. By expanding habitat restoration programmes, reforming dam operations, and using non-structural alternatives to flood control-like helping repeatedly flooded homes and businesses relocate out of harm’s way-we can repair thousands of river miles.”

The five most threatened rivers are:

  1. Lower Snake River (Washington). Four federal dams on the lower Snake River have driven salmon and steelhead to the brink of extinction. Scientists agree that the dams must be breached to remove obstacles to migration, improve river conditions and let the river flow more naturally. American Rivers say investment in transportation, power and irrigation infrastructures can replace the benefits the dams provide and protect rural communities. Position unchanged since last year
  2. Missouri River (Montana, North Dakota, South Dakota, Nebraska, Iowa, Kansas, Missouri). Dam operations to support barge traffic threaten native species, including the pallid sturgeon and least tern. American Rivers have urged the Army Corps to change the way the dams operate to improve river flows to help the ecosystem and bring more tourism to the area. Position unchanged
  3. Ventura River (California). Numbers of southern steelhead returning to the Ventura each year have crashed from 5,000 to less than 100. American Rivers recommends the removal of the Matilija Dam to allow sand to flow downstream. The dam no longer provides its intended flood control benefits and minimal water storage benefits, the group claims. New entry
  4. Copper River (Alaska). A logging road is scheduled to be built in the Copper River Delta. The road would degrade water quality, destroy habitat and sever dozens of salmon streams in the Delta, the largest wetlands complex on the Pacific Coast of North America. New entry
  5. Tri-State River Basins (Georgia, Alabama, Florida). Freshwater species are under threat from dams, over-consumption of water and poor water quality. As the three states battle over water supplies, the health of the Alabama-Coosa-Tallapoosa (ACT) River Basin and the Apalachicola-Chattahoochee-Flint (ACF) River Basin hangs in the balance. The ACT Basin was number three on last year’s list

Action inspires action. Stay ahead of the curve with sustainability and energy newsletters from edie