Sediment Behind Klamath River Dams Not Harmful


On August 12, federal scientists released data indicating that sediment stored behind the Klamath River dams targeted for removal do not pose a threat to communities or the river. Scientists tested for mercury, PCBs, dioxins, and other harmful substances. You can read the data from the latest study here.  This federal study confirms the findings of the 2006 California Coastal Conservancy analysis of reservoir sediments (PDF).

Contaminated sediments behind the Klamath dams have been a cause for concern, but the federal and state studies should put those concerns to rest. This positive result is an important piece of the comprehensive study being done by the federal government that will lead to a final decision on Klamath dam removal in 2012.

The dams will be removed as part of the two Klamath Restoration Agreements, which will also improve water security for Klamath Irrigation Project farmers, resolve some of the more contentious water rights disputes in the basin, and reintroduce salmon to their historic range upstream of the dams.

More than 55 dams were removed in 2009 across the US, and beginning in 2011, the two massive Elwha River dams will be removed in Washington.  Contaminated sediments can complicate dam removal projects, but there are usually ways to manage the risks.  In fact, the removal of Milltown Dam on the Clark Fork River in Montana involved successfully dealing with 6.6 million cubic yards of contaminated sediments. 

American Rivers works for clean water for fish and wildlife, and recreation opportunities. The non-toxic sediment report supports our effort to remove the four Klamath Dams in order to restore salmon runs and river function in the Klamath River.