Klamath dam removal poses serious risks
There is an estimated 20 million cubic yards of sediment stored behind the dams. Siskiyou County had a consultant do a preliminary analysis of the sediment studies that had been done. The 2006 Klamath River Dam and Sediment Study was not comprehensive, nor did it detail negative impacts. In fact, it listed a large group of additional studies that would need to be done to develop that information. The American Rivers study did not use the accepted and vetted engineering model for sediment transport, nor did it use available detailed topographic reservoir profiles. The model it did use accounted for sand-sized sediment, when the majority is silt-sized. The study is questionable. The studies done by the California Coastal Conservancy relied on the defective American Rivers study. They failed to take into account that no study had been done on how the flows will carry the sediment.
Dam removal would likely raise the river bed and height of the river. (In the recent decommissioning of Oregon's Marmot Dam with 955,000 cubic yards of stored sediment and erosion of 131,000 cubic yards of sediment, the downstream channel rose 13 feet.) This could inundate adjacent land downriver where there are homes and infrastructure. The fine sediment could also be trapped in gravel spawning beds, requiring a 100-year flood event to return them to a suitable state for salmon.
A review of sediment bore samples showed some presence of ethylbenzene and creosote compounds. Three bore samples taken in each of the reservoirs indicated that the sediment contains dioxin. Two samples were above human health standards. (You can read about that toxin and its carcinogenic health impacts at www.ejnet.org/dioxin.) It is likely that the levels of dioxin could kill the benthic community or bottom ecology of the river and that a large quantity of floating organic toxic waste particles would pollute the mouth of the estuary.
The Klamath dam removal proposal would be the largest in the United States and evidence is that there may be significant risks involved. It is evident that the comprehensive scientific studies needed to assess this option to determine the impact on human beings and the environment have not been done. This includes: (1) detailed studies using a well-vetted model of sediment transport and deposition; (2) evaluation of the impact of resultant sediment loads on fisheries habitat; and (3) further evaluation of sediment toxicity. On behalf of the health and welfare of my downriver communities, I call for a halt of further action on the agreement until such analysis has been done.
On another note, ratepayers should take note that, according to PacifiCorp, the cost of retrofitting of the dam to accommodate fish bypass can be amortized over 30 years and rate increases spread out over that time. Dam removal, however, is an immediate expense and will be felt up front by the ratepayers. Claims that dam removal is the better option do not pencil out, nor do they withstand scientific scrutiny.
Marcia H. Armstrong is a Siskiyou County supervisor for District 5, representing the communities downriver of the dams.