A total of as many as 900 test steel and concrete test panels, held in specially designed frames, are hanging in the boisterous waters of the lower Columbia to test the resilience over time of three silicon-based coatings.
The overall purpose of the study led by Portland State University researchers and funded by the Bonneville Power Administration is to see if those silicon coatings provide relatively long-term protection for Columbia River basin infrastructure that would potentially be attacked by invasive freshwater mussels -- quaggas and/or their zebra mussel cousins.
A research project under way at the Port of Camas-Washougal docks in Washington aims to make sure the Northwest is better prepared if -- or when -- the tiny but, often, overwhelming mollusks do arrive.
The anti-fouling experiments being conducted in the lower Columbia River – above Portland-Vancouver but 40 or so miles downriver from Bonneville Dam – are expansions of work that has been done in recent years by the U.S. Bureau of Reclamation, which operates hydro-irrigation projects on the Colorado River, including Hoover Dam, which creates Lake Mead along the Arizona-Nevada border.
Quagga mussel infestations in Lake Mead and associated infrastructure have caused problems both with hydro-water operations and the natural environment. Quagga and zebra mussels were first introduced to the United States in the Great Lakes region and have since made a steady progression westward, though not, as far as it is known, to the Northwest. Officials fear the potential impact to irrigation, hydro system, water supply and other systems, as well as to environment and food chain. Fish passage systems for salmon also would likely be affected by a mussel invasion.
The panels put in place this late winter and spring are intended to gauge whether such coatings reduce impacts from a mussel invasion. The theory is that the cluster-prone mussels will “not be able to get a good grip” on coated structures such as water intake grates that could be clogged, said PSU’s Mark Sytsma. He is professor of Environmental Sciences and associate vice-president for Research at PSU and director of the Center for Lakes and Reservoirs, and co-director of the Aquatic Bioinvasion Research and Policy Institute.
The idea is that the slicker grip would allow the river to self-clean by flushing mussels downstream with typical water volumes and velocities instead of letting the mollusks colonize on the steel and concrete surfaces.
The key question for the three-year, $221,000 study is the durability, the longevity of the coatings.
“It’s going to be expensive” to use the coatings, Sytsma said, so those involved want to know it will work over time.
“If it lasts for 20 years it’s not a bad price,” Sytsma said.
The framed panels, which can weigh up to 900 pounds, will also be tested at Lake Mead to see how mussels there interact.
The idea is to figure out the cost-benefit ratio as opposed to untreated or traditionally treated surfaces. The silicon coatings may be able to reduce overall maintenance costs associated with invasive mussel infestations, PSU research assistant Steve Wells said.
The research will also be used to cement the belief that the silicon solutions are non-toxic and would not, even if they flaked off in protected areas such as fish ladders, harm fish. Many of the salmon and steelhead stocks that ply the Columbia-Snake hydro system are protected under the Endangered Species Act. Others, such as Pacific lamprey, have experience large drops in populations in recent years.
A goal is to find quagga-unfriendly measures “that are cost effective and don’t affect fish passage,” Wells said.