Invasive freshwater mussels so far haven’t found a foothold in the Columbia River. That doesn’t mean regional hydropower managers and researchers are sitting idle, waiting for them to show up.A research project under way at the Port of Camas-Washougal aims to make sure the Northwest is better prepared if — or when — the tiny mollusks do arrive.“They’re not here yet,” said Mark Sytsma, a Portland State University environmental sciences professor. “That we know of.”Fast-breeding quagga and zebra mussels have a known track record of causing costly problems elsewhere, notably in the Great Lakes and, more recently, in Lake Mead at the Nevada-Arizona border. They’ve encrusted dam structures, clogged pipes and crowded out other wildlife, requiring millions of dollars in management and mitigation efforts.Local officials worry that mussels could cramp the Northwest’s hydroelectric facilities and irrigation systems connected to the Columbia. They may also crowd fish passage facilities built into the dams.Before that happens, the Bonneville Power Administration and PSU are testing a set of chemical coatings they hope will keep mussels from attaching themselves to the Columbia’s steel and concrete infrastructure. Researchers will finish placing nearly 900 small test panels in the river next week, beginning a three-year evaluation of how the treatment holds up in the water. Later this year, they’ll take panels directly to Lake Mead to see how mussels themselves react to the coating. Researchers will test how much force it takes to get them off the treated surfaces, hoping water current alone might be enough.