Photo by Meenerke Bloem from Wikimedia Commons
Federal authorities will need to review the potential effect on protected species of removing an invasive weed before the plants can be yanked from the Columbia River.
Over the summer, several new patches of flowering rush were found growing in shallow waters of the river near Umatilla, Ore., which is the first time the weed was discovered in Oregon.
Flowering rush is already a problem for irrigators in Washington, Idaho and Montana because it grows so thickly that the flow of water in canals is impeded. The weed can also clog irrigation intakes and create habitat for introduced fish that prey on native salmon.
The Oregon Department of Agriculture wants the flowering rush plants to be pulled out before they have a chance to spread further, but the sites can’t be treated without permits from the U.S. Army Corps of Engineers, which has jurisdiction over the river.
To grant those permits, the federal agency must review the proposed removal under the Endangered Species Act, the National Environmental Policy Act and conduct an archeological assessment of cultural resources at the sites, said Damien Walter, a biologist for the corps. The corps may also need to negotiate a contract with divers who would pull the weeds.
The corps recently decided the removal is “categorically excluded” from in-depth NEPA review and would have negligible impact on cultural resources, said Bruce Henrickson, public affairs specialist for the corps.
However, the agency must still get ESA approval for the project from the National Oceanic and Atmospheric Administration and the U.S. Fish and Wildlife Service, he said. The quickest route would be an informal consultation.
Removal of the new flowering rush sites will be reviewed separately from a broader “big picture” proposal to remove aquatic pests from the Columbia River, which has been studied for several years, Walter said.
“The bottom line is there are still some hoops to jump through,” said Tim Butler, supervisor of ODA’s noxious weed control program.
Ideally, ODA wants the flowering rush removed before the plants go dormant during winter, at which point their leaves fall below the water line and they’re no longer visible, said Butler.
However, the ODA will settle for covering the plants with mats weighed down with sand bags, which would at least prevent them from spreading until they can be removed later, he said.
But even that step might require ESA review.
Butler said he understands that the federal government must work within the constraints of federal statutes, but he’s hopeful the review won’t delay the removal of an invasive species that poses real environmental threats.
“It should be a no-brainer to say we need to act on this,” he said. “The risks are much higher by not doing anything.”
Even if the new flowering rush sites are removed quickly, it may not end the threat of the weed further invading Oregon, said Jenifer Parsons, aquatic plant specialist at the Washington State Department of Ecology.
Larger sites of the species are established farther upstream in the Columbia and Yakima rivers, she said. “There’s fragments floating down from those populations as well.”