A watercraft inspection station near Owyhee Reservoir’s north access would help keep invasive quagga and zebra mussels out of the southeast Oregon impoundment, according to supporters.

Increased momentum for the idea — for which funding and multiple approvals are needed — reflects increased visitation from the growing greater Boise area and the September 2023 discovery of quaggas in the Snake River near Twin Falls, Idaho, said Friends of the Owyhee executive director Tim Davis and Malheur County economic development director Taylor Rembowski.

Owyhee Reservoir impounds the Owyhee River, a Snake tributary.

Quagga and zebra mussels can clog irrigation, drinking water and hydropower systems, and impact water quality and habitat. The mussels can attach to watercraft transported between water bodies.

Owyhee-bound watercraft users originating from the Boise area or a small slice of southeast Oregon do not pass existing inspection stations on Interstate 84 near Ontario or on U.S. 95 near Marsing, Idaho.

The additional inspection site, if developed, likely would be on Owyhee Lake Road, where some improvements would be needed, Rembowski said. An exact location and opening schedule are yet to be determined.

A broad group of stakeholders, including representatives of local, state and federal agencies and the Owyhee Irrigation District, supported the concept at Sept. 13 online meeting, he said.

“We all agree it’s an important issue,” Rembowski said. “We would like to be very expeditious with this, but a lot of entities are involved.”

Working proactively costs less than trying to remove the mussels once they are in the waterway.

“We are all aware the reactionary cost and prevention cost are vastly different,” he said.

Rembowski plans to apply for a grant, through the Oregon Invasive Species Council, by mid-October. Proceeds would fund education and outreach.

The county wants people to visit the reservoir, he said. “We don’t intend to hinder the enjoyment of the river and lake.”

The Owyhee watershed has seen a “huge change in the amount of visitation,” Davis said. “Without having infrastructure such as these check stations, there is a high likelihood there could be impacts from more visitation” including on fish and wildlife.

The population of the Treasure Valley, which includes the Boise area, has grown by some 120% in 30 years, a period over which recreation infrastructure on the Owyhee system’s Oregon side has gone largely unchanged, he said.

The reservoir is a favorable habitat for mussels, which could “attach on top of things and each other, and plug everything up” at great expense, said Clancy Flynn, who manages the Owyhee Irrigation District.

The Oregon Department of Fish and Wildlife manages the state’s invasive species program.

The department currently does not have a plan to add Owyhee inspection capacity, whether through a permanent station or roving crew, although “it is a high-risk water body and there is community support,” said east region public information officer Adam Baylor.

“ODFW supports any increase in our programming as it is needed,” he said.

Owyhee Reservoir is second on Oregon’s list of water bodies at high risk of invasive species contamination, behind Prineville reservoir, Baylor said.

Owyhee risk factors include high recreation-related traffic, high calcium — which would help quagga and zebra mussels thrive — and proximity to the Middle Snake detection area near Twin Falls, he said.

Idaho State Department of Agriculture officials in late September announced another quagga mussel detection near Twin Falls, and planned eradication.