Ruedi Reservoir leading charge to intercept invasive mussels on boats

Inspectors at Ruedi Reservoir intercepted six boats that were carrying invasive mussels over six months in 2019. This year, that number has more than doubled in just seven weeks.

“We have 13 boats so far this year and will probably have more,” said Jaime McCullah, inspection site supervisor for Rocky Mountain Recreation Co. The company is under contract to inspect boats entering and exiting the public ramp at Ruedi and to undertake decontaminations.

Throughout the state this year, there have been 60 mussel boats flushed out by the inspections, so Ruedi has accounted for 22% of the total, according to Randy Hampton, public information officer for Colorado Parks and Wildlife’s Northwest Region. It’s uncertain why Ruedi accounts for such a large percentage.

The interception of that many boats this early in the summer demonstrates the growing threat to Colorado waterways in general and Ruedi Reservoir specifically, said April Long, executive director of the Ruedi Water and Power Authority.

The problem has been growing since 2008, when freshwater clams called quagga mussels and the closely related zebra mussels infested Lake Powell, a mecca for many boaters in the Roaring Fork Valley. The mussels, labeled an aquatic nuisance species by CPW, have spread to other waterways throughout the Southwest. They have been present in the Great Lakes, the Mississippi River and waterways in the eastern U.S. for decades. They are native to Eurasia and hitched rides to North America on cargo vessels in the 1980s.

People are supposed to have their boats inspected at Lake Powell when they depart, but a high number of boats and a limited number of inspectors at places like Bullfrog Marina has reduced compliance.

“The line to come out can be (several) hours long,” Long said.

That has created a greater threat to waterways in Colorado. Nearly all of the mussel boats intercepted at Ruedi this year had previously been at Powell, said McCullah.

If the mussels make it into Ruedi, it would have a drastic impact on the reservoir.

“They would destroy the fishery at the reservoir because they eat all the macroinvertebrates,” Long said.

The fast reproducing mussels glom onto virtually any surface — including beaches, other aquatic life and vegetation. Visitors to Lake Powell have reported seeing a thick crust of shells on the sandstone walls when water levels drop. The shoreline is deep with sharp-edged shells. The mussels create a thick crust on any surface they latch onto.

One of the biggest risks is to the pipes and other infrastructure that release water from Ruedi dam. The intake at the hydroelectric plant operated by the city of Aspen also is under threat. The mussels could clog cooling systems in motorboats, foul hulls and jam the centerboard wells under sailboats, according to CPW.

“Once they’re there, eradicating them can be impossible,” Long said.

So Colorado has adopted a strong inspection program, headed by Colorado Parks and Wildlife and partners. At Ruedi, the water and power authority is contributing $70,000 to the inspection program this year. The contributors are Aspen, Snowmass Village, Basalt, Carbondale, Glenwood Springs, Pitkin County and Eagle County, all members of the authority. The Colorado River District and Ute Water Conservancy District, which contract for water from Ruedi, contribute via the water authority.

That $70,000 covers the inspection program from May through August. The boat ramp didn’t open until June this year because of COVID-19 precautions.

CPW, the U.S. Forest Service and U.S. Bureau of Reclamation cover the staffing expenses for September and October.

2018 was the first year that enough money was raised to cover all hours the public boat ramp is open.

The theory is an ounce of prevention is worth a pound of cure. There is currently a team of five inspectors staffing the ramp between 6 a.m. and 10 p.m. The ramp is closed to all traffic when inspectors are not on site.

The water authority’s rallying cry is, “Don’t move a mussel.”

McCullah said a big part of the program is education. The inspectors talk to boat owners about what’s at stake from the invasive mussels and how they can do their part.

“One of the mottos of the program is ‘clean, drain and dry,’” she said.

Boat owners are urged to thoroughly wash everything — boats, trailers, vehicle hitches and motors as well as gear such as fishing equipment, waders and boots.

Every space or item that holds water should be completely drained, including live wells, bait containers, ballast and bilge tanks and engine cooling system.

Boats should be completely dry before launching in other waters.

Inspectors at Ruedi are always looking for a green seal, which shows the boat was inspected at the last waterway it visited. No green seal requires a lengthier inspection and potentially sleuthing to find out where the boat has been.

With the green seal, the inspection can be over in just a few minutes, McCullah said. They start with the hull, then go through all compartments and check ballast tanks.

“I’m always happy when I find a clean, dry boat,” McCullah said.

The 13 boats that were intercepted so far this year weren’t carrying live mussels, but even finding shells shows the craft was in water where mussels were present. McCullah said inspectors also have found settlers, a stage between larvae and adults.

“The settlers look like toasted bread crumbs,” she said.

The microscopic larvae are extremely difficult to detect, so scores of decontaminations are undertaken each summer out of an abundance of caution. Decontamination could be required when water is found in the ballast tanks to evidence there was no inspection after a boat departed Lake Powell.

The mussels are nearly indestructible and have even been found in antifreeze, according to McCullah. “They only need a drop of water,” she said. “They don’t need water standing at the bottom of the boat.”

In a busy weekend, the inspectors deal as many as 100 boats entering and existing the water in a day.

“Every boat is different,” McCullah said, so that makes the job more difficult.

Decontamination, which occur at a site close to the ramp, can take hours. Each suspect spot must be hit with pressurized water that is 140 degrees or hotter for at least two minutes.

“It’s time and temperature,” McCullah said. “At two minutes, we know we’re going to kill anything in there.”

No adult, live mussels have been found in Colorado waterways though larvae were found in Green Mountain Reservoir in Summit County in 2017.

Long said Colorado waterways remain mussel-free because the inspection program is so rigorous. CPW operates the inspections at most sites in the state and it provides training for inspectors at Ruedi.

“We do our due diligence,” McCullah said. “We don’t cut corners. The protocols work.”

scondon@aspentimes.com