By Marcy Stamper
It’s a 150-mile swim from Wanapum Dam to Winthrop, but fish biologists in the Methow Valley are keeping careful tabs on proposed fixes that will enable salmon to get through when the first spring Chinook reach the dam next month, en route to upstream spawning grounds.
Water levels at the dam near Vantage have been lowered 26 feet to enable engineers to analyze and devise workarounds that will allow fish to pass through the dam, where a long fracture was discovered at the end of February.
“Right now, fish ladders aren’t operable, so that’s a huge concern,” said Charlie Snow, a fish biologist with the Washington Department of Fish and Wildlife (WDFW) based in Twisp. “If they can’t get them operating, we wouldn’t have any fish up here—it’s hard to even fathom.”
The first spring Chinook reach Wanapum in mid-April on their more-than-500-mile journey from the Pacific Ocean to the Methow River. It takes at least another two weeks before they traverse the last three dams and reach the Methow River, said Snow.
A horizontal fracture 65 feet long and up to 2 inches wide was found in a spillway pier at Wanapum Dam in late February, according to Chuck Allen, public affairs officer with the Grant County Public Utility District (PUD), which operates the dam. That level is too low for water to flow into the fish ladders that the salmon use to get over the top of the dam.
The nonfunctional fish ladders could have a serious impact on half a dozen species of salmon, both endangered and non-listed, that return to the Methow, Twisp and Chewuch rivers and their tributaries to spawn. Spring Chinook are listed as endangered, and steelhead as threatened, in four tributaries above Wanapum—the Methow, Entiat, Wenatchee and Okanogan rivers, said Snow.
If the fish don’t make it to their spawning grounds to lay eggs, it would have a monumental effect on future generations, said Snow. Most species lay between 3,000 and 7,000 eggs each, depending on the size of the females and of their eggs, he said.
“If they don’t let any up, we would lose a complete brood of spawning fish,” said Snow. While the majority of spring Chinook return at age 4 to spawn, some return when they are 3 years old, and some at 5.
Engineers at Wanapum are exploring a number of temporary measures, including pumping water into the ladders to create a stream that would course over the top of the dam, said Allen. Even with that scenario, however, engineers must devise a system to get the fish from the top of the dam into the reservoir, since 26 feet is too far for the fish to jump safely, he said. One option is a temporary slide that would take fish from the top of the dam down to the reservoir.
Grant County PUD’s intention is to have a system in place by April 15, but because numerous permits have to be secured, technicians are also contemplating moving the earliest spring Chinook by truck. They would trap the salmon at Priest Rapids Dam, downstream of Wanapum, and truck them past Wanapum, releasing them at a safe place upriver, said Allen. “It’s not very attractive—fish ladders are better for fish,” he said.
Moreover, trucking fish would be a short-term solution, since the spring Chinook run past Bonneville Dam (the first in the system) is expected to be over 200,000 this year, and there is no practical way to move all those fish by truck, said Allen.
The notion of moving aquatic creatures on land may seem incongruous, but “trucking small numbers of fish is a pretty straightforward endeavor and fairly common,” said Snow. “They go through these nine dams—that’s not that natural, either,” he said.
“The fish ladders work well,” said Snow, who noted that WDFW also traps and handles fish at Priest Rapids as part of their regular operations.
“We certainly can’t tell the fish to stop running. We invest millions of dollars to ensure fish survivability and we want to make sure we’re doing everything we can,” said Allen.
Juvenile fish passage OK
In addition to the adult salmon swimming upstream to spawn, a million juvenile salmon will be heading the other way, traversing the dams on their way to the ocean, according to Chris Pasley, hatchery manager at the Winthrop National Fish Hatchery. The hatchery will start releasing juvenile fish in April and May—about 550,000 spring Chinook, 150,000 steelhead and 300,000 Coho, he said.
The gates that allow juvenile fish to traverse Wanapum Dam are still functioning, since they are designed to open even at lower water levels, said Allen.
“I’m pretty confident they will take care of the fish—they’re funded to take care of fish passage. I’m not personally concerned,” said Pasley.
WDFW is forecasting record runs of several species this year, with about 3,000 endangered spring Chinook returning here to spawn from April through June, said Pasley. In addition, almost 1 million Coho are expected to return to the Columbia River system.
The spring Chinook travel pretty quickly, with all making the trip in the course of two months, but summer Chinook arrive every day throughout the summer, with the last individuals recorded in November, said Snow. Coho are expected to pass through Wanapum in September.
Steelhead, listed as threatened, will start passing through Wanapum in July and continue through the fall.
Summer Chinook and sockeye, both species not considered endangered, reach Wanapum between June and August, said Pasley. Sockeye runs are also expected to be very high this year, with most going to the Okanogan and Wenatchee rivers.
Impacts on irrigators, hydropower
The Columbia River dams are integrated into so many aspects of modern infrastructure that the situation at Wanapum Dam is also having an impact on irrigation and hydropower, primarily downstream of Okanogan County.
About 150 irrigators rely on the Columbia River and on reservoirs in Chelan, Douglas, Grant and Kittitas counties, and could be affected by the drawdown at Wanapum, according to the Department of Ecology, which is working with the utility districts and irrigators to get them the water they need.
The Okanogan County PUD does not expect its ratepayers to be affected by price fluctuations caused by the drawdown at Wanapum, since the utility gets most of its power from Wells Dam, upriver of the current problems, according to PUD General Manager John Grubich.
Because Wanapum is currently generating only half of its typical electricity, Douglas, Chelan and Grant County PUDs are coordinating their output to accommodate the Wanapum drawdown, said Grubich.
The only possible ramifications for Okanogan County ratepayers would arise if the utility has to purchase additional power on the spot market later in the season, Grubich said.
As they troubleshoot the situation at Wanapum, engineers and dam operators are focusing on four main areas: analyzing and fixing the fracture, providing fish passage, raising the reservoir to allow recreational use, and assisting irrigators, said Allen. Engineers are optimistic because the fracture has closed since the pressure was relieved after the reservoir was drawn down, he said.
“It’s a monumental undertaking—it needs to be some kind of engineering solution,” said Snow. “It’s a technical problem, not really an environmental problem.”