Will overhauling Scott Dam save native fish?
By Alastair Bland, The Bohemian, November 6, 2019
DAM’D IF YOU DON’T Some see an opportunity to revive fish runs by overhauling the Scott Dam and related infrastructure pieces collectively called the “Potter Valley Project.”
Salmon three feet long seem to clog the water as the chrome-colored fish, fresh from the ocean, begin their journey upriver toward the high-elevation gravel riffles where they were born. Here, in the remotest tendrils of the watershed, they will lay and fertilize the eggs that ensure the next generation of salmon.
At least that’s how it once was early each autumn on the Eel River. But nature’s security system for fish survival is only as good as the health of a river. In the case of the Eel, a local power company built a dam on the Eel’s main fork in 1920. As a result, Chinook salmon lost access to about 100 miles of spawning habitat. Steelhead, which swam farther upstream into smaller tributaries, suffered even greater impacts. Intensive in-river commercial fishing, water diversions, logging and other land degradation took their toll, too. Today, annual salmon runs in Eel River that once may have totaled a million or so adults consist of a few thousand. Lamprey eels, too, have dwindled.
Now, there is serious talk of removing Scott Dam, owned by PG&E since 1930.
For fishery proponents, such a river makeover is the optimal way to revive the Eel’s salmon runs.
“We want to see volitional passage, both ways,” says Curtis Knight, executive director of the conservation group California Trout.
Volitional, in this context, means the salmon are able to make their historic migration on their own—downstream as newly born juveniles and, later, upstream as sexually mature adults—all without the assistance of human hands.
“We think dam removal is one possibility here,” Knight says.
California Trout is one of several local groups and agencies now formally considering taking over the operation of Scott Dam from PG&E. As a hydroelectric facility, Scott Dam is not very productive, and with PG&E’s operating license scheduled to expire in 2022, the utility giant recently stepped away from the project. PG&E even briefly put the Potter Valley Project up for auction, though the offer attracted no takers.
Potter Valley Project
Congressman Jared Huffman began eyeing the orphaned dam-and-diversion operation as the future of the project came into question over the past several years. Recognizing an opportunity to revive fish runs by overhauling the dam and a variety of connected infrastructure pieces—collectively called the “Potter Valley Project”—Huffman rounded up more than two dozen local stakeholder groups, including tribes, environmental groups, government agencies and farmers, to weigh in and help steer the process.
Huffman determined that everyone with a stake in the Eel River, its fish and its water would need to make compromises.
“The two-basin solution is built around a fairly central compromise,” Huffman explains. “There are certainly folks in the Russian River basin who, in their perfect world, would not be making changes to provide fish passage or alter the way the project is operated, and there are people in the Eel River drainage who would like to see the dam and the diversions go away completely.”
Huffman describes his vision as one of “coequal goals,” and a “two-basin solution,” which treats the needs of fish and people with equal consideration. The hope is that no stakeholders will be left high and dry, says Huffman, who represents people in both river basins.
But keeping this process civil to the end could prove a challenge in an era where water management often takes shape as a tug-of-war between farmers and fishery advocates.
A core consideration in amending the project to help fish will be a community of about 150 farms in Potter Valley, actually in the upper Russian River basin, which receive water from Lake Pillsbury, contained by Scott Dam, via a one-mile tunnel bored through a mountain in the first years of the 20th century.
Scott Dam effectively creates a pool of water that can be drawn from in the summer months. If the dam comes down, Potter Valley farmers will need an alternative source of summertime water—a complicated problem.
“If we didn’t have that diversion, you’d be putting a whole lot of people out of business,” says Mac Magruder, who irrigates 300 acres in the Potter Valley for his grass-fed meat farm.
Altering the operation of Scott Dam and the diversion tunnel a few miles downriver will require a new license—what California Trout, Humboldt County, the Sonoma County Water Agency, the Mendocino Inland Water and Power Commission and the Round Valley Indian Tribes are now pursuing. They will first conduct a feasibility study and submit it to the Federal Energy Regulatory Commission no later than April.
Currently, representatives for the relicensing stakeholder groups try to talk in careful terms, without showing strong preference for one plan over another.
“All options are on the table,” says Janet Pauli, the chair of the Inland Water and Power Commission.
However, there is no doubt that the interests of farmers and fishery advocates hardly align. For farmers in Mediterranean climates where virtually no rain falls for four straight months, dams and aqueducts make farming possible.
But for 21st-century river and salmon advocates, dam removal is the holy grail of achievements.
“A free-flowing river without dams is optimal for anadromous fish,” says Joshua Fuller, a fisheries biologist with the U.S. National Marine Fisheries Service. “Unfortunately, in today’s world that setting doesn’t exist in a lot of places. It’s a major reason why we have many listed salmonid species.”
In Washington, the removal of two dams on the Elwha River five years ago reportedly resulted in increased returns of depleted salmon.
On the Klamath River, four dams face dismantling as part of an aggressive effort to revive the river’s Chinook and Coho salmon runs, once among the largest on the West Coast.
Fuller says providing access to the spawning habitat upstream of Lake Pillsbury is a key component of his agency’s Chinook-and-steelhead recovery plan. Creating that access would be, in some ways, simplest by removing Scott Dam.
But it’s not the only way. Building fish ladders is another means of opening the higher reaches of the watershed to spawning salmon and steelhead. These winding stairways of cascading water allow migrating fish to climb up and over otherwise impassable dams. They allow juveniles to safely return downstream, too.
But the Eel River system poses complications. Scott Dam bridges a deep canyon, and building a fish ladder up and over the dam could prove technically difficult. Ascending such a ladder might be difficult for fish, too.
The other big problem with relying on a fish ladder system at Scott Dam involves a non-native predator called the pikeminnow that was somehow introduced to the system in the late 1970s. Pikeminnows, which can grow to about four feet in length, prey aggressively on smaller fish and are abundant in Lake Pillsbury. Thus, a system that requires young salmon and steelhead to swim across the lake to the outflow might be a death sentence for many, if not most, of the fish.
The pikeminnow is a major reason why dam removal remains a favored option among environmentalists.
“A salmon smolt in a reservoir full of pikeminnows hardly stands a chance,” says Craig Tucker, a natural resources consultant working for the County of Humboldt.
David Keller, with the Friends of the Eel River—a stakeholder group but not one of the relicensing applicants—says elaborate systems are necessary for assisting the juveniles across the lake.
“It would be extremely labor-intensive and time-intensive,” he says. “You’d have to have people there at the right time, when the fish are coming through.”
Like Knight, he wants to see fully volitional passage.
“The only way that makes ecological sense is to allow the fish to do it themselves, and that means taking out the dam,” Keller says.
Keller thinks more efficient storage in Lake Mendocino, on the Russian River’s east fork just upstream from its confluence with the main fork at Ukiah, could meet summertime irrigation needs for Potter Valley farmers. This would involve pumping systems that push water various directions, often against gravity. It could also require increasing the height of Coyote Valley Dam to store more water in Lake Mendocino—what stakeholders say would be a very expensive strategy.
Using Lake Mendocino for new storage would be complicated, too, since the U.S. Army Corps of Engineers, which operates Coyote Valley Dam, prefers not to fill Lake Mendocino in the winter months and instead maintain significant available storage for flood control purposes. Only in the spring could surplus water be retained in the lake—though relying on late-winter rains in California is a chancy gamble. In many years under such a system, they may find it impossible to top off the reservoir with water for the Potter Valley farms.
“We don’t see increased storage in Lake Mendocino as a very likely, affordable option,” says David Manning, the environmental resources manager with the Sonoma County Water Agency.
Keller also says Scott Dam is a hazard and “a disaster waiting to happen.” He says its south side is “anchored to an ancient landslide” that is liable to continue sliding.
The dam is also situated almost on top of Bartlett Springs Fault, an offshoot of the Hayward fault that runs beneath Lake Pillsbury and which seismologists have modeled for the potential to cause a 7.5 earthquake.
“Scott Dam was not built for that level of shaking,” Keller says.
Writers have cited the hydroelectric barrier before as a poster child for poor dam building.
“This dam is literally a textbook example of where not to build a dam,” Keller says.
Water wonk and a fish-head
The evolutionary sharpening stone that honed the Chinook into the most resilient and adaptive species of the Pacific salmon could not prepare the fish for the advent of the concrete hydroelectric dam. Beginning early in the 20th century, state and federal agencies reengineered California’s major rivers with massive walls of cement and steel, connecting canals and tunnels, and pumps to move water.
In their respective waterways, Chinook salmon nosed up against the newly built barriers. In the San Joaquin River, where salmon runs of half a million to a million fish survived for millennia migrating every summer through a valley as hot as the deserts of Saudi Arabia, Chinook evaporated into extinction about five years after Friant Dam’s completion.
While effective fish hatcheries maintained the Chinook of the Sacramento River, the Eel River’s salmon were already nearly gone. So was the Eel’s namesake representative species, the Pacific lamprey.
Now, salmon in California face even greater challenges than dams. Global warming will make the cold water the fish require for spawning a rarer and rarer asset. In fact, Knight, at California Trout, co-authored a report in 2017 warning that most of the salmon and trout species and subspecies in California are likely to go extinct if efforts are not made to preserve their habitat. In some watersheds, there may be no saving the fish.
But rivers born in high elevations, and fed by year-round, ice-cold springs, have the potential to keep salmon and steelhead alive and running.
The uppermost tributaries of the Eel River constitute precisely this type of habitat.
“It’s high and it’s got cold water and it’s going to be cold for a long time,” Knight says.
Fuller, with the National Marine Fisheries Service, also sees that habitat as critical for maintaining salmon runs in a warmer future.
“Tributaries above Scott Dam contain high-value habitat with cold water and perennial flows essential for long-term population viability and recovery of anadromous salmonids within the Eel River,” he says.
Human beings are more adaptable than salmon, and if they remove Scott Dam, nobody will perish, though the livelihoods some now enjoy could be shaped by new and unwelcome pressures.
“We have more than a lot to lose—we have everything to lose,” Magruder says.
Tucker, with Humboldt County, says he is open to all options now being discussed in the relicensing feasibility study.
But full dam removal is the one he thinks may be most amenable to salmon while still allowing human users to get the water they need.
“There are engineering possibilities for producing agricultural diversions without Scott Dam,” he says.
Huffman calls himself a “water wonk and a fish-head.” He says the potential of creating “a win-win” solution that sustains fish populations amid dense human populations and thriving farm economies drew him to the project.
But he also knows all bets are still off.
“There’s no guarantee that this plan holds together,” he says. “There are centrifugal forces at play that could pull it all apart before the end.”