Salmon success story
But hotter summers and a declining snowpack could threaten the Butte Creek fishery
This could be a hard year for the salmon in Butte Creek. Hot weather has warmed the water, and runoff is the lowest since 2001. Already Pacific Gas and Electric has had to release increased amounts of cold water from its Philbrook Reservoir to keep water temperatures at healthful levels for the fish.
Butte Creek is one of the last undammed waterways in the northern Sierra, and these days hundreds of spring-run chinook salmon can be found swimming lazily in its deep pools upstream and down- from the Centerville Powerhouse.
It wasn’t easy for them to get there. Bypasses, weirs, blind channels, degraded San Francisco Bay water—all were obstacles the fish overcame in their primal urge to return to the site of their birth.
But they made it, and now they are spending the summer in the creek, waiting for fall and cooler water suitable for spawning. The question is whether they will survive that long. That’s where people and their water policies come in.
Since 1900, when the powerhouse was built, more than half the water in the creek has been diverted into a canal that runs along the canyon’s eastern wall until it drops into the powerhouse below, creating electricity.
It’s part of a complicated water-transfer and power-generation system, called the DeSabla-Centerville Project, that connects Butte Creek with the West Branch of the Feather River to the east and also to two small reservoirs, Philbrook and Round Valley, about 15 miles northeast of Magalia. Along the way, the water feeds powerhouses at DeSabla and Toadtown and, finally, Centerville.
On a recent helicopter tour of the system, Bill Zemke, a senior license coordinator with PG&E, pointed out that Round Valley Reservoir, popularly known as Snag Lake, already was empty, and Philbrook was being drawn down at the rate of 35 cubic-feet per second.
That was an increase from earlier rates of release, he said, and was being done “because of the hot weather we’ve had lately.” If it became necessary to continue releasing water at that rate, he added, the 1,500 cubic-feet of cold water in the lake could be used up before summer was over, putting the fish at risk.
From Philbrook Reservoir, the water flows down the West Branch until it is diverted into a canal and then into a tunnel. The tunnel runs under the ridge to the Butte Creek watershed and then, via canal and penstock (pipe), through the Toadtown Powerhouse to the DeSabla Forebay, on a bluff overlooking Butte Creek just off the Skyway in Magalia.
There the water is commingled with water diverted from Butte Creek into a canal several miles upstream and drops through a penstock into the DeSabla Powerhouse next to the creek below. Then, almost immediately, roughly two-thirds of Butte Creek’s water is again diverted, this time into the Centerville Canal.
Because it uses so much of the public’s water to create electricity, PG&E is required by the Federal Energy Regulatory Commission to make sure there’s sufficient cold water in Butte Creek to keep the fish healthy. Since 1999, it has been working under terms of annual operations plans developed in collaboration with the National Oceanic and Atmospheric Administration, the U.S. Fish & Wildlife Service and the California Department of Fish & Game.
PG&E is in the process of preparing an application for FERC relicensing in 2009, so it’s eager to make the public aware of what it’s doing to protect the fish—hence the helicopter tours provided separately to reporters from three local newspapers.
Zemke said the utility plans to include further efforts to help the fish—new fish ladders and improved diversion dams, for instance—in its application. In the meantime, it is doing all it can to keep water flows strong and cool.
It’s a delicate balancing act. Somehow the utility must maintain cool water temperatures from day to day while keeping enough water in Philbrook for future “extreme heat events.” To keep track of water temperatures, it has set up 10 monitoring stations. And, based on readings, it is constantly adjusting water flows, opening and closing valves up and down the system.
The biggest worry, Zemke said, is an outbreak of disease among the fish like the one that killed some 70,000 Klamath River salmon in 2002, the largest adult salmon kill in the history of the West. California Fish & Game officials blamed the outbreak of a fatal gill-rot disease on low water flows resulting from federal water policies favoring ranch and farm irrigators.
As a result of the die-off, commercial salmon fishing along the coast of California has been curtailed for several years—cut by as much as 90 percent in 2006, for example, the largest such closure in the history of the country. The cost to coastal economies: more than $60 million. And consumers can’t help noticing that the store price of wild salmon has risen dramatically.
If all goes well and the Butte Creek salmon remain healthy this summer, PG&E will take steps to increase water flow during spawning season in the fall.
The numbers of returning spring-run chinook salmon in Butte Creek have been high in recent years, thanks to both the increased sophistication of waterflow management and the removal of some major downstream obstacles under the Central Valley Project Improvement Act.
In fact, the creek may have as many fish as it can handle. Because of natural barriers upstream, spawning habitat is limited to the reaches three miles above and five miles below the Centerville Powerhouse.
Fish & Game studies have shown that, even when the number of returning fish varies greatly, the number of juvenile chinook stays high, ranging from 51,000 in 2002-03 to 697,000 in 2000-01. Fish experts believe that during large runs much of the spawning is unsuccessful, most likely because the fish often lay their eggs in marginal habitat or on top of each other.
In any event, the salmon of Butte Creek appear to be in better shape than they have been in many decades. Tracy McReynolds, an associate fishery biologist with the Department of Fish & Game who regularly conducts salmon surveys on Butte Creek, credits PG&E.
“If it were not for the water that the PG&E DeSabla-Centerville Project provides,” she writes in an e-mail, “Butte Creek would not have the numbers of spring-run chinook salmon that we have today.”
Whether that can be sustained is another matter. Global warming is expected to reduce the Sierra snowpack dramatically in coming years, and without sufficient cold water in storage, PG&E will have a hard time keeping the fish cool.