Nature waits on fate of dam
The Matilija structure and others like it are targeted for removal to restore U.S. rivers.
|November 19, 2002 -- The Sacramento Bee presents a look at Matilija Dam in Ventura and similar efforts to deal with fish passage and the effects of aging, outmoded dams.|
|Laura Mecoy, Bee Los Angeles Bureau|
|LOS PADRES NATIONAL FOREST -- So much water leaks from the cracks in Matilija Dam that clumps of grass and moss have sprouted on its concrete face.|
So much sediment has settled behind the dam that Matilija's reservoir holds just 7 percent of its original capacity, and the lakebed has risen to within 20 feet of the top of the 165-foot structure.
Steelhead once so plentiful that public schools shut down for trout season's opening day have all but disappeared because this dam and another block their annual migration.
"The watershed above here is just beautiful," Paul Jenkin, Matilija Coalition coordinator, said as he surveyed the Ventura County dam 16 miles from the Pacific Ocean. "It represents over 80 percent of the potential steelhead habitat in this area."
The coalition seeks the dam's removal. Jenkin represents the Surfrider Foundation, whose members count on rivers to deliver sand to beaches.
With all its failings, Matilija (pronounced ma-til-a-ha ) is considered a poster child for the burgeoning movement to restore rivers, recover endangered species and replenish California beaches by removing antiquated dams.
At least 465 dams have been removed from U.S. waterways since 1912, and the environmental group American Rivers says another 100 are slated for elimination or being studied for it.
By the end of this year, the environmental group says, 14 states plan to take out 53 dams -- the most since the 1999 breaching of Edwards Dam in Maine kicked off a national movement.
"Dam removal has been going on since the 1900s ... but the Edwards Dam removal got national attention and got communities to start looking at the benefits of removing dams," said Elizabeth Maclin, the organization's Rivers Unplugged Program director.
For more than a century, America led the world in building these massive structures to generate power and trap water, both for irrigation and flood control.
They became symbols of humanity's ability to harness nature and made the settlement of the arid West possible.
Demand for new dams persists, as shown by the continued push by the Sacramento region's Republican lawmakers for a multipurpose dam at Auburn.
But new dam proposals must overcome a growing recognition that dams can hurt as well as help. They can block annual fish migrations, submerge valuable habitat and stop the flow of sand.
During the 1990s, then-Interior Secretary Bruce Babbitt became an evangelist for restoring rivers by tearing down outdated and abandoned dams.
He swung sledgehammers at California dams set for demolition and helped direct the removal of a section of the Matilija to show the structure could be dismantled piece by piece.
With a few notable exceptions -- such as the controversial campaign to remove the dam that inundated Yosemite's beautiful Hetch Hetchy Valley -- Babbitt and others have focused on structures like the Matilija that have outlived their usefulness.
Nearly 30 percent of the 75,000 listed on the nation's dam inventory are more than 50 years old, a dam's typical design life span.
By 2020, American Rivers said, that figure will reach 85 percent. And the group estimates the nation has tens of thousands more dams below the 6-foot height threshold of the Army Corps of Engineers' inventory.
Some owners agree to dam removals because maintenance costs exceed benefits. But others have fought to keep their dams.
In 1997, the Federal Energy Regulatory Commission ordered the breaching of the Edwards Dam for environmental reasons -- the first ruling against a dam's owners. The decision opened the door to more challenges when dam license renewals are sought from FERC every 30 or 50 years.
Like most dams removed in recent years, the Edwards was relatively small at 24 feet tall.
Dam consultant Ron Corso of Virginia has criticized environmental groups for exaggerating the size of the dam-removal movement by including small structures that don't qualify for the nation's dam inventory.
"Let's not mislead people that there is some wholesale dam-removal movement in this country that will affect dams that still have some purpose," Corso said.
Maclin said American Rivers counts smaller dams because they can pose as big a barrier as larger structures to migrating fish and that their removal can ensure a species' survival.
Two scientists who have studied dam removals said the subject needs more research to determine costs and benefits that follow from removing a dam.
In one of three dam removals she studied, Emily Stanley said, sediments and nutrients migrated downstream and harmed plant and animal life.
"There are some things that happen in the short term that you would prefer not happen," the University of Wisconsin assistant professor said. "We don't know yet about the long-term effects."
Taking out a dam also could unleash toxic materials buried in the soil behind it, said David D. Hart, Patrick Center for Environmental Research vice president.
The Philadelphia-based scientist cited the release of tons of PCB-laden soil with the 1973 breaching of Fort Edward Dam on New York's Hudson River, turning part of the river into a Superfund cleanup site.
"We are still learning how to do this," Hart said. "The number of comprehensive studies on dam removals can be counted on one hand."
The possibility that mercury from California's gold-mining era could be lurking in sediments behind the Yuba River's Englebright Dam is one reason the state and others are considering ways to restore fish populations there without removing the dam.
Environmentalists pushing to take out the 280-foot structure have run into opposition from Englebright Lake's recreational users, local property owners and the dam's power plant owner.
Hart said decision-makers should weigh lost recreation and other benefits against environmental advantages. In most cases, he said, smaller structures are the best removal candidates.
But the cost -- even for small dams -- adds up, creating big bills for taxpayers and dam owners.
Between 1920 and 1956, the removal of 22 dams on the Klamath River cost about $3,000. More recently, taking out four small irrigation dams on Northern California's Butte Creek cost $9 million.
Since the dams' removal, however, the spring-run Chinook salmon have returned to the creek in record numbers.
"A phenomenal number of fish returned -- beyond what anyone involved there had expected," said Dan Castleberry, chief of CALFED Bay-Delta Program's ecosystem recovery program.
Many other dams, including five hydropower dams on Battle Creek, have been targeted for removal to restore Northern California's salmon and steelhead runs.
In some cases, fish runs can be restored by merely changing a dam's operation.
Steve Evans, conservation director for Friends of the River, said opening the Red Bluff Diversion Dam's floodgates year-round would achieve the same increase in fish runs as removing it.
"I see the so-called dam-removal movement maturing into a fish-passage program," he said. "Now we ask, 'How can we get these threatened and endangered fish where they should be?' "
On Matilija Creek, though, taking out the dam is considered the only way to achieve that goal, leaving only the question of how to remove it without causing further damage.
Long before the dam was built, the Corps of Engineers predicted soil washing down from the surrounding mountains would fill up Matilija Reservoir. Ventura County voters approved the dam's construction anyway.
Shortly after its completion in 1947, cracks began to appear in the dam's surface because builders used faulty materials. To avoid a collapse, the county twice lowered the dam's center, reducing it from its original height of 198 feet to 165 feet.
Now the corps is considering incrementally lowering the dam so the 6 million cubic yards of trapped sediment can slowly wash downstream.
Dale Bulick, the corps project manager, said such an approach would take at least 20 years.
The corps also is considering quicker fixes, such as using a slurry pipeline, a conveyor belt or trucks to remove the soil.
A $4.4 million study is under way to explore these options. Depending which is chosen, Bulick said, the project could cost $40 million to $180 million.
Paying for the dam's removal may be the biggest hurdle of all. But Bulick and others who want it taken out are optimistic.
"This is a win-win project," he said. "Everybody is behind it, and everybody wants to get it done."
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