Matilija Dam Will Come Down
Just about everyone who knows about Matilija Dam on Matilija Creek in the Ventura River watershed agrees that it should be taken down. Now a project is moving forward that promises to make it happen. A highly unusual degree of consensus has been reached on how to dismantle the massive concrete structure 15.6 miles upstream from Surfer's Point. A feasibility study has been done; federal and state environmental documents have been completed without challenges; the final design process has begun. In October 2005, the Ocean Protection Council committed $2 million for pre-engineering and design.
“A lot of environmental issues seem abstract—wetlands, for instance,” said Paul Jenkin, coordinator of the Matilija Coalition, an alliance of community groups, businesses, and individuals committed to restoring the river system, starting with deconstruction of the dam. “But people get excited about a huge piece of concrete blocking the river, which could be removed.”
In 1947, when the Ventura County Watershed Protection District (then the Flood Control District) built the dam at a favorite fishing spot on Matilija Creek, just above the point where it joins with North Fork Matilija to become the Ventura River, the builders knew it would not be useful for long. Sue Hughes, legislative analyst for the County, says a recently found memorandum from the District, written in the late 1940s, makes that clear. “When they pencilled it out—the cost of building the dam, the cost of supplying water—they knew it would only be 34 to 36 years before it filled with sediment. However, they concluded that the dam was the most cost-effective way to provide water for agricultural and residential use.”
Now it's been years since the dam lost its flood control function, and its water storage capacity is barely worth mentioning. Designed to store 7,000 acre-feet, it holds less than 500. Current estimates show that its storage capacity will be zero by 2020. “Directly behind the dam we have a 140-foot-deep hole filled with two million cubic yards of mud,” said Jenkin. “Stretching almost a mile upstream of that, the dam has trapped another four million cubic yards of sand, gravel, and cobble, sediment once destined to flow down the river to the beach.”
What Matilija Dam continues to do to this day, however, is to kill life in the river, erode the riverbanks, and tear up the ocean shore. The dam has choked off passage to steelhead trying to reach their spawning grounds, and caused sediment-starved “hungry” water to carry away the wide beach that was once at Surfer's Point. “I grew up here. I have to tell you, the beaches here in the late '60s had hundreds of yards of sand,” said Hughes.
Without the cushion of sand to protect it, the shoreline was subjected to such severe wave attacks that concrete barriers have been built to keep a waterside trail and parking lot from washing away. The dam may also be a potential safety hazard, because its concrete face has cracked. Although it is inspected annually and has been declared safe for the next 50 years, some people worry that an earthquake or other extreme event could prove otherwise.
Today Matilija Dam stands as a monument to obsolete thinking, the kind that ignores the environmental effects of large projects. “It makes me think of fossil fuel use today,” Jenkin says. “We know there will be long-term consequences, but we go for the short-term benefits.”
The dam was designed to recharge groundwater in the Ojai Valley, but since 1956 Lake Casitas has served as the primary water supply for Ojai, as well as providing almost one-third of the City of Ventura's water. Almost half of Lake Casitas water originates from a diversion on the Ventura River located about two miles downstream from Matilija Dam.
When built, the dam was 200 feet (20 stories) high and 620 feet (about two football fields) wide, but as sediment accumulated behind it—including sand that would have nourished beaches from Surfer's Point to Point Mugu—and the concrete, under pressure, began to crack and lose strength, it was notched twice, reducing the height of the center section.
The movement to take the dam down began in the early '90s. Getting rid of it made sense to local residents who remembered the good fishing, to surfers who saw what had happened to one of the best surfing spots in the state, and to business people who saw economic benefits in a restored river that would attract recreation-minded visitors. In 1999, the County Board of Supervisors asked Watershed Protection District (WPD) staff to investigate options for removal. As the WPD launched a study, Hughes said, an important early decision was to secure maximum participation, and “this commitment actually accelerated the process.” The U.S. Army Corps of Engineers joined the WPD as a partner, opening the way for federal funding. Darrell Buxton, project manager for the Corps, said the project was “a tremendous opportunity for ecosystem restoration along the Ventura River system.”
Goals were established: improve native habitat, restore sediment transport to the shore, improve recreational opportunities on the river, and “keep stakeholders ‘whole,'” meaning that those now receiving water from the river would not get less, or poorer quality water, than they do under current conditions with the dam in place. Consensus was most difficult to achieve on this last point, as community members were most concerned about the water supply.
Several methods of taking down the dam were considered: remove it fully and either remove the sediment behind it mechanically or let it move downstream naturally; remove the dam incrementally and allow sediment to flow downriver gradually; do nothing; or—the alternative eventually chosen—take down the entire dam, stabilize sediments on the site, and use both mechanical and natural means to let it reach the ocean. Some of the fine sediments are to be slurried past the water intake of Lake Casitas to sites in the floodplain. From there, large storms will eventually carry them to the ocean.
Larger sediments (sand, gravel, cobble, boulders) will be stored above the dam site. A 100-foot channel will be excavated in the sediment behind the dam, mimicking pre-dam conditions. Larger storms will be expected to bring these stored sediments downriver. All measures necessary to protect the water-supply infrastructure and water quality will be taken throughout the project. In addition, two bridges will be modified, some levees will be upgraded, and one new levee will be installed to protect private property. Giant reed (Arundo donax) will be removed along the river, which will both improve habitat and increase river flow, because Arundo outcompetes native plants for water. The dam site will become a gateway for hikers into Matilija Canyon and the wilderness upstream.
The Los Angeles District of the Corps and the WPD are proud of the speed with which the project has advanced and of the recognition it has received: It was chosen from among Corps projects worldwide (in the U.S. and 93 other countries) for the Corps' National Planning Team of the Year Award for 2004, and also received the Merit Award for Project Delivery Team of the Year for 2005. “If current momentum is maintained,” said Hughes, “we will be under deconstruction in 2009, with three years to complete.”
Much more money will be needed to get the job done, of course, including $8 million more to complete preparations. As a Corps project, it requires federal funding. The WPD Board of Supervisors has requested $2 million in the year 2007 federal budget, but what funds, if any, might be forthcoming from Washington is not certain. As of late March, the President's budget included $400,000 toward the dam's removal and the river's restoration. Project advocates hope Congress will provide support as well.
“It's a constant battle to keep the money coming, to keep the work going,” said Jenkin. Nevertheless, the Corps and the WPD expect to be ready to begin deconstruction in 2009. To raise the $100 to $130 million needed for that work will be difficult, but not impossible. “I think we have extremely strong political support at the local level,” Jenkin said. Buxton said the high level of support assures that the project will go ahead.
Word of the prospective dam removal has spread and visitors have come from as far away as Korea and Japan, where new dams are being built, but removal of some obsolete ones is also being considered. Paul Jenkin accepted an invitation to travel to Japan, where he visited rivers that had been killed by dams, but also kayaked on a living river. “It's amazing to see the contrast with a dead river,” he said. “It's not easy to paint a picture of how dead most of our rivers have become, as many of the current generation have never experienced a living ecosystem.”
Sue Hughes, meanwhile, has been taking groups of people up into the canyon to see how beautiful it is, and to imagine what great hikes and bicycle rides will be possible when the river again flows free from the mountains to the sea.