California Coast & Ocean

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.