Pictured: The mouth of the Ventura River where it meets the Pacific Ocean. 

by David Goldstein, Ventura County Public Works Agency, IWMD

No matter where you live in Ventura County, recent progress on removal of the Matilija Dam may be inspiring to you because it reveals the relationships inside our local watersheds. 

A watershed is the area draining rain and runoff to a single water body. Ventura County watersheds include Calleguas Creek, which drains Thousand Oaks, Simi Valley, Moorpark, Camarillo and the Oxnard Plain, meeting the ocean at Mugu Lagoon; the Santa Clara River, starting in Los Angeles County, draining the Sespe Wilderness and running through Piru, Fillmore and Santa Paula and flowing to the Pacific between Ventura and Oxnard; and the Ventura River, from the Los Padres National Forest, flowing over the sediment-clogged Matilija Dam, down the valley and into the ocean near the Ventura County Fairgrounds.

Public agencies, nonprofit organizations, farmers, other businesses, and community members coordinate in each watershed to resolve issues such as competition for water, reduction of pollution, protection from flooding and environmental conservation. Balancing these issues requires cooperation, and most solutions require funding. 

Funding needs in the Ventura River watershed have included millions of dollars for removal of the Matilija Dam, which reduces the health of the Ventura River by restricting flow, limits the replenishment of beaches by holding back sediment, and excludes fish from access to 17 miles and 491 acres of potential headwaters habitat.

Tearing down the dam will be expensive because many steps must be taken carefully. Simple application of dynamite, or a green light for the military to use the dam for target practice, could reduce the dam to rubble in an hour, but communities downstream would probably not appreciate the resulting deluge of mud and rubble. 

Millions of tons of sediment have built up over the years, pressing against the dam, an aging structure subject to decay and risk of failure. In the future, if sediment can resume its historic path down to the ocean, it will contribute to more resilient beaches. However, in the short term, unless properly managed, sediment could roll down the river in great, grey, gooey globs, impacting infrastructure and changing the elevation of the Ventura River.

With dam removal, the Santa Ana bridge is one place where sediment would have accumulated, causing a backup of floodwaters during large storms. Recent progress averts this problem. Using a $13 million grant from the California Department of Fish and Wildlife, the Ventura County Public Works Agency will soon finish overseeing construction of a replacement bridge, with 50% longer, stronger spans capable of withstanding anticipated flow of sediment from upstream. (The project also includes improved pedestrian and bicycle ways).

Six additional downstream restoration and infrastructure improvements, as well as many smaller projects, will still be needed. The website of the Matilija Coalition (matilija-coalition.org), a nonprofit organization, and the project website (matilijadam.org), explain these additional projects. Among these, a recent $740,000 grant from the California Coastal Conservancy will fund redesign of the Camino Cielo bridge; a $61,000 FEMA grant will support dam removal engineering; and a $5 million California Wildlife Conservation Board grant will fund the final design for the dam removal and downstream flood protection.

The coalition calls for an “aggressive schedule” and makes optimistic assumptions, predicting the dam could be ready for a flush of sediment by 2028, and dam removal could take place two years later. 

While hundreds of people work professionally on expensive watershed infrastructure issues, you can affect the quality of your own watershed with simple, low-cost actions in your daily life. Pick up after your pet; avoid run-off of fertilizer and pesticide from your lawn; don’t wash your car on your driveway; and install landscaping capable of slowing, spreading and sinking water. Watershed pollution is regulated by many entities, but one of the most significant in Ventura County is the Los Angeles Regional Water Quality Control Board, which records measurements, sets strict standards, and requires remediation for contamination in all Ventura County watersheds. Taking action in your personal life to ensure watersheds shed only water, and not pollution, will not only improve the water quality of our rivers and beaches, you could also help avoid expensive stormwater clean-up mandates.  

David Goldstein, an Environmental Resource Analyst with Ventura County Public Works, may be reached at 805-658-4312 or david.goldstein@ventura.org.