San Clemente Dam The San Clemente Dam on California's Carmel River. Photo © NOAA/Creative Commons

Dam, That’s a Good Idea

Removal of a 100-plus-foot dam lets river and fish do their thing.

Making History: California’s Biggest Dam Removal

Read the San Jose Mercury News, San Francisco Chronicle and National Geographic stories.

Once a hotbed for steelhead trout, the Carmel River has rapidly eroded since the San Clemente Dam was built on it in 1921. Steelhead populations in the river are down a staggering 90 percent from what they were 50 years ago.

Over the decades, the seismically unsafe and obsolete dam had become more of a risk than a benefit for people and nature. But removing a 100-plus-foot, 92-year-old dam is easier said than done

The Nature Conservancy chipped in $1 million to support and advise the groups (State Coastal Conservancy, NOAA’s National Marine Fisheries Services, and California American Water) implementing the massive $83 million San Clemente Dam Removal and Carmel River Reroute Project.

One of the major challenges of the project was what to do with the sediment that had built up behind the dam, a result of the disruption of the natural flow of sediment on the river. An innovative idea to reroute the river around the sediment proved to be the solution.

The Results:

• 1,500 homes no longer in danger of a potential dam collapse.

• 25 miles of essential spawning and rearing habitat for our threatened south-central California coast steelhead.

• 900+ acres of protected coastal watershed lands connecting 5,400 acres of regional parks.

The dam removal is a huge first step in revitalizing California’s rivers, the lifeblood of our state’s diverse ecosystems and economy. Taking down the San Clemente Dam is setting the precedent for other dam removal and river restoration projects in California and nationwide. 

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