San Clemente Dam was constructed in 1912 on the Carmel River to provide water supply for the Monterey Peninsula. It was 106 feet tall and had a reservoir storage capacity of approximately 1,425 acre-feet.
Once constructed, the reservoir quickly filled with sediment. Toward the end of its life, the reservoir was filled by more than 2.5 million cubic yards of sediment, leaving a storage capacity of only 70 acre-feet, or 5% of what it was built for. The dam no longer served a useful purpose.
In the early 1990s the dam was declared by officials to be unsafe, as it was at risk of failing in the event of either a large earthquake or flood. Something needed to be done to address the public safety issue.
Strengthening the dam was the least costly option. But that would not address the impact of the dam had on steelhead trying to access 25 miles of upstream habitat nor the impacts of the dam blocking sediment to flow downstream and to Carmel River beach. Partners came together to develop the concept of removing the San Clemente Dam into a feasible option.
In 2013, work finally began to remove the dam. It took monstrous machines, creative engineering, millions of dollars, and a tremendous group effort among partners. The dam was finally removed in 2015 and the Carmel River was restored.
The project involved:
(1) plugging sediment trapped behind the dam in place (as removing it was infeasible)
(2) re-routing the river to connect with the adjacent San Clemente Creek, and finally...
(3) removing the dam
Before and After. The red arrow indicates the same location in both pictures.
Restoration of the river occurred after deconstruction of the dam.
Goals of the restoration were to provide a gentle climb up the river for migrating steelhead fish, provide areas of slow-moving water for steelhead to rest, shady areas to escape from heat, and in-stream habitat to hide from predators.
The river restoration included installing boulders, woody structures, channels/pools, and vegetation. In 2017 a large flood reorganized these elements, resulting in more natural structural diversity as the river reclaimed itself.
Now the Carmel River is free-flowing and the transformation of the Carmel River will continue as the river “re-wilds” itself.
Steelhead numbers in the upper watershed appear to be slowly increasing as steelhead are now able to travel upstream to more of historic spawning grounds. In 2019 over 127 made it to Los Padres Dam, located five miles above the former dam site.