1. What are the benefits of the project?
The San Clemente Dam Removal and Carmel River Reroute Project represents one of the best opportunities for river restoration on California’s Central Coast. Permanently removing the dam eliminated the public safety risk posed by San Clemente Dam, which was declared seismically unsafe by the State of California and threatened 1500 homes and other buildings.
The removal of the dam will also aid in the recovery of South-Central California Coast steelhead, a threatened species, by providing unimpaired access to over 25 miles of spawning and rearing habitat. The National Marine Fisheries Service has determined restoration of the Carmel River steelhead population is critical to the recovery of the species, in part because it serves as an “anchor” providing occasional dispersal of fish to nearby smaller coastal populations which would not persist otherwise,.
Additional benefits of the project include: restoring the natural sediment regime, reducing channel incision and reducing beach erosion that now contributes to destabilization of homes, roads and infrastructure; improving habitat for threatened California Red-Legged Frogs; and expanding public recreation opportunities in the region by preserving over 900 acres of watershed lands, resulting in over 5400 acres of contiguous park land.
2. Did San Clemente Dam provide flood protection?
San Clemente Dam never provided any flood control, and its removal will not affect the volume or timing of flood flows on the river. The project team completed sediment transport and flood modeling studies to verify that removal of the dam will not exacerbate the existing downstream flooding problems.
3. Will the project affect water supply for Monterey Peninsula residents?
There will be no change to the water supply available to Peninsula residents as a result of removing the dam. The primary purpose of the San Clemente Dam has been to serve as a diversion point for Carmel River water. The San Clemente Dam reservoir is now over 95% full of sediment which has greatly impaired its ability to continue to function as a diversion point. Currently, all water supplies from the Carmel River are diverted from groundwater wells situated along the river that pump from the alluvial aquifer.
4. What will happen to the land after the dam is removed and the river restoration is complete?
925 acres of California American Water property will be transferred to the U.S. Department of Interior’s Bureau of Land Management (BLM). BLM is working with the Monterey Peninsula Regional Parks District (MPRPD) to develop a long-term management plan for the property that will include public access and recreational trails on the property. BLM and MPRPD will provide more information to the public about the future use of the site closer to the time of transfer (expected in 2017).
5. Why was the river rerouted into San Clemente Creek?
2.5 million cubic yards of sediment had built up behind the dam structure over 85 years. Allowing this sediment to flow downstream could have caused significant flooding and damage to downstream homes and businesses. Other options such as trucking the sediment out of the area or moving the sediment to another site were also determined to be infeasible because of cost, difficult access to the site, environmental impacts, and lengthy timelines for undertaking these activities. The rerouting of the Carmel River into San Clemente Creek moved the confluence of these two waterways upstream by one-half mile. This allows the sediment to stay in place without risk of the river transporting the sediment downstream. The sediment area is being restored into a vegetated landscape that is integrated into the natural contours of the watershed.
6. How is project being funded?
The estimated project cost is $84 million. California American Water (CAW) is contributing $49 million, which is equivalent to the lowest cost project for addressing the dam’s seismic safety issue (buttressing the dam). The California State Coastal Conservancy and National Marine Fisheries Service raised the additional $34 million for project implementation through public and private sources. See details here.