News Release: Dredged Sediment from San Francisco Bay to be used for Wetland Restoration
OAKLAND, CA – This summer, in an innovative contract, sediment dredged from within the San Francisco Bay will be placed at Bay restoration sites to support healthy wetlands, rather than offloaded into the ocean or Bay.
The U.S. Army Corps of Engineers (USACE or The Corps) maintains federal navigation channels in the Bay for shipping, which require periodic dredging of accumulated sediment. Typically, this sediment is disposed of at In-Bay disposal sites or miles offshore at Deep Ocean Disposal Sites. In early 2019, the Corps and the Coastal Conservancy signed a Memorandum of Agreement (MOA) allowing the sediment to be placed at beneficial use sites around the Bay. This month, the first contract to conduct this work was awarded.
Sediment is a valuable resource to wetlands. Historically, sediment would have been washed down watersheds to the Bay, accreting at wetlands and replenishing sediment lost to tidal action. After centuries of development, however, the Bay’s wetlands have largely lost their connection to sediment sources, leaving them increasingly vulnerable to inundation as sea levels rise.
“Sediment supply is one of the biggest hurdles for wetland restoration work. Several restoration sites around the Bay are ready to receive sediment, and are in desperate need of it.” said Amy Hutzel, Deputy Executive Officer at the California State Coastal Conservancy. “The Corps is a great partner on many restoration projects, and has access to millions of cubic yards of dredged sediment every year so this was a natural fit. We knew that if we could overcome the logistical challenges, we could use Bay sediment for Bay restoration.”
In May 2019, under the terms of the MOA, the Conservancy disbursed funding to USACE San Francisco District to pay for the incremental cost of placing the sediment at restoration sites. Sediment dredged by the Corps must be placed at permitted placement sites, such as the Deep Ocean Disposal Site, or In-Bay disposal sites, or at beneficial use sites. The Corps, when implementing its navigation mission is required to place the sediment at the most cost- effective, environmentally sound site, consistent with best engineering practices, and that meets federal environmental requirements. In general, beneficial placement is usually not the most cost effective option. The Corps can use a beneficial placement site if the cost are paid by a non-federal sponsor. In this case, the Conservancy acted as non-federal partner to make the beneficial placement possible.
“Initially USACE San Francisco District was only able to deliver the dredged material for in-bay disposal. It became a win-win situation when the Coastal Conservancy joined forces with the Corps as a non-federal partner in contributing funds to the project for beneficial use upland.” said Jay Kinberger, Chief of the Navigation Program at the Corps San Francisco District. “We are looking forward to a successful contract this year and hope to continue the partnership for future projects.”
Under this arrangement, 70,000 cubic yards of sediment dredged from Redwood City Harbor will be placed at a beneficial use upland site this summer, helping the upland sites create thriving wetlands that are resilient to sea level rise.
“Bay sediment will be used for the benefit of the Bay, rather than offloaded where it will wash out to sea.” Hutzel continued. “Getting to this point has taken several years and would not have been possible without the steadfast commitment from the USACE San Francisco District who have been dedicated partners throughout the entire effort. Now that it’s happening, we’re looking at how effectively this contracting model works and how we can expand the program to place more Bay sediment where it is needed most.”
Notes to Editors:
The contract for the dredging of Redwood City Harbor was awarded to R. E. Staite Engineering, Inc. of San Diego on June 17, 2019. The contract value is $7,052,735.00. Of that, approximately $1,700,000 will come from Conservancy funding to cover the incremental cost for disposal at a beneficial use site.
Approximately 486,000 cubic yards of sediment will be dredged from Redwood City Harbor this summer. Of that, 70,000 cubic yards will be placed at beneficial use sites.
Currently, there are two restoration sites in San Francisco Bay accepting dredged sediment for beneficial use: Cullinan Ranch and Montezuma, both in Solano County. In addition, Bel Marin Keys in Marin County has gone through environmental review and permitting and is in the site preparation phase; Bel Marin Keys will be available to accept dredged sediment starting in 2-3 years. Eden Landing in Alameda County is currently in the environmental review stage and may be available to receive dredged sediment starting in 2-3 years. These four sites have the capacity to receive over 20 million cubic yards of dredged sediment. The Corps dredges approximately 1.5 million to 2 million cubic yards of sediment each year as part of its Operations and Management dredge program in San Francisco Bay, maintaining federal navigation channels for shipping. Redwood City Harbor is currently dredged by the Corps every two years, and has a planning volume of 300,000 to 600,000 cubic yards per dredge episode, to maintain its authorized 30-foot depth.
Wetlands provide a number of ecological and economic benefits to the Bay. They filter pollutants from the water and sequester carbon, as well as providing habitat to hundreds of fish and wildlife species and recreational opportunities to communities. Approximately 85% of the Bay’s tidal wetlands have been lost since the Gold Rush.