The Sea Level Rise Solution that is as Charismatic as Mud

By Sara S. Moore

This past fall, when soon-to-be President Trump used “drain the swamp”  as an anti-corruption rallying cry, some biologists and wetlands advocates pointed out that swamps are actually quite useful. Also called wetlands, swamps can be a critical part of natural infrastructure for the purposes of protecting the shoreline from storm surge and sea level rise, in addition to providing habitat and improving water quality.

Sediment, matter that settles to the bottom of a body of water, nourishes wetlands. Sediment, literally as charismatic as mud, is not given the same attention as a natural resource as fresh water or plant life. It is not photogenic. It is out of sight and out of mind. It is a waste product, an impediment to shipping traffic. But in areas where wetlands have been identified as strategically valuable in the defense against rising sea levels, sediment’s star is rising.

One of these areas is the San Francisco Bay, where sea level has been measured as rising steadily since its first tide gauge was installed in 1854. Numerous wetlands restoration projects are underway to help protect the bay shoreline, and sediment is in demand to nourish them. Right now, there is a shrinking supply of sediment in the SF Bay. According to Bodega Marine Laboratory oceanographer Doug George, the primary culprit is dams trapping sediment, but also the petering out of the large pulse of sediment that came with placer gold mining during the Gold Rush, and current sand mining practices. Meanwhile, the U.S. Army Corps of Engineers (ACE), responsible for dredging to maintain channel depths for ship navigation at U.S. harbors, is dumping dredged materials from the bottom of the bay—useful but uncharismatic mud—outside the Golden Gate Bridge. ACE is bound by federal statute to do the least-cost disposal method, and it costs more to reuse sediment for wetlands.

A Lawsuit over Mud

Some of the dredged material is being redistributed to nourish bayside wetlands, but not enough. A 1998 environmental impact statement (see the Long Term Management Strategy [LTMS] for the Placement of Dredged Material in the San Francisco Bay Region) indicates that 40% of that dredged material should be put to “beneficial reuse,” including wetlands nourishment. However, in 2016 ACE allocated less than 40% of its dredged materials to reuse. According to the Bay Conservation and Development Commission (BCDC) Executive Director, Larry Goldzband, and Sediment Program Manager, Brenda Goeden, other dredgers in the bay are keeping up with the 40% reuse policy, but ACE, the largest dredger, has been falling short.

BCDC, formed in 1965 in response to heavy shoreline development on the SF Bay, is the agency tasked with keeping the bay from shrinking in size. So, in theory, it would be all in on dredging. However, BCDC is concerned about the bay’s landward-shifting shoreline. It was one of the first government agencies in the U.S. to issue guidelines responding to sea level rise. Its staff report, Living with a Rising Bay (2011), informed SF Bay Plan revisions, including the assertion that “[a]n adequate supply of sediment is necessary to ensure resilience of the Bay ecosystem as sea level rise accelerates.”

The San Francisco Bay

The San Francisco Bay

ACE has worked closely with BCDC for years on the question of sediment management in the SF Bay.  ACE carries out its responsibility regarding navigation channels in compliance with the Coastal Zone Management Act which gives BCDC its accreditation. BCDC reviews ACE practices and determines whether they are consistent with that federal act. Now, BCDC, chafing under the shortfall in beneficially reused sediment, on Sept. 22, 2016, filed a lawsuit against ACE to force it to stop dumping good mud. While ACE falls back on the federal requirement of using a least cost disposal method as a rationale for its shortfall, the lawsuit focuses on the full language of the regulation, which dictates that the disposal method be “environmentally acceptable” (per L. Goldzband). The lawsuit was filed after months of discussions and attempts at mediation. In late March 2017 representatives of ACE and BCDC will attend an “Alternative Dispute Resolution,” a last-ditch attempt to avoid the courts.

A SF Bay Wetlands Restoration Project Roll Call

There are many pilot projects involving sediment in various stages of development in the SF Bay. Here are some of the most completed projects:

  • Bel Marin Keys/ Hamilton Airfield

This ACE/ California Coastal Conservancy project is celebrated as a successful transformation of a military site into a wetland. Click here to see a 1:38 video with images of the breaching of the levee, opening the land to the SF Bay waters in 2014. This project benefited from beneficially reused sediment.

  • Oro Loma Horizontal Levee Project

This, the first horizontal levee in the SF Bay, using vegetation on a slope to slow waves rather than a vertical wall, was set to be fully operational in 2016. It might be the first levee of its kind in the world. After more than four years in the permitting process it took six months to build (per Nate Kauffman in Save the Bay, 2016).

  • Cullinan Ranch

This project in the North Bay, now near completion in the Napa River Delta, came out of a movement to block fill and residential development on the former wetlands. Read about its return to recreational use in “Into the Breach: Paddlers and Ducks Return to Cullinan Ranch” (2016).

  • South Bay Salt Pond

This is “the largest tidal wetland restoration project on the West Coast.” It is fully underway, and will convert 15,100 acres of commercial salt ponds at the south end of SF Bay into mud flats and tidal marsh. It will rely mostly on natural sedimentation processes rather than reused dredged material.

What’s Next for the SF Bay?

There’s no time to lose

While BCDC and ACE are locked in a legal battle, the Pacific climate cycle called the Pacific Decadal Oscillation (PDO) has shifted as of the beginning of 2014 according to NOAA Fisheries: the switch brings a wind pattern that warms surface waters, causing seas near the West Coast to expand and rise according to NASA (2015). It may bring a rapid increase in sea level rise, and one NASA climate scientist, Josh Willis, says “we could be in for wild ride over the next 20 years or so.” 

Funding is on the horizon

In 2016 the SF Bay Area passed Measure AA, providing the first funding for the San Francisco Bay Restoration Authority. While a good first step to sustained sea level rise preparation, the funding falls far short of the need. There is some hope (according to L. Goldzband of BCDC) that Measure AA funds could be augmented by the 2016 Water Infrastructure Improvements for the Nation Act (WIIN Act), which includes the Water Resources Development Act (WRDA), providing funding for 10 pilot projects to maximize beneficial reuse of sediment. These projects would not be subject to the “least cost” regulation that currently poses a barrier to beneficial reuse. ACE should announce the locations of these projects by mid-March 2017.


In 2013 BCDC facilitated “speed dating” sessions between dredgers and restoration project managers to see where dredged material could be beneficially reused. This turned into the development of a simple online tool called Sedi-Match. It was scheduled for release in January 2017. Read more about its development.

Rethinking fill policy

BCDC is about to launch a series of public meetings to discuss whether the agency should change its bay fill policy to prepare for sea level rise. If you are local to the SF Bay, you can attend these meetings beginning on April 20, 2017, from 1-4 PM at 375 Beale St., San Francisco.

Resilient by Design

This competition—aimed at “design[ing] solutions that protect the bayshore and mak[ing] us more resilient”—received a $4.6 million grant from the Rockefeller Foundation on January 31, 2017, and should be ready to roll in April 2017. It is modeled after the “Rebuild by Design” Hurricane Sandy Design Competition.

More reading

See the full text of the Sept. 22, 2016, lawsuit filed by California Attorney General Kamala Harris on behalf of BCDC against Army Corps of Engineers.

Rising Reality, Part 4: The Shorelines (“Battle on Many Fronts”) – a November 2016 article by the SF Chronicle’s John King from a series on the SF Bay’s sea level rise problem.

About the Author: Sara S. Moore is a climate change adaptation researcher based in Oakland, California. She worked on the Sonoma County Adaptation Strategy (2015) as part of its Climate Action 2020 plan. She wrote a white paper on the Marin case study in scenario planning for the California Climate Vulnerability Assessment (Moore, Zavaleta, Shaw, 2012) and a guidance on implementing scenario planning for natural resource managers for the California Coastal Conservancy and Point Blue Conservation Science (Moore, Seavy, Gerhart, 2013). She holds a Master of Public Policy degree and an MA in International and Area Studies from UC Berkeley.