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State allots $20M for massive Novato marsh restoration project

A tractor stands in what had been tidal marshland near Bel Marin Keys in Novato, Calif., on Thursday, Sept. 29, 2022. State funding of $20 million will go to restoring the agricultural land to wetlands.

Posted on October 3, 2022

One of the largest wetland restoration projects around San Francisco Bay is closer to launching its final phase of construction after receiving a $20 million infusion of state funding.

The funding, approved by the California State Coastal Conservancy in a unanimous vote last week, will be used to restore 1,600 acres of former tidal marshland near Bel Marin Keys that had been converted to agricultural fields.

“This will be one of the biggest restoration projects in the bay,” said Jessica Davenport, the agency’s Bay Area program manager. “It’s vital for restoring the habitats that were lost over the past 100 years, especially with sea level rise. It’s so important to restore these wetlands now so that they can keep up with sea level rise.”

Led by the conservancy and the U.S. Army Corps of Engineers, the estimated $165 million Bel Marin Keys Wetland Restoration Project began work in late 2019. It is the largest piece of the 2,600-acre Hamilton Wetlands Restoration Project. About 650 acres of marshland near the former Hamilton Army air field were restored in 2014.

An egret forages in restored wetlands at the former Hamilton Air Force Base in Novato on Thursday, Sept. 29, 2022.

The project will also add 3.5 miles to the San Francisco Bay Trail.

Nearly 90% of the historic wetlands around San Francisco Bay, or about 200,000 acres, were lost during the 19th and 20th centuries when they were diked and drained to make way for development and agriculture, according to a report by the San Francisco Estuary Institute. An effort to restore about 100,000 acres of wetlands throughout the bay has been underway for several years and is about halfway complete.

At Bel Marin Keys, the former marshland was converted to agricultural fields. As a result, the landscape has subsided by as much as 10 feet below sea level in some areas, creating a basin surrounded by levees where water has to be pumped out after heavy storms.

To restore the wetlands near Bel Marin Keys, state and federal agencies plan to breach the 60-foot-wide levee keeping San Pablo Bay from flooding the vast fields of peat soil. But significant work is required to take place before then in order to create the precise conditions needed for tidal marshland.

After two years of construction, an army of tractors and excavators replaced the levee with a new levee 2 miles and up to 400 feet wide farther inland. The fields on the eastern side of the new levee are what would become the new tidal marshland once the old levee is breached. That project cost $23 million and was paid for by the conservancy.

The project is moving on to a much more complicated, longer and far more expensive phase. Before the old levee can be breached, the U.S. Army Corps of Engineers plans to bring tons of dredged bay sediment to sculpt the land back into formations conducive to wetland habitat. This includes a gently sloped landscape that allows for tides to wash bay water into the habitat, but not to the extent that it would drown out any vegetation or wildlife that are established there.

Homes in Bel Marin Keys stand near agricultural lands in Novato on Thursday, Sept. 29, 2022. A project to restore the area to seasonal wetlands has received $20 million in state funds.

As much as 24 million cubic yards of dredge materials — equivalent to 1.5 million large dump truck loads — might be required, though the conservancy is studying whether less could be used.

“That will be a big factor in how fast it can go,” Davenport said.

Tommy Williams, the U.S. Army Corps of Engineers San Francisco District program manager, said the specific source of dredge materials has not been identified, but will likely come from dredge materials in the bay. About 1.6 million cubic yards of sediment are dredged from the bay by the federal agency each year, depending on the projects.

“Also, there are rigorous testing requirements for all of our dredging projects in order to determine the best or most ‘suitable’ placement for all the material,” Williams wrote in an email.

The testing is performed by the federal agency’s Dredged Material Management Office, which is a state-federal program that includes the U.S. Environmental Protection Agency, the San Francisco Bay Regional Water Quality Control Board, the San Francisco Bay Conservation and Development Commission and the California State Lands Commission.

Other wetland restoration projects throughout the bay will also be competing for these dredged sediments as well as the proposed Caltrans project to temporarily widen a 10-mile section of Highway 37.

Heavy machinery is used during the Hamilton Wetlands Restoration Project in Novato in 2019.

How long the project is expected to take is unknown, though Davenport said it will likely take five years or more depending on the availability of dredge materials.

“It does take a while. But we’ll go as fast as we can,” she said.

The California State Coastal Conservancy is expected to cover about 25% of the project cost. The rest will be covered by the federal government.

Davenport said the $165 million estimated cost is likely low because it was last calculated in 2013. The cost is set to be recalculated once the conservancy enters into a new agreement with the Army Corps of Engineers.

Congress approved a $1 million allocation for the Army Corps to begin planning the project. Another $40 million is being proposed as part of a Senate appropriations bill, but has not been approved, Davenport said.

“Once a substantial amount has been committed, there is a bit of momentum to keep it going in future years when the full amount has already been authorized,” she said.

The $20 million allocation approved by the coastal conservancy on Sept. 22 is expected to be the final state funding required to complete the project, Davenport said. The agency spent $23 million on the new levee, which the conservancy is looking to credit to its 25% cost share for the project.

“It’s a lot of money but it’s a lot of restoration that’s going to happen,” conservancy board member Donne Brownsey said before the Sept. 22 vote. “And the Bay Trail is going to get expanded, so I agree it is leveraging money effectively.”


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