Levee breach returns tides to inner Bair Island: Project converts former salt pond to natural wetlands

With the decadelong project to restore Bair Island now achieved, it becomes the largest undeveloped island in south San Francisco Bay.

The tides from San Francisco Bay were formally returned to Bair Island by breaching the levees Dec. 10 during ceremonies sponsored by the U.S. Fish and Wildlife Service, Peninsula Open Space Trust, Ducks Unlimited, the Friends of Redwood City and other partners including the Port of Redwood City and the city of Redwood City.

The Port of Redwood City played a key early role in jump-starting the restoration process. During the winter of 2008-09, the port’s dredge material from its maintenance dredging was used by the wildlife service to help restore the tidal marsh.

The U.S. Army Corps of Engineers awarded a $3.6 million contract to move sediment from the bottom of the port channel into barges. The barges were towed up Redwood Creek to a pumping station across from the former Pete’s Harbor, where the sediment was removed and piped to Bair Island. The process took six weeks.

“It was unique because it was the first time the sediments dredged from the channel were placed on Bair Island to help the restoration of the tidal marsh,” Michael J. Giari, Port of Redwood City executive director, wrote in a statement about the project.

Sediment was used on a 35-acre portion of Bair Island, where the Fish and Wildlife Service had created temporary containment levees. The sediment was about half water and half mud and, when the liquid separated, mud was left to raise the land level.

When the levees were breached this week for the area to be restored to marshland, the mud will have restored the area to a level between high tide and low tide — the level of a more natural tidal wetland, Giari wrote.

“Then you have an area subject to tidal action,” Giari wrote.

After the placement of the dredged material, Redwood City contributed $300,000 to the construction of a pedestrian access bridge to the top of the levee.

It provides access to the trail and various platforms that are part of the restoration project.

The project, located on the Don Edwards San Francisco Bay National Wildlife Refuge, also features interpretive displays. Native plants were also planted to provide habitat for endangered species.