There’s a big new development going up in Mountain View along the edge of San Francisco Bay. But it’s not a tech company headquarters or a condo project. It’s for birds, and fish and hikers.
Workers are putting the finishing touches on a three-year effort to restore 435 acres of former industrial salt evaporation ponds to natural wetlands and tidal marshes, along with building new public bayfront hiking trails.
The $20 million project, which is scheduled to be completed by the end of December, is the latest chapter in an ongoing saga in which the state, federal government and environmental groups are slowly converting 15,100 acres of former salt ponds that ring the South Bay, Peninsula and East Bay back to habitat for ducks, shorebirds, fish, even leopard sharks, bat rays and harbor seals. It’s expected to open early next year.
In 2003, Cargill Salt, a Minneapolis-based agribusiness company, sold the lands to the state and federal government for $100 million as part of the largest wetland restoration project on the West Coast. Since then, the goal has been to turn back the clock to the bay’s natural conditions, lost when roughly 85% of its wetlands were filled or developed between 1850 and the 1970s, when modern environmental laws stopped the trend.
“Marshes clean the water,” said Dave Halsing, executive project manager of the South Bay Salt Pond Restoration Project, which is overseeing the Mountain View work. “They absorb wave energy to reduce flooding and sea level rise. They provide richer, more productive wildlife habitat. It’s what belongs here. We are putting things back to the way they were as much as we can.”
The Mountain View segment, near Shoreline Amphitheater and about 1 mile north of Google’s headquarters, is called Pond A2W.
For nearly a century it was essentially a giant bathtub — an area of open water as large as 329 football fields — diked off from the bay where bay water was slowly drawn in and evaporated by Cargill crews to make salt for road deicing, industrial uses and human consumption.
Although Cargill sold much of its property in 2003, the company continues to make salt in the East Bay on about 12,000 acres at a plant it owns at Newark. People flying in planes over the bay can see the huge piles of white salt, and the colorful mosaic of orange, red, brown and green salt ponds, which draw their colors from different types of algae, bacteria and brine shrimp that live in the varying salinity.
Of the 15,100 acres of South Bay salt ponds that Cargill sold, so far about one-third have been converted to tidal marsh by the California Coastal Conservancy, the state Department of Fish and Wildlife, the U.S. Fish and Wildlife Service, Ducks Unlimited and other organizations and agencies.
“Progress has been excellent,” said David Lewis, executive director of Save the Bay, an environmental group in Oakland. “After years of reducing and paving over tidal marsh in the bay, we’ve brought back a huge amount in the past quarter century. It’s making the bay healthier and protecting the shoreline better. And there are still big opportunities to do more.”
The Mountain View project required bringing in 180,000 cubic yards of dirt, enough to fill 18,000 dump trucks, over three years. Most of it came from construction sites in Sunnyvale, Stanford University and other areas.
Crews working for the contractor, Gordon N. Ball Inc., based in Walnut Creek, have strengthened levees around the huge pond, which is between 2 and 5 feet deep.
They also are using floating conveyer belts to build five islands for birds.
“Islands are good for nesting, but also just as a place to rest,” Halsing said. “Birds need a safe place from predators where they can rest.”
Workers also are constructing two new 100-foot-long bridges on the pond’s eastern edge, as part of a new 1.2-mile public trail that will be open for hiking and biking early next year.
Funding came from a variety of state and federal sources, along with Measure AA, a $12 per year parcel tax for wetland restoration and flood control projects that was approved in 2016 by 70% of voters in the nine Bay Area counties.
Starting as soon as this week and continuing through December, crews plan to breach the pond’s levees in four locations, each about 100 feet wide. That will open the pond to the tidal actions of San Francisco Bay for the first time in roughly a century. The tides bring in huge amounts of sediment along with fish, and seeds of plants.
Within a few years, the bath-tub-like pond will become shallower, planners say, and marsh plants will begin to grow. Two years ago, the Coastal Conservancy finished a similar project about 6 miles north of the Mountain View location on former salt ponds at Ravenswood, near the Dumbarton Bridge and East Palo Alto.
“It was dry salt pan,” Halsing said. “Now two years later vegetation is everywhere and it is flush with wildlife.”
The wetland restoration projects have made some cities nervous about potential flooding risk. Planners have spent years obtaining permits and permissions.
In the Mountain View project, the city of Mountain View helped pay to install large rocks called rip-rap along the southern edge of the pond, where it connects with Shoreline park. The park was the site of a former landfill that operated from 1968 to 1981. The city converted it to a 750-acre park that opened in 1983 with a golf course, lake, hiking trails, and Shoreline Amphitheater, which hosted its first concert in 1986.
To help wildlife, crews are converting the southern levee to a sloped habitat called an “ecotone,” that Save the Bay will plant with native plants, providing flood protection for the city and a refuge for birds and wildlife as sea level slowly continues to rise.
“It’s doing what we can to replicate what we destroyed over the last century,” Lewis said. “It’s not returning the area to exactly what it was. But these projects are making the bay healthier for wildlife, and are also protecting communities from rising tides.”
