In The News
Marshland restored in North Bay as tides flow in
By Mike Taugher
Contra Costa Times, 8/26/10
AMERICAN CANYON -- Behind the amphibious excavators stretched a vast expanse of salt flat that had not been flooded by the tides in a century.
In just a matter of minutes, the levee was breached and the tides pushing up from San Pablo Bay and into the Napa River began, gradually, to flood more than 1,000 acres that for decades had been used to crystallize salt.
It is a scene that is increasingly frequent around the Bay, where machines occasionally break open levees to restore historic marshes walled off and dried out for farms or salt production ponds.
Before Wednesday, the site of the old Napa salt crystallizer essentially was a biological desert with just a couple of recently built islands being used by California least terns and western snowy plovers.
However, biologists say that will change -- and fast.
Fish, birds and other wildlife will move in soon. Salmon, splittail, striped bass and all sorts of shore birds and waterfowl will populate the new tidal marsh. Harbor seals, too.
"This area is going to be used for hunting and fishing, bird-watching, photography "... boating, especially kayaking," said Chuck Armor, regional manager for the California Department of Fish and Game.
At one time, about 200,000 acres of tidal marsh surrounded the Bay; by 1999, scientists estimated only about one-fifth, or 40,000 acres, were left. In a report that year, scientists and others called for restoration of enough tidal marsh to bring the total to 100,000 acres, or half of the historic marsh area.
That effort received a major boost in 2003, when Cargill sold 16,500 acres of salt production sites around the Bay for $100 million. Most of that property was in the South Bay, but 1,400 acres were connected to a plant near Napa that mostly sold salt to a chemical manufacturer.
In the past few years, biologists have opened a couple of smaller parts of the Napa site to tidal flooding. But the project stalled when the economy turned sour and bond money that had been used for the project was frozen.
Last year, however, $8.4 million in stimulus funds from the American Recovery and Reinvestment Act provided a new boost to bring about an ecological recovery after decades of other uses.
The Napa site was leveed off for farming sometime before 1915, and from 1952 to 1993 it was used to produce salt. Like other salt-producing plants around the Bay, water was moved from pond to pond in order to increase the concentration of salt in the water.
By the time the water reached the crystallizer site, it was so concentrated the salt makers let the ponds dry out and the salt could then be hauled off.
Cargill removed most of the salt, but a white crust of salt was left.
Envision a square 1.5 miles on each side -- that's how big the salt flat is that was opened up to tidal flooding Wednesday.
To prevent a toxic slug of brine from discharging into the Bay, the levee breach was designed in two phases.
On Wednesday, a small breach was made to allow tides to flood the entire site. As water flows out from new marsh on the outgoing tide, a "sill" of salty water is expected to sit on the bottom as the lighter, less salty water flows out to the Bay.
The project's designers expect that within a couple of weeks, the salty "sill" will be diluted enough that more breaches can be dug.
Because the crusty salt that will be left behind is not expected to dissolve as quickly as the salt on the surface now, they expect the saltwater will remain under control.
David Lewis, executive director of Save the Bay in Oakland, said that restoration of the Napa crystallizer site shows these heavily salt-crusted sites can be restored.
Of Cargill's other two former crystallizer sites, one remains in production in Newark.
But the other, in Redwood City, is the site of a proposed housing development that would include as many as 12,000 homes.
"What the North Bay Napa site demonstrates in a stark way is that crystallizers absolutely can be restored to tidal marsh," Lewis said. "Not only can you turn it into marsh, but it's completely inappropriate for housing. "... The Bay needs more tidal marsh."
Not so, says Pete Hillan, a spokesman for the project, Redwood City Saltworks.
"If you were to (break) up the levees like they are going to do in Napa you would have an ecological disaster," he said. "It can be restored, but at what cost?"
In order to restore the Redwood City site, Hillan said, taxpayers would have to pay for the environmental work and the Peninsula would not get the housing or jobs that would come with development of the project.