Salt Ponds: West of the Dumbarton Bridge

The San Mateo County Baylands Preserve, at the west end of the Dumbarton Bridge, appears to consist of a parking lot, a narrow berm of marsh, high voltage wires, various salt evaporators, pipeline, and a sign that says "San Francisco Bay Trail"—but no appreciable trail. The environment doesn't appear to be very appealing to wildlife: on a visit in 2002, I saw one swallow, one ibis, a small flock of small birds I didn't recognize, and an army of dead flies stuck on the salt as if on flypaper.

A rock-hard crust of crystalline white against the deep rusty red of the algae-riddled water, the salt covers everything like a mortal sickness. It is hard to imagine how this can be a going concern in an area of sky-rocketing real estate prices and gleaming urbanity. This tolerance for decay, this apparent indifference to economic opportunity suggests a lack of options so profound, you'd next expect to see underfed and barefoot children trudging to school in raggedy overalls.

Cargill
The salt works are operated by Cargill, a huge conglomerate of agriculture, food-processsing, financial services, and other businesses. The company takes a million tons of salt out of the bay each year. It doesn't look like much, then, but it's a pretty major business.

Cargill also owns the pipeline over the old railroad bridge that runs parallel to the Dumbarton using it to circulate "brine" and control the salinity in the evaporators. At harvest time, extremely salt water is pumped to special reservoirs at the Newark and Redwood City plants, where the last of the water is evaporated and the salt is processed.

Cargill claims that the salt ponds are a boon to local fauna, supporting a variety of birds as well as providing a home to brine shrimp. Hmm. It's possible, but it's obviously not here. The birds are so much more plentiful virtually everywhere else, and the brine shrimp are very carefully hidden if they are here. The final-stage ponds are "so salty that outflows are poisonous to wildlife and plants," the San Francisco Chronicle notes. Since there hasn't been any commercial use for "bittern" (the extremely saline water that is a by-product of solar salt production), Cargill has simply been storing it for the last 30 years.

Restoration
In 2002, Cargill sold off about two-thirds of their baylands acreage. The state of California has taken 16,500 acres in the South Bay for $100M, with the intention of restoring the original wetlands. Sounds like a sweet deal.

The restoration (desalinization and removal of the levies) is estimated to cost in the hundreds of millions, and even after the work is completed, the land will take a long time to revert to the marshy tidal flats that occur naturally in the absence of levies. The Cooley Landing restoration apparently took nearly 10 years. All the same, it's heartening to think of a time when we can drive up to the Dumbarton bridge in summer through fields of waving green.

Marijke Rijsberman

More Information
Area Map: Preserves (PDF)
Area Map: Trails (PDF)
South Bay Restoration Project