Trading Salt Ponds for Salt Marshes

A high salinity pond at low tide. The pond is so salty that it actually has a layer of gypsum on it’s surface.(Photo: Andrea Kissack)

Fertile wetlands once lined the southern shore of the San Francisco Bay. But these wetlands have since been replaced by ponds used to harvest salt. Now, a collaborative effort to bring back tens of thousands of acres of those original marshes is underway. Andrea Kissack reports.

GELLERMAN: One of the biggest and most ambitious environmental restoration projects in the country is now underway in San Francisco Bay. It will take decades and upwards of a billion dollars to turn thousands of acres of industrial salt ponds back into wetlands. As Andrea Kissack reports from San Francisco, the work is helping nature make a comeback.

KISSACK: If you've ever flown into San Francisco International Airport then you've seen the salt ponds. A checkerboard of orange, red and yellow hues formed by algae from high salinity levels. Go a little closer still and some of the salt ponds look like the surface of the moon: sinuous water channels flow through a layer of chalky white crust. Back in the 1800's this former tidal marsh was diked off by levees to create ponds for salt making. In fact in some parts of the Bay, they're still making salt, for food, medicine and road de-icing.

MOPELLI: This is our reclaim area here. This is where the salt after it's harvested it's been washed and it has been stacked.

KISSACK: This East Bay salt plant is owned and operated by Cargill, the Minnesota-based multinational food firm. Pat Mopelli stands dwarfed by an 80-foot high stack of salt that looks like the white top of a circus tent.

KISSACK: We crunch our way over a salt covered road until we reach the edge of the bay. In front of us is a surreal site, what looks like a frozen alpine lake just beginning to melt. These are Cargill's crystallizer beds --the heart of the company's evaporative salt making operation.

MOPELLI: You actually start to see almost what looks like ice or glassy look on the surface. As those crystals continue to grow, and they do grow, they become heavy and drop to the bottom of the crystallizer bed. And so what we are looking at is this nice even flat surface for us to be able to harvest on.

KISSACK: The water in these engineered shallow beds is going through the final stages of evaporation. The process ends here, but it actually begins out in the ponds that ring the bay.

MOPELLI: If you follow a salt molecule from the time it is pumped in from the bay through the concentration process, until it actually is precipitated out on the crystallizer, it takes on the average about four to five years.

KISSACK: Cargill sold the majority of its ponds, in 2003, to the state and federal government for 100-million dollars. Now a coalition of groups is overseeing an effort to turn 16,000 acres of former salt ponds - an area the size of Manhattan - back to natural wetlands. It's a gargantuan effort to roll back the clock 150 years.
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