Virtual Tour

The Outdoor Solar Plant

Evaporation Ponds

Roughly 9,200 acres in the South San Francisco Bay are devoted to salt evaporation ponds – and all of them protected by the Don Edwards San Francisco Bay National Wildlife Refuge. Through natural evaporation, water is drawn out of these ponds, creating increasingly saline brines. Some minerals in the water crystallize at different rates and under different conditions. The art of modern salt-making involves keeping these minerals in solution (or liquid phase) while sodium chloride precipitates into its pure white crystals. The remaining minerals stay in solution longer and are harvested after the salt has crystallized.

Flying over the bay or driving over some of the area's bridges, you will notice that evaporation ponds have distinctive colors: beautiful green and red hues. Learn more about the unique salt pond colors.

These evaporator ponds and the marshes that surround them are important habitat for more than 70 species of birds, including several endangered species. Because the ponds are shallow - an average of 1.5 feet deep - it's easy for shorebirds and waterfowl to find a meal in the low- and mid-salinity ponds.

We circulate our brines through our salt pond system so they get closer to our crystallizer beds as the brine becomes more concentrated. We even pump some concentrated brine through a pipeline that parallels the Dumbarton Bridge, allowing us to manage the harvest between our plants in Newark and Redwood City.

Let's visit the crystallizer beds.

Virtual Tour

© 2005, Cargill, Incorporated. All Rights Reserved.