San Francisco Bay Salt Ponds

Our solar saltworks uses natural power from the sun and wind to crystallize 500,000 tons of sea salt each year.

Donating more than US$150 million in land value, Cargill has conveyed more than 40,000 acres of salt ponds to public wildlife agencies, a legacy that helped launch San Francisco Bay's environmental renaissance and Cargill's continued commitment to the Newark, Freemont and Redwood City communities.

Cargill's salt works in the San Francisco Bay Area is one of only two sea salt works in the entire United States. It is an ideal area for salt making, thanks to clay soils and a Mediterranean climate - just enough rain in the fall, winter and spring, followed by dry summers with steady breezes and plenty of summer sunshine.
 

Through land transfers and donations exceeding US$150 million, Cargill has conveyed more than 40,000 acres of salt ponds to public wildlife agencies. This legacy helped launch San Francisco Bay's environmental renaissance.  

Cargill’s operation in the San Francisco Bay Area is one of only two sea salt works in the entire United States. Since the Gold Rush, it has been recognized as ideal for salt making, thanks to the topography, the clay soils and a Mediterranean climate - just enough rain in the fall, winter and spring, followed by dry summers with steady breezes and plenty of summer sunshine.

Evaporation ponds

Roughly 8,000 acres along the South San Francisco Bay are devoted to salt evaporation ponds.  Micro-organisms lend the ponds their bright colors ranging from blue-green to deep magenta, depending on the salinity and season.  All of this land is owned by the Don Edwards San Francisco Bay National Wildlife Refuge. Evaporation ponds provide habitat for more than 70 species of birds. 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.

The intake pond begins the series of evaporation ponds (sometimes called evaporators, concentrators or concentration ponds). This is where we pump bay water into our pond system.  Once inside our system, the fresh water evaporates.  For the next three years, the brines slowly concentrate as we move them several miles through the pond system.  

Crystallizers

When the brines reach full saturation, they are pumped into crystallizer beds at our harvest sites.  Crystallizers are precipitation beds, usually rectangular in shape and surrounded by wooden bulwarks.  They are engineered beds that have been rolled, graded, sloped and compacted for the smooth precipitation and mechanical harvesting of salt. Here we harvest about 500,000 tons of salt each fall.

Cargill's legacy: The environmental renaissance of San Francisco Bay

Cargill’s land value donations of US $150 million have enabled public wildlife agencies to acquire more than 40,000 acres of San Francisco Bay salt pond properties and launch an environmental renaissance.

slideshow SF Bay Salt Ponds 4 The pumpkin color of this salt pond comes from the salt-saturated brines and contrasts with the chartreuse of a nearby marsh and the blue unsaturated brines in a nearby concentrator pond. San Francisco Bay Salt Newark, California. United States

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, colored by the microorganisms that thrive at varying salinity levels. As the sun and wind evaporate water from the brines, they get saltier. The saltiest brines are moved to crystallizers within our industrial plant sites.

Landmark activities and outcomes from this effort

  • Don Edwards San Francisco Bay National Wildlife Refuge. A century of sustainable land use led to creation of the Don Edwards San Francisco Bay National Wildlife Refuge on 15,000 acres of salt ponds in 1979. This private-public partnership has expanded over the years and continues to protect wildlife habitat for four endangered species and more than one million shorebirds and waterfowl.
  • Napa-Sonoma Marshes Wildlife Area. In 1994, Cargill’s donation and sale of 10,000 acres of salt ponds in Napa created the Napa-Sonoma Marshes Wildlife Area, operated by the
  • California Department of Fish and Wildlife. In 2003, 1,400 acres were added to this state wildlife preserve, and opened to tidal action in 2010.
  • South Bay Salt Pond Restoration Project.  State and federal wildlife agencies acquired 15,100 acres of South Bay salt pond properties in 2003, aided by donations from four private foundations and Cargill’s donation of $100 million in land value. This acquisition launched the South Bay Salt Pond Restoration Project, the largest wetland restoration project on the West Coast.
  • Bay Trail connection. Over the years, has provided more than 78 miles of trail ringing the San Francisco Bay.
  • Local governments and non-profits have acquired about 3,000 acres through Cargill land grants and sales to improve open space, public access, and environmental education throughout the San Francisco Bay Area.

Community Commitment

Cargill is a well-known benefactor of scores of non-profit, educational and civic organizations in Newark, Fremont, and Redwood City where the company provides 200 union and management jobs and meets the needs of salt customers throughout the Western United States.

A committee of Cargill employees chooses which civic organizations to support financially and assist through volunteer activities.

Whether picking up trash at the wildlife refuge, collecting and sorting food for the needy, or coaching and tutoring kids, Cargill employees demonstrate their commitment to the community in which they live and do business.

Not only do Cargill employees volunteer their time, but they give generously out of their paychecks through the annual United Way campaign.

More Information

Newark Community ActivitiesCargill is a well-known benefactor of scores of non-profit, educational and civic organizations in Newark, Fremont, and Redwood City where the company provides 200 union and management jobs and meets the needs of salt customers throughout the Western United States.

A committee of Cargill employees chooses which civic organizations to support financially and assist through volunteer activities.

Whether picking up trash at the wildlife refuge, collecting and sorting food for the needy, or coaching and tutoring kids, Cargill employees demonstrate their commitment to the community in which they live and do business.

Not only do Cargill employees volunteer their time, but they give generously out of their paychecks through the annual United Way campaign.

The salt ponds vary from chartreuse to magenta depending on salinity. In this image, the Dunaliella microorganism imparts a green cast to the brine of one salt pond and an orange cast to the brine of a saltier pond.

Overhead view
San Francisco Bay Salt
Newark, California. United States

Salt deposits form along edge of this orange-colored pond.

Overhead view
San Francisco Bay Salt
Newark, California. United States

An overhead view of the mosaic of salt crystals.

Close up
San Francisco Bay Salt
Newark, California. United States

The pumpkin color of this salt pond comes from the salt-saturated brines and contrasts with the chartreuse of a nearby marsh and the blue unsaturated brines in a nearby concentrator pond.

San Francisco Bay Salt
Newark, California. United States

As the deep magenta brine evaporates, it leaves behind a glistening white bed of salt crystals.

San Francisco Bay Salt
Newark, California. United States
Photo by Cris Benton

Clouds are reflected on the red “pickle,” or saltiest brine, that covers the Newark crystallizers, prior to harvest.

San Francisco Bay Salt
Newark, California. United States
Photo by Cris Benton