San Francisco Bay and Estuary

The Bay’s shoreline is approximately half the length of the California coastline.  The Bay is approximately 550 square miles, which is larger than all but nine cities in the United States.  It is almost 20% larger than the City of Los Angeles and is larger than the combined sizes of San Diego and San Jose.  Nine counties and over 40 cities touch Bay waters.

The Bay is filled by fresh water that flows west in the Sacramento River from near Mount Shasta and in the San Joaquin River, which starts three hundred miles away in the Sierra Nevada.  Until they were dammed and diverted, these two rivers carried about half of the precipitation that fell on California into the Delta where the rivers meet about 40 miles northeast of San Francisco.  The water then flows into San Francisco Bay itself.  Like all estuaries, San Francisco Bay has a wide river mouth flooded by the sea, which flows on ocean tides east through the Golden Gate.

The mixture of salt and fresh water is the foundation of the Bay’s biological diversity and richness.  The San Francisco Bay is the largest estuary on the west coast.  It includes unparalleled marshes and mudflats along the shoreline that provide food and shelter to fish and wildlife and account for 77% of California’s remaining perennial estuarine wetlands.  It is home to over 1,000 species of animals, including endemic, threatened, and endangered species.  It is a critical stopover for hundreds of thousands of birds on the Pacific Flyway and hosts more wintering shorebirds than any other estuary on the west coast outside of Alaska. The Bay supports over 130 species of fish, including salmon and other anadromous fish, which spend most of their lives in the ocean but return to fresh water to reproduce.  Harbor seals, gulls, sea bass, geese,

thousands of other species of fish, plants, mammals, reptiles, and birds thrive in the San Francisco Bay estuary.  Indeed, its diversity of key habitats and production of environmental benefits such as flood protection, water quality maintenance, nutrient filtration and cycling, and carbon sequestration compelled the international community to designate San Francisco Bay in late 2012 as a “Wetland of International Importance.”

The Bay also helps provide a high quality of life for residents.  Its natural harbor supports the world’s 19th largest economy.  The Bay shoreline hosts two major international airports (a third airport is very close by), which reduces noise and danger to those nearby.  Over 40% of California’s petroleum refinery capacity is located within BCDC’s jurisdiction.  The Oakland seaport is the Nation’s fifth largest and moves a startlingly large portion of California’s crops to international markets.  Considerable commerce takes place on the water and in the shoreline band on a daily basis.  The salt harvested from the Bay waters is an important raw material.  The Bay has also served as an important base for America's military forces.  The diversity of watercraft that appears on the Bay at any one time rivals that of any port.

With unparalleled recreational opportunities and beautiful scenery, San Francisco Bay is one of the world’s greatest tourist destinations.  Its stunning beauty and its contributions to such a high quality of life help make the Bay Area one of the country’s most desirable places in which to live.  The consistent temperature of the Bay water cools the surrounding region in the summer and warms it in the winter, making the Bay area climate among the world's most enjoyable.  The Bay is inextricably woven into each resident’s sense of place, culture, and community; it is a dynamic and interconnected system whose value is crucial to the region’s environmental, economic, and social prosperity.  While most of the people who live in the Bay Area may not see the Bay on a daily basis, their knowledge that it continues to thrive is evident by the support that BCDC enjoys.