Basic baylands facts

Ventura County Star

July 21, 2002

The baylands exist around San Francisco Bay between the lines of high and low tide. They are the lands touched by the tides, plus the lands the tides would touch in the absence of any levees or other unnatural structures.
There are 73,000 acres of tidal baylands and 139,000 acres of diked baylands.
There used to be 23 miles of sandy beaches. Now there are about 7 miles of beaches. Most of the current beaches are in different locations than the historical beaches.
There used to be 190,000 acres of tidal marsh with 6,000 miles of channels and 8,000 acres of shallow pans. Now there are 40,000 acres of tidal marsh with about 1,000 miles of channels and 250 acres of pans.
Only 16,000 acres of the historical tidal marsh remain. The rest of the present tidal marsh has naturally evolved from tidal flat, been restored from diked baylands or muted by water control structures.
There used to be 50,000 acres of tidal flat. Now there are 29,000 acres of tidal flat. The reduction is due to bay fill, erosion and tidal marsh evolution.
There used to be about 174,000 acres of shallow bay and 100,000 acres of deep bay. Now there are 172,000 acres of shallow bay and 82,000 acres of deep bay. About 16,000 acres of deep bay have become shallow and 18,000 acres of shallow bay have become tidal, diked or filled baylands.
The total area of high tide downstream of the Delta used to be about 516,000 acres. Now it is about 327,000 acres.
The total amount of shallow ponds in the baylands and in the adjacent grasslands used to range from 16,000 acres to 22,000 acres, depending on the amount of rainfall. Now there are between 63,000 and 92,000 acres, depending on rainfall and water management practices. The increase is due to ponding in diked baylands.
One-hundred thirty-seven thousand acres of baylands have been diked.
Fifty thousand acres of baylands have been filled.
There are about 500 species of fish and wildlife associated with the baylands. Twenty of these species are threatened or endangered with extinction.
About 7 million people live around the baylands.

Source: San Francisco Bay Area Wetlands Ecosystem Goals Project