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Pacific Coastal and Marine Science Center

Coastal Processes


(a) Vulnerable areas during 100-year storms. (b) Current land use.
(a) Vulnerable areas during 100-year storms. (b) Current land use.

The biggest changes to San Francisco Bay over the next century include:

  • Reduced fresh water from the Delta
  • Increased salinity
  • Reduced sand and mud suspended in the water
  • Major increase in coastal flooding

Climate models predict less snow and more rain in the Sierra Nevada, which will cause higher river flows earlier in the year, weaker snow melt flows later in the year, and higher salinity throughout the San Francisco Bay and Delta.

By 2100, San Francisco Bay sea level could rise 1.66 meters (5.4 feet). Currently, San Francisco Bay wetlands receive just enough sand and mud to keep up with recent rates of sea level rise. Sand and mud from the Delta will continue to decline slowly.

By 2100, San Francisco Bay wetlands will need about 40 times more sand and mud to keep up with expected sea level rise.

By 2050, today's 100-year storms and floods, could occur every year due to climate change. Those storms and floods will be major threats to marshes, shorelines, ecosystems, and critical infrastructure (including San Francisco and Oakland airports), and increase risks for 270,000 people and $62 billion of development.


Adapted from:

Sediment transport in the San Francisco Bay Coastal System: an overview, Barnard, P.L., Schoellhamer, D.H., Jaffe, B.E., McKee, L.J., Marine Geology, 2013,

Potential Inundation Due to Rising Sea Levels in the San Francisco Bay Region, Knowles, N., San Francisco Estuary and Watershed Science, 2010,



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Page Last Modified: 21 March 2014 (lzt)