Credit: Karl Nielsen

A Look at the Risks

Monday, December 18, 2017

Threats to the Bay Area’s urban and social resilience include many hazards associated with the region’s geographic setting and changing climate. With its low-lying shorelines and major active earthquake faults, the Bay Area faces risks including earthquakes, flooding, sea level rise, drought, heat, changes in precipitation and fire. For example:

  • More than 8,000 acres of developed land along the Bay are already at risk from 100-year coastal storms, according to BCDC. Many of the region’s existing sea walls, levees and flood control structures are inadequate, seismically unsafe, or in need of maintenance and upgrades, while other areas have little or no flood protection at all.
  • The National Research Council’s 2012 projections for San Francisco Bay suggest that by 2050, the Bay is likely to be 12 to 24 inches higher. Beyond 2050, the rate of sea level rise may increase to 36 to 66 inches above current levels. Sea level rise of 66 inches would inundate tens of thousands of acres of developed land along the Bay — with particular impacts on housing for disadvantaged communities as well as critical transportation infrastructure — and hundreds of thousands of acres of conservation land.

Transportation Infrastructure and Sea Level Rise

  • One hundred thirty-four of the 188 Priority Development Areas (PDAs) identified for future housing and job growth in Plan Bay Area 2040 — the region’s long-range transportation plan and sustainable communities strategy jointly developed by MTC and ABAG — are vulnerable to existing or predicted flooding due to sea level rise. Forty-nine of the 188 PDAs are vulnerable to permanent flooding at 66 inches of sea level rise.
  • The United States Geologic Survey estimates there is a 72 percent probability of at least one earthquake of magnitude 6.7 or greater striking somewhere in the San Francisco Bay region before 2043, potentially displacing hundreds of thousands of residents.

  • The rainy winter of 2016-17 brought unprecedented flooding to the cities of San Jose and Santa Clara with the Santa Clara Valley Water District reporting over $102 million in flood damage. Additionally, state Route 37 linking Solano, Napa, Sonoma and Marin counties was closed for weeks due to flooding.
  • In October 2017 the devastating North Bay wildfires claimed 43 lives and caused the damage or destruction of 8,400 structures in Sonoma and Napa counties, with thousands of residents left homeless and many unable to find affordable replacement or temporary housing.

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