San Mateo County in Flood Danger?

May 14, 2014

While most of us are focused on the water shortage with the epic drought this year, that is not the only potential problem which our weather can cause. San Mateo County has the most land at risk from sea-level rise than any other county in the Bay Area.

The Pacific Institute, with support from the California Energy Commission (CEC), California Department of Transportation, and the Ocean Protection Council, has produced inundation maps for the shores of San Francisco Bay that indicate which areas are vulnerable to 16inch and 55inch rises in sea level by 2100.

The County of San Mateo Government Operations Climate Action Plan dated September 2012 noted that the State of California projects that sea level will rise 14 inches by 2050 (using 2000 as the baseline) and between 40 and 55 inches by 2100. The Bay shoreline, from Brisbane to East Palo Alto, is a typical San Francisco Bay low lying shoreline vulnerable to inundation from both tidal and fluvial sources. Both the San Francisco International Airport and the Port of Redwood City are at risk, as are segments of critical transportation infrastructure including sections of Highway 101, approaches to the Dumbarton and San Mateo Bridges, and the Caltrain rail lines. As shown in Figure 2, many neighborhoods in Redwood City, the unincorporated area of the County, Menlo Park and East Palo Alto are particularly susceptible to sea level rise.

The report notes that according to a 2009 study, 110,000 people live in areas of San Mateo County that are vulnerable to a 100 year flood event with a 1.4 meter rise in sea level. Infrastructure and facilities at risk from the same event include:

• $24 billion worth of buildings and contents, mostly along the Bay (replacement value);
• 530 miles of roadways;
• 10 miles of railroads;
• San Francisco International Airport (SFO), including the 31 MW United Cogen power plant located there;
• Wastewater treatment plants operated by the Cities of South San Francisco/San Bruno, City of Millbrae, City of San Mateo, South Bayside System Authority, Mid?Coastside Sewer Authority, and SFO (total treatment capacity of approximately 44 MGD);
• 78 EPA?regulated hazardous materials sites;
• 34 square miles of coastal wetlands.

Just this past December. a conference spear headed by Congresswoman Jackie Speier, Assembly member Rich Gordon and Supervisor Dave Pine was held. The thrust of the meeting, which brought together experts from FEMA, the California State Coast Conservancy, the U.S. Army Corps of Engineers and the San Francisco Bay Conservation and Development Committee, is that “a regional or county-wide flood protection district dedicated to sea level disaster preparations should be assembled immediately.” The keynote speaker John Englander, oceanographer who is the author of “High Tide On Main Street: Rising Sea Level and the Coming Coastal Crisis” made several important points:

• We should realistically plan for severe storms, extreme tides, and sea level rise, going beyond the cautious projections most scientists and planners typically use.
• Looking ahead just three decades allows us to do better planning now, yielding a better return on our investment.
• Those that can see the “tsunami on the horizon” can reduce their risk and may find new opportunities.

You can see the discussion of the panel on local initiatives here. Other parts of the conference can be watched here.

While of course we hope that the effects of sea level rise are less than feared, it is smart to begin looking into hardening our coast against the worst effects. Artificial wetlands and sea walls were touted as possible solutions to flooding in the county. Not just SFO needs protection – our neighbors of Redwood City and Menlo Park are low-lying, and large parts of Silicon Valley are at risk as well from storm surges and sea level rise.
The potential impacts of sea-level rise in several areas of San Mateo County will be studied under a grant from the California Coastal Conservancy. San Francisco International Airport, along with the confluence of San Bruno and Colma creeks, will be the focal point of the study.

More information here and here.

For an idea on what the future may hold for San Mateo County, check out this recent article on the phenomenon of so-called “King Tides”.

While we as a Town may not be directly affected, we certainly will be indirectly impacted. Our staff and COWncil need to make sure that this issue is on their radar and should play a role in education of COWs on climate related threats and efforts our Town and we COWs can play in addressing all climate related issues.

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