A Bridge Over Troubled Waters: How the Bay Bridge Was Rebuilt Without Considering Climate Change

February 6, 2015 | 12:45 pm
Juliet Christian-Smith
Western States Regional Director

The Metropolitan Transportation Commission recently released a report identifying infrastructure vulnerable to climate change in the San Francisco Bay Area. It should be surprising that topping the list was the brand new San Francisco-Oakland Bay Bridge ramp, which connects Oakland to the new span of the Bay Bridge. (See Figure 1 from the report below.)

Say what?

The Bay Bridge is a regional workhorse that carries 270,000 vehicles each day between San Francisco and the East Bay, including Oakland and Berkeley. The new eastern span of the bridge cost $6.4 billion and took nearly six years to build. And yet, less than two years after the completion of this massive public works project, the report by the Metropolitan Transportation Commission finds that sea level rise is expected to permanently inundate several areas of the new span of the Bay Bridge and recommends a series of construction projects to protect the Bay Bridge, costing taxpayers an additional $17 million. Say what?


This blog is the first of a series on Climate-Water Disconnects, which will profile key climate change planning failures related to water infrastructure.

This blog is the first of a series on “Climate-Water Disconnects” that will profile key climate change planning failures related to water infrastructure.

How did this happen? And why does it keep happening? While California is a leader when it comes to climate policy, the state is farther behind when it comes to incorporating climate science into water planning. Bridges, reservoirs, hydroelectricity, streams and rivers—all kinds of water projects are likely to be affected by warming temperatures. Yet water planners haven’t yet caught up to the scientists when it comes to ensuring water planning and operations are climate resilient.

Graphic from the MTC report: Climate Change and Extreme Weather Adaptation Options for Transportation Assets in the Bay Area Pilot Project

Graphic from the MTC report, Climate Change and Extreme Weather Adaptation Options
for Transportation Assets in the Bay Area Pilot Project

Climate science tells us to expect rising sea levels

What does climate science tell us about the San Francisco Bay? The National Research Council concludes that the Bay may rise by at least 1 foot by 2050 and 3 feet by 2100; however, it is possible that sea levels could rise by as much as 2 feet by mid-century and 5.5 feet by end-of-century. The biggest source of uncertainty around these estimates is the level of greenhouse gas emissions that will be released into the atmosphere and the related contribution of water from melting ice sheets and glaciers in Greenland and West Antarctica.

Approach to the new span of the Bay Bridge will be “permanently inundated” by sea level rise

Despite clear information about rising sea levels, the ramp to the new span of the Bay Bridge was rebuilt at an elevation that is at risk of flooding today under a 50-year storm surge, and is below the FEMA 100-year base flood elevation. The Metropolitan Transportation Commission report finds that the approach to the new span of the Bay Bridge “is expected to be permanently inundated by 3 feet of sea level rise.”

The report defines permanently inundated areas as those which can no longer be used in the same way due to the frequency of exposure to sea water. At 3 feet of sea level rise, the westbound lanes of the approach will be permanently inundated at three distinct sites. This spells trouble for the hundreds of thousands of commuters who use the Bay Bridge daily and the economic activity that depends on these commuters.

Climate change must be factored into planning process

Despite climate science telling us to expect rising sea levels in and around the San Francisco Bay, the new span of the Bay Bridge was built without consideration for sea level rise. Had the planning process taken climate science into account, it’s possible that additional construction to protect the ramp to the new span would not be needed.

In 2008, then-Governor Schwarzenegger issued an Executive Order requiring that sea level rise be taken into account in planning projects that are vulnerable. Yet, the order exempted projects that were already underway or would be constructed within the following five years (Executive Order S-13-08). Unfortunately, a considerable number of projects fit through this loophole since they only needed to have filed a “Notice of Preparation” by 2008 to be exempted, including the Bay Bridge.

Almost every aspect of our water infrastructure is impacted by a warming climate. When considering long-lived infrastructure, it is particularly important to take the time to ensure that the infrastructure will work under future conditions in order to not waste time and money. That’s just sound planning.

In future blog posts, I’ll share some other examples of the disconnection between what we know based on climate science and how we manage our water. There are serious risks throughout our water system and a lot more we could be doing to prepare for a changing climate in the West. Please check back over the coming weeks for more “say what?” stories.