On February 26, over 70 people, including local elected officials, attended Committee for Green Foothills’ Flooded Out: Development in the path of sea level rise event at the Redwood City Public Library.  The event featured presentations by Jeremy Lowe of the San Francisco Estuary Institute (SFEI), Dan Ponti of Redwood City Neighbors United (RCNU), and Green Foothills’ Legislative Director Alice Kaufman, who also answered questions from the audience.

The event is one of a series Green Foothills is planning around the impact of sea level rise on our communities and what to do about it at the local level.

Impacts before inundation

A key message from the event was that sea level rise is not slow and steady, nor are its impacts confined to the distant future. We are already experiencing more frequent and extensive seasonal flooding in low-lying areas due to rising oceans. As SFEI’s Jeremy Lowe pointed out, we are now subject to “sunny day flooding” during king tides in November and December. Flooding due to winter storms is also causing greater and more costly property damage. And it will only get worse as seas rise.

Currently, severe rainstorms cause flooding when creeks overtop their banks or when stormwater runoff can’t drain into creeks or into the Bay. As sea levels rise, storm drains will back up sooner and creeks will overflow more often. The result will be flooding that is more frequent, more extensive, deeper, and longer-lasting.

In the case of Redwood City, studies show among the first areas to flood will be the lands east of Highway 101, especially the Cargill salt ponds and lands adjacent to Redwood Creek. By mid-century, it’s possible that flooding would spread into Redwood City’s downtown. RCNU’s Dan Ponti called attention to the fact that Redwood City, like many other cities in the path of sea level rise, has not yet undertaken any planning efforts to address this threat. Although some developments, such as the massive Harbor View proposal, would be required to raise their buildings up several feet, nothing has been done to address flooding on nearby roads.

Nature provides a solution

Green Foothills’ Alice Kaufman noted that the most inexpensive and most environmentally-friendly way to protect against sea level rise is restoring Bay wetlands and creating horizontal levees – long, sloping tidal marshlands that can buffer storm surges and absorb floodwaters while also providing habitat and filtering the waters of the Bay. Many of the Bay’s historic wetlands have been lost to development, but others are being restored. The Cargill salt ponds in Redwood City are a prime example of former wetlands that could very easily be restored to their historic state as tidal marsh, which would protect the residential community of North Fair Oaks against sea level rise.

What can be done at the local level?

Clearly, with over $23 billion of development already at risk in San Mateo County, cities must stop putting new development in the path of sea level rise.  We need to act now to ensure that we can protect our communities from increased flood risk in an ecologically sensitive way. If we delay action, we may be forced into the most expensive and most environmentally harmful solutions, or risk losing billions of dollars in assets.

The good news is that local governments recognize that sea level rise is a problem. The bad news is that very few cities in San Mateo County are actually taking action to address it. With the County of San Mateo’s recent launch of a new joint agency to address flooding and sea level rise resiliency, we hope that cities will be motivated to take action.

How can you help?

• Tell your elected officials that you support nature-based solutions for climate change, such as wetland restoration
• Sign our petition to stop development on the Redwood City salt ponds and urge restoration of the site to wetlands

Support our work as we educate elected officials and the public about this important issue