What Islais Creek tells us about rising sea levels in San Francisco

Islais Creek is an unassuming waterway along San Francisco’s eastern industrial shoreline, meandering its way inland and providing a natural...

Islais Creek is an unassuming waterway along San Francisco’s eastern industrial shoreline, meandering its way inland and providing a natural border between The City’s Bayview and Dogpatch neighborhoods.

There’s a nice little park there, tucked under a bridge, that locals visit. But it’s not the kind of place most people think about much. Environmentalists and urban planners, on the other hand, think about it a lot.

Here’s why: Rising sea levels and flooding.

By 2050, the area surrounding the artificial creek is expected to be more than five feet underwater during major storms. Flooding will increase significantly thanks to rising sea levels caused by climate change. And that could cause industrial contaminants to seep into the ground, flow out to the Bay and create a toxic mess.

Valuable public assets like industrial facilities that sit atop city piers, the Third Street bridge crossing, and a nearby Muni yard are also at risk. To help prepare for what looks to be inevitable, San Francisco officials are finalizing a strategic plan this month to minimize the impacts. Solutions could include constructing raised or rebuilt pier edges, creating wetlands and tidal marshes, and replacing bridge crossings.

The conversation surrounding Islais Creek comes at a time that urban planners and environmentalists are wrestling with the questions rising seas will pose for San Francisco, where a history of toxic industry and a massive coastline pose a series of unique problems in search of solutions.

In the 1990s, both Islais Creek and its northern neighbor, Mission Creek, were deemed toxic hot spots by state regulators. Subsequent studies concluded the two waterways had improved, but both still contain areas with high levels of contamination common along the San Francisco shoreline.

“There was some positive discussion and consideration of the many threats posed by rising sea levels,” said Bradley Angel, executive director of the nonprofit Greenaction for Health and Environmental Justice, regarding The City’s Islais Creek draft of a strategic plan to address environmental issues. “What really stood out is the ominous omission [of] the threat that shoreline contamination sites…will be flooded. In all those issues, it’s barely mentioned and certainly not highlighted as a priority.”

A separate city report, released in 2020, addresses the “high” threat of hazardous materials spreading due to increased flooding. Between 2007 and 2017, The City counted 414 hazardous material incidents, such as fuel spills, according to the Hazards and Climate Resilience Plan.

“San Francisco’s commercial sector and transportation routes share space with several bodies of water, wetlands, environmentally sensitive areas, and a densely-populated urban environment, creating areas of great potential risk for a hazardous materials release,” the report read. “Hazardous materials have properties that make them potentially dangerous and harmful both to human health and to the environment.”

Contaminants like pesticides, heavy metals, and polychlorinated biphenyls (commonly referred to as PCBs) are a byproduct of San Francisco Bay’s industrial past. The former naval shipyard at Hunters Point is a good example. Radioactive waste was found on land set to become housing, once properly remediated.

Flooding will also surface sewage waste from overloaded systems, introducing bacteria onto city streets and, eventually, into the Bay.

Ian Wren, staff scientist studying the issue at the environmental advocacy nonprofit Baykeepers, doesn’t expect the effects to be significant for area residents. The Bay’s surrounding ecology and wildlife will bear the brunt. But there could be some crossover. In the case of Islais Creek, some people still fish there. That won’t make for a healthy meal.

“We know that waters are making it up to where they didn’t previously on a more frequent basis,” said Wren. “It can mobilize contaminants that can be toxic to communities and residents that have to experience this flooding. It’s not just the water that is impeding people’s access to living their daily lives, it’s also the fact that this water will be fairly contaminated.”

To address these environmental issues, The City’s Hazards and Climate Resilience Plan would expand education efforts for residents, with an emphasis on removing hazardous materials keeping them from being improperly disposed of in landfills or drains. Another is to pursue a workforce training program where participants would remove toxic waste at properties impacted by flooding. Targeted completion for both initiatives would be five years.

The San Francisco Bay Regional Water Quality Control Board, a state regulator tasked with protecting ground and surface water, has more recently focused on cleaning up the area around Crane Cove and Potrero Power Station to the north. Agencies are also addressing the sewage system, which is combined with the stormwater system and will get overloaded as flooding increases.

While conditions have improved at sites like Islais and Mission creeks, the water agency acknowledges that any work done on them and lingering contamination may not hold up against intensive flooding in the future.

“This is a new effort we have begun,” said Thomas Mumley, assistant executive officer at the local Water Quality Control Board. “In the big picture, the board is aware of the possibility that contaminated sites that may be considered OK today could pose a problem in the future and we are beginning to give attention to them.”

But these efforts are largely new, or just getting started, as climate change becomes more urgent. Environmental advocates bemoan the lack of a regional approach to address rising sea levels in the Bay. The strategies that do exist are behind the curve on addressing toxins and contaminants along the shoreline, Wren noted.

The precise next steps, which will include a groundwater study, are unclear. The Planning Department and Department of Public Health did not respond to requests for comment.

Community advocates have long called for more robust remediation, which have gotten more attention in areas booming with development, such as The City’s eastern shoreline. They warn there is still time, but not much, to clean up contaminants like those found in Islais Creek before it spreads.

“I don’t think it’s too late to address this problem but the clock is ticking,” Angel said. “The best and the brightest in this field need to get together. It has to be done before it’s too late.”


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