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Flooding Reaction Guidelines: pt. 2, Sea Level Rise -- Strike for the Planet week 171 [1]
['This Content Is Not Subject To Review Daily Kos Staff Prior To Publication.']
Date: 2023-12-30
You can make a difference to the hurt being caused by climate chaos and the great extinction event in your town or your city! How? Reuse, repurpose, and recycle this information. You can push your local politicians to act. It will make a difference!
This is the letter for week 171 of a weekly climate strike that went on for 4 years in front of San Francisco City Hall, beginning early March 2019. For more context, see this story. For an annotated table of contents of the topics for all the strike letters, see this story. Meanwhile…
STRIKE FOR THE PLANET
When the flood calls
You have no home, you have no walls
Reaction Guidelines for Flooding, pt. 2: Sea Level Rise
This is a resource for flooding caused by sea level rise. The goal is to have procedures you can pick up off the shelf and start putting in place when it’s too late to avoid disaster.
Glossary of terms used
erosion a surface action process that removes solid materials from one location to another, usually by water flooding water or other liquids submerging land that is usually dry hardening artificial structures built on shorelines to “harden” them against erosion and flooding, such as seawalls, bulkheads, revetments, groins, gabions, and jetties peninsula a piece of land extending from the mainland, surrounded on 3 sides by water precipitation water condensed from the atmosphere, often in the form of rain or snow riprap rock, concrete, and rubble put by humans on shorelines, intended to slow erosion seawall a part of constructed coastal defense infrastructure, intended to prevent erosion and flooding sediment rocks, soil, silt, and other solid material carried in streams and runoff and differentially deposited (based on mass and water flow rates) in shore ecosystems silt fine soil and rock runoff soft shorelines natural ecosystems (dunes, marshes, seagrasses, vegetation) that slow and absorb storm impacts and flooding
SF will flood from sea level rise
We’re already at a global average 1.1°C warming and rushing toward 1.5°C. Based on our current emission trends, we are unlikely to stop at 1.5°C. But 1.5°C was the Paris Agreement figure so, even though landing there would require immediate massive decarbonization across the globe, let’s imagine we somehow do that.
If every government immediately does everything right, and the world gets very lucky and doesn’t trigger any runaway positive feedback loops (ex. melting the permafrost, releasing massive amounts of carbon in the form of methane into the atmosphere), and we manage to stay at 1.5°C warming, at 1.5°C downtown San Francisco is still flooded. Here is a graphic from Climate Central to remind you.
“Picturing Our Future”. Climate Central.
https://picturing.climatecentral.org . Also see Strike letter for week 129.
Flood strategies in SF are completely insufficient for what’s coming
Due to past flooding events and other emergency situations, San Francisco has the following resources in place and mostly available when flooding happens:
a distribution system to get sandbags out to people before possible flooding events the “adoption” of storm drains by locals to keep those storm drains clear the dispatching of crews pre-storm to put up flood barriers and clean out catch basins in flood-prone areas good emergency broadcast systems posted tsunami evacuation routes (useful for flood evacuation as well) designated evacuation locations on higher ground water rescue equipment and personnel, located mostly on the west side of the city
These strategies work for precipitation flooding but please refer to the image above. Sea level rise is not precipitation. Storm drains won’t help. Flood barriers and sandbags can route some water elsewhere, but “elsewhere” will be either an already flooded location or low-lying land that hadn’t flooded yet but now will because you’re pushing water onto it.
Other planned flood defenses are insufficient as well as destructive
Hardening, or gray infrastructure plans, from riprap to seawalls to total encirclement, whether at Sloat or the Embarcadero, don’t work. They are expensive, require enormous amounts of resources to build, take a long time to finish, destroy ecosystems and habitats, prevent sediment deposition from rebuilding shorelines, damage neighboring shores, suffer from erosion, and inevitably fail. Sloat and the Embarcadero are excellent examples of all these problems.
There are cheaper, quicker alternatives but they still require lead time
Soft, or green, infrastructures slow flooding, absorb water, soften storm impacts, and provide needed habitat. Their efficacies have been well documented, from the dune-and-pump system (such as those extensively used by the Netherlands) to mangrove forests (such as protect against cyclones and tsunamis) and everything in between. But they require time to grow.
A peninsula is defined by water
The plans SF has in place for flooding are all based on precipitation, and cannot cope with sea level rise. The hard infrastructure SF has in place is old, and was built to create more land in areas that are naturally marsh, sand dune, or water. As a result, SF’s hard infrastructure is not capable of coping with sea level rise.
And the sea is rising.
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