It's annoying for coastal areas, and a problem for beach houses, but California isn't really that vulnerable to rising sea levels. The Pacific Coast is mountainous and the ground slopes upward in short distances.
Here's the US topo map.[1] Look at vulnerable spots, such as Malibu and Oceanside. Three blocks inland you're 20 feet above sea level. Almost all problems are on the ocean side of the Pacific Coast Highway, which was a marginal place to build anyway.
Cliff edge erosion is an ongoing problem. That's why CALTRANS gave up on Devil's Slide as a road route and built the Tom Lantos Tunnels further inland. Small changes in sea level don't affect hundred-foot cliffs that much, though.
The places that really suffer from rising sea level are river deltas, sitting on deposited sand just barely above sea level. In the US, New Orleans has the worst problem. New York City has problems, and they're building coast defenses against storms. China's coastal cities are mostly on river deltas with really flat terrain. That's why China has to build ports way off shore, reached by miles of bridges, to get to deep water.
The Bay Bridge channel is so shallow it has to be dredged. There was a 1946 plan to fill it in.[1] There were Corps of Engineers plans for a lot of filling, but they didn't go that far. I have a copy of their 1960-2020 plan for the Bay Area.[2] Their vision was to make the SF bay area a major industrial city, building on the facilities built for WWII. Aluminum smelter in Sausalito. Steel mills at Tiberon. Five freeways up the Peninsula (101, 280, 35, 1, and one on stilts in the bay.) Another Bay Bridge. Maybe a SF-Alcatraz-Angel Island-Tiberon link. It would have been like Pittsburgh.
This plan also resulted in a real-world scale model of the bay: <a href="https://en.wikipedia.org/wiki/U.S._Army_Corps_of_Engineers_Bay_Model" rel="nofollow">https://en.wikipedia.org/wiki/U.S._Army_Corps_of_Engineers_B...
The topographic map says, the Bay Area is just around the first bay, there's a whole second bay opening up behind it (Sacramento area valley) which could flood with enough sea level rise.
CA already floods at high tide so I think another 10 ft is really gonna mess stuff up. There are so many rivers that empty at sea level and a lot of roads that cross over low points that will need reworking.
The Bay Area is one big river delta, going inland to Sacramento.
It's not the Pacific coast communities you have to worry about like Half Moon Bay or Santa Cruz. They have a beach, and then cliffs, and then the actual city is like 50-100 feet above sea level.
It's the bayside communities. Foster City. Redwood Shore. The Embarcadero. SFO. Port of Oakland. Highway 101.
All of these are pretty critical parts of Bay Area infrastructure, and gone with as little as a 1.6' sea level rise + 20yr storm.
Foster City has a pretty hefty levee [1]. Palo Alto is building a "horizontal levee" [2]. Looks like Redwood Shores will be raising theirs [3].
This work has to be done for good reason, but looks like they're on it?
It's striking how much preparedness the SF bay area does. After the 1989 earthquake, all of the following were done:
- All freeway pylon supports were beefed up. They were already on the heavy side, but huge metal supports were built around them. You can still see those.
- The SF bay bridge eastern span was entirely replaced with a new bridge.
- The western span, the suspension bridges, was made more flexible. The roadway was jacked up and stainless steel slide plates were inserted to allow the roadway to slide relative to the towers if necessary.
- The Golden Gate Bridge had been strengthened a few decades previous, after the Tacoma Narrows bridge disaster.
- Most, but not all, unreinforced masonry buildings in SF have been strengthened or demolished.
- The backup water system (three hilltop tanks and an entirely separate plumbing system) for fire protection has been beefed up. In 1989, there were some water main breaks and nobody up at the tank to close the valves, and the Twin Peaks reservoir drained out.
- Three new fire boats. (There were zero in 1989, and that was a problem.)
The SF Embarcadero seems completely unprotected, and the bay front buildings get a bit wet at peak tides if there is any sort of storm surge lately. It seems to me that even another foot could be quite problematic.
Earlier this year the road was flooded as bay water went the wrong way through the storm drains…
I just dodged being stuck on the Outer Banks or evacuating for a hurricane which has now closed Hwy 12 based on which week the family agreed on for the annual beach vacation:
Animats · · focus · HN ↗
Here's the US topo map.[1] Look at vulnerable spots, such as Malibu and Oceanside. Three blocks inland you're 20 feet above sea level. Almost all problems are on the ocean side of the Pacific Coast Highway, which was a marginal place to build anyway.
Cliff edge erosion is an ongoing problem. That's why CALTRANS gave up on Devil's Slide as a road route and built the Tom Lantos Tunnels further inland. Small changes in sea level don't affect hundred-foot cliffs that much, though.
The places that really suffer from rising sea level are river deltas, sitting on deposited sand just barely above sea level. In the US, New Orleans has the worst problem. New York City has problems, and they're building coast defenses against storms. China's coastal cities are mostly on river deltas with really flat terrain. That's why China has to build ports way off shore, reached by miles of bridges, to get to deep water.
[1] <a href="https://en-us.topographic-map.com/map-9t5k57/Venice-Beach/?center=33.18363%2C-117.36954&zoom=16" rel="nofollow">https://en-us.topographic-map.com/map-9t5k57/Venice-Beach/?c...
gboss · · focus · HN ↗
comrade1234 · · focus · HN ↗
gboss · · focus · HN ↗
Animats · · focus · HN ↗
The Bay Bridge channel is so shallow it has to be dredged. There was a 1946 plan to fill it in.[1] There were Corps of Engineers plans for a lot of filling, but they didn't go that far. I have a copy of their 1960-2020 plan for the Bay Area.[2] Their vision was to make the SF bay area a major industrial city, building on the facilities built for WWII. Aluminum smelter in Sausalito. Steel mills at Tiberon. Five freeways up the Peninsula (101, 280, 35, 1, and one on stilts in the bay.) Another Bay Bridge. Maybe a SF-Alcatraz-Angel Island-Tiberon link. It would have been like Pittsburgh.
[1] <a href="https://www.sfgate.com/local/article/second-bay-bridge-plans-history-freeway-alameda-sf-14018498.php" rel="nofollow">https://www.sfgate.com/local/article/second-bay-bridge-plans...
[2] <a href="https://archive.org/details/futuredevelopmen00unit" rel="nofollow">https://archive.org/details/futuredevelopmen00unit
cyberax · · focus · HN ↗
kzrdude · · focus · HN ↗
stymaar · · focus · HN ↗
bix6 · · focus · HN ↗
nostrademons · · focus · HN ↗
It's not the Pacific coast communities you have to worry about like Half Moon Bay or Santa Cruz. They have a beach, and then cliffs, and then the actual city is like 50-100 feet above sea level.
It's the bayside communities. Foster City. Redwood Shore. The Embarcadero. SFO. Port of Oakland. Highway 101.
All of these are pretty critical parts of Bay Area infrastructure, and gone with as little as a 1.6' sea level rise + 20yr storm.
<a href="https://www.kqed.org/science/1973624/maps-see-which-bay-area-locations-are-at-risk-from-rising-seas" rel="nofollow">https://www.kqed.org/science/1973624/maps-see-which-bay-area...
skybrian · · focus · HN ↗
This work has to be done for good reason, but looks like they're on it?
[1] <a href="https://fostercitylevee.org/" rel="nofollow">https://fostercitylevee.org/ [2] <a href="https://www.sfchronicle.com/climate/article/palo-alto-sea-level-rise-21217371.php" rel="nofollow">https://www.sfchronicle.com/climate/article/palo-alto-sea-le... [3] <a href="https://www.smdailyjournal.com/news/local/new-200m-levee-upgrades-coming-to-redwood-shores/article_09e9d3d8-b174-4573-9e70-5f2cf9e818ec.html" rel="nofollow">https://www.smdailyjournal.com/news/local/new-200m-levee-upg...
Animats · · focus · HN ↗
- All freeway pylon supports were beefed up. They were already on the heavy side, but huge metal supports were built around them. You can still see those.
- The SF bay bridge eastern span was entirely replaced with a new bridge.
- The western span, the suspension bridges, was made more flexible. The roadway was jacked up and stainless steel slide plates were inserted to allow the roadway to slide relative to the towers if necessary.
- The Golden Gate Bridge had been strengthened a few decades previous, after the Tacoma Narrows bridge disaster.
- Most, but not all, unreinforced masonry buildings in SF have been strengthened or demolished.
- The backup water system (three hilltop tanks and an entirely separate plumbing system) for fire protection has been beefed up. In 1989, there were some water main breaks and nobody up at the tank to close the valves, and the Twin Peaks reservoir drained out.
- Three new fire boats. (There were zero in 1989, and that was a problem.)
amluto · · focus · HN ↗
Earlier this year the road was flooded as bay water went the wrong way through the storm drains…
skyberrys · · focus · HN ↗
WillAdams · · focus · HN ↗
<a href="https://www.outerbanksnews.org/post/n-c-highway-12-damaged-closed-on-pea-island-as-nor-easter-impacts-the-outer-banks" rel="nofollow">https://www.outerbanksnews.org/post/n-c-highway-12-damaged-c...
(and they have an on-going beach replenishment effort as well)