Managed Retreat
Jun. 28th, 2021 03:12 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
ysabetwordsmithI'm pleased to see someone else admitting that not all cities can stay where they are. This article gives several examples of how cities could adapt to climate change, including the option of moving inland.
Some of these are viable solutions for problems like sunny-day floods, saltwater encroachment, or land loss.
However, none of them will defend against the increasingly violent storms that batter the coastlines. Those range for many miles inland. Some whole states are at risk, and many more have significant areas at risk. That's before accounting for the inland impact of hurricanes. Since human habitations require water and often hug the coastlines, a complete inland retreat is probably unfeasible. We'll have to figure out ways of coping with both floods and winds, which is difficult. But the farther from the coast, the better, for both of those hazards.
In order to choose appropriate response strategies, each city must look at its current and projected problems, along with its general needs and available resources. The bottom line is that a lot of people will have to move due to environmental foreclosure, and many more will have to change the way they do things. This can be done in safer, more logical ways through managed retreat or in risky evacuations as people flee just ahead of disasters.
Some of these are viable solutions for problems like sunny-day floods, saltwater encroachment, or land loss.
However, none of them will defend against the increasingly violent storms that batter the coastlines. Those range for many miles inland. Some whole states are at risk, and many more have significant areas at risk. That's before accounting for the inland impact of hurricanes. Since human habitations require water and often hug the coastlines, a complete inland retreat is probably unfeasible. We'll have to figure out ways of coping with both floods and winds, which is difficult. But the farther from the coast, the better, for both of those hazards.
In order to choose appropriate response strategies, each city must look at its current and projected problems, along with its general needs and available resources. The bottom line is that a lot of people will have to move due to environmental foreclosure, and many more will have to change the way they do things. This can be done in safer, more logical ways through managed retreat or in risky evacuations as people flee just ahead of disasters.
(no subject)
Date: 2021-06-28 09:22 pm (UTC)Well ...
Date: 2021-06-28 10:28 pm (UTC)However, there are many urban design techniques to cope with challenges, and these are often easier to build new than to retrofit. Examples include:
* porous pavement that lets water soak through
* rainwater harvesting so it can be used
* rain gardens to soak up water
* hugelkultur to direct, trap, and/or absorb water; one-plant pits can be invisible at the surface
* bioswales to slow runoff and minimize flooding or erosion
* swamp filters to clean runoff before it reaches natural waterways
* integrated stormwater management to fit all the pieces together for maximum benefit
Inland retreat will work best on areas of moderate slope, where moving a modest distance gains you a good yardage above the waterline. Where the coastline is very flat, it's not enough. Where the coastline is very steep, it's rarely needed unless the cliffs are crumbling.
Re: Well ...
Date: 2021-06-29 12:35 am (UTC)Unfortunately the newer construction has a much larger amount of pavement and much less porous surface or exposed dirt/vegetation. There has been a general level of disregard across the city even for what could be done easily. When new construction takes runoff and flood prevention into account it is in the form of culverts and holding ponds and cisterns which have specific limits to their capacity and as far as I am aware (and I did some study on this as a social issue while I was in grad school) there is not much being done beyond that.
I find it super frustrating that so much of what should have been done all along to prevent and mitigate these issues would have been relatively simple "common sense" kinds of things that mostly just require a dose of good planning.
Re: Well ...
Date: 2021-06-29 01:07 am (UTC)(no subject)
Date: 2021-06-28 09:25 pm (UTC)Well, Florida is a write-off whatever you do. The salt-water encroachment up through the porous limestone bedrock alone is going to wreck agriculture and destroy concrete foundations. Indeed, the recent collapse of that condo might be the result of that! There's talk of the concrete slab foundation suffering from salt-water damage, but I doubt that's the whole story.
Well ...
Date: 2021-06-28 10:01 pm (UTC)Conservative Map
Worse Map
(no subject)
Date: 2021-06-29 12:37 am (UTC)Well ...
Date: 2021-06-29 01:08 am (UTC)(no subject)
Date: 2021-06-29 02:25 am (UTC)I wonder if such buildings could be placed to act as windbreaks or tsunami buffers? (In case of tsunami, evacuate and come back later!)
Thoughts
Date: 2021-06-29 02:38 am (UTC)They are inherently the most storm-resistant structures we can build. Trouble is, that stuff is heavy, so you don't want to put them on ground that can flood because they might sink. Other materials, such as sprayfoam insulation, are much lighter but less strong. Geodesic domes are also fairly lightweight but their shape still gives them good storm resistance.
>> I wonder if such buildings could be placed to act as windbreaks or tsunami buffers? <<
I had not thought of that. Possibly they would help, or some other baffle might work better. I'd want some mathematicians and engineers to study this with water tables and wind tunnels to derive the most effective approach.
>> (In case of tsunami, evacuate and come back later!) <<
I love the Egyptian solution. They built heavy stone structures. When the Nile began to rise, they moved valuables to upper stories and packed off to the desert for 2-3 weeks. After the flood receded, they rinsed off the buildings and put everything back, then went out to plant the freshly watered and fertilized fields. \o/
The Japanese solution was the opposite: they built with flimsy, lightweight materials that were easily destroyed but also easily replaced.
Re: Thoughts
Date: 2021-06-29 03:58 am (UTC)Also look at history and nature.
_For historical stuff:_
Were there societies that arrainge buildings so that they could serve as windbreaks or sunshades? A Brother's Price mentioned using farm buildings as windbreaks, and I believe I've heard of folks arrainging wagons to protect against precipitation or wind. (Trees are commonly used as windbreaks and sunshades, but they aren't buildings.)
_For nature:_
See how animals move. Geese and fish move in ways that cut air/water resistance. Emperor penguins can only overwinter by working together against the blizzards. Many grazing animals will stand in ways that protect them from the elements.
_And if you are looking at architecture:_
What sort of features (geographical or manmade) protect against the given disaster, or similar small-scale weather events?
What of these features could be built in such a way that they are inhabitable?
I could imagine a house-on-stilt setup, where underneath the house functions as a patio or pavilion most of the time...but for floods everyone just chills upstairs. (Inspired by my musings on architecture designed for a tidal floodplain...)
And any kind of a levee or wall could have housing on the land ward side. It could even be set up as two or more walls, with the habitable space as compartments in between. (Think compartmentalization as on the Titanic.) Just be sure to evacuate for big storms!
_If we were protecting against flooding specifically:_
- Costal houses can be arrainged so that they function as a seawall in the event of a flood. (I am unsure if how much of a dent they might put in a tsunami, but it is worth thinking about.)
- If building a high-rise building, try to design it so it will work even when the lower levels flood. If frequent floods are expected, it may be possible include technology to harvest electricity from the tides in the floodable levels.
- Related, I'll bet something designed like a Mesoamerican pyramid would be a great tall structure for a tsunami - alarm goes off, everyone inside goes upstairs and opens the pper doors, everyone outside walks up the (decorative and functional) stairs, and can watch the mayhem, or wait it out inside.
- If you can't /stop/ the water, can you /channel/ it? (This would likely work better with freshwater...but theoretically a catchment pond in a desert could be set up for solar distillation.) Conversely, flooding coming from uphill could be used as a street-washing service...or as musical stairs / a musical fountain. (Do be sure people in the streets have a quick & easy way to escape the flooding, though!.)
- Design streets so they can double as canals. Paint addresses, street names and depth markers on the tops of buildings. (Possibly also stick flags on the roofs, if the floodwaters get really high - and put depth markers on the flagpoles, too!)
Not architecture, but if you expect floods, train as many people as possible in water rescue. Offer incentives for boat owners to register, get training, and do drills. We're gonna need more Cajun Navies, unfortunately.
Also, does anyone know if Roman aquatic concrete can be set above water? Can it be used in sometimes-wet-sometimes-dry environs?
There's other ideas I could suggest for different disasters, but this is what I've got for wind-precipitation-flood stuff.