Managed Retreat

[ysabetwordsmith]

I'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.

Comments

[erulisse]

Another really unfortunate potential effect of strategic retreat/relocation when you are in a coastal area is that new construction tends to significantly reduce the ability of the ground to absorb water and route it in ways that won't cause problems. A lot of the inland flooding that happens in the Houston metro is because of this.

Well ...

[ysabetwordsmith]

That's true if people are careless. Houston is fucked; it's on the flats in a hurricane zone, with nowhere for the water to go.

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 ...

[erulisse]

Houston could definitely do a lot more to mitigate than it currently does. And it used to build a lot smarter. In the neighborhood where we lived, all the yards had a good slope down to the street and the houses were pier and beam on top of that meaning that in total there was typically a four foot elevation change between the gutter and doorjam. Plus a good bit of setback meant that there was plenty of space for water to go and yard to absorb some before it could get up toward the houses. The streets would flood and if we had enough warning before a nasty storm blew in we'd park some of the cars in the parking garage at the university for the duration but the houses pretty much never did.

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 ...

[ysabetwordsmith]

Most older developments are much better designed than newer ones. If people make foolish choices, they will have to deal with consequences. And when stupid people do most of the design work, smarter people are left with few choices for good living space.