10 ms·

How to Build a City That Doesn’t Flood? Turn It into a Sponge

169 points by fern12 9y ago

gipp 9y ago
The last time I saw something about these highly porous pavement alternatives, it was pointed out they tend to be very vulnerable to freeze-thaw damage and that this damage also lowers the porosity dramatically. Basically making these kinds of materials unsuitable for urban use outside of tropical- or near-tropical areas. Has this changed?
- galobtter 9y ago
  http://www.cement.org/cement-concrete-applications/paving/pervious-concrete/pervious-concrete-and-freeze-thaw http://www.cement.org/cement-concrete-applications/paving/pe... "However, in climates prone to severe freeze-thaw cycles, some are hesitant to use pervious concrete pavements until it has been proven that pervious concrete can be made to resist freeze-thaw damage." Pittsburgh does go through freeze thaw cycle, so I assume there aren't much problems https://www.unh.edu/unhsc/sites/unh.edu.unhsc/files/pubs_specs_info/unhsc_houle_thesis_9_08.pdf https://www.unh.edu/unhsc/sites/unh.edu.unhsc/files/pubs_spe... According to this, it also reduces the amount of salt needed 75% for deicing and the pavement doesn't seem to have been damaged from reading the abstract.
  - mcgrath_sh 9y ago
    Well, if Pittsburgh is using it, it is terrible. We have so many potholes (and huge ones). It has become much worse over the last ~5 years. For several months we had a multi-foot hole blocked off by cones until the city could fix it. It essentially was in the middle of a two way road. It was terrible. I see more and more each winter.
    - sonar_un 9y ago
      That's not because of the cement but the geology of Pittsburgh itself. Limestone bedrock and the "underground river" contributes to potholes and other geologic anomalies. If anything, adding bioswales and having a way to put the water back into the ground would stop the potholes from happening in the first place.
      - vwcx 9y ago
        Yes, but that still doesn't mitigate the rapid freeze/thaw effects on the concrete/asphalt that the City of Pittsburgh uses.
      - keenerd 9y ago
        I think you are confusing sinkholes and potholes. The two aren't really related.
    - ensignavenger 9y ago
      That sounds, from your description, more like a sink hole than a freeze-thaw induced crack? Hard to tell without seeing it.
- roel_v 9y ago
  Water flows through them, they don't really 'absorb' water. Of course there will be moments when it freezes when there's still water in them, but it's not equivalent to freezing a sponge. The parking lot on one of my buildings is paved with blocks like this (condition for getting the building permit), works great. Never slippery in winter, either. They weren't even more expensive than alternatives.
- mabbo 9y ago
  The main problem I see with them is people's perception about what porous pavements do. Great, water goes through them... and then what? The ground underneath the pavement is not some unlimited sinkhole for water. The ground table can and does fill up. Then it doesn't matter how porous your pavement is. Trees, grass, wetlands, etc, do better in part because they are preventing the water from leaving. They pool water in small puddles, they absorb water, leaves have water sit on them, etc.
dsego 9y ago
Solutions mentioned are I think referred to as BMPs - best management practices [1]. Regulations exists and there are scientific software tools for tracking and planning [2]. [1] https://en.wikipedia.org/wiki/Best_management_practice_for_water_pollution https://en.wikipedia.org/wiki/Best_management_practice_for_w... [2] http://www.2nform.com/tools/ http://www.2nform.com/tools/
Retric 9y ago
I suspect it's cheaper to simply build a large enough drainage system initially. This is useful if you have already failed and are trying to cope with failure. Still, many people are pushing it because you get more plants not because it's cost effective.
- galobtter 9y ago
  Like the other guy pointed out, there isn't always an area to drain too. Also I'd say having more plants has other benefits, and so does draining water into the ground, which would lead to more ground water edit: and into an aquifer (like wanderr pointed out) instead of wasted into an ocean
- 24gttghh 9y ago
  There are certain ways of building swales[0] in an urban environment that can help absorb or slow the leeching of nasty chemicals in runoff into groundwater or communities downstream. [0]http://nwrm.eu/measure/swales http://nwrm.eu/measure/swales
- mnw21cam 9y ago
  It depends if you have somewhere benign to drain all the water into. If there is a population downstream that might get annoyed if you dump lots of run-off on them, then making your land more sponge-like can be really useful. If "downstream" is the ocean a mile away, not so much.
  - wanderr 9y ago
    There is also potentially a lot of benefit to having the water enter the soil and eventually make its way down into the aquifer instead of just shunting it "away".
n0us 9y ago
anyone who hasn't watched a clip on Tokyo's massive drainage system should check this out https://www.youtube.com/watch?v=o85teh1vU_0 https://www.youtube.com/watch?v=o85teh1vU_0
- bob_theslob646 9y ago
  Super interesting. Essentially, they built an underground river which is connected to many of Tokyo's rivers (many kilometer underground tunnel) that diverts overflow water from the rivers to prevent catastrophic flooding. It cost 3 billion dollars and took 13 years to build. I would like to see how these held up during the tsunami.
- TorKlingberg 9y ago
  Japan has spent a LOT of effort to mitigate floods. It does mean that all river banks anywhere near a city look the same, and very artificial.
AhtiK 9y ago
There's a related story on Berlin being built into a sponge city. https://www.bloomberg.com/news/videos/2017-08-18/sponge-city-making-berlin-cooler-video https://www.bloomberg.com/news/videos/2017-08-18/sponge-city...
- baldfat 9y ago
  I think Berlin's approach is better for colder climates. It just makes sure the water lands in soil and stays there. Each new construction site must do the same. So the roofs are green with soil and the road's water goes into the soil and the buildings have a layer of soil on top of underground garages.
hsnewman 9y ago
Broad statement for the subject. I suspect even a sponge can be saturated.
- Arnt 9y ago
  Obviously, but that's not the test. The test is whether the sponge can absorb rain as fast as it can fall for a long-enough time that other consequences of the rain become serious problems (e.g. deferred outdoor maintenance), while the sponge still isn't saturated.
  - galobtter 9y ago
    It's mostly I think the limit of how fast the ground can absorb water after it has passed through the pavement. If the water rises through the pavement..
- thinkMOAR 9y ago
  and imagine what happens when a freeze comes by and what it does to the sponges' life
- avs733 9y ago
  The issue is one of rates not volume. They briefly mention Houston in passing, which is a perfect example. The water is all part of the same cycle and same watershed, but where it goes within that watershed and at what rate become critical. If you make 50% of an area impervious to absorbing water (i.e., you pave it) then the remaining 50% has to absorb much more water, and likely will become saturated. But first, the impervious nature of pavement will cause those low lying areas to flood. Because the water flows faster on the surface than it migrates through heavily packed soil, the result is a water build up that can not only flood the now saturated area, but will in fact flood the lowest areas period. Dirt has an absorption rate that is (somewhat counter-intuitively) actually negatively impacted by becoming excessively dry. This is why Phoenix, notable for rare but massive rain storms, has enormous flooding problems that they deal with mostly by creating buffer areas in the form of intentionally designed flood zones (e.g., parks with berms around them or underpasses). Houston is designed like this as well (the Addicks and Barker reservoirs). But they are designed based on a given rate of rain over a given area. That assumption wasn't actually violated that badly by Harvey, it was within the margin of error. What was violated in the Houston flood model was the amount of hardscape and where the homes were. The assumptions about the amount of hardscape affects how much of a given rain will reach the reservoir (a lot never does to to evaporation or local use) as well as the rate at which that water reaches the reservoir. That whole system is designed to rate limit the flow of water into the core of the city of Houston. The model and assumptions were built when the core of the city was the main part of the city and the suburbs were much smaller. The water has to go somewhere, and it wants to go into the gulf of mexico...but the rivers and canals in the city core have a limited discharge rate into the gulf. Therefore the goal was based on creating a system that tolerated the hardscape based reduction of the cities 'sponge' and a greater reliance on the sponges of the suburbs. This is all not to mention that they actually built homes INSIDE the reservoirs that are a lot of what we talk about when we talk about the Houston flooding...those homes flooding was the system working as designed, the only people out of the loop were homeowners (slightly more true: and realtors, developers, and local officials who aren't hydrological engineers) [0]. They should have known better but they didn't, because people tend to not notice, understand, or take seriously these details of municipal planning. Then they are shocked when either it works as designed (as a net positive for society at potential costs to individuals) or when it fails because choices made from lack of knowledge have blithly broken a system that is designed for emergencies. Think of it this way, there were people in the Houston gov who knew exactly what was going to happen...do you think talking about a biblical level flood in Houston was going to be taken as a more powerful narrative than 'economic growth, jobs, housing, american dream' when deciding on zoning permits? TL;DR any sponge can become saturated but the point is that you should not artificially reduce the size of your sponge. Cities know how big their sponge is, its the ground around them. They make predictions and plans on it...and then subdivisions and growth massively seal off parts of the sponge. [0] https://projects.propublica.org/graphics/harvey-reservoirs https://projects.propublica.org/graphics/harvey-reservoirs
WillReplyfFood 9y ago
How to build a City that doesent swarm with mosquitos? Design the sponge to kill live near the surface
- chmod775 9y ago
  Birds?
lerie82 9y ago
The problem isn't flooding, the problem is that people built the city in the wrong place.
- galobtter 9y ago
  I wouldn't say that. Cities were built next to rivers and seas because they provided ways of transport, water, and places to dump waste etc. You can't build a city inland without a lot of trouble. But rivers and oceans flood and have hurricanes..
  - lerie82 9y ago
    Of course that's true but ships need water not buildings, I think we our civilization is old enough to know about flooding, we just don't care to address it until sometime happens. Can we not just transport the goods just a bit farther and start moving away from the flooded areas without having to waste money and manpower on sponges? Lol
    - Feniks 9y ago
      Not in my country, there are rivers every 50 kilometres and canals between those.
nbrigmon 9y ago
Hmmm... this invites some unintended consequences, no?
Dowwie 9y ago
Or you can build a ginormous cistern beneath the city, as Tokyo did: https://gizmodo.com/tokyo-has-the-largest-underground-water-tank-in-the-wor-1696967098 https://gizmodo.com/tokyo-has-the-largest-underground-water-...
- jbeales 9y ago
  Which may not be large enough: http://www.todayonline.com/world/tokyo-preparing-floods-beyond-anything-weve-seen http://www.todayonline.com/world/tokyo-preparing-floods-beyo...
geebee 9y ago
San Francisco has a similar problem to the one described in Pittsburg. We use an old, single pipe, gravity based system that carries both storm water and sewage. When it rains heavily, the system backs up at various bottlenecks. Unfortunately, some of these are in heavily populated and residential areas, which get flooded with human waste. Even areas not at the bottlenecks may see more mild drainage backups. Sadly, SF has done a pretty bad job managing this: http://www.sfweekly.com/news/shit-storm-why-wont-sf-stop-flooding-homes-with-sewage/ http://www.sfweekly.com/news/shit-storm-why-wont-sf-stop-flo... SF's esponse to this problem has shaken my confidence in the city's governance. SF is going in the opposite direction from what is suggested in this article - we are paving over (with non-permeable surfacing) more than ever. The common practice of paving over your front year for extra parking is generally illegal, but like most quality of life issues in SF, enforcement is so rare that the city created an entitlement - and it has become the norm in some neighborhoods. I know some people my chuckle that this particular issue would cause me to question SF's government, considering what is going on. But I think it's the straightforward nature of this - the clear engineering failure, the cause and effect between excessive paving and storm system overflow, the unenforced legislation to curtail it, the massive city budget and projects without adequate funding for critical infrastructure... it's the mundane failures that really drive home how badly SF's government is handling serious problems.
- teekert 9y ago
  Amsterdam has this problem as well, it is now generally discouraged to pave your garden. Moreover projects using the "rain away tile" are popping up: http://rainaway.nl/ http://rainaway.nl/
  - sharpercoder 9y ago
    And also a the term "tegel-tax" (tile-tax) is introduced. The idea is to tax real estate based on the amount of non-permeable surface it has. More non-permeable surface resulting in a higher tax bill. Satellite & plane imaging combined with computational analysis would enable enforcement.
- closeparen 9y ago
Spooky23 9y ago
I think a great example of a good outcome when people give a hoot about stormwater (and other water removal options since it is an low lying coastal island!) and the environment is Hilton Head Island, SC. The town is aggressive or even militant about unnecessary tree removal. The result is really interesting suburban infrastructure that reducing demand on the storm sewer. The Walmart parking lot isn't 5 acres of asphalt -- they left trees in place and have soil buffers with grass or other landscaping. Curbs are designed to direct water flow to those buffers. I live in upstate NY, and even in that very different environment, those types of techniques as well as things like retaining pounds can really improve the situation with respect to flooding. Otherwise, the only way to remediate the impact of the increasing number of high volume thunderstorms is to dig up streets and build cisterns to sudden inflows.
- galobtter 9y ago
  While I think having more trees is good, I wonder if those trees and grass could lead to problems in the concrete and asphalt.
  - beached_whale 9y ago
    Winter takes care of that for the tree's. No worries, the surface will be potted and uneven in a year or two.
  - Spooky23 9y ago
    Depends on the tree and how the lots are built.
  - robotresearcher 9y ago
    Won't somebody think of the concrete and asphalt!?
    - jliptzin 9y ago
      One of the rare comments that actually made me LOL
- 9y ago
peterwwillis 9y ago
Dig up all the paved streets and replace with soil, with train tracks on top. Adapt vehicle wheels to train wheels and provide platforms on train wheels for the ones you don't adapt. Provide overhead lines to power vehicles adapted to use them. You get 1. drainage, 2. reduction of heated urban micro-climates, 3. elimination of emissions, 4. "driving automation" in the sense that you don't really need to steer something on rails.
- heartbreak 9y ago
  Are we planning to use manual labor to dig up the streets? Otherwise that sounds like a significant emissions problem in itself.
  - swimfar 9y ago
    Depending on where you live, they may already be doing that every 2-3 years anyways.
    - heartbreak 9y ago
      I’m aware of resurfacing projects, but I’m not aware of total replacement projects.
- dsfyu404ed 9y ago
  >Dig up all the paved streets and replace with soil, with train tracks on top. Adapt vehicle wheels to train wheels and provide platforms on train wheels for the ones you don't adapt. Provide overhead lines to power vehicles adapted to use them. Seriously? Steel wheels on steel tracks are way more efficient than rubber on asphalt. There are many reasons this hasn't been done already.
dogprez 9y ago
Michigan has be fighting a similar fight for the past couple decades. Wetlands were disappearing quickly from development and they realized how important they were to environmental health, essentially turning the state into a sponge/filter. There is a law there now that removal of wetlands requires developers to build a new wetlands elsewhere. They still have 40% less wetlands than pre-european times.
brudgers 9y ago
The techniques in the article will mitigate the effects of storm water. As was the case in Houston, urban flooding results from global weather events. No matter how Houston had been planned, all the water had to go somewhere and it was going to the low spots. The only counter-factual in which Houston would not have had some flooding is if there was no Houston. Ancient cities in Mesopotamia flooded. Ancient Rome flooded. Cities flood because they are built on or near bodies of water and bodies of water flood. The reason cities are built on or near bodies of water: water is a necessary condition for any city. Water is also an economic engine: fisheries, agriculture, waste removal, transport, trade. This makes flooding a price of doing business. It's not that mitigation is a bad idea. The bad idea is that a city will never flood. Though it is theoretically possible, it is practically unlikely.
- utexaspunk 9y ago
  One way to deal with flooding is to build highways in a manner where they become channels in such events. Kuala Lumpur, for example, has their SMART tunnel[1] which acts as a roadway normally but can be turned into a stormwater drainage tunnels. Houston had a prime opportunity in 1996 to do something similar[2] when I-10 W was rebuilt- and engineers recommended building a conduit under I-10 to carry flood water from the Barker and Addicks reservoirs to the ship channel. Alas, that proposal was ignored so West Houston flooded during Harvey. https://en.wikipedia.org/wiki/SMART_Tunnel https://en.wikipedia.org/wiki/SMART_Tunnel https://www.dallasnews.com/news/harvey/2017/09/05/houston-grew-officials-ignored-lifetime-chance-spare-thousands-flooding https://www.dallasnews.com/news/harvey/2017/09/05/houston-gr...
  - sliverstorm 9y ago
    Mis-step after mis-step. Is anything now being done differently in TX? Or is the plan to forget about it as soon as possible and cling to NFIP for next time?
    - utexaspunk 9y ago
      I live in Houston and there may be something in the works but if so I haven't heard about it yet. I sure hope someone is working on it...
mlinksva 9y ago
Some ideas along these lines (spongy waterfronts) for SF bay area cities at https://neighborland.com/resilientbay https://neighborland.com/resilientbay
deleted 9y ago
[deleted]
emersonrsantos 9y ago
In Brazil, there’s a capital called Curitiba that use rivers and parks with artificial lakes to control flooding with great success. http://i2ud.org/2013/08/flood-management-in-curitiba-metoropolitan-area-brazil/ http://i2ud.org/2013/08/flood-management-in-curitiba-metorop...

169 points by fern12 9y ago

gipp 9y ago

The last time I saw something about these highly porous pavement alternatives, it was pointed out they tend to be very vulnerable to freeze-thaw damage and that this damage also lowers the porosity dramatically. Basically making these kinds of materials unsuitable for urban use outside of tropical- or near-tropical areas. Has this changed?

galobtter 9y ago
http://www.cement.org/cement-concrete-applications/paving/pervious-concrete/pervious-concrete-and-freeze-thaw http://www.cement.org/cement-concrete-applications/paving/pe... "However, in climates prone to severe freeze-thaw cycles, some are hesitant to use pervious concrete pavements until it has been proven that pervious concrete can be made to resist freeze-thaw damage." Pittsburgh does go through freeze thaw cycle, so I assume there aren't much problems https://www.unh.edu/unhsc/sites/unh.edu.unhsc/files/pubs_specs_info/unhsc_houle_thesis_9_08.pdf https://www.unh.edu/unhsc/sites/unh.edu.unhsc/files/pubs_spe... According to this, it also reduces the amount of salt needed 75% for deicing and the pavement doesn't seem to have been damaged from reading the abstract.
- mcgrath_sh 9y ago
  Well, if Pittsburgh is using it, it is terrible. We have so many potholes (and huge ones). It has become much worse over the last ~5 years. For several months we had a multi-foot hole blocked off by cones until the city could fix it. It essentially was in the middle of a two way road. It was terrible. I see more and more each winter.
  - sonar_un 9y ago
    That's not because of the cement but the geology of Pittsburgh itself. Limestone bedrock and the "underground river" contributes to potholes and other geologic anomalies. If anything, adding bioswales and having a way to put the water back into the ground would stop the potholes from happening in the first place.
    - vwcx 9y ago
      Yes, but that still doesn't mitigate the rapid freeze/thaw effects on the concrete/asphalt that the City of Pittsburgh uses.
    - keenerd 9y ago
      I think you are confusing sinkholes and potholes. The two aren't really related.
  - ensignavenger 9y ago
    That sounds, from your description, more like a sink hole than a freeze-thaw induced crack? Hard to tell without seeing it.
roel_v 9y ago
Water flows through them, they don't really 'absorb' water. Of course there will be moments when it freezes when there's still water in them, but it's not equivalent to freezing a sponge. The parking lot on one of my buildings is paved with blocks like this (condition for getting the building permit), works great. Never slippery in winter, either. They weren't even more expensive than alternatives.
mabbo 9y ago
The main problem I see with them is people's perception about what porous pavements do. Great, water goes through them... and then what? The ground underneath the pavement is not some unlimited sinkhole for water. The ground table can and does fill up. Then it doesn't matter how porous your pavement is. Trees, grass, wetlands, etc, do better in part because they are preventing the water from leaving. They pool water in small puddles, they absorb water, leaves have water sit on them, etc.

dsego 9y ago

Solutions mentioned are I think referred to as BMPs - best management practices [1]. Regulations exists and there are scientific software tools for tracking and planning [2]. [1] https://en.wikipedia.org/wiki/Best_management_practice_for_water_pollution https://en.wikipedia.org/wiki/Best_management_practice_for_w... [2] http://www.2nform.com/tools/ http://www.2nform.com/tools/

Retric 9y ago

I suspect it's cheaper to simply build a large enough drainage system initially. This is useful if you have already failed and are trying to cope with failure. Still, many people are pushing it because you get more plants not because it's cost effective.

galobtter 9y ago
Like the other guy pointed out, there isn't always an area to drain too. Also I'd say having more plants has other benefits, and so does draining water into the ground, which would lead to more ground water edit: and into an aquifer (like wanderr pointed out) instead of wasted into an ocean
24gttghh 9y ago
There are certain ways of building swales[0] in an urban environment that can help absorb or slow the leeching of nasty chemicals in runoff into groundwater or communities downstream. [0]http://nwrm.eu/measure/swales http://nwrm.eu/measure/swales
mnw21cam 9y ago
It depends if you have somewhere benign to drain all the water into. If there is a population downstream that might get annoyed if you dump lots of run-off on them, then making your land more sponge-like can be really useful. If "downstream" is the ocean a mile away, not so much.
- wanderr 9y ago
  There is also potentially a lot of benefit to having the water enter the soil and eventually make its way down into the aquifer instead of just shunting it "away".

n0us 9y ago

anyone who hasn't watched a clip on Tokyo's massive drainage system should check this out https://www.youtube.com/watch?v=o85teh1vU_0 https://www.youtube.com/watch?v=o85teh1vU_0

bob_theslob646 9y ago
Super interesting. Essentially, they built an underground river which is connected to many of Tokyo's rivers (many kilometer underground tunnel) that diverts overflow water from the rivers to prevent catastrophic flooding. It cost 3 billion dollars and took 13 years to build. I would like to see how these held up during the tsunami.
TorKlingberg 9y ago
Japan has spent a LOT of effort to mitigate floods. It does mean that all river banks anywhere near a city look the same, and very artificial.

AhtiK 9y ago

There's a related story on Berlin being built into a sponge city. https://www.bloomberg.com/news/videos/2017-08-18/sponge-city-making-berlin-cooler-video https://www.bloomberg.com/news/videos/2017-08-18/sponge-city...

baldfat 9y ago
I think Berlin's approach is better for colder climates. It just makes sure the water lands in soil and stays there. Each new construction site must do the same. So the roofs are green with soil and the road's water goes into the soil and the buildings have a layer of soil on top of underground garages.

hsnewman 9y ago

Broad statement for the subject. I suspect even a sponge can be saturated.

Arnt 9y ago
Obviously, but that's not the test. The test is whether the sponge can absorb rain as fast as it can fall for a long-enough time that other consequences of the rain become serious problems (e.g. deferred outdoor maintenance), while the sponge still isn't saturated.
- galobtter 9y ago
  It's mostly I think the limit of how fast the ground can absorb water after it has passed through the pavement. If the water rises through the pavement..
thinkMOAR 9y ago
and imagine what happens when a freeze comes by and what it does to the sponges' life
avs733 9y ago
The issue is one of rates not volume. They briefly mention Houston in passing, which is a perfect example. The water is all part of the same cycle and same watershed, but where it goes within that watershed and at what rate become critical. If you make 50% of an area impervious to absorbing water (i.e., you pave it) then the remaining 50% has to absorb much more water, and likely will become saturated. But first, the impervious nature of pavement will cause those low lying areas to flood. Because the water flows faster on the surface than it migrates through heavily packed soil, the result is a water build up that can not only flood the now saturated area, but will in fact flood the lowest areas period. Dirt has an absorption rate that is (somewhat counter-intuitively) actually negatively impacted by becoming excessively dry. This is why Phoenix, notable for rare but massive rain storms, has enormous flooding problems that they deal with mostly by creating buffer areas in the form of intentionally designed flood zones (e.g., parks with berms around them or underpasses). Houston is designed like this as well (the Addicks and Barker reservoirs). But they are designed based on a given rate of rain over a given area. That assumption wasn't actually violated that badly by Harvey, it was within the margin of error. What was violated in the Houston flood model was the amount of hardscape and where the homes were. The assumptions about the amount of hardscape affects how much of a given rain will reach the reservoir (a lot never does to to evaporation or local use) as well as the rate at which that water reaches the reservoir. That whole system is designed to rate limit the flow of water into the core of the city of Houston. The model and assumptions were built when the core of the city was the main part of the city and the suburbs were much smaller. The water has to go somewhere, and it wants to go into the gulf of mexico...but the rivers and canals in the city core have a limited discharge rate into the gulf. Therefore the goal was based on creating a system that tolerated the hardscape based reduction of the cities 'sponge' and a greater reliance on the sponges of the suburbs. This is all not to mention that they actually built homes INSIDE the reservoirs that are a lot of what we talk about when we talk about the Houston flooding...those homes flooding was the system working as designed, the only people out of the loop were homeowners (slightly more true: and realtors, developers, and local officials who aren't hydrological engineers) [0]. They should have known better but they didn't, because people tend to not notice, understand, or take seriously these details of municipal planning. Then they are shocked when either it works as designed (as a net positive for society at potential costs to individuals) or when it fails because choices made from lack of knowledge have blithly broken a system that is designed for emergencies. Think of it this way, there were people in the Houston gov who knew exactly what was going to happen...do you think talking about a biblical level flood in Houston was going to be taken as a more powerful narrative than 'economic growth, jobs, housing, american dream' when deciding on zoning permits? TL;DR any sponge can become saturated but the point is that you should not artificially reduce the size of your sponge. Cities know how big their sponge is, its the ground around them. They make predictions and plans on it...and then subdivisions and growth massively seal off parts of the sponge. [0] https://projects.propublica.org/graphics/harvey-reservoirs https://projects.propublica.org/graphics/harvey-reservoirs

WillReplyfFood 9y ago

How to build a City that doesent swarm with mosquitos? Design the sponge to kill live near the surface

chmod775 9y ago
Birds?

lerie82 9y ago

The problem isn't flooding, the problem is that people built the city in the wrong place.

galobtter 9y ago
I wouldn't say that. Cities were built next to rivers and seas because they provided ways of transport, water, and places to dump waste etc. You can't build a city inland without a lot of trouble. But rivers and oceans flood and have hurricanes..
- lerie82 9y ago
  Of course that's true but ships need water not buildings, I think we our civilization is old enough to know about flooding, we just don't care to address it until sometime happens. Can we not just transport the goods just a bit farther and start moving away from the flooded areas without having to waste money and manpower on sponges? Lol
  - Feniks 9y ago
    Not in my country, there are rivers every 50 kilometres and canals between those.

nbrigmon 9y ago

Hmmm... this invites some unintended consequences, no?

Dowwie 9y ago

Or you can build a ginormous cistern beneath the city, as Tokyo did: https://gizmodo.com/tokyo-has-the-largest-underground-water-tank-in-the-wor-1696967098 https://gizmodo.com/tokyo-has-the-largest-underground-water-...

jbeales 9y ago
Which may not be large enough: http://www.todayonline.com/world/tokyo-preparing-floods-beyond-anything-weve-seen http://www.todayonline.com/world/tokyo-preparing-floods-beyo...

geebee 9y ago

San Francisco has a similar problem to the one described in Pittsburg. We use an old, single pipe, gravity based system that carries both storm water and sewage. When it rains heavily, the system backs up at various bottlenecks. Unfortunately, some of these are in heavily populated and residential areas, which get flooded with human waste. Even areas not at the bottlenecks may see more mild drainage backups. Sadly, SF has done a pretty bad job managing this: http://www.sfweekly.com/news/shit-storm-why-wont-sf-stop-flooding-homes-with-sewage/ http://www.sfweekly.com/news/shit-storm-why-wont-sf-stop-flo... SF's esponse to this problem has shaken my confidence in the city's governance. SF is going in the opposite direction from what is suggested in this article - we are paving over (with non-permeable surfacing) more than ever. The common practice of paving over your front year for extra parking is generally illegal, but like most quality of life issues in SF, enforcement is so rare that the city created an entitlement - and it has become the norm in some neighborhoods. I know some people my chuckle that this particular issue would cause me to question SF's government, considering what is going on. But I think it's the straightforward nature of this - the clear engineering failure, the cause and effect between excessive paving and storm system overflow, the unenforced legislation to curtail it, the massive city budget and projects without adequate funding for critical infrastructure... it's the mundane failures that really drive home how badly SF's government is handling serious problems.

teekert 9y ago
Amsterdam has this problem as well, it is now generally discouraged to pave your garden. Moreover projects using the "rain away tile" are popping up: http://rainaway.nl/ http://rainaway.nl/
- sharpercoder 9y ago
  And also a the term "tegel-tax" (tile-tax) is introduced. The idea is to tax real estate based on the amount of non-permeable surface it has. More non-permeable surface resulting in a higher tax bill. Satellite & plane imaging combined with computational analysis would enable enforcement.
closeparen 9y ago

Spooky23 9y ago

I think a great example of a good outcome when people give a hoot about stormwater (and other water removal options since it is an low lying coastal island!) and the environment is Hilton Head Island, SC. The town is aggressive or even militant about unnecessary tree removal. The result is really interesting suburban infrastructure that reducing demand on the storm sewer. The Walmart parking lot isn't 5 acres of asphalt -- they left trees in place and have soil buffers with grass or other landscaping. Curbs are designed to direct water flow to those buffers. I live in upstate NY, and even in that very different environment, those types of techniques as well as things like retaining pounds can really improve the situation with respect to flooding. Otherwise, the only way to remediate the impact of the increasing number of high volume thunderstorms is to dig up streets and build cisterns to sudden inflows.

galobtter 9y ago
While I think having more trees is good, I wonder if those trees and grass could lead to problems in the concrete and asphalt.
- beached_whale 9y ago
  Winter takes care of that for the tree's. No worries, the surface will be potted and uneven in a year or two.
- Spooky23 9y ago
  Depends on the tree and how the lots are built.
- robotresearcher 9y ago
  Won't somebody think of the concrete and asphalt!?
  - jliptzin 9y ago
    One of the rare comments that actually made me LOL
9y ago

peterwwillis 9y ago

Dig up all the paved streets and replace with soil, with train tracks on top. Adapt vehicle wheels to train wheels and provide platforms on train wheels for the ones you don't adapt. Provide overhead lines to power vehicles adapted to use them. You get 1. drainage, 2. reduction of heated urban micro-climates, 3. elimination of emissions, 4. "driving automation" in the sense that you don't really need to steer something on rails.

heartbreak 9y ago
Are we planning to use manual labor to dig up the streets? Otherwise that sounds like a significant emissions problem in itself.
- swimfar 9y ago
  Depending on where you live, they may already be doing that every 2-3 years anyways.
  - heartbreak 9y ago
    I’m aware of resurfacing projects, but I’m not aware of total replacement projects.
dsfyu404ed 9y ago
>Dig up all the paved streets and replace with soil, with train tracks on top. Adapt vehicle wheels to train wheels and provide platforms on train wheels for the ones you don't adapt. Provide overhead lines to power vehicles adapted to use them. Seriously? Steel wheels on steel tracks are way more efficient than rubber on asphalt. There are many reasons this hasn't been done already.

dogprez 9y ago

Michigan has be fighting a similar fight for the past couple decades. Wetlands were disappearing quickly from development and they realized how important they were to environmental health, essentially turning the state into a sponge/filter. There is a law there now that removal of wetlands requires developers to build a new wetlands elsewhere. They still have 40% less wetlands than pre-european times.

brudgers 9y ago

The techniques in the article will mitigate the effects of storm water. As was the case in Houston, urban flooding results from global weather events. No matter how Houston had been planned, all the water had to go somewhere and it was going to the low spots. The only counter-factual in which Houston would not have had some flooding is if there was no Houston. Ancient cities in Mesopotamia flooded. Ancient Rome flooded. Cities flood because they are built on or near bodies of water and bodies of water flood. The reason cities are built on or near bodies of water: water is a necessary condition for any city. Water is also an economic engine: fisheries, agriculture, waste removal, transport, trade. This makes flooding a price of doing business. It's not that mitigation is a bad idea. The bad idea is that a city will never flood. Though it is theoretically possible, it is practically unlikely.

utexaspunk 9y ago
One way to deal with flooding is to build highways in a manner where they become channels in such events. Kuala Lumpur, for example, has their SMART tunnel[1] which acts as a roadway normally but can be turned into a stormwater drainage tunnels. Houston had a prime opportunity in 1996 to do something similar[2] when I-10 W was rebuilt- and engineers recommended building a conduit under I-10 to carry flood water from the Barker and Addicks reservoirs to the ship channel. Alas, that proposal was ignored so West Houston flooded during Harvey. https://en.wikipedia.org/wiki/SMART_Tunnel https://en.wikipedia.org/wiki/SMART_Tunnel https://www.dallasnews.com/news/harvey/2017/09/05/houston-grew-officials-ignored-lifetime-chance-spare-thousands-flooding https://www.dallasnews.com/news/harvey/2017/09/05/houston-gr...
- sliverstorm 9y ago
  Mis-step after mis-step. Is anything now being done differently in TX? Or is the plan to forget about it as soon as possible and cling to NFIP for next time?
  - utexaspunk 9y ago
    I live in Houston and there may be something in the works but if so I haven't heard about it yet. I sure hope someone is working on it...

mlinksva 9y ago

Some ideas along these lines (spongy waterfronts) for SF bay area cities at https://neighborland.com/resilientbay https://neighborland.com/resilientbay

deleted 9y ago

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emersonrsantos 9y ago

In Brazil, there’s a capital called Curitiba that use rivers and parks with artificial lakes to control flooding with great success. http://i2ud.org/2013/08/flood-management-in-curitiba-metoropolitan-area-brazil/ http://i2ud.org/2013/08/flood-management-in-curitiba-metorop...