5 ms·

Rainfall flooding is becoming an issue

57 points by prostoalex 5y ago

thrower123 5y ago
Becoming an issue? I would suggest anybody who thinks this is a novel problem examine the history of north-central China. Every few centuries flooding is bad enough, and hydraulic infrastructure degrades enough that the Yellow river drastically changes its course.
- croes 5y ago
  Did you consider that China is just a recent example of flooding and the article is about flooding as such? The floods in Germany, Belgium and the Netherlands just happened last week.
  - thrower123 5y ago
    You're just being inflammatory. And the European floods are the same problems as well. In the USA, every other year there's some awful looking flooding on the Mississippi or the Missouri or the Ohio, because some heavy snowmelt, or heavy rain, and then a levee breaks, and the people that built in the floodplain get swamped out. It's a thing that happens, and has always happened, and will always happen, so long as human beings build cities in floodplains.
    - croes 5y ago
      That's the problem. These floods didn't happen at the usual locations like Rhine and Moselle because they weren't caused by snowmelt but usual heavy rain. You are trivializing the problem, just like some trivialize climate change by saying that these also happened in the past. In both cases these things happened slower than now. The flood is one problem, the short time frame another and you are completely ignoring the latter.
baxtr 5y ago
I really wonder how people think valleys were created in the first place?
- arethuza 5y ago
  Does rather depend where you are - in lots of places glaciation has had far more effect on the landscape than running water.
- long_time_gone 5y ago
  I don't think most people spend time thinking about such things. They are likely more focused on finding/maintaining clean water, food, shelter, and health.
mc32 5y ago
Yes it’s becoming an issue because over the past century the pop of China has approximately tripled and people are living in flood zones. Historically these flood plains have been both a boon and a curse. They bring nutrient rich soil for crops to grow in but also bring potential devastation, hence the dam building since the revolution. It’s always been an “issue”. I’m not saying climate change isn’t a thing. It is. I just hate opportunistic misinformation where things are framed in a particular way to spook people. This is like saying malnutrition in underdeveloped countries is becoming an issue. It’s always existed.
- Jyaif 5y ago
  I agree that floods in places where they haven't gone through centuries of natural selection of cities are not surprising. What's surprising is that floods also killed hundreds of people in the old continent.
- scrollaway 5y ago
  As someone living in Belgium, less than an hour away from various places that days ago experienced their worst floods ever and with friends who lost their homes… I wonder what the hell China has to do with those. Go on? The article may talk about China but this is a general problem.
  - lexa1979 5y ago
    China also got floods 2 days ago. (Hi from Hotton ! ...with dry feet now)
    - selimthegrim 5y ago
      How are the melons doing or is that just Hami?
    - scrollaway 5y ago
      Hi Hotton! I was in your area just a couple weeks ago. HMU for coffee if you're ever in Brussels or Mechelen. Email in my profile :)
baybal2 5y ago
The West has money to build drainage networks. The most of Asia, doesn't.
- dv_dt 5y ago
  Drainage networks take a lot of time and money to build. They are built for the best flood information at the time - but time and climate crisis has changed the inputs. Even if you have the money, it seems likely like a major risk that many areas will have shifted flood inputs and it will take more time than our current capacity to respond quickly. This is another reason to start addressing climate crisis more seriously ASAP.
- brainless 5y ago
  Had this article mentioned a nation other than China, I would have give your opinion any value. China has been putting so much money into its water management infrastructure (including dams, water re-routing) that most, if not all "western" nations put together are dwarfed. Go check your numbers before you spread more rumor, I will wait. Just one sample (currently most ambitious and expensive engineering projects in human history): https://en.wikipedia.org/wiki/South%E2%80%93North_Water_Transfer_Project https://en.wikipedia.org/wiki/South%E2%80%93North_Water_Tran...
  - deleted 5y ago
    [deleted]
  - baybal2 5y ago
    > Had this article mentioned a nation other than China, I would have give your opinion any value. Yes, a very notable exception. Most of China is catastrophically prone to floods, and would be unlivable without dams. I don't think there is anybody not knowing that. The "Most of Asia" here still stands. Even the rich Japan, and Korea don't particularly care to build drainages in their 2nd tier cities. The richest city in India, Mumbai, turns into Venice every mid-summer. South-East Asia... no comments. Cities other than their capitals turn unto bogs for most of the summer.
guerrilla 5y ago
Looking at the comments here right now, it seems like "don't build in valleys" is the new "but humans didn't cause it" which was the new "climate change is a hoax." The thing is, in the case of Germany at least, the reason people built there is because it hadn't flooded in those places in nearly a thousand years. That's why it's called a 500-year flood (due to the probability of it occurring.) They would have been washed away long ago if that weren't the case. I didn't follow the weather running up to or the analysis following the flooding in Henan but in Germany the flooding was caused by a dense low pressure system hanging around too long and there seems to be consensus that this was caused by the disruption of the jet stream and increased temperatures. We're not going to solve climate change by blaming people for living in the wrong place.
- mschuster91 5y ago
  > We're not going to solve climate change by blaming people for living in the wrong place. German here. We can and must blame politicians for handing out build permits in areas that once were flood beds for rivers that have been "straightened out". Also, ffs we need to restore rivers to their natural beds again. The pictures of the flooded areas exactly show that the rivers took their millennia old paths back!
  - guerrilla 5y ago
    Yes, the Greens have been talking about it forever, but don't use it as a distraction from the fact that there were actually torrential rains and that most of these places were relatively safe without such torrential rains.
    - praptak 5y ago
      It doesn't have to be one xor the other.
- praptak 5y ago
  I don't think it is about just not building in valleys. There are two approaches to floods: one is to leave enough space for the river to meander, flood and soak into the ground. The other is to regulate the river - dig it deeper, more straight, build embankments, basically making it an effective drain pipe. The second approach was popular in Europe because economy: it frees up valuable land (hence "building in valleys") and makes the river useful for things like transport. But it has downsides: it destroys habitat and efficient drainage here means a flood elsewhere. And then when you have superefficient drainage everywhere, it becomes a problem for ground water levels. So "don't build in valleys" is rather: don't over-regulate rivers to make buildable land.
PicassoCTs 5y ago
It should be relatively easy to calculate the max flood height and path of a area, with a given amount of rain on google maps. Anyone know such a tool?
- rmah 5y ago
  In the US, FEMA maintains flood maps for areas of the USA that are prone to flooding. Your tax dollars at work! You can access them here: https://www.fema.gov/flood-maps https://www.fema.gov/flood-maps
- montalbano 5y ago
  If there was such a tool, and it was accurate, do you think insurance companies would have insured the parts of Germany that recently flooded? I think you may be underestimating the complexity of both weather and climate modelling.
  - Proven 5y ago
    But we can predict average temperatures decades into the future!
  - PicassoCTs 5y ago
    Where i live, i know the whole water from a defined area flows through in a little stream. I know the areas watersheds and i know how much poured down in extreme cases. Thus i can mark the area on a topographic map, i can calculate the area and multiply it with the max amount of downpour. In my area thats 4490887(m^2) ×0,2(m^3 water) = 898 177.4 ^ m3 max rain water. Now all i want is a model of what areas would be reached on a stream if it received this much water. I know that some here are grumpy because there houses may loose value like a sinking ship very soon. But knowing is better then not knowing. Always. No fluid-simulations needed, just a basic Topographic map fill the pond.
    - woeirua 5y ago
      In the US at least the USGS builds floodplain predictions for most of the major streams/rivers using this exact method. The problem is that those maps typically underestimate the amount of water that falls during these extreme events.
villgax 5y ago
Cities usually don't have patches of green without concrete/paving of some kind to allow for proper drainage.
cmpb 5y ago
>Houston is trying to adapt. ... developers are now required to practice a kind of “leave no trace” policy when it comes to rainfall—once ... as a result, alongside Houston’s ubiquitous parking lots, many new projects feature grassy flood pits. There's a strong case to be made here for more community parks & woodland trails. They serve as extremely good water containment areas
- jounker 5y ago
  A comedic part about Houston flooding is that at least one large suburb on the west side was built within an overflow reservoir. The neighborhood is literally a water containment area.
  - caseysoftware 5y ago
    Which one is that?
    - nicwolff 5y ago
      Canyon Gate, among others, in Barker Reservoir's flood zone. Typically excellent interactive NY Times article on it here https://www.nytimes.com/interactive/2018/03/22/us/houston-harvey-flooding-reservoir.html https://www.nytimes.com/interactive/2018/03/22/us/houston-ha...
      - caseysoftware 5y ago
        Thanks! I hadn't seen that before.
  - oliwarner 5y ago
    That's alarmingly common. It only takes one idiotic or corrupt planning team to flip decades of sensible flood planning. All this land set aside gets built on and everyone acts surprised when it's foot-deep in raw sewage. Happens frequently in the UK. Too many fingers at every level of government happy to take a "donation" from a developer.
- 5y ago
gzu 5y ago
I wonder much of this is caused by recent installments of agricultural field drainage tile? Land price increases allow for more farmers to afford to "improve" their farmland by adding underground pipes that quickly wick standing water away into nearby creeks and rivers. What used to be evaporated or absorbed into soils is dumping straight into waterways.
- guerrilla 5y ago
  You're asking if over 600mm of rain (i.e. more than half a year's worth) in a 24 hour period in Henan was caused by recent installments of agricultural field drainage? Or if that caused the jet stream to hold the storm over NRW to drop months worth in a 24 hour period? 1. https://weatherspark.com/y/127378/Average-Weather-in-Zhengzhou-China-Year-Round https://weatherspark.com/y/127378/Average-Weather-in-Zhengzh... 2. https://weatherspark.com/y/58162/Average-Weather-in-Wuppertal-Germany-Year-Round https://weatherspark.com/y/58162/Average-Weather-in-Wupperta...

57 points by prostoalex 5y ago

Becoming an issue? I would suggest anybody who thinks this is a novel problem examine the history of north-central China. Every few centuries flooding is bad enough, and hydraulic infrastructure degrades enough that the Yellow river drastically changes its course.

croes 5y ago
Did you consider that China is just a recent example of flooding and the article is about flooding as such? The floods in Germany, Belgium and the Netherlands just happened last week.
- thrower123 5y ago
  You're just being inflammatory. And the European floods are the same problems as well. In the USA, every other year there's some awful looking flooding on the Mississippi or the Missouri or the Ohio, because some heavy snowmelt, or heavy rain, and then a levee breaks, and the people that built in the floodplain get swamped out. It's a thing that happens, and has always happened, and will always happen, so long as human beings build cities in floodplains.
  - croes 5y ago
    That's the problem. These floods didn't happen at the usual locations like Rhine and Moselle because they weren't caused by snowmelt but usual heavy rain. You are trivializing the problem, just like some trivialize climate change by saying that these also happened in the past. In both cases these things happened slower than now. The flood is one problem, the short time frame another and you are completely ignoring the latter.

baxtr 5y ago

I really wonder how people think valleys were created in the first place?

arethuza 5y ago
Does rather depend where you are - in lots of places glaciation has had far more effect on the landscape than running water.
long_time_gone 5y ago
I don't think most people spend time thinking about such things. They are likely more focused on finding/maintaining clean water, food, shelter, and health.

mc32 5y ago

Yes it’s becoming an issue because over the past century the pop of China has approximately tripled and people are living in flood zones. Historically these flood plains have been both a boon and a curse. They bring nutrient rich soil for crops to grow in but also bring potential devastation, hence the dam building since the revolution. It’s always been an “issue”. I’m not saying climate change isn’t a thing. It is. I just hate opportunistic misinformation where things are framed in a particular way to spook people. This is like saying malnutrition in underdeveloped countries is becoming an issue. It’s always existed.

Jyaif 5y ago
I agree that floods in places where they haven't gone through centuries of natural selection of cities are not surprising. What's surprising is that floods also killed hundreds of people in the old continent.
scrollaway 5y ago
As someone living in Belgium, less than an hour away from various places that days ago experienced their worst floods ever and with friends who lost their homes… I wonder what the hell China has to do with those. Go on? The article may talk about China but this is a general problem.
- lexa1979 5y ago
  China also got floods 2 days ago. (Hi from Hotton ! ...with dry feet now)
  - selimthegrim 5y ago
    How are the melons doing or is that just Hami?
  - scrollaway 5y ago
    Hi Hotton! I was in your area just a couple weeks ago. HMU for coffee if you're ever in Brussels or Mechelen. Email in my profile :)

baybal2 5y ago

The West has money to build drainage networks. The most of Asia, doesn't.

dv_dt 5y ago
Drainage networks take a lot of time and money to build. They are built for the best flood information at the time - but time and climate crisis has changed the inputs. Even if you have the money, it seems likely like a major risk that many areas will have shifted flood inputs and it will take more time than our current capacity to respond quickly. This is another reason to start addressing climate crisis more seriously ASAP.
brainless 5y ago
Had this article mentioned a nation other than China, I would have give your opinion any value. China has been putting so much money into its water management infrastructure (including dams, water re-routing) that most, if not all "western" nations put together are dwarfed. Go check your numbers before you spread more rumor, I will wait. Just one sample (currently most ambitious and expensive engineering projects in human history): https://en.wikipedia.org/wiki/South%E2%80%93North_Water_Transfer_Project https://en.wikipedia.org/wiki/South%E2%80%93North_Water_Tran...
- deleted 5y ago
  [deleted]
- baybal2 5y ago
  > Had this article mentioned a nation other than China, I would have give your opinion any value. Yes, a very notable exception. Most of China is catastrophically prone to floods, and would be unlivable without dams. I don't think there is anybody not knowing that. The "Most of Asia" here still stands. Even the rich Japan, and Korea don't particularly care to build drainages in their 2nd tier cities. The richest city in India, Mumbai, turns into Venice every mid-summer. South-East Asia... no comments. Cities other than their capitals turn unto bogs for most of the summer.

guerrilla 5y ago

Looking at the comments here right now, it seems like "don't build in valleys" is the new "but humans didn't cause it" which was the new "climate change is a hoax." The thing is, in the case of Germany at least, the reason people built there is because it hadn't flooded in those places in nearly a thousand years. That's why it's called a 500-year flood (due to the probability of it occurring.) They would have been washed away long ago if that weren't the case. I didn't follow the weather running up to or the analysis following the flooding in Henan but in Germany the flooding was caused by a dense low pressure system hanging around too long and there seems to be consensus that this was caused by the disruption of the jet stream and increased temperatures. We're not going to solve climate change by blaming people for living in the wrong place.

mschuster91 5y ago
> We're not going to solve climate change by blaming people for living in the wrong place. German here. We can and must blame politicians for handing out build permits in areas that once were flood beds for rivers that have been "straightened out". Also, ffs we need to restore rivers to their natural beds again. The pictures of the flooded areas exactly show that the rivers took their millennia old paths back!
- guerrilla 5y ago
  Yes, the Greens have been talking about it forever, but don't use it as a distraction from the fact that there were actually torrential rains and that most of these places were relatively safe without such torrential rains.
  - praptak 5y ago
    It doesn't have to be one xor the other.
praptak 5y ago
I don't think it is about just not building in valleys. There are two approaches to floods: one is to leave enough space for the river to meander, flood and soak into the ground. The other is to regulate the river - dig it deeper, more straight, build embankments, basically making it an effective drain pipe. The second approach was popular in Europe because economy: it frees up valuable land (hence "building in valleys") and makes the river useful for things like transport. But it has downsides: it destroys habitat and efficient drainage here means a flood elsewhere. And then when you have superefficient drainage everywhere, it becomes a problem for ground water levels. So "don't build in valleys" is rather: don't over-regulate rivers to make buildable land.

PicassoCTs 5y ago

It should be relatively easy to calculate the max flood height and path of a area, with a given amount of rain on google maps. Anyone know such a tool?

rmah 5y ago
In the US, FEMA maintains flood maps for areas of the USA that are prone to flooding. Your tax dollars at work! You can access them here: https://www.fema.gov/flood-maps https://www.fema.gov/flood-maps
montalbano 5y ago
If there was such a tool, and it was accurate, do you think insurance companies would have insured the parts of Germany that recently flooded? I think you may be underestimating the complexity of both weather and climate modelling.
- Proven 5y ago
  But we can predict average temperatures decades into the future!
- PicassoCTs 5y ago
  Where i live, i know the whole water from a defined area flows through in a little stream. I know the areas watersheds and i know how much poured down in extreme cases. Thus i can mark the area on a topographic map, i can calculate the area and multiply it with the max amount of downpour. In my area thats 4490887(m^2) ×0,2(m^3 water) = 898 177.4 ^ m3 max rain water. Now all i want is a model of what areas would be reached on a stream if it received this much water. I know that some here are grumpy because there houses may loose value like a sinking ship very soon. But knowing is better then not knowing. Always. No fluid-simulations needed, just a basic Topographic map fill the pond.
  - woeirua 5y ago
    In the US at least the USGS builds floodplain predictions for most of the major streams/rivers using this exact method. The problem is that those maps typically underestimate the amount of water that falls during these extreme events.

villgax 5y ago

Cities usually don't have patches of green without concrete/paving of some kind to allow for proper drainage.

cmpb 5y ago

>Houston is trying to adapt. ... developers are now required to practice a kind of “leave no trace” policy when it comes to rainfall—once ... as a result, alongside Houston’s ubiquitous parking lots, many new projects feature grassy flood pits. There's a strong case to be made here for more community parks & woodland trails. They serve as extremely good water containment areas

jounker 5y ago
A comedic part about Houston flooding is that at least one large suburb on the west side was built within an overflow reservoir. The neighborhood is literally a water containment area.
- caseysoftware 5y ago
  Which one is that?
  - nicwolff 5y ago
    Canyon Gate, among others, in Barker Reservoir's flood zone. Typically excellent interactive NY Times article on it here https://www.nytimes.com/interactive/2018/03/22/us/houston-harvey-flooding-reservoir.html https://www.nytimes.com/interactive/2018/03/22/us/houston-ha...
    - caseysoftware 5y ago
      Thanks! I hadn't seen that before.
- oliwarner 5y ago
  That's alarmingly common. It only takes one idiotic or corrupt planning team to flip decades of sensible flood planning. All this land set aside gets built on and everyone acts surprised when it's foot-deep in raw sewage. Happens frequently in the UK. Too many fingers at every level of government happy to take a "donation" from a developer.
5y ago

gzu 5y ago

I wonder much of this is caused by recent installments of agricultural field drainage tile? Land price increases allow for more farmers to afford to "improve" their farmland by adding underground pipes that quickly wick standing water away into nearby creeks and rivers. What used to be evaporated or absorbed into soils is dumping straight into waterways.

guerrilla 5y ago
You're asking if over 600mm of rain (i.e. more than half a year's worth) in a 24 hour period in Henan was caused by recent installments of agricultural field drainage? Or if that caused the jet stream to hold the storm over NRW to drop months worth in a 24 hour period? 1. https://weatherspark.com/y/127378/Average-Weather-in-Zhengzhou-China-Year-Round https://weatherspark.com/y/127378/Average-Weather-in-Zhengzh... 2. https://weatherspark.com/y/58162/Average-Weather-in-Wuppertal-Germany-Year-Round https://weatherspark.com/y/58162/Average-Weather-in-Wupperta...