These kinds of techniques are often claimed to be effective against flash floods, which makes sense since they slow down water transfer to rivers. Does anyone know any studies about how effective it could be against seriously heavy precipitation of the scale of Harvey or South Asia floods right now? In other words, how well does the approach scale?
Civil engineering has pretty well quantified the rate at which water is absorbed by certain soils, accounting for groundcover, trees, pavement, local detainment, etc. Berlin's sponge mission is baiscially distributed detainment, working to offset hardscaping (driveways and roofing). In other words, it's a well known and very predictable science, but we (we being US land development industry) has not cared. HOWEVER rain at the scale of Harvey cannot practically be planned for beyond "don't build on land that's lower than average"
Well, that's partly true. A lot of the flooding is due to the fact that the entirety of Texas doesn't care about hydrology, and all that water is ending up downstream, in Houston.
There'd still be flooding, and it would still be bad, but a certain degree of flooding was avoidable.
The other thought, I imagine, is that they felt the probability was low that they would see a flood of this scale even within their lifetime; that ended up being a poor bet. Even so, flood insurance is also cheaper when the perceived likelihood of a flood is low.
As you almost certainly know, the city controls permissions for every building.
A city that gives planning permission for a development that is probably going to be destroyed with loss of life in the next hundred years is not serving people well.
Eh it is wholly true. Distributed detention schemes still have a finite volume of containment, and once the detention zones are saturated, those areas behave equally to pavement for each additional unit of water. 50 inches of water across the majority of Texas with severe storm surge cannot be practically prepared for beyond insurance, evacuation, and/or a boat. To say “it was avoidable” is a strong and expensive assertion requires some hard backup. Heres an introduction to runoff coefficient (disclaimer! exciting stuff!). Everything is based on a “design storm” with a specified duration and intensity, where those two variables lead to a sigmoid curve (as i recall) for runoff, or the greater the intensity and longer the duration, the less water that gets detained. http://www.brighthubengineering.com/hydraulics-civil-enginee...
I remember a demonstration from my childhood where water is released into 2 similar models. One model is dry, one model is wet. The water quickly overtakes the dry model and splashes on the other side (as in a flash flood). On the wet model, water takes longer to make it to the other side. Sort of how a wet sponge is far more absorbent than a dry sponge.
I know I didn't really answer your question, but these models were made to represent fields and swamps. So yes, I believe there are lots of studies on large scale effects.
I don't know of any studies but I would imagine a lot of variables come into play.
Soil Type & how deep of soil effects how much water the ground can soak up & how fast the water will run. All would be slower runoff than concrete.
Also the slope of the land would make a difference.
These are just the obvious ones. Bottlenecks, whether created on purpose or not would have a huge impact. Where I live we have large snowfall in the winter which creates ice jams & flash flooding in the spring.
Every inch of rain absorbed makes a rather dramatic difference. Because, floods are moving a lot of water but they also contain a lot of water which is time shifted over a longer period of time.
Think of it like a building being evacuated though a stairwell. Being say 10 vs 11 floors can make a significant difference in average wait time. Except average weight time is equivalent to the height of flood waters.
My first thought is that it might be hard to prevent decay and leaks into the structures supporting these spongy surfaces. 80cm of water logged soil above a parking garage, for example.
The renderings they are showing for newer plans (at 1:27 of the video) seem to indicate a soil later running a long the wall of the building, in addition to the roof. As the result water would naturally travel down that wall and into the surrounding soil, preventing the buildup on the roof and negating need for a traditional drain.
That said, what would be required to make sure no barrier formed, say from the roots system or something else is really hard to say.
You'd also need some sort of lining that would prevent the moisture from being obsorbed by the building materials themselves.
Planting grass on top of parking garages isn't that unusual or new in Germany (though usually done for aesthetic reasons), so I assume this is a solved problem.
Sufficiently deep buildings and parking garages might also encounter ground water, so adding soil on top might not even add new problems to the engineering side.
Similarly, the rooftop plants are shown on rooftop designs that would already have to deal with stagnating water
funny just watched this yesterday night. Was really surprised by it. When you live in Berlin it's not something you see that yet. But of course Berlin is a more green city than something of the size of New York just by being smaller.
Not answering your main question, but the video shows relatively small buildings because that's what Berlin looks like[1]. High rise towers are not very common there.
The problem you are talking about is different and can be solved with traditional means (i.e. sprinklers) if needed. But due the fact the prior rain water is present on site for a longer time instead of being drained off in sewers they may not need to run the sprinklers as often (another benefit!)
Berlin was a sump before becoming a city, it still has ground water almost up to ground level in some areas. Has a bunch of pumping stations to lower ground water, too.
The grass areas will need occasional watering in the summer, but most of the plants shown look like robust native species that can survive summer without problems
Your argument is a total non-sequitur. Work to make a city more ecologically friendly is completely independent from whatever social problems there are. You can use this argument to oppose literally anything except for whatever issue is from your perspective the most important. You can't govern a city this way.
Their post is also a fallacy of relative privation, IIRC. It's been years since debate club, but I think that's the name. 'There's kids starving in Africa!'
I can pull up prices for other goods, too if you want. Especially rents (in e.g., Munich where I lived all my life) went up similarly while salaries stagnate. Munich rents are on par with Swiss rents, which is crazy if one looks at the difference in salaries.
Clearly the answer is to increase the proportion of the population who are Muslim, to reduce the demand for beer and bring the price down. At least, I think that's the point you were trying to make.
> Men usually wear a baseball-cap over the Kippah in public
But this is right-wing bullshit.
The rise in anti-Semitic crimes is used by Pegida to stir up fear of refugees, Muslims, and Islam, and it's also used by Netanyahu and the Israeli / Jewish right to encourage immigration to Israel.
The reality is that the rise in anti-Semitism begins in 2014, prior to the refugee crisis. It's tracked the Europe-wide rise of the right, not anything related to "Muslim integration" (which in turn is often a code-word for not letting other people wear other kinds of head coverings). Much of it is even linked to Pegida-adjacent groups or people.
This study [0] (sorry it's in German, English reporting on it: [1, 2]) supports your claim that integration is more or less equally bad across the studied countries. Different countries fail at different aspects of it.
Ehm, you won't see any Kippah in public because Jews in Germany are scared since decades. I did not say anything about refugees or recent events although these things surely amplified the bad things already happening in Germany since a long time.
Go stand next to a (usually Police guarded) Synagogue for an hour and see for yourself how guys leaving the thing put on baseball caps. Unfortunately, this is not right-wing bullshit.
Right-wing extremism is bad but negligible compared to uneducated Muslims. There are 5 million Muslims in Germany and 32% say openly they prefer a Sharia-state to a German-democratic state (http://www.br.de/nachrichten/emnid-studie-tuerken-koran-grun...). The left is blind to this because they think it's America's/Europes fault that they behave so badly.
Tolerance means that you can tolerate opposing views, that you respect the people who have them. Violence against people you disagree with is intolerance, and is the way of fascism (among others). You cannot create tolerance through intolerance. You can control people through violence and intolerance, but control is the opposite of tolerance.
I don't get it, aren't germans super-touchy about nazi issues and the holocaust? I would imagine jews would be in some sort of "protected class" status in germany, at least culturally.
> It's tracked the Europe-wide rise of the right, not anything related to "Muslim integration"
Go to any schoolyard and observe members of which ethnic groups use anti-semitic slurs. (I'm not talking about "more frequent", I'm talking about using them at all.)
I seriously implore you to think about what it would be like to be a Jewish pupil in certain districts of Köln or Berlin and implore you to say with a straight face that anti-semitism is caused by the (far-)right.
There was always a strong anti-semitic vibe in community who migrated from the middle east. But hey, no need to call it out- its part of there culture.
Like its part of pegidas culture to squash the left who was idiotic enough to welcome every radical conservative as long as he had exotic flair.
Germany as a whole has a pathetic relationship towards cultures and religions. Due to the excessive guilt-culture it is political suicide to openly criticize some obvious problems. There is also widespread over-tolerance and leniency with regards to religious or cultural excuses and demands for privileges. Germany is currently a non-secular state with strong dogmatic public-opinion in some areas.
For example for families that don't want their girls to take part in physical education including swimming.
Another example is animal slaughter according to tradition that would be illegal due to cruelty without religious excuse.
Yet another example is permission to build mosques including permission for adhan. Without religious excuses you are not allowed to do equivalent things because it is sound pollution. A simple majority of germans is officially atheist. No, Germany doesn't need mosques just because it has churches, yet some politicians say so.
These are just some examples I'm aware of. However, I feel the underlying cause: guilt-culture. It starts with indoctrination in school and is semi-official part of the German state. I hope it will end soon.
Prices doubling every 7-10 years, and Berlin is still by far the cheapest big city in Europe to do anything in. I love going to Berlin because it's so cheap to do everything.
Interesting, but no new ideas. These rain water management ideas are being implemented for a couple of years now in The Netherlands when developing new real estate.
What's your point? They acknowledge taking inspiration from another city where they already implemented this 20 years ago, that these particular ways of coping with climate change are considered proven technology, and that the only thing preventing more wide-spread adoption is political will.
Hopefully they steal good ideas from all over the place. The video mentions swales, which is a mainstay of permaculture, which has been tried out in various ways all over the world since the 70s.
