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Comment by jurmous | Hacker News Reader

Here in Utrecht the Netherlands they are trying to greenify the city to reduce heat stress during the hot months. They try to plant as much trees and plants as possible, they try not to mow grass often and let it grow, they encourage homes to remove tiled gardens and add green, they have programs to turn roofs into green roofs.

I like it, the city feels nicer to life in.

https://healthyurbanliving.utrecht.nl/fileadmin/_processed_/...

https://healthyurbanliving.utrecht.nl/our-vision-for-utrecht...

https://aiph.org/floraculture/news/utrecht-is-crowned-the-ne...

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Same in Zurich, where the city tries to establish a “Schwammstadt”. But the tree growth is actually negative, because on private properties people are chopping down their trees to build lucrative housing.

If you look at bellevue i personally think it's disgusting, that loveless massive sechseleutenplatz, lot's of cars always using the horn, what a waste of that iconic place constricted between traemli and a always busy street, tbh even Delhi is less stressful, let alone Vienna.

EDIT: Do you mean Schwanstadt right? That lovely smell of birdshit in the sommer plus the massive stink of piss and puke after (and up to 10 days) streetparade is the pure soul of Zurich ;)

No, he means "schwammstadt" (sponge city), the concept idea that you need to create the capacity to soak up excess rainfall and store it like a sponge instead of relying on drainage entirely.

https://en.wikipedia.org/wiki/Sponge_city

Which isn't a bad idea generally, but for cities like Zurich (and its sister city Geneva which is the same also in this regard) there isn't much need - it sits at the end of a massive lake, most of the city center isn't much higher than lake itself.

Effect of the lake subsides somewhat with distance form it, but it definitely creates its own micro-climate thats always colder and more humid than further away from it. To have more high trees that prevent all that tarmac, concrete and stone from heating up during day is definitely a plus, but these cities are not some scorched Phoenix, AZ equivalent.

Berlin, one of the leading cities in Germany on those concepts is located on two rivers, plenty of canals and between a few lakes. Hamburg is another very active place and it's close to the seaside, with a huge river and plenty of water in the city. A lot of concepts refer back to city planning that Kopenhagen started after a massive rainfall event in 2011 - a city which is fairly flat, has a large river front and plenty of canals.

Still, there's need to evaluate such city planning concepts because the lakes and rivers do not solve all of the problems associated with heavy rainfalls and drought cycles. They do nothing to handle the runoff if you get massive rainfalls in a short period of time because the water management gets overwhelmed. Also, city trees do not benefit substantially from the high ground water level and still suffer in drought.

So while not all of the concepts ideas may be applicable to Berlin, Hamburg, Kopenhagen, Zurich or Geneva, concepts like green roofs, local water storage etc. are still required to respond to the incread frequency of high rainfall events and increasing summer temperatures.

I'm so old I can still remember when Sechseleuten Square was green grass, now replaced with searing heat assemblers of stone....so even the city is working against that sponge thing, but yeah it sounds good from a politician's mouth.

It's a relatively novel concept, though the problems of replacing open surfaces with stone slabs and asphalt could have been obvious decades ago :(

Ah, but you see, stone slabs and asphalt cost nothing to maintain. /s

(...Even this is, of course, untrue, but it seems true when you're only paying attention to the next year or so.)

Just 17 milion swiss franks made out of "Valser Quarzit" and a "fountain" that needs constant maintenance because it has to be drinking quality instead of lake-water, just look at that sh*t:

https://aquatransform.ch/projects/sechselaeutenplatz-opernha...

EDIT: But please don't waste energy otherwise (your politician)

Zürich needs Lärmblitzer against pointless revving and honking.

Or a bridge/tunnel before bellvue, and make the whole bellvue+niederdoerfli up to hauptbahnhof carfree...just imagine that! But yeah you are right with those Lärmblitzer too.

I live at the boundary between city and forests and in summer the temperature drop is really 'incredible'. The amount of energy wasted by urban areas is as much so. But at the same time it's nice because we can restore more trees for shade easily

I live in foothills of a lower range of hills (European Jura), and it has numerous effects. The air is normally blowing down the mountains towards us in the evening (katabatic wind), so it doesn't matter how hot the day was, evenings are pleasantly cool and night gets colder than expected. This wind also cools hot surfaces pretty effectively.

Even just entering a dense natural forest during the day, one can sense drop in temperature around 3-4C during summer, and increase in humidity during dry periods.

Lived in French Jura for 5 years. It is so beautiful. And I am not the only one to have noticed. The Last Man or Frankenstein have also the Jura mountains as landscape.

I miss that place... (except its prices)

> katabatic wind

I've noticed this while doing evening walk, I didn't know it was a named phenomenon.

Paragliders like me (or similar sports) have to be very familiar with meteorology and wind, its the most important but largely invisible force that can literally make you or break you.

I love that overreach expected by a passion like that, meteorology is fascinating to engineer in me and its effects are very much visible every day and affect us all.

Since I've been bike commuting I've become more in touch with climate. For the simple need of avoiding rain. You start to pay attention to wind, direction, clouds .. it's strange cause you have to think more but it's also funny because you're sharper and smarter in a way. And that's just noob / surface level :)

Portland, OR, has similar green roof code mandates, as well as tree replacement laws as well... although there is pressure from "developer-friendly" electeds to suspend these mandates. Boo for being short-sighted.

I live there as well, and while I'm sure it could be worse, it's nothing compared to Johannesburg. I would like to see much more green throughout the city. Hopefully they will keep up the trend.

Well they are still in transition. My street is next. They will plant quite a bit more trees and plant areas. Looking forward to them :)

Sounds nice but it seems to be all at the cost of personal freedom of movement. That's a shame.

that made me want to live there lol

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