To launch its 14th anthology, Water, Alphabet City has organized a series of events this week in Toronto, two of which are the HYDROCity symposium and its accompanying exhibition at the University of Toronto. Another event is a lunchtime talk in which Jeroen Bodewits will discuss Waterpleinen, a project designed by Florian Boer and Marco Vermeulen to reconfigure the stormwater infrastructure of Rotterdam.
In Florian Boer and Marco Vermeulen's proposal, rainwater runoff isn't funneled into a complex system of underground pipes, a system that is rather expensive to build and maintain, but is managed instead through a network of surface reservoirs, the Waterpleinen, or Watersquares. These storage spaces will be dry for most of the year, but during storm events, they will collect water from the surrounding neighborhood. If one reaches capacity, excess water will overflow into another basin. After the rain, the collected water will slowly recede into nearby bodies of water or seep into the soil.
So instead of being buried in concrete, excised from the daily life of the city and only experienced by municipal workers, urban hydrology is visibly, even prominently, incorporated into the surface fabric of the city. Programmed with recreational opportunities when its dry and even while inundated, its infrastructure provides active public spaces for the local area, not dark playgrounds for a handful of urban explorers. It even becomes an event, its frolicking rivulets and interior lakes staged for the young and old.
Originally developed in 2005, this concept has since become official urban policy. At least 25 watersquares are planned for Rotterdam in the coming years, with a prototype to be constructed soon.
Hyperlocalizing Hydrology in the Post-Industrial Urban Landscape
I'm assuming you were there at Jeroen Bodewits' lunchtime talk on November 3, so can you elaborate on how the system will filter out debris and pollutants from the stormwater before it enters the Waterpleinen? That is, if it was discussed at all. This seems to be the one aspect of the project that a lot of the comments (e.g. here) have fixated on.
I suspect details of a filtration system lie here [pdf; 4.2MB], but the text is in Dutch.
I've encountered many similar projects before, and they filter the stormwater through a step-by-step process. The first step usually involve something simple like a grate to catch leaves, stones and other large debris, after which the water moves into a settling tank to allow sediments to fall out. The water may move through one or more settling tanks, allowing for more finer sediments to settle to the bottom. These tanks would be periodically cleaned out.
Other filtration devices might include mesh fabrics, aggregate (gravel, sand, etc.) and even porous asphalt or grasscrete. Vegetation is also commonly used, since plants can phytoremediate chemical pollutants.
So in other words, apart from the rain that falls directly on the watersquares, the water falling on the streets and rooftops will not be "flushed" untreated into these spaces.
Not all of the watersquares will have the same spatial scheme as what you see in the images above. According to this pdf, some of the them will indeed be skateparks. Others will have basketball courts, soccer pitches and spaces for informal gathering or for other sports. As one diagram seems to show parked cars, I'm assuming some of these spaces will be used as parking lots when dry. So in other words, there will be different types of "squares".
Alexander you studied our material quite well, thank you for that.
Indeed the watersquare is no sewerage treatment facility. it catches the stormwater from public space and rooftops and that is filtered before running into the square. There it will be hold untill the "city system" is back to normal and the water can run of to the nearest open water (canals or a singel in the Rotterdam case). The water will never be in the square for a long period. Depending on the amount of rain falling, the worst case would be a 32 hours (once a year statistically). This will not be a health threat, even in summertime
Some research still needs to be done off course. But as it is in Rotterdam, the municipality liked the idea and we are trying to get a more elaborate example to be built. In this sense not all has been solved but the dirt and debris are not that difficult to take care of. It can be filtered and the square will have to be swept clean afterwards obviously.
As for deceiving renderings... They are three images that are popping up on all different kind of places and they start to lead a life on their own. They should not be judged by themselves.
The whole idea of the watersquares originates from our desire as spatial designers to spend money used for flood basins in such a way that they become spaces people can enjoy. Most of the time these spaces can be used normally as public space, only 5% to 10% of the time the space is needed for temporal stormwater storage. Therefor money spend for technical infrastructure can be turned into money spend to create better places in the city. This is only applicable where there is very little public space and stormwater problems are urgent.
In the dense urban fabric of the innercity our proposal makes sense because of pressure on public space and the need to spend money not just on technical facilities that only solve the technical problem, but leave no added value to the public space.
we are preparing a modest book that explains the idea more thorougly. It will be published by 010-publishers in Rotterdam and will be in both dutch and english. In stores end of january, next year. So i hope all will become a bit more clear to you all then.
Thanks for all the interest in our project.
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