Water squares

Introduction to a type

The Netherlands has a tradition of discharging rainwater underground via an extensive sewerage system. Despite having a number of visually-prominent canals, the Dutch city has relatively little surface water where the rain can be retained. And the sewerage system already has difficulty coping with the rainwater when it rains heavily. In the coming decades it will not only rain more frequently, the downpours will also be more intense. These peak downpours create problems in the densely-populated urban area: the rainwater cannot drain away because of all the surfaced space. When the sewerage system becomes overloaded the streets become flooded. This flooding leads to difficulties and damage. These large puddles and pools of water are a nuisance, pedestrians cannot keep their feet dry when walking about the city. The flooding causes damage to cellars and houses, shops and catering basements. This is why we are introducing a new type of rainwater storage: the water square.

In order to be able to collect peak downpours (temporarily), areas in the public space are laid out in such a way that the flooding can be regulated. We call these areas water squares. Not a square in the traditional sense of the word, but a square as a central space in a water management collection unit, a collecting basin. Rainwater is collected and retained in this basin. From this basin it can either be gradually infiltrated into the groundwater or finally, at a later point in time, discharged via the existing sewerage system. The water square is dry for the great majority of the time and then it is used like any other public space in the city. After a heavy downpour the form and the use of the water square are transformed. This means that, when designing a water square, the main focus is on its use and recreational value in a dry state. The elements that are necessary for the water storage are, wherever possible, deployed to create an attractive recreational area.

year
2006

in cooperation with
VHP, City of Rotterdam ( Municipal Public Works, Urban Planning and Public Housing Department, Development Corporation), Higher water board from Schieland and Krimpenerwaard, Urban Affairs

programme
Rainwater storage

client
Initiative Urban Affairs, financed by the Netherlands Architecture Fund

website
www.architectuurfonds.nl

more...
1. The water square as central area in a unit | 2. Rotterdam as a collection of water storage units
1. The water square as central area in a unit | 2. Rotterdam as a collection of water storage units
The usual tools for the extensive underground network of pipes and tubes can`t handle an intensive rain shower any longer
The usual tools for the extensive underground network of pipes and tubes can`t handle an intensive rain shower any longer
1. Schematic functioning sewerage system | When rain continued: 2. Buffering in the system | 3. Overflow - level fluctuation canal | 4. Overflow street gully - overflow canal
1. Schematic functioning sewerage system | When rain continued: 2. Buffering in the system | 3. Overflow - level fluctuation canal | 4. Overflow street gully - overflow canal
1. Uncoupling of rainwater storage: from conventional mixed system through an improved system to decoupling and local collection of clean water | 2. Proposal for other investments
1. Uncoupling of rainwater storage: from conventional mixed system through an improved system to decoupling and local collection of clean water | 2. Proposal for other investments
Samples water squares: 1. Buoyed square | 2. Playground | 3. Purification square | 4. Canal | 5. Canyon | 6. Cork mat | 7. Sponge square | 8. Purification gravel
Samples water squares: 1. Buoyed square | 2. Playground | 3. Purification square | 4. Canal | 5. Canyon | 6. Cork mat | 7. Sponge square | 8. Purification gravel
Reference costs per cubic metre water storage: 1. Digging a pond (350 euro/m3) | 2. Digging a canal(500 euro/m3) | 3. Underground basin (1000 euro/m3) | 4. Restructure with water (1000 euro/m3) | 5. Water square
Reference costs per cubic metre water storage: 1. Digging a pond (350 euro/m3) | 2. Digging a canal(500 euro/m3) | 3. Underground basin (1000 euro/m3) | 4. Restructure with water (1000 euro/m3) | 5. Water square
Three basic principles: 1. Buffering regardless of the system with a permeable basin | 2. Buffering for the system with an open basin | 3. Additional buffer in the sewer system with a closed basin
Three basic principles: 1. Buffering regardless of the system with a permeable basin | 2. Buffering for the system with an open basin | 3. Additional buffer in the sewer system with a closed basin
Example open basin | 1. Several sports facilities with the rainwater storage capacity | 2. The open basin as sporting landscape with a water storage capacity of 5.000m3
Example open basin | 1. Several sports facilities with the rainwater storage capacity | 2. The open basin as sporting landscape with a water storage capacity of 5.000m3
Important factors for rainwater collection
Important factors for rainwater collection
Urban strategies for Rotterdam with three principles and six typologies
Urban strategies for Rotterdam with three principles and six typologies
The positioning of the six example types of water squares in four districts of the city
The positioning of the six example types of water squares in four districts of the city
Centre (district Cool): a shallow square on Het Landje
Centre (district Cool): a shallow square on Het Landje
District Oude Noorden: a system of dams
District Oude Noorden: a system of dams
Centre (district Oude Westen): a series of recessed squares
Centre (district Oude Westen): a series of recessed squares
Crooswijk: water balloon on the Mariniersweg
Crooswijk: water balloon on the Mariniersweg
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