Water – threat or resource

“Water is the bloodstream of the biosphere and the determinant of our future”, says Johan Rockström from the Stockholm Resilience Centre. When it comes to cities, water has long been the wellspring of their development, remains today a strategic asset. Considering the yearly recurrence of extreme weather events, increasing in the face of climate change, most cities, according to the Arcadis Sustainable Cities Water Index, have come to realise the urgency of improving their urban resilience. And as many resilience specialists have pointed out, urban resilience cannot be achieved and sustained without urban water resilience.

Cities need to think of water as an opportunity and as a resource for economic development while also meeting the critical needs of their residents and the environment. A blue revolution is underway in cities, and this photo and sound essay demonstrates some of the creative ways cities are using water to increase resilience, and bring comfort and stability to the lives of residents.

A water resilient city should be well prepared to overcome the challenges associated with both too little and too much water. Cities and residents understand their vulnerability in the face of unpredictable weather. Extreme rainfall, floods generating sewer overflow, droughts and rising sea levels are new daily realities for many environment departments in cities.

It is, however, the dose that makes the poison. Water is also a tremendous asset, too long under-utilised by urban planners. In a creative upsurge, cities are bringing long-buried water back to the surface for great environmental, cultural and creative ends. New rivers, pools, ponds, lakes and fountains, and their green banks, are reducing the effect of urban heat islands, becoming community gathering spots, and improving local health and wellbeing.

 

Daylighting

‘Daylighting’ cracks open the pipes that have hidden rivers for decades and lets them flourish once again, reconnecting people with the water.

 

The plans for Porto's Rio Tinto.
The plans for Porto’s Rio Tinto.

 

Porto is linking blue and green infrastructures, creating natural spaces that improve water quality and function as permeable and shaded areas, engaging people with water.

 

Dewatering of the Granja stream_source Águas do Porto Porto Water Company
Dewatering of the Granja stream. Source: Águas do Porto Porto Water Company

 

The new green spaces absorb excess rainwater to prevent flooding during rainy seasons. This image from Águas do Porto (Porto Water Company), shows machinery renovating the Granja stream.

 

Granja stream before and after
This image from Águas do Porto shows the Granja stream before and after.

 

Unleashing the water creates a chain reaction. First comes the water, then the greenery, then the people. Porto puts water at the heart of the city’s biophysical, economic, and social wellbeing. Water resources of the cities are for its citizens and public participation is a key factor. Water for the people, by the people.

 

River plan from above
This final image from Águas do Porto shows the renovation plan from above.

 

Trouble over bridged water

Rochdale, in Greater Manchester, opened up a 500 meter section of its river Roch which had been buried for a century. When it was discovered that a medieval bridge lay under the concrete cover, there was a movement to bring the bridge back to the city.

 

 

The movement was initially quashed, but just over a decade later the decision was made to go ahead with the plan. The city reduced the height of the bank and built a drop-in centre for the river’s history.

 

This image shows the works mid-way.

 

Increased footfall in the area brought economic benefits to local businesses. However, an interesting dilemma arose during the excavation.

 

River Roch, Greater Manchester
The lowered bank of the Roch

 

Dilemma: The concrete river covering was also of heritage significance. Dating from 1904, it was one of the earliest applications of the Hennebique reinforced concrete system.

 

Rochdale bridge
Rochdale bridge. Copyright David Dixon and licensed for reuse under CC BY-SA 2.0 via geography.org.uk.

 

It is important to remember that heritage involves recent as well as distant history, concrete as well as stone. Nevertheless, the outcome of the dilemma in this case may be summarised by the image above.

 

Consciousness of stream

In Lille, an old cotton and linen factory is today headquarters of a ‘site of excellence’ for new technology. The canal crossing this district had been relegated to its industrial role, invisible to the surrounding neighbourhoods.

 

cotton factory in Lille, Leblan Lafont
Cotton factory in Lille, Leblan Lafont. © Yves Bercez

 

Land surrounding the city is flood-prone due to topography and to groundwater close to the surface. Surface water spread ‘eutrophication’, that is green slime from nutrient-rich stagnant pools, to water courses.

 

Lille roadside stream
Lille roadside stream. © Yves Bercez

 

Lille decided to redirect the water to the people! New water basins and watersheds that regulate discharge into the canal were integrated into public spaces, roadside streams and water gardens.

 

Lille canal
Lille canal

 

In the slow, deep canals, larger impurities sink away from the water, and in the water gardens, the smaller matter is absorbed by tree roots, natural and inexpensive ways to improve water quality.

 

Lille river view
Lille river view

 

The location of new buildings is also now decided based on soil composition so that the balance of groundwaters is respected.

 

concrete
Concrete seals soil

 

Lille’s new policy against ‘soil-sealing’ (covering ground with impermeable materials like concrete) mandates that at least 20% of land must be able to absorb rainwater.

 

Lille water park
Lille water park © Yves Bercez

 

The new plants, waterways and open green spaces reduce flooding by absorbing and redirecting excess water.

 

Sink or swim

1997 was the year that Wroclaw’s river leapt up and swept across the city. The flood claimed 54 lives, cost around €3 billion and ravaged 40% of Wroclaw’s surface. Rebuilding the city’s flood protection was not just a matter of repair, or improvement, but of rebirth. The new floodway system developed of river embankments, boulevards, and flood plains.

 

Wroclaw waterboat
Wroclaw Riverboat © Municipality of Wroclaw

 

With the flood having destroyed enormous amounts of agricultural land, urban farming is now springing up, with more than 1,000 farms in the city. As well as improving food security, stimulating the local economy, and preserving agricultural traditions, this farmland keeps improves the city’s water retention capacity, strengthening it against future floods.

 

Wroclaw grassy bank
Wroclaw grassy bank © Municipality of Wroclaw

 

You can bring the people to water, but you can’t make them drink. Wroclaw has sought to make the waterway a democratic issue through stakeholder engagement, public consultation and debate. The city is using a multilateral governance model that brings it together with state institutions, as wells as collaborating with entrepreneurs, to develop its ‘riverside identity’.

 

Tamka Island, Wroclaw © Municipality of Wroclaw

 

Fit to burst

In Copenhagen, the cloudburst system means that the shape of the city and its amenities are subtly adjusted to prepare for floods. When the clouds ‘burst’ a road serves as a viaduct to siphon water out of the way while skateparks and football fields become temporary reservoirs.

 

Copenhagen, retention road, illustration from “Cloudburst typologies” developed by HOFOR, EnviDan and Urbanisten for the city of Copenhagen (2014)

 

A cloudburst road is a road which in normal weather functions as a road in the city and when torrential downpours and large volumes of water occur transport the water to places from which they can either be collected or discharged (typically to the harbour or similar receiving body).

 

Copenhagen, retention space in Sankt Annae Plads (photo credit: Søren Svendsen)

 

The central avenue is brought to a level lower than the pavement and inclined downwards towards the water’s intended destination. This can be combined with a retention road. The retention road, pictured above, is convex with porous or green spaces on one or more flank and stripes of porous stones running across it. The green areas allow excess water to be stored below the street and improve the safety and ambience of the walkways.

 

 

Copenhagen, retention space, illustration from “Cloudburst typologies” developed by HOFOR, EnviDan and Urbanisten for the city of Copenhagen (2014)

 

A retention space is a square or a park arranged to store stormwater. When the downpour is over, the facility is drained either to the sewers or to the cloudburst management system. An example of such a space is Tåsinge Plads. You wouldn’t have much fun rollerblading in this weather anyway!

 

This article is based on content originally collected during our EU-funded ROCK project on cultural heritage for the journal started as part of the project, the European Journal of Creative Practices in Cities and Landscapes.

Author:
Cécile Houpert Project Officer - culture