Water management in public spaces

Public space needs to be considered in the context of wider issues of water management.

Cheonggyecheon stream restoration project in the centre of Seoul, South Korea. Photo by Nepal Asatthawasi.

At a sub-regional level, that means considering its links to river catchment systems and flood plains but the issues need to be kept in mind at site and material scale too.

Designers and managers of public space need to think about the use of materials to minimise environmental impacts. Public space can also provide a way to intercept or stop running water through the design of drainage and other systems.

For example, a study at the National Air Traffic Services car park in Edinburgh compared pervious paving with nearby traditional impervious tarmac. The pervious area prevented run-off from 60 per cent of rainfall events, while the tarmac area produced run-off during all events.

Water is used in hotter climates as a microclimate ameliorant. The sound of running water is as much a part of this as the evaporative heat transfer effect. Streets and courtyards can help to accommodate this resource as part of the wider green infrastructure network.

Of vital importance in maximising the role of green spaces is the supply of water for irrigation. Native plants are crucial to cooling the local microclimate through evapotranspiration, a role which drought tolerant plants cannot fulfil. However, to survive in future climates native plants will require a supply of water for irrigation. This supply should be planned and integrated at the outset to ensure long term maintenance and optimum operation. In Australia the cooling impact of urban vegetation has been found to reduce building energy consumption by between 7 and 47%, with associated financial savings as well as environmental benefits.

At a detailed and materials scale, designers should seek to:

• use porous materials in new surfaces
• use appropriate vegetation that aids drainage, especially in areas that are prone to flooding
• provide for irrigation to support vegetation’s critical role in cooling the microclimate.
   

Priority: adapt public space to climate change
Tags: public space, water, neighbourhoods, buildings and spaces