Integrating water management into site and building design

At the site and building scale it is important that buildings are well integrated into the landscape and contribute to the overarching hydrology of the site.

Ecotrust Building in Portland, Oregon incorporates building scale measures to support sustainable drainage. Robert Bray

Water management must be considered at the outset of the design process, with input from water management and environmental specialists alongside urban designers and landscape architects. This will enable development of plans which not only minimise flood risk but also enhance the value of the place. At the Upton urban extension in Northampton where the SUDS system was integral from the project outset this has delivered a range of high quality green infrastructure features.

The social, economic and environmental costs and benefits and the inter-actions between SUDS features and building components are complex. It is important that decisions are based on a balanced and well-informed assessment of the relevant factors and do not ‘externalise’ the costs.

Potential to deliver multiple benefits should be assessed. For example green roofs can provide insulation, increase biodiversity and potentially treat waste water whilst rainwater or greywater recycling can reduce the amount of potable water required. An example of this is Earthship Brighton, a community centre which harvests 73,000 litres of rainwater annually and treats grey and brown waste water through a system of planters and reed beds.

Porous materials including permeable paving (i.e. gravel, block paving or porous asphalt) can be used for new ground structures, and are now mandatory for paving above five square metres in front gardens. This not only limits flood risk but also absorbs pollutants such as oil and petrol which would otherwise wash into streams and rivers.

Use of raw materials can also be minimised through open structures and surface systems as well as sourcing sustainable and recycled materials.

Priority: manage surface water and flood risk
Tags: water, buildings and spaces