There are many planted SUDS techniques that left me excited with new ideas after my CIRIA course last week, but this month I’m focussing on how green roofs fulfil SUDS functions.
The concept of Sustainable Urban Drainage Systems looks at a whole site to see where water can be intercepted, infiltrated, stored and cleaned on its route to the lowest point to exit the site. This reduces or eliminates normal rainwater runoff and provides overflow storage which reduces flooding.
Green Roofs are a source control, which means they deal with the water as soon as it hits the site. Not only do they reduce the total amount of water that needs to be dealt with in the rest of the site, the plants can also clean large amounts of pollutants from the water.
The deeper the roof substrate the more storage and attenuation will be provided, and the type of substrate and planting can be tailored to suit the rainfall management requirements.
By combining a green roof with rain gardens, swales, permeable paving in a management train that has a final, planned destination the value of each individual measure is hugely increased. It can also result in great cost savings compared to traditional drainage methods if designed into a scheme at master planning stage.
www.ciria.org has a lot of technical resources and case studies on integrated SUDS schemes. With SUDS Advisory Boards expected to be up and running by April next year, it’s time to get an understanding of what different industries can contribute.