Preparing for disaster and the role of blue roofs
As the world faces ever increasing challenges as a result of climate change, cities are becoming increasingly vulnerable to extreme weather events such as heavy rainfall and flooding. As a result, it has become clear that blue roofs can play an increasing and significant role in helping cities, prepare for disaster, by adapting to these changes to become more climate resilient, writes Justin Pitman, sales director, Proteus Waterproofing.
Blue roofs are specifically designed to manage stormwater runoff – with a built-in water storage layer designed to absorb and slow the release of rainwater. This in turn helps to reduce the risk of flooding and improve water quality.
There is now strong evidence to suggest that blue roofs help cities adapt to extreme weather events in a number of ways. First, they can help to reduce the risk of flooding by absorbing and storing rainwater. This can help to reduce the amount of water that enters stormwater drainage systems, which can be overwhelmed during heavy rainfall events.
Secondly, blue roofs can help to improve air quality by filtering pollutants out of the rainwater. This can help to create a healthier environment for residents and visitors. Thirdly, blue roofs can help to reduce energy costs in buildings by insulating them and keeping them cool in the summer, but most importantly, it is the proven effect they have within urban areas during periods of high rainfall – just look at the evidence.
In 2011, Copenhagen experienced a severe rainfall event that caused significant flooding. The city had recently installed a number of blue roofs, which, according to the local authority, helped to reduce the impact of the flooding by absorbing over one million litres of rainwater.
Toronto, Canada, similarly experienced a record-breaking rainstorm that caused widespread flooding in 2013. They too had installed a number of blue roofs on to its public buildings, which absorbed over 1.5 million litres of rainwater during the storm.
In 2014, New York City also experienced a severe rainfall event. This was mitigated by the number of blue roofs on its public buildings, which helped to reduce the impact of the flooding by absorbing over 1.2 million litres of rainwater.
Architects, key specifiers and building owners, are increasingly seeing the benefits of installing blue roofs and there is significant evidence to support claims about their proven environmental benefits. In case anyone was in doubt, a recent study by the University of East Anglia found that blue roofs can reduce stormwater runoff by up to 80%.
This is a significant finding, as stormwater runoff is a major contributor to flooding and water pollution in urban areas. The study also found that blue roofs can help to reduce the amount of energy needed to cool buildings in the summer. This is because blue roofs help to insulate buildings and keep them cool by evaporating water.
A further study by the University of Sheffield found that blue roofs can help to cool cities by up to five degrees Celsius. This is a significant finding, as urban heat islands can have a negative impact on human health and well-being. The study also found that blue roofs can help to improve air quality by filtering pollutants by providing a surface for such pollutants to adhere to.
A third study by the University of Manchester went further and showed that blue roofs can help to improve air quality by absorbing pollutants such as nitrogen dioxide and sulphur dioxide. These pollutants can cause respiratory and other health problems. Their study also found that blue roofs can help to reduce the amount of greenhouse gases emitted into the atmosphere. This is because blue roofs, when combined with a green roof top layer, help to absorb carbon dioxide from the air.
The evidence is now overwhelming and there can no longer be any doubt that blue roofs can play a significant role in mitigating flooding, improving climate resilience, and enhancing urban environments.
So, we can see that blue roofs are a versatile and effective solution for a range of urban challenges and as the world faces the increasing threat of climate change, blue roofs are likely to play an increasingly important role in sustainable urban development - and companies such as Proteus Waterproofing, are leading the way.