A green roof facility has been designed and built at the University of Birmingham that will be used to investigate the value of green roofs for nature conservation, stormwater and water quality management.
The design aims to mimic brownfield sites which are home to a wide variety of rare species of birds, plants and insects and which are threatened by housing, office and retail space development.
The facility will enable researchers from the University of Birmingham’s School of Geography, Earth and Environmental Sciences to study ways of improving the management of urban water by investigating the way green roofs can reduce the volume and pollution levels in the water that runs off them.
Urban rainfall contains pollutants such as heavy metals and nutrients, which the plants and soils on green roofs can help to remove. The water is used by plants and soaked up by the soil and this means that much less water runs off a green roof than a conventional roof. The study aim is to maximise the potential of green roofs to decrease pressure on urban drainage systems, reduce flooding, and improve the quality of groundwater and streams.
The new research facility, which is situated on top of the University’s Watson Building, has already been seeded with a variety of flowers, many of which are declining in the British countryside such as corn cockle, cornflower, pansy, great mullein and poppy. These plants will attract birds, butterflies, bees, wasps, beetles and spiders – all of which will be studied on the roof.
The researchers will investigate how different mixes of three different types of recycled green roof ‘soils’ affect the wildlife on the roof, how much water is soaked up by the roof and how much pollution is removed. The soils used are crushed house bricks, crushed demolition aggregate, which is mainly concrete, bricks, mortar and ceramics, and treated incinerator bottom ash, which is mainly fused material, glass and ceramics.
‘Brownfield sites are very important ecological habitats within the urban setting, but the landscaped areas that replace them do not equate to the habitat lost due to development. We are investigating the best ways to mitigate for this habitat loss by recreating the habitat on rooftops while not compromising the known beneficial effects of green roofs for urban water management,’ said Dr Adam Bates from the University’s School of Geography, Earth and Environmental Sciences.
The research is part of a large international project called SWITCH (Sustainable Water Management Improves Tomorrow’s Cities’ Health) which is funded by the European Union and organised by UNESCO.