In 2008 the Government’s Water Strategy for England acknowledged that the below-ground piped systems were insufficient when coping with extreme rainfall and identified the importance of Sustainable Drainage Systems (SUDS) and green roofs, for climate change mitigation and water management.
The Green roofs inclusion within the SUDS strategies have been limited to date however must surely be desirable, as they:
Extend the roofs waterproofing durability
Reduce energy consumption
Provide amenity space
The feasibility of the green roofs within the SUDS strategies shall therefore be evaluated against SUDS design criteria.
1) Water Quality Improvement by ways of reducing water runoff velocity, filtering pollutants such as nitrogen, copper, zinc, lead and calcium.
2) Amenity Benefits by ways of providing green space (e.g. roof gardens, communal parkland, areas of recreation and entertainment.
3) Ecological Enhancements: Almost 90% of England’s population live in approximately 10% of land cover. Habitat lost to urban development therefore lowers species diversity-threatening future food and medicine sources. Whilst not directly replacing habitats green roofs can create compensatory habitat for a variety of flora and fauna.
4) Hydraulic Performance: Conventional drainage systems typically convey greater and faster run off however green roofs manage storm water more sustainably through the evaporation of rainfall intercepted by the plant surfaces.
The Future?
Hopefully in the future green roofs schemes will feature more predominantly within SUDS Strategies, as they must recognise the physics-based research of the hydraulic benefits.
