So-called “grey” infrastructure solutions for water engineering, such as large concrete storage tanks, are outdated and inappropriate for modern times, experts said last week at a seminar hosted by consultant Aecom.
Speaking on creating water sensitive cities in the UK water experts said that large-scale hard engineering solutions for drainage and flooding issues are old fashioned and inefficient. Water sentitive urban design — a term referring to urban design that incorporates multi-functional sustainable drainage systems (Suds) and makes water infrastructure environmentally, socially and financially beneficial — is more appropriate for the 21st century, they said.
Aecom sustainability associate director Celeste Morgan said developers and town planners tend to favour infrastructure that keeps water out of sight. “We have to stop hiding water, and bring it into the public realm,” she said. Morgan compared the planned Thames Tunnel mega-sewer project in London to solutions in Philadelphia, where surface water runoff will be tackled by retrofitting a third of the city’s roads with permeable paving. “Is London really being a leader?” she asked.
Aecom landscape architect Deborah Kuh cited an example of an unnamed development where a planned concrete storage tank underneath a road was swapped for a large-scale Suds pond which also functions as a natural swimming pool, contributing to ecology and local amenity and providing a revenue opportunity for the local council.
Construction industry research and information association (Ciria) associate Paul Shaffer said infrastructure such as Bazalgette’s large sewer tunnels were a good solution for the 19th century but may not be “fit for purpose” in the modern world.