Internationally water management is the purview of the Dutch, who consulted in the rebuilding of New Orleans after the horrific hurricane and also worked with China on the concept of Sponge Cities to improve drainage and provide flooding mitigation. This is achieved by innovative sewage and waste water techniques, and combining spatial planning and water management, an interdisciplinary approach to flood proofing cities.
Similar work has been successful in the Dutch city of Nijmegen where flooding capacity of a river was enlarged by creating an extra stream channel, which as part of that City’s policy also enhanced economic development and place making. In Rotterdam plazas have been created that hold rainwater in extreme weather events replacing infrastructure basins. There have also been pioneering work on the use of dry river bed “wadis” incorporated in new residential housing developments to mitigate flooding.
As reported to the World Economic Forum China is utilizing the spongy city design concept in 30 cities including Shanghai, Wuhan and Xiamen. With an investment of 12 billion US dollars the project hopes to have 80 per cent of urban areas in China reusing almost 3/4 of their rainwater in the next three years.
Vancouver is riddled with underground streams, many lost in development~and there is a treasure trove of materials available at the University of British Columbia. There are great stream stories-by mistake the Mount Pleasant stream that used to move logs and power wood mills was excavated during work near Main Street and Broadway decades ago. There is also a large aquifer and flowing stream below the Oakridge Mall. City Engineers have calculated that the Oakridge aquifer can supply 120 US gallons a minute or approximately 7.5 litres of water per second. Indeed the water is used by the mall as a coolant, and has been used that way since the 1970’s.
New York City’s urban ecologist Eric Sanderson has created a “digital elevation” of New York pre-development and is discussing how these ancient watersheds and streams can be reincorporated into city landscapes for resiliency and public amenity. It is this interdisciplinary approach to flooding, flora and fauna that will bring streams back to New York City and provide a new amenity in the concrete signature of the city. As outlined in this piece from Mountain View’s Vancouver Street Stories, everything old is new again~and streams and old river beds have a renewed purpose in weatherproofing and providing new recreational spaces in spongy cities.