If current trends continue, it’s possible that 2013 could end up one of the quieter hurricane seasons in recent years. In coastal Louisiana, however, where parts of New Orleans have yet to be rebuilt after the catastrophe of Hurricane Katrina in 2005, city planners aren’t assuming that this so far mild season is anything like what the future holds.
Last week, Greater New Orleans Inc. — a regional economic development organization — unveiled its Urban Water Plan for Orleans, Jefferson and St. Bernard parishes. The plan re-envisions New Orleans as a flexible, permeable metropolis of canals and ponds, instead of a desperately fortressed city hiding behind higher and higher levies.
In addition to protecting New Orleans from the effects of extreme weather and erosion, the plan could have a major economic impact. GNO, Inc. estimates that full implementation of the Urban Water Plan would result in an $8 billion reduction in flood damages, for example.
For years, New Orleans’ only real strategy for coping with the floodwater that is sure to come when you build a city on swampland between a river and a lake in an area prone to hurricanes, has been to pump — pump more and pump faster. Water pumped out of the city ends up in Lake Pontchartrain. This historical approach is not only expensive, but also increasingly futile in the face of climate change and the predicted increases in sea-level rise and hurricane frequency and intensity.
“Water management doesn’t have to look like a wall a pump or a fence,” Mark Davis, director of the Tulane Institute on Water Resources Law and Policy told a local radio station.
The new approach to storm water management is all about living with water instead of constantly trying to get rid of it — possibly a hard sell for people who know water as a destroyer of homes (and even cities) and where the draining of standing water decades ago was crucial to combating mosquito-borne diseases.
GNO’s vision for New Orleans, which was created by Waggonner & Ball Architects in partnership with Dutch consultants, is to create an urban landscape dotted with rain gardens and bio-swales and connected with new or upgraded canals and ponds. The plan to keep water, and lots of it, inside the levees is being advertised as a means to mitigate flood risk and combat subsidence, but also as a way to create more waterfront property and potentially boost home values.
Subsidence is the sinking of the ground, which in the New Orleans area is mostly caused by artificially maintained dry soils. Subsidence causes enormous damage to infrastructure, from the ever-annoying pothole, to cracked pipes and building foundations.
Piet Dircke, a Dutch consultant who helped advise on the project, said at the plan’s unveiling that New Orleans could become an international leader in water management.
“Mayor Bloomberg also looked at New Orleans from that perspective, and also learned that he wants New York to become a water city — a leading water city,” Dircke said. “Also in technology and in knowledge and in science and innovations.”
In June, Mayor Bloomberg announced a $20 billion storm protection plan for New York City, comprised of a network of flood walls, levees and bulkheads along the city’s waterfront.
The New Orleans plan, which cost $2.5 million to draft, is for seven initial demonstration projects with a price tag of $6.2 billion. Each site is designed to showcase a different approach to water management. They include a park on Mirabeau Avenue, sites along the Canal Street Canal in Old Metairie, streets in Lakeview, the Lafitte Greenway project, gardens in Elmwood, a “water walk” near Lake Forest Boulevard in eastern New Orleans and a wetland near the Forty Arpent Canal.
Mirabeau Garden Wetland Filtration Sequence: After the water is pumped, it enters the wetland filtration sequence. A series of terraced open-bottom beds become a constructed wetland. The terraces provide for both infiltration and become an ecosystem, filled with plants and organisms that filter the water before it overflows into a fresh-water swimming pool. Click here for more detail.
Some parts of the city are already incorporating forward-looking, urban design elements, like a playground in Jefferson Parish, walled in by earthen berms and pipes, which will flood during heavy rain drawing water away from people’s homes.
The Dutch, who advised GNO, Inc. on its plans, are of course no strangers to floods and are seen worldwide as experts on water management. While New Orleans and Rotterdam have more in common than meets the eye — built on very similar soil types — not even the Dutch have experience fortifying a low-lying city against abrupt and dilluvial floods or powerful hurricanes that barrel in from across the Caribbean. If New Orleans can find a way to manage its water, it could serve as a model for vulnerable cities around the world.
