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Stormwater Strategies in New Orleans07-25-13 | News

Stormwater Strategies in New Orleans

The New Orleans Wetlands Assimilation Demonstration Project is funneling treated wastewater into the Central Wetlands to rebuild the wetlands and eventually reestablish the cypress-tupelo forest.

New Orleans is looking at various means to handle surplus stormwater. Strategies include developing new zoning regulations to require the use of water-holding and permeable materials for new streets, sidewalks and parking lots.

A five-part series of urban water workshops in New Orleans, sponsored by the Greater New Orleans Foundation, the Urban Institute and more than 30 community organizations, brought officials from Philadelphia, D.C. and Portland, Ore. to New Orleans to explain how their communities handling stormwater, without building new and expensive piping infrastructure.

New Orleans averages nearly 60 inches of rainfall a year. The levees have been fortified, but parishes can barely handle a 1-year rain event (two inches of rain in an hour, or 4.2 inches in 24 hours), much less a 10-year rainfall event (8.5 inches within 24 hours), despite the city's 60 square miles of wetlands.

Jeff Hebert, director of the New Orleans Redevelopment Authority, believes one prominent opportunity for stormwater collection is the thousands of vacant and abandoned lots still in disuse after Katrina. The city is also looking to require new land developers to adopt water management strategies, which will be spelled out in the revision of the city's comprehensive zoning ordinance now underway. This will include rethinking streetscapes by installing rainwater capturing wetland patches beneath existing oak trees, and incorporating them into commercial developments.

Such rules are unlikely to be welcomed by developers concerned with the increased costs of installing permeable pavements, or the loss of parking or building space for required rainwater-collection gardens or bioswales.

Also underway is the New Orleans Wetlands Assimilation Demonstration Project, which is diverting treated water from the sewerage plant into the Central Wetlands that borders the Lower 9th Ward. This increase in freshwater will help rebuild the wetland area and eventually reestablish the cypress-tupelo forest.

Still, the rainwater conservation projects under discussion aren't expected to significantly reduce neighborhood flooding; that would require a projected $11 billion in infrastructure improvements to the city's sewerage, water and drainage system.