According to an 18 July 2016 article in The New Orleans Advocate, New Orleans is about to embark on a $115 million, three-year project to upgrade drainage in eight neighbourhoods, the largest effort to date to enact new strategies focused on retaining – rather than immediately pumping out – rainwater.
While the two projects will complement each other, they represent dramatically different philosophies about stopping the street flooding that can plague the city. Unlike the Corps project, which is focused on upgrading the huge underground culverts and other infrastructure that channels water out, the city’s new projects will rely on using green space and open areas to store water, lessening the amount that pumping stations have to deal with and potentially reducing subsidence within the city.
Nearly all of the projects are still in the early design stages, but they must be completed by August 2019 to meet federal guidelines. The projects are all built around the basic concepts — outlined in the Greater New Orleans Urban Water Plan and promoted by the S&WB — that are generally characterized as “living with water.” While the city’s drainage system historically has been designed to funnel rainwater into canals where it can be quickly pumped out of the city, the new strategy focuses on retaining it – at least temporarily – within the city.
Officials say that approach can have multiple benefits. Slowing the rate at which water enters the traditional drainage system, which can pump out between a half-inch and an inch of rainfall per hour, can help reduce flooding from heavy rains. In lighter storms, pumps may not be needed at all — or can be run at a lower rate — which can reduce wear and tear and reduce power usage. In addition, the approach is considered to be more ecologically appropriate. Pumping groundwater out of the city’s spongy soil has been linked to high rates of subsidence in New Orleans, as drier ground compacts more. That in turn leads to a multitude of problems, such as cracked streets and foundations.
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