‘Green roof’ on S&WB headquarters building to help keep rainwater out of city’s drainage system

The New Orleans Sewerage & Water Board’s headquarters near Lee Circle will soon be sprouting grass from its roof as one of three demonstration projects the agency hopes will encourage new ways of thinking about how to deal with water.

The projects, formally unveiled Tuesday night, tie in with efforts to come up with alternatives for dealing with stormwater beyond just pipes and pumps. Advocates say those efforts not only are needed to keep up with the rainfall New Orleans receives but also can result in new techniques and ideas that can be exported to other areas.

“This is our future. This is what we have to start thinking about,” S&WB Executive Director Cedric Grant said. “We cannot build our way out of our problems.”

The grants are part of an agreement the S&WB cut with federal regulators giving the agency additional time to come into compliance with the terms of a consent decree for fixing leaky sewage pipes. In exchange, the S&WB pledged to spend $500,000 a year for five years on “green” infrastructure.

Last year’s projects were the first to receive grants. This year, Grant said, the projects — which were selected during a competitive process — will help demonstrate various techniques urged by engineers and planners as ways to better handle stormwater in the city.

“We definitely want to crawl before we walk,” Grant said. “We’ll put some demonstrations in place to show the community what we’re talking about and then get the community to do it themselves.”

Those efforts are aligned with the ideas of the Greater New Orleans Urban Water Plan, an ambitious effort that focuses on “living with water” through the use of techniques that allow it to be slowly absorbed into the ground. That contrasts with the way the city has handled rainwater for the past century, quickly pumping it out in a process that critics say exacerbates soil subsidence and is costly to expand and maintain.

The plan includes both major infrastructure projects and more individually scaled efforts, such as setting up rain barrels or retention ponds in yards to reduce the rate at which water ends up in the street.

The bulk of the money distributed by the S&WB this year will go toward a “green roof” on the agency’s building on St. Joseph Street in the Warehouse District. The $324,000 project by Hanging Gardens LLC will cover the 10,000-square-foot roof with dirt and grass.

The effort is primarily aimed at keeping rainwater that hits the roof from flowing directly off of it onto the street and into the drainage system. But it could yield a secondary benefit by keeping the building from heating up as much, lowering its electrical usage, Grant said.

The grant also will pay for a 600-foot-long bioswale along Coliseum Square Park a few blocks away. A bioswale is essentially a drainage ditch planted with vegetation to filter water that flows through it. Planners say such a feature can aid stormwater management by slowing the rate at which water is flushed into the drainage system.

The bioswale is being built by Gaea Consultants LLC for about $109,000.

Gaea also will build the Aurora Rain Garden on a half-acre parcel next to a sewer pump station in Algiers. The $66,100 project is designed to collect and filter rainwater on the site.

Follow Jeff Adelson on Twitter, @jadelson.

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