Rainfall should be diverted out of Uptown via the Mississippi River instead of carrying it all the way to Lake Pontchartrain, and major drainage ditches like the Monticello Canal should be expanded into interior floodplains and water-storage features, according to two recommendations that illustrate how New Orleans should be better managing its water instead of just pumping it away.
The Water Management Strategy presented by architect David Waggonner to a standing-room only crowd Thursday evening at Xavier University is a regional plan for making more efficient use of rainfall, slowing it down and storing it in natural canals to reduce the sinking of the land that contributes to flooding. The recommendations in the Uptown area are only a small part of the plan, but they illustrate some of its key elements and some of its challenges.
“We’re proposing this is a new era for water management,” Waggonner said. “It’s not just about flood protection any more. It’s really about quality and sustainability.”
The ridge and the floodplains
One major change envisioned by the plan is to respect the natural ridge through the center of the city as a drainage barrier. Instead of pumping all the water from the neighborhoods along the Mississippi River across the entire city to the lake, the new plan would use the existing canals to bring Uptown-area rainwater to a new pumping station on the Mississippi River, near the current Sewerage and Water Board facility. (Similarly, downtown rainwater between the ridge and the river would be pumped into the Industrial Canal.)
The change would have two major structural effects, Waggonner said. Currently, junctures in the drainage system can get backed up in major rainfall events, causing flooding backwards along the overloaded system, but “disconnecting” the Uptown water from the lakeside drainage system would prevent that buildup from happening. Secondly, it would separate the city into discrete “water units” that would minimize damage if heavy flooding occurred.
A second major change would be to create major natural floodplains along the current canals — the Monticello Canal would be a major example, but it would be applied to canals around the city. The canals are now intended to funnel water out of the city as quickly as possible along a narrow chute. Instead, Waggonner proposed a dramatic widening of the spare around the canals, creating parks and greenspace that could flood naturally during heavy rainfall.
The new spillways would be wide enough to preserve drainage capability but also take direct aim at reducing subsidence, the sinking of the soil that breaks the streets and will cost New Orleans $20 billion in increased flood exposure in the coming decades, Waggonner said. Subsidence is caused by dry soil that compacts easily, so the large new swaths of green space would provide more opportunity for rainwater to soak in and fight that process naturally (similar to rain gardens, on an individual level). Further, if the canals were used for storing water, instead of remaining empty, that would allow the water table under the soil to rise, further combating subsidence.
Between rains, these spillways would serve as parks that will increase New Orleanians’ quality of life with 18 miles of new waterfront inside the city, Waggoner said. Whereas the canal areas are currently hidden in the “back of town” areas like Hollygrove, the spillway parks would instead become assets. And creating open canals is much less expensive than expanding underground drainage.
Changing the old ways
Many of the questions surrounding Waggonner’s presentation concerned the political will to bring his $5.2 billion vision to reality, perhaps most succinctly put by City Councilwoman Susan Guidry, who noted the preponderance of recommendations around her district, which runs from Uptown to Lakeview and includes Hollygrove.
Guidry said major projects are already happening at many of the key points in the Waggonner plan — the Lafitte Greenway, remediation of the Monticello Canal flooding, and the SELA drainage-canal installations along South Claiborne, Jefferson and Napoleon avenues. But the Lafitte Greenway is under criticism for insufficient attention to water management, and she’s seen no indications of Waggonner’s ideas for how the neutral grounds will be built after the SELA projects, she said — with so much work already ongoing, is anyone buying into this strategy?
“Everything seems to have already been planned, and it’s been planned in the traditional way,” Guidry said. “When are we going to put the brakes on?”
Marcia St. Martin of the Sewerage & Water Board responded that her agency was fully on board with Waggonner’s ideas. When the neutral grounds are rebuilt above the SELA canals, for example, she has received a commitment from the U.S. Army Corps of Engineers to include some water-management features (an idea City Councilwoman LaToya Cantrell has also recently proposed). It won’t be a “Ph.D.”-level change like Waggonner proposes, St. Martin said, but more at the “kindergarten” level, a “baby step” in the right direction.
The presence of other city leaders voicing support for the ideas — Deputy Mayor Cedric Grant and GNO Inc. President Michael Hecht both participated in the presentation — suggests that the proposed water-management strategy is on its way to becoming part of the city’s long-term planning. Architect Ray Manning, a new member of the Sewerage & Water Board who participated in Waggonner’s research trips to the Netherlands, said that a whole host of changes are coming to the agency’s leadership, and that he expects ideas like Waggonner’s to find a strong foothold in the immediate future.
“I think we are poised, with the completion of this work, to be able to embark on a new way of looking at these issues,” Manning says. “It is the only reason I’m on this board — to do it in a different way.”
The full plan will be made public Sept. 6 at the livingwithwater.com website. To read more details of Waggonner’s presentation, see below for our live coverage of Thursday’s meeting.