Historians say the term “neutral ground” for street medians in New Orleans dates back to the 1800s, when Anglophones and Creoles — who had no great love for one anther — decided they could use the space on Canal Street to discuss business without crossing into the other’s side of town.

But there is nothing neutral about the opinions surrounding the way the U.S. Army Corps of Engineers is rebuilding the median on Napoleon Avenue between South Claiborne and St. Charles avenues.

City Councilwoman Stacy Head calls it “outrageous.”

And Keith Twitchell, president of the Committee for a Better New Orleans, calls it “just plain stupid.”

The Corps disagrees.

The dispute concerns the shape of the median. The Corps is fashioning a crown — meaning the center is higher than the two sides. That’s what was there two years ago when the agency tore up the street for the Southeast Louisiana Urban Flood Control Project.

Opponents want the neutral ground to be flat or even concave. That’s because a crown can rapidly dump water into adjacent streets, adding stress on drainage systems. The other options can slow it down by storing it for short periods and letting some of it seep into the ground.

The latter design is favored under the Urban Water Plan, part of the green infrastructure initiative the Sewerage & Water Board adopted in 2014.

And Head said that’s the design the Corps promised her.

“I’m fit to be tied because for the last seven or eight years, I had been promised by the Corps the neutral ground would be at most flat but hopefully more of a swale or a concave to allow retention of some rain,” she said.

“Frankly, until yesterday, when I saw the hills awaiting sod along Napoleon, I believed that the Corps was going to do the right thing.

“What’s happening now is outrageous.”

Corps spokesman Ricky Boyett said Head is mistaken about what the Corps promised.

Boyett said correspondence shows the agency agreed several years ago to change the South Claiborne Avenue median from a crown to the “greener” designs — such as rain swales and concave landscaping — at the urging of Head and others. But no such deal was made for Napoleon Avenue.

He said the managers for the project considered swales and concave designs in the planning phase but elected to stay with the crown shape for several reasons:

They needed to leave enough earth to protect the new concrete box culvert, which comes within 2 to 6 feet of the surface.

The concrete culvert would limit the ability of any retained water to seep into soils.

Poorly draining neutral grounds could lead to mosquito breeding and make them less useful for others who may use the area, including parade watchers.

The legislation authorizing the project specified the median must be returned to its original shape. Any redesign and engineering would cost more money, which would have to be provided by another organization.

None of that appeased Head or other critics.

“The Corps’ response is unacceptable, but honestly, it is expected,” she said via email. “Since the beginning of New Orleans’ post-Katrina introduction to the ‘living with water’ method of dealing with storm water, the Corps has not embraced the concepts.”

Twitchell, whose organization supports green infrastructure, agreed.

“This is yet another example of how decision-makers at all levels keep talking the water management talk but then do not walk the walk,” he said.

The neutral ground dispute is just the most visible of many long-standing frustrations green infrastructure advocates have had all along over the massive drainage construction — a project they would rather have seen delayed if not killed.

Authorized by Congress after the historic May 8, 1995, rainstorm flooded much of the city, the Southeast Louisiana Urban Flood Control Project is a vast expansion of the traditional system the city has always used to fight heavy rains. Congress eventually appropriated $2.9 billion for all SELA projects, including $93.2 million for the Napoleon Avenue construction. The local share of those costs is 35 percent.

But since then, studies have shown pumping all the rain out adds to the costly problem of sinking soils, and it leads to the need for heavier drainage and pumping systems. In the words of Cedric Grant, head of the Sewerage & Water Board: “We can’t build our way out of this.”

The green infrastructure alternatives use features to store some stormwater on the surface, slowing its travel to drainage pipes. That lets some of it seep into soils to sustain the groundwater that resists subsidence.

The Urban Water Plan’s central ethos of “living with water” includes using the drainage system to improve the city’s aesthetics. It recommends turning drainage canals into landscaped bayous and opening long-buried concrete culverts such as the one under the Napoleon Avenue median.

But while the city began to embrace the green movement during the rebuilding after Hurricane Katrina, policymakers faced a tough decision.

Halting and trying to redesign SELA would not only leave the city’s drainage capacity at the status quo for years but also might mean the loss of federal funding. That’s because the plan would be significantly different from what Congress approved, so the project would have to be resubmitted for approval.

So while the city declared the Urban Water Plan a guiding strategy of its drainage overhaul, it was never fully incorporated into the SELA project.

“We wave the flag of green infrastructure, we have a resiliency czar, we shout about the national awards and grants we win for resiliency and thinking green, and then we let something like this happen?” Head said. “We know crowns increase the flooding on the streets and are ruining the foundations of the homes along Napoleon. But we can’t change that?

“This is outrageous.”

Jeff Thomas, a leader of the New Orleans Citizen Sewer, Water And Drainage Reform Task Force in 2012, said the neutral ground controversy should be a wake-up call for the city to try to use green infrastructure to mitigate the impact of poor decisions.

“I think what this whole episode should teach us is we have to change our way of thinking and put drainage at the center of every decision we make,” he said. “Cities that have earthquakes don’t build anything without making sure it will be earthquake safe.

“We shouldn’t do anything — rebuild streets, sidewalks, parking lots, drainage systems — without making sure they don’t add to our drainage problem but help it.”