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When Jefferson Parish leaders unveiled a nearly half-mile stretch of porous pavement in Fat City two years ago, they hailed it as a first step in changing the parish's often fraught relationship with water.

The pavement was supposed to act as a sponge during heavy storms, helping the thirsty soil absorb more moisture and slowing the subsidence that has plagued concrete-rich Fat City and surrounding areas of the east bank, while still getting the water off the street.

But at least some of the new paving was laid improperly, preventing rain from reaching the soil on those stretches, parish officials conceded this month. Meanwhile, the parish lacks the equipment needed to stop other sections of the porous stretch from becoming clogged by dirt, which could render them useless as well.

The result is that Edenborn Avenue residents have not seen the benefits of the innovation they were promised. When it rains in the area, much of the water rolls right off the new, supposedly porous surface and into the street, where it is captured by the parish drainage system — just as happened in the past.

As a result, the area is still using the same pumping strategy Jefferson has employed for decades, one that experts say has accelerated the sinking that imperils it and the rest of the New Orleans region.

"It looks like they got caught in the rain when they poured it, and then they came and tried to smooth it out after," Brook Burmaster, director of Jefferson's Streets Department, said in an interview.

Burmaster was referring to a portion of the supposedly permeable concrete near Edenborn and 18th Street. When a reporter poured water onto it, the material did not perform as advertised.

During another test on a portion of concrete near West Esplanade Avenue, water appeared to be sinking into the concrete, but at a glacial pace.

Burmaster and other parish officials said that could be because of the strength of the concrete, rather than because it was clogged. But they did note that parish crews do not have the equipment to prevent clogging.

The Fat City project should serve as a cautionary tale for other parishes and property owners who have turned to permeable pavement for green infrastructure projects, said Darwin Sutton, whose firm, DJ Sutton Construction, specializes in pervious paving installations.

Though he thinks permeable paving is "a great idea" for flood-prone parishes like Jefferson and Orleans, project managers have to be sure that contractors are up to the job, he said.

"I can’t imagine how many millions of dollars they put into this water management system, and none of it works," Sutton said. 

New Orleans has invested more than $120 million in green infrastructure, including porous paving, over the past five years. The city also recently passed a law requiring businesses to install the material in all new parking lots.

For one upcoming project, involving a combination of porous and traditional pavement along Union Street in the Central Business District, the city has tapped the same firm that worked on Edenborn in Fat City, Hard Rock Construction.

Calls and emails to the offices of Hard Rock and Lafarge Concrete, Jefferson's concrete supplier, were not returned in recent weeks.

The Fat City project was announced in 2017 as a way to mitigate flooding in a 40-block section of Metairie which is brimming with concrete and asphalt but short on green space.

It consisted of a new, six-foot-wide drainage pipe that was much larger than the smaller pipes traditionally used in that area, and a mix of permeable and traditional concrete along the sidewalks and driveway aprons that line Edenborn from 18th Street to West Esplanade Avenue.

The permeable paving was supposed to help Jefferson meet standards embraced by the Greater New Orleans Urban Water Plan, released in 2013 by water management experts hoping to slow the region's rapid descent below sea level because of soil subsidence.

Experts said the traditional methods of paving streets with impervious materials and pumping rainwater from them as quickly as possible are major contributors to that subsidence.

Jefferson Parish paid $409,655 for the paving installation on Edenborn and $2.9 million for the overall project. Hard Rock was the general contractor, LaFarge supplied the concrete and Meyer Engineers was the architect.

Because it was deemed too expensive, the parish did not purchase the kind of vacuums that crews could use to remove debris that could clog the voids in the concrete that allow water to pass through, parish spokeswoman Samantha de Castro said. As a result, the pavement could lose its permeability over time.

Such concrete should be cleaned two to four times a year for peak performance, according to the University of New Hampshire's Stormwater Center, which provides technical support to water managers across the country.

The parish's inspections also apparently missed at least one stretch of the concrete near Edenborn and 18th Street that, in multiple tests, did not appear to absorb water at all.

Parish officials initially said the project worked as intended, but they conceded after a site tour with a reporter that concrete in that space appeared to have been poured incorrectly.

There are many ways a crew can botch a permeable paving job, according to reviews of best practices. For instance, if a contractor fails to put a rock layer underneath a permeable surface, the system can be rendered useless. Crews also should install drains under the paving that have openings.

Too much or too little water used in the concrete mix also can affect the material's porosity.

De Castro said the parish considers the Edenborn project a pilot. She did not say if the parish's contract with its vendors gives it any recourse in the event of substandard work, but she said future projects will likely be vetted more closely.

"There's a whole other evaluation process that will come into play if we decide that (this paving) makes sense parishwide," she said.

New Orleans' Public Works Department did purchase vacuums recently to clean the city's pervious concrete. The city has used Fleming Construction and Command Construction on past porous projects; Hard Rock is performing the work on Union Street.

The city "is confident" in Hard Rock's ability to complete that work properly, said New Orleans Public Works Director Keith LaGrange. The department will inspect the job when it is complete, and the city has a one-year warranty on the project, he said.

In Fat City, the paving's defects were immediately apparent to Sutton, who used to live on Edenborn Avenue and remembers how water would creep to his door during storms.

If that sort of intense flooding isn't as prevalent today, it's because of the new drainage pipe installed with the project, not the permeable paving, Sutton said. He said residents may not even realize that the parish was trying to retain water through the sidewalks in a bid to slow subsidence.

That's true of Jesse Mahan, who lives in a nearby apartment building and walks down Edenborn to get to work.

While he had no idea about the permeable paving, he said he's seen less flooding in the neighborhood since the project wrapped.

"I think that has to do with the new drains on the street," Mahan said.