Mayor Helena Moreno spent her first day in France touring an underground stormwater basin built to keep Paris from flushing raw sewage into the Seine, part of a trip aimed at finding new ideas for New Orleans' own flood-prone streets. The basin she walked through can temporarily hold 13.2 million gallons of water during heavy rain, dwarfing the roughly 4-million-gallon capacity of a stormwater project New Orleans is building at the old Mercy Hospital site.
Moreno toured Paris's Austerlitz Stormwater Basin and met with city officials there to talk through drainage and flood solutions for New Orleans, according to fox8live.com. The outlet reported that Paris officials enthusiastically agreed to pursue a technological collaboration with the Sewerage and Water Board of New Orleans and the city's infrastructure team, with the partnership centered on sharing expertise and exploring stormwater-management solutions. Moreno also said she was interested in how Paris uses modeling and predictive technology to prepare for and manage heavy rainfall, per the same report.
As WWLTV.com reported, Moreno departed New Orleans for Paris on Wednesday to attend the Saints game against the Pittsburgh Steelers, then planned to meet with city officials and explore infrastructure and economic development opportunities while there. She said she hoped to establish a partnership between Paris and New Orleans engineers to bring new ideas to the city's drainage system, and said New Orleans is making major stormwater-retention investments but has nothing quite like the Paris basin, according to the station.
What the Austerlitz Basin Actually Does
The Austerlitz basin, finished in 2024, holds 50,000 cubic meters of water and is designed to prevent wastewater from being discharged into the Seine during heavy rainfall, according to paris.fr. Construction cost around 90 million euros, the city government reports — though WWLTV's reporting on Moreno's trip put the figure at around $98 million, a discrepancy the available record does not resolve. Paris began construction on the project in 2021, with the goal of cleaning up the Seine in time for open-water swimming events at the 2024 Paris Games, according to missioncapitale.paris.fr. That outlet described the basin as a cylinder 50 meters in diameter and more than 30 meters deep.
The payoff, according to the city, is a sharp drop in how often Paris has to open overflow gates that let untreated water spill into the river. Paris officials expect the gates to open for the heaviest rainfall only about twice a year now, down from 10 to 15 times previously, per paris.fr.
New Orleans' Smaller-Scale Answer
New Orleans' own version of this idea is taking shape beneath the former Mercy Hospital site, where crews are building an underground basin capable of holding about 4 million gallons of water, according to axios.com. The project is designed to help reduce flooding in the city's Mid-City neighborhood, Axios reported, and officials are aiming to have it ready before the 2027 hurricane season. Moreno's office said the broader push behind projects like this one is to give the drainage and pumping system more time to handle heavy rainfall, and that the Paris collaboration may help identify additional approaches to better protect New Orleans neighborhoods from flooding.
The scale gap between the two projects reflects the underlying challenge facing New Orleans' drainage system. The Sewerage and Water Board's network includes more than 68,000 catch basins, 1,500 miles of underground drainage pipes, 200 miles of canals and 120 pumps, according to swbno.org. Even so, the agency's engineers estimate the system can move only about half an inch of water per hour once canals and pipes fill up, and rainfall exceeding an inch per hour will most likely outpace that capacity, leading to street flooding until the system catches up, per the same source.
Aging Infrastructure, Fragmented Oversight
Those capacity limits sit on top of deeper structural problems. New Orleans faces drainage challenges rooted in an inadequately sized system, aging infrastructure with substantial deferred maintenance, and fragmented governance, according to thewaterinstitute.org. The same assessment warns that future climate change and demographic trends are likely to make those challenges worse in the decades ahead.
Day to day, the Sewerage and Water Board's operations crews track canal levels and monitor weather forecasts through a direct tie to the National Weather Service Radar System, according to swbno.org's drainage overview. That real-time monitoring is the kind of system Moreno pointed to in Paris, where she said she wanted to learn more about how predictive technology helps the French capital get ahead of major storms before they hit.
