Officials look to permanent solutions after intrusion situation improves
Local and federal officials are focusing on permanent solutions for saltwater intrusion after the Army Corps of Engineers said last week much of the greater New Orleans region would escape the worst of the immediate threat.
Why it matters: Officials expect the region's local water supplies to face intrusion again in the future with ongoing climate change and manmade Mississippi River alterations like dredging.
Driving the news: NOLA Ready director Collin Arnold said in a press conference last week he expects to host federal officials "in the very near future" to develop a "permanent solution."
- "We really want to resolve this issue," he said.
Catch up fast: The Army Corps' latest forecast indicates the salt water's creep up the Mississippi River has slowed considerably.
- It now predicts smaller water treatment plants in Algiers and Gretna won't see salt until Nov. 23 and Nov. 26, respectively. The region's largest plants — East Jefferson and Carrollton — may not get impacted at all.
- The Corps says reverse osmosis technology and barging in freshwater to dilute intakes in Algiers and Gretna will be sufficient to desalinate to safe levels.
- As of Monday, the Army Corps reported that salt water was located at river mile 65, marking a 5-mile retreat from earlier reports.
Zoom in: Prior to the forecast's improvement, the largest and most expensive permanent mitigation measure planned was a $250 million pipeline to direct fresh water to the East Jefferson and Carrollton plants.
- Jefferson Parish President Cynthia Lee Sheng said in last week's press conference construction would continue on the first half of the 15-mile flexible pipeline.
- "We don't want to lose any time or get flat-footed if something were to change on us," she said. Plus, "we want to see if it works."
- In Orleans Parish, "no plans are being canceled," SWBNO interim general superintendent Ron Spooner said in the press conference, but pipe won't be laid unless the forecast worsens.
Yes, but: The intrusion slowdown is caused by a few factors, including the shoring up of the underwater sill, said Col. Cullen Jones of the Army Corps of Engineers during the press conference.
- Sill construction is going faster than expected, with completion due this week, Jones said. Plus, once the salt water gets past that sill, it's less salty.
- A deep pocket in the riverbed south of Belle Chasse also serves as a saltwater speed bump as the denser salt water takes more time to advance toward New Orleans, Jones said.
Threat level: Saltwater impacts are still expected in Plaquemines and St. Bernard parishes in October, Jones said.
- Plants in Pointe à la Hache and Port Sulphur are receiving barged water to try to alleviate the problem.
What's next: Corps' updates on saltwater advances will be shared on Thursdays.
- The city sewerage and water board publishes salinity reports daily.
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