BOOTHVILLE-VENICE, La. — A drinking water advisory is now in place in lower Plaquemines Parish from the Empire Bridge to Venice.
The parish water system is now experiencing higher levels of sodium from a saltwater wedge now moving up the Mississippi River. The parish water supply comes from the river.
“As long as the river is very low, salt’s going to keep creeping up the river,” Plaquemines Homeland Security and Emergency Preparedness Director Patrick Harvey said. “In 2012, it was past the Belle Chasse area.”
When the rate of freshwater on the river slows down, it allows saltwater to drift upstream from the Gulf of Mexico. To keep that from happening, the Army Corps of Engineers is now preparing to build a temporary underwater levee.
“It could be about 45 foot tall across the span of the Mississippi River,” Army Corp Emergency Manager Heath Jones said. “It’s goes through the channel, ties into the banks.”
It’s designed to block the wedge of heavier salt water from reaching Belle Chasse, New Orleans and other upriver communities.
“We’re going to begin construction in the next two to three weeks,” Jones said. “We hope construction will be done in early November.”
Plaquemines is also installing two reverse-osmosis machines at its water treatment plants on the south end of the parish already impacted by saltwater.
Ten years ago, the last time the river was this low, the parish spent millions of dollars to barge fresh water to the plants.
Harvey said the desalination devices are more cost effective and should be installed in the next several days.
“They will be able to remove the salt, high chlorides from the river water, the intake into our water treatment plants,” Harvey said. “With the reverse osmosis, it’s going to remove I think about 90-95 percent of the salt in the system.”
Plaquemines neighbor Dean Phillips lives in Belle Chasse.
“I think they’ve learned from previous times,” Phillips said. “So, I think it’s going to be a minimal impact. I think they have a good handle on it, what they’re trying to do.”
As a precaution, Plaquemines Parish has ordered all towers and reservoirs to remain full of fresh drinking water for the duration of the low water event.
The underwater levee would be located on the bottom of the river near the old Alliance Refinery south of Belle Chasse.
Plaquemines officials expect it to remain in place for the next 3 to 6 months.