Louisiana sounds the intruder alert

Louisiana Governor John Bel Edwards said in a press conference on Friday that he’s “days away” from asking for a federal emergency declaration to help combat a saltwater intrusion that’s flowing up the Mississippi River and threatening his state's drinking water supplies.

What is a “saltwater intrusion”?

Saltwater (seawater) is denser, so it sits underneath freshwater. When the freshwater volume drops – like the nearing record-low Mississippi River due to a period of drought – saltwater can begin to replace it, mixing with and contaminating the freshwater supply. This is referred to as saltwater intrusion.

And, similar to when Greeks sails appeared on the horizon of Troy, this sea intruder only signals problems. High concentrations of salt in drinking water can lead to hypertension and corrosion of the water infrastructure, the latter of which can cause metals in the pipes to leach into the water.

• In this particular instance, saltwater has already entered the drinking water of communities south of New Orleans – from Empire Bridge to Venice, Louisiana – making the water undrinkable for about 2,000 residents and causing water outages at local schools.

👀 Looking ahead… To combat the saltwater wedge – which is expected to be in the New Orleans area by October 28 – officials are working to heighten an existing underwater sill (used to block or slow the salt), as well as bus in up to 36 millions of gallons of water per day for residents in the impacted areas.