Salt water from the Gulf is traveling up the Mississippi River due to drought, threatening south Louisiana's drinking water for the second year in a row.
The mighty Mississippi has reached one of the lowest levels in recent history and the U.S. Army Corps of Engineers said this saltwater could threaten drinking water in New Orleans by the end of October if efforts to stop it don’t work.
Last month, the Corps announced plans to shore up and heighten an existing underwater barrier, called a “sill,” to prevent the saltwater from traveling too far north. This salt water is denser than freshwater, so in times of low river output and levels, the saltwater travels under the freshwater up river. A “saltwater wedge” as it is known, occurs once a decade; however, this is the second year in a row that drought has left the Mississippi River’s flow far lower than normal.
The construction being done on the sill was about 14% as of this weekend, and crews are working around the clock.
The second line of defense is the dilution of the Mississippi to salinity levels safe to process. The U.S. Army Corps of Engineers started the process of barging freshwater to water treatment facilities in Plaquemines Parish. The first load of water on Sunday consisted of 500,000 gallons and was delivered to the Port Sulphur Water Treatment Facility to be mixed with the salinated water.
The USACE is planning on delivering up to 36 million gallons of water per day if other facilities are affected by saltwater intrusion.
Plaquemines Parish has been affected by this phenomenon since June, receiving almost 1.5 million gallons of water from the state since then. If this issue persists, it could affect 20,000 more residents in the parish alone.
The only recorded drought worse than this was 1988, which allowed the saltwater wedge to travel to Kenner, 13 miles up river. The Corps have also proposed the possibility of shipping in freshwater to dilute the Mississippi as it reaches New Orleans water facilities.
Officials say that if the water supply has been tainted by freshwater to avoid drinking it or running appliances that could be corroded by the saltwater.