1 of 2 | Col. Cullen Jones, U.S. Army Corps of Engineers, New Orleans District commander, speaks to the media Sept. 15 about steps being taken to augment an existing underwater sill to delay the progression of saltwater up the Mississippi River. Photo by Ryan Labadens/U.S. Army/UPI
Sept. 28 (UPI) -- President Joe Biden has approved a disaster declaration in Louisiana where officials are scrambling to prevent saltwater in the Gulf of Mexico from seeping into the state's drinking supplies.
The president approved the declaration Wednesday, the White House said in a statement, authorizing the Federal Emergency Management Agency to coordinate disaster relief efforts, specifically the mobilization of resources necessary to alleviate the situation.
The declaration was made in response to a request for assistance from Louisianan Gov. John Del Edwards, who thanked Biden in a statement for granting the disaster declaration.
"Efforts to mitigate the impact of the saltwater intrusion are currently underway and other projects are being considered based on the projections being received from the United States Army Corps of Engineers," the Democratic governor said.
"This 90-day approval of our emergency declaration will help our state and local partners with the costs of any mitigation efforts and protective measures. As this event unfolds, we will continue to analyze the emergency efforts and impacts to determine if further requests will be necessary."
The influx of saltwater threatening Louisiana's drinking water supplies is the result of extended drought conditions in the state and across the Mississippi River Valley. The governor's office said the "historic low flow conditions" has resulted in saltwater from the Gulf of Mexico making its way up the upriver.
The U.S. Army Corps of Engineers, New Orleans District, explained that the intrusion of saltwater is a natural phenomenon that occurs when the bottom of the riverbed, which in this case is between Natchez, Miss., and the Gulf of Mexico, is below sea level.
Under normal conditions, the downstream flow of the river prevents the progression of the saltwater, but the extremely low volume of water flow caused by the drought is allowing the saltwater unimpeded travel upriver, threatening municipal drinking water supplies.
State officials said Plaquemines Parish is already being affected with projections showing other parishes, which are analogous to counties, will also be impacted over the next month.
Among efforts to delay upriver progression of saltwater is construction on an underwater sill to reduce its depth of -55 feet to -30 feet.
The sill was originally constructed in July to create an artificial basin to delay the increase of saltwater but the U.S. Army Corps of Engineers said it was "overtopped" Sept. 20.
"Our modeling indicates that by augmenting the existing sill, we can support state and local preparedness and response efforts by delaying further upriver progression of the saltwater by approximately 10 to 15 days," Col. Cullen Jones, U.S. Army Corps of Engineers New Orleans District commander, said in a statement.
The U.S. Army Corps of Engineers said it was also working to secure water barges to support affected water treatment facilities by transporting water collected from portions of the river unaffected by saltwater to downriver facilities.