BATON ROUGE, La. (AP) — A mass inflow of salt water from the Gulf of Mexico creeping up the drought-stricken Mississippi River is threatening drinking water supplies in Louisiana, prompting President Joe Biden to sanction federal help.

Edwards sent a letter Monday evening saying the issue “is of such severity and magnitude” that state and local authorities can no longer manage it on their own. Federal assistance is “necessary to save lives and to protect property, public health and safety or to lessen or avert the threat of a disaster,” Edwards wrote.

The emergency declaration will help Louisiana secure federal money and logistical assistance from partners such as the Federal Emergency Management Agency.

Read the full statement from the Office of the Governor below: 

Today, Gov. John Bel Edwards announced that President Joseph R. Biden, Jr. has approved his request for an Emergency Declaration due to the lower Mississippi River saltwater intrusion. As a result of the historic drought throughout the Mississippi River Valley, the rate of freshwater flowing down the Mississippi River has been dramatically low, allowing an intrusion of saltwater from the Gulf of Mexico to make its way upriver. Plaquemines Parish has already been affected by the intrusion, and other parishes are projected to be impacted over the next month including St. Bernard Parish, Jefferson Parish and Orleans Parish.

“I’m grateful to the Biden administration for making this request a priority and responding quickly to help the people of South Louisiana," said Gov. Edwards. “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 (USACE). 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 President’s approval authorizes the Department of Homeland Security, Federal Emergency Management Agency (FEMA), to support all disaster relief efforts, which have the purpose of alleviating the hardship and suffering caused by the emergency on the local population, and to provide emergency protective measures, including direct federal assistance, under the Public Assistance program limited to temporary measures that address reduced water treatment capability due to saltwater intrusion resulting from low water levels of the Mississippi River for no more than 90 days from the date of declaration, as authorized under Title V of the Stafford Act, in Plaquemines, St. Bernard, Orleans and Jefferson parishes.

The Governor’s Office of Homeland Security and Emergency Preparedness (GOHSEP) continues to work with leadership in the impacted areas, along with our state and federal partners, on response and preparation.

For the second year in a row, salt water from the Gulf of Mexico has moved further up the Mississippi to threaten drinking water in communities that rely on the river for fresh water, including New Orleans. Typically, the river’s mighty flow keeps mass amounts of salt water from reaching too far inland, but hot and dry conditions across the country this summer triggered drought that slowed the Mississippi’s flow and lowered its water levels.

In parts of Plaquemines Parish, residents have relied on bottled water for drinking and cooking since June.

“We have had discussions with FEMA about the unique challenges we face with this event,” Edwards said in a news release. “We are optimistic the President will approve our Federal Emergency Declaration, which will be crucial to help our communities.”

Edwards said 23,515 residents in Plaquemines Parish have been affected by the salt water, including those at a military base, a nursing home, 11 schools, a prison and citrus farms.

Residents have reported skin irritations and damaged appliances, including water heaters and washing machines, from salt exposure.

The salt water is expected to reach other drinking water supplies further upriver — including Orleans, St. Bernard and Jefferson parishes — by mid-to-late October, Edwards said.

Officials are addressing the issue in multiple ways, including raising the height of an underwater levee used to block or slow the salt water and bringing in 15 million gallons of fresh water to treatment facilities in impacted areas.