Days of heavy rain in the Deep South have triggered flooding and landslides that have closed several major roadways. At least three deaths are connected to the rains.

As a result of the prolonged, impactful flooding, Mississippi Gov. Phil Bryant declared a state of emergency for affected counties, while Kentucky Gov. Matt Bevin declared an emergency for the entire Bluegrass State. Fourteen Tennessee counties are also under a state of emergency.

So much water is heading down the Mississippi River that the U.S. Army Corps of Engineers announced Monday that it will open the Bonnet Carre Spillway, located about 12 miles upriver from New Orleans, later this week. This will divert some of the river's water into Lake Pontchartrain in southeastern Louisiana, which will keep the New Orleans levees from being further stressed, according to the Associated Press.

This will be the first time in the 88 years of the spillway's existence that it needed to be opened in consecutive years, and only the 13th time it has been opened at all, the report added.

(MORE: Flood Threat Lingers in the South)

Middle Tennessee was especially hard hit. In Hawkins County, Tennessee, State Road 66 was completely washed away.

Interstate 40 remains closed from Clyde, North Carolina, to the Tennessee state line after a landslide Friday night tumbled dirt and rocks onto the westbound lanes.

By Sunday, the heavy rain had ended, but forecasters warned that river flooding will persist and even worsen in some parts of the South this week.