Bonnet Carré Spillway opens for 12th time to relieve swollen Mississippi River

ST. CHARLES PARISH, La. -- The U.S. Army Corps of Engineers opened the Bonnet Carré spillway Thursday morning, marking the 12th time in history that the flood control gates have been used to ease pressure on the New Orleans levee system and the rising Mississippi River.

Only a few -- eight -- of the spillway's gates were opened. Officials expect to open more of the 350 gates as water levels and water pressure continue to rise.  Some of that water will be diverted into Lake Pontchartrain and eventually into the Gulf of Mexico, bypassing New Orleans.

The spillway is part of the Mississippi River and Tributaries Project, which protects a population of more than 4.5 million people, according to the Corps of Engineers. It also protects crops valued at more than $51 billion and a $106 billion a year manufacturing base.

The levee system in New Orleans is designed to accommodate 1.25 million cubic feet of water per second, and when the Mississippi approaches that level and reaches 17 feet at the Carrollton gauge, the Spillway is opened.

The river has already overflowed its banks in north Louisiana.

The Spillway was constructed in response to the catastrophic flooding of 1927. It was completed in 1931.

The last time it opened was in 2016.

Officials said the spillway gates could be open anywhere from two-to-four weeks.

Watch the live video below: