The Mississippi River continues to swell after a heavy rain event from up north a few weeks ago. Officials are now taking steps to limit impacts, especially near New Orleans.

The Army Corps of Engineers conducted a test opening of the Bonnet Carré Spillway on Monday morning. This gave crews a chance to get out and become familiar with the process. Only one out of the 350 bays was briefly operated.

But even without all gates closed, water was still seeping through control structure dividing river from spillway. Matt Roe with the U.S. Army Corps of Engineers said "...that's very close to when we operate."

The process is labor-intensive. One by one, wooden needles are removed from each gate by cranes. The design is consistent with the technology at the time of its construction—nearly 100 years ago. 

The Army Corps has yet to provide a recommendation for an actual opening of the spillway, but they are monitoring the situation closely. Roe said that they "...look for a flow exceeding 1.25 [million] cubic feet per second." That is in the forecast, but observations need to hit that trigger point before taking action. 

Based on current forecasts, Roe explained that a large amount of water will not need to pass through as compared to past openings. That is, if the spillway were opened later down the line.

Operation of the Bonnet Carré Spillway is not uncommon. Partial openings took place in 2016, 2018, 2019, and 2020. The last full opening occurred with the major river flooding event of 2011.