The Bonnet Carré Spillway needs to be opened — possibly as soon as Saturday — to divert the slug of floodwater coming down the Mississippi River after heavy December rainfall up north, the head of the U.S. Army Corps of Engineers’ New Orleans office said Tuesday.

The spillway structure, built after the deadly 1927 flood, is made up of 350 bays that are closed off by 7,000 wooden pins. It has been opened 10 times since its construction, most recently in 1997, 2008 and 2011. Here’s a video of when it was opened in 2011:

A decision on whether to open the Morganza Spillway, which sends floodwater into the Atchafalaya River Basin, is still being discussed. Here’s a video of the Morganza Spillway when it was opened in 2011: