These huge flood gates were erected after the devastation from hurricane Katrina. The flood waters from nearby Lake Ponchartrain inundated this area as well as far north from here. In addition to levees, these gates will hopefully protect these marshlands and homes from future destruction from rising waters and storm surge.
The cache is a nano. Thanks for hunting, I hope it's warmer for you when you find it than when I placed it! Sleeting and 29 degrees!