The U.S. Army Corps of Engineers opened the gates of an emergency spillway along the Mississippi River in an effort to divert the water from reaching New Orleans and Baton Rouge. But the Morganza Spillway is diverting the water through a populated area, putting about 11,000 structures and 25,000 people in the path of the floodwaters, though officials had previously warned residents to leave. Also, every year the engineers warn residents in written letters that they may have to open the spillway. The coming rush of water could end up submerging about 3,000 square miles in up to 25 feet of water. However, without opening the spillways, engineers feared that the water pressure would overpower the New Orleans' levees, drenching the city with 20 feet of water, which would be a worse disaster than Hurricane Katrina in 2005.