Morganza Spillway to open or shut any spillway gate or perform maintenance while the roadway is in use. The land on both sides of the Morganza Control Structure is above normal river water levels, and usually dry. In order for water to reach the spillway, the Mississippi must first rise well above its flood stage, overtopping its banks. The Corps of Engineers considers opening the Morganza Spillway when the flow of the Mississippi at Red River Landing, Louisiana, is greater than and rising. Water from the Mississippi is normally diverted into the Atchafalaya Basin at only one place, the Old River Control
Spillway Spillway A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure that the water does not overflow and damage or destroy the dam. Floodgates and fuse plugs may be designed into spillways to regulate water flow and reservoir level. Such a spillway can be used to regulate downstream flows – by releasing water in small amounts before the reservoir is full, operators can prevent sudden large releases