Morganza Spillway Structure (ORCS), in use since 1963, where floodgates are routinely used to redirect the Mississippi's flow into the Atchafalaya River such that the volume of the two rivers is split 70%/30%, respectively, as measured at the latitude of Red River Landing. During the 1973 Mississippi flood, the ORCS was being damaged due to high flow rates, leading to the opening of the Morganza Spillway to help relieve this pressure. Subsequently, the nearby Old River Control Auxiliary Structure (ORCAS) was constructed, adding additional floodgates for use during major floods. The Morganza Spillway, about downriver from ORCS and ORCAS, is designed for
Morganza to the Gulf Morganza to the Gulf The Morganza to the Gulf Hurricane Protection Project is a flood protection system for Terrebonne Parish and Lafourche Parish in the U.S. state of Louisiana. The targeted area is bounded on the west by Bayou Du Large and LA 311 (Louisiana State Highway 311) and on the east by Bayou Lafourche. The U.S. Army Corps of Engineers is the federal sponsor for this project, and the Louisiana Department of Transportation and Development with the Terrebonne Levee and Conservation District jointly serve as the local sponsor. The Terrebonne Levee and Conservation District will provide operations and maintenance