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
Flow control structure dam across a shallow stream, forcing all of the water to one side to allow it to be easily collected in a canal. This can keep a canal full even with very low flows in a stream. Another simple device is a series of concrete piers installed in a spillway to slow down the descending water so that it does not cause damage at the bottom of the spillway. Flow control structure A flow control structure is a device that alters the flow of water in a stream, drainage channel or pipe. As a group these are passive structures since