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
Pequannoc Spillway which lies on the Pompton River. The Pequannoc Spillway is an early 20th-century concrete spillway over 270 feet wide, equal in girth to the Great Falls of Paterson located along the Pompton River a quarter-mile south of the Pompton dam and associated guard bank in Pequannock Township's Aquatic Park. The dam is a run-of-the-river spillway, which traverses the width of the river and at normal water elevation allows water to spill over its face. The structure is 22 feet tall, though possesses only an 8-inch over 3 foot grade on the upstream side. An associated guard house sits near the