Morganza Spillway Basin. In such an event, the water level of the Mississippi, high enough to overtop the Spillway, would already be flooding some areas in the Basin downstream of the spillway, due to increased flow through the ORCS and the ORCAS, as well as possible overtopping of levees near the spillway. This flooding, plus any additional water from a Morganza Spillway release, together determine the total extent of flooding throughout the Atchafalaya Basin during a major Mississippi River flood. At risk in the Atchafalaya Basin are Morgan City (population 13,500), various smaller populated places, many farms, thousands of oil and gas
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