The Bonnet Carré Spillway is a vital element of the comprehensive plan for flood control in the Lower Mississippi Valley. This multi-state plan, called the Mississippi River and Tributaries Project (MR&T), provides flood protection for the alluvial valley between Cape Girardeau, Missouri, and the mouth of the river. Due to the wide expanse of the project and the complex problems involved, the plan contains
an array of features. The MR&T Project provides for levees to contain flood flows, floodways such as the Bonnet Carré
to redirect excess flows away from the Mississippi River, plus features such as channel improvement and river bank stabilization for efficient navigation and protection of the levee
system. It also involves reservoirs and pumping plants for flood control drainage. 
The Bonnet Carré Spillway is the southernmost floodway or flood bypass in the MR&T system. Located in St. Charles Parish, Louisiana, the spillway protects New Orleans and other downstream communities during major floods on the Mississippi River. This protection is accomplished by diverting
a portion of the flood waters into Lake Pontchartrain and thence into the Gulf of Mexico, bypassing New Orleans. This spillway was first opened during the flood of 1937, and seven times thereafter through 1997
to lower river stages at New Orleans. 
The Bonnet Carré Spillway consists of two basic components: a control structure along the east bank of the Mississippi
River and a floodway that conveys the diverted flood waters to the lake. The control structure is a mechanically controlled
concrete weir which extends for over a mile and a half parallel to the river. Confined by guide levees, the floodway stretches
nearly six miles to Lake Pontchartrain.
The spillway stretches from the Mississippi River northward to Lake Pontchartrain.
In addition to its flood control function, the project's nearly 8,000-acre floodway is the site of diverse and extensive
recreational activities. Also of importance are the fish and wildlife benefits derived from the floodway's varied habitats
and the introduction of fresh water and nutrients into