The Bonnet Carré Crevasse (1871) was one of several levee breaches in the Bonnet Carré area in the mid-to-late 19th century. Bonnet Carré was approximately from

New Orleans, Louisiana New Orleans (commonly known as NOLA or The Big Easy among other nicknames) is a Consolidated city-county, consolidated city-parish located along the Mississippi River in the U.S. state of Louisiana. With a population of 383,997 at the 2020 ...

. The breach occurred when excess water from the

Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...

flowed over the east bank levee of Bonnet Carré. The original levee was over high, and the

Crevasse A crevasse is a deep crack that forms in a glacier or ice sheet. Crevasses form as a result of the movement and resulting stress associated with the shear stress generated when two semi-rigid pieces above a plastic substrate have different rate ...

itself spanned about . Local drainage systems were unable to contain the floodwater. The water rushed at 8 miles per hour, causing the width of the breach to increase by the day. Strong northerly winds caused the excess water entering

Lake Pontchartrain Lake Pontchartrain ( ; ) is an estuary located in southeastern Louisiana in the United States. It covers an area of with an average depth of . Some shipping channels are kept deeper through dredging. It is roughly oval in shape, about from w ...

to flow into populated areas to the east, including neighborhoods Metairie and Gentilly. The increasing force of the flood also caused another nearby levee to break. Although the devastation to the Bonnet Carré area was great, its ecological impacts were somewhat beneficial. By diverting river water and sediment, the crevasse saved a greater portion of land surrounding the area from succumbing to total flooding and land erosion. Therefore, the crevasse served as a buffer for wetland erosion. Recognizing the benefits, the local government commissioned the construction of an artificial crevasse that could be periodically opened to drain excess water from the Mississippi into Lake Pontchartrain. The river levee was not restored at Bonnet Carré until 1883. The area is now the site of the

Bonnet Carré Spillway The Bonnet Carré Spillway is a Flood#Flood defences, planning, and management, flood control operation in the Lower Mississippi River, Mississippi Valley. Located in St. Charles Parish, Louisiana, about west of New Orleans, it allows floodwat ...

References

{{DEFAULTSORT:Bonnet Carre Crevasse 1871 in Louisiana Floods in Louisiana 19th century in New Orleans 1871 natural disasters in the United States