During the Great Mississippi Flood of 1927 , city and state leaders used dynamite to breach a levee at Caernarvon , thirteen miles ( 19 km ) below Canal Street , in order to save the city of New Orleans from flooding . This action resulted in the flooding of much of the less-populated St. Bernard and Plaquemines parishes , causing widespread destruction to agriculture and housing
Great Mississippi Flood of 1927
Great Mississippi Flood of 1927
Plaquemines Parish, Louisiana