ABSTRACT
The oldest type of flood protection system is the dike. The city of New Orleans, Louisiana, is situated between the Mississippi River and Lake Pontchartrain. If water happens to pass over the top or around the sides of the seawall, it can remain trapped there and cause the soil underneath the seawall to erode, thereby lessening its strength and hastening its potential demise. Water may seem benign, but over time it causes the erosion of banks and other natural retaining devices. Katrina first struck land in the southern part of Florida and temporarily weakened. Flood barriers are movable walls that can be placed perpendicular to a river to keep it from flooding homes or other occupied portions of a city Floodgates are adjustable doors that are usually installed under a bridge or on one side of a reservoir or river.
