A variety of humanly constructed structures are used in an effort to limit the extent and severity of flooding (Gregory, 1995), Dams and levees are common flood control structures designed to contain water within designated areas (Brookes, 1985, 1988). These structures can fail because of construction errors, poor design, and overtopping by water (Biswas and Chatteijee, 1971; Costa, 1988), Flood control structures can fail becausc of the failure of a key component. For example, a spillway that erodes away has the potential to lead to the catastrophic failure of the entire dam as the water cuts downward. Sound structures may fail when the water retained by the structure exceeds the height of the structure. Large precipitation events or the displacement of water in a reservoir have the potential to send water flow ing over the flood control structure (Kiersch. 1964}. This may lead to the failure of the structure through erosion. Flooding may be exacerbated by these structures since a feature such as a levee tends to raise the stream level well above the floodplain. When a levee fails, a large amount of fluvial energy is concentrated through that break and a great deal of damage can occur near the break.
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