Factors that cause levee failure include overtopping, erosion, structural failures, and levee saturation. A gated spillway protects the dam from overtopping. Levee overtopping along Lake Pontchartrain resulted in the flooding of much of western New Orleans. The Sacramento-San Joaquin River Delta also experienced several levee breaks and levee overtopping. The waters came within five feet of overtopping the East St. Louis levee. Breakwaters are subject to damage and overtopping in severe storms. The contract includes addressing the identified overtopping, seismic, and seepage concerns. It was constructed of local clay; a masonry overflow weir protects the reservoir from overtopping. The ice stagnated and melted behind this moraine, without the meltwater overtopping the terminal moraine. Record flooding occurred along Econfina Creek, overtopping a Florida State Road 20 bridge. Before the river crested, the water came within feet of overtopping the dam. White sweetclover degrades natural grassland communities by overtopping and shading native species. A yellow warning for coastal overtopping and a yellow wind warning were also issued. Fruits generally not overtopping the flowers - a feature distinguishing it from "Cardamine hirsuta".