Areas of Flood Risks
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Rivers
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Areas that are close to rivers---especially large rivers---can be prone to flooding. Excessive rainfall, usually from thunderstorms, over extended periods of time can cause a rise in water that extends beyond the shoreline. When this happens, the threat of flooding occurs.
Rivers are often designed to avoid flash floods. Levees are built, which prevent high water from flooding the surrounding land; however, they can fail when situations arise. In 1993, levees along the Mississippi river failed, leading to flooding issues. During 2005 when Hurricane Katrina hit Louisiana, there were also many levee failures, which resulted in significant flooding.
Coastal Flooding
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With any area that has significant amounts of water surrounding it, there is a threat of flooding. Coastal areas are some of the most "at-risk" areas since they are surrounded by huge amounts of ocean water. Hurricanes and tropical storms can cause huge surges to combine with normal tides. This can increase water levels by up to 15 feet. Hurricanes take the life of many people every year. Flooding due to a hurricane in Galveston during the year 1900 caused the death of over 8,000 people.
Low-Level Areas
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Anywhere that is significantly lower than the surrounding land is a potential risk for flooding. These areas are also often difficult to spot as the flow of the landscape cannot always be seen with the naked eye. Rainfall can easily be several inches over the course of several days due to continuous storms. Tropical cyclones have been known to bring downpours of up to 40 inches over only a couple of days. All water will seep its way into low lying areas first, making them a location that can be prone to significant flooding.
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