When designing roads, buildings, and bridges in a floodplain, engineers consider the statistical probability of a flood of a given size happening in a given year. A 50-year flood has a 2 percent probability (1/50) of occurring in a given year.
A floodplain, also known as a flood plain or bottomlands, is an area of land next to a river that extends from the banks of its course to the foot of the valley walls and suffers flooding during high discharge times.
Floodplains help wildlife by providing a range of habitats for fish and other creatures. Furthermore, floodplains are crucial for water storage and conveyance, water quality preservation, and groundwater recharge.
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