Civil Engineering PE

Answer: A - The statement that best describes the difference between a floodplain and a floodway is that a floodplain may span across a vast area while a floodway is generally contained within the channel of a river. Floodplains include any land area that may be inundated by floodwater from any source (river, lake, or ocean). A floodway is defined as the channel of a river and a portion of the overbank floodplain that carries most of the base flood. Federal regulations require that the construction of structures in a floodway will not obstruct flood flows or increase the elevation of floodwaters.