Advantages and Disadvantage of Flood Plain Zoning?

A: Flood Risk becomes much lower as Impermeable Surfaces aren't Created meaning the Surface Run Off is Much lower, and the Impacts of Flooding is Lower as Buildings isn't Present D: Urban Areas on a Flood plain make this Concept Completely Useless, and even then, Expanding onto a Flood Plain may be to Sustain Population Growth [Urbanisation]