Floodplains are terrestrial areas adjacent to waterways that are exposed to periodic inundation (DRDEESESAOSA 1991). Inundation refers to the submergence of vegetation in water. Rivers and stream constantly change to some degree due to precipitation and runoff events. A major source of river and stream modification is anthropogenic development. When a river or stream experiences a heavy or continuous rainfall that exceeds the ability of water to percolate the adjacent soil and the flow capacity of a stream or river, flooding occurs (DRDEESESAOSA 1991). Flooding is when the water in a river or stream pores over the banks and onto the terrestrial area surrounding it.
Floodplain modification policies may prohibit development projects that cause river and stream modification or require methods aimed at flood control (DRDEESESAOSA 1991).