Legal Definitions - floodplain

Floodplain refers to any low-lying land area adjacent to a river, stream, or other body of water that is naturally susceptible to being covered by water when that body of water overflows its banks, typically during heavy rainfall or snowmelt. These areas are characterized by their flat topography and close proximity to a watercourse, making them prone to inundation when the water flow exceeds the capacity of its usual channel.

• Example 1: A new housing development is planned on a wide, flat stretch of land bordering a major river that historically experiences seasonal flooding. Local zoning regulations require specific building codes and flood insurance for properties in this area.

  Explanation: This flat land next to the river is a floodplain because its elevation and location make it vulnerable to being submerged when the river's water levels rise and spill over its banks, which is a known historical occurrence.

• Example 2: A farmer owns fields situated along a winding creek. During periods of intense rain, the creek frequently swells, causing water to spread across the adjacent fields, sometimes delaying planting or damaging crops.

  Explanation: The farmer's fields are part of the creek's floodplain. Their low elevation and direct adjacency to the creek mean they are regularly inundated when the creek's volume of water exceeds its normal channel capacity during storms.

• Example 3: A city constructs a public park with walking trails and picnic areas in a broad, level basin next to a large urban river. While beautiful, the park is designed with flood-resistant materials because it is expected to be submerged during significant high-water events.

  Explanation: This park occupies a floodplain. Its location in a low-lying, flat area directly beside the river means it is naturally prone to being covered by floodwaters whenever the river's flow becomes too great for its channel to contain.