What is a Floodplain?

A floodplain, also spelled as two separate words "flood plain," is a broad area of flat land that extends out from a river. Typically, when a river rises above the capacity where it can hold its water, the water will flow onto the adjacent flat land, causing it to flood. The increase in water can be due to heavy rain or snow melt, for example. The flood plain will usually have a current running through it, similar to the river’s current, called a floodway. It will also have a fringe area that is free from a current.

It is not unusual for homes or commercial buildings to be located on a floodplain. As a result, there are flood maps that will show the likelihood that a building or a section of land will be damaged because of flood waters. In addition, the flood maps help local government organizations manage the areas when floods occurs. The maps may also be used to prevent damage by moving a particular group of buildings, setting up dams or levees, and alerting people to the risk of flooding.

While many floodplains are areas of high risk, others are less affected. As a result, the flood maps can help people determine whether or not they want to live or run a business on a floodplain. The risk level of an area influences the cost of flood insurance as well, in the event a flood does cause damage to a building and materials within it.

Interestingly, the boundaries of a floodplain can change. Causes of change include the development of the land, such as a dam, levee, bridge, or even the construction of new buildings. Erosion, changes in the pattern of the weather, and even an earthquake can also change the size, shape, and boundaries of a floodplain.

A floodplain is often inhabited by a variety of wildlife. Since the soil is typically very fertile, plants will often grow well. River animals, such as beavers and otters, might make their homes in the plain areas, too. In most cases, a variety of birds will nest in the wetlands on the inner fringe of floodplains, making these areas popular destinations for birdwatchers. Some environmental groups have begun to encourage the protection of floodplains, stating that these areas should not be populated by humans, but only by native birds, plants, and animals. In fact, some groups have pushed for the relocation of entire towns, including hundreds of homes and businesses.