The Floodplain . . .

The Floodplain

Historically, people have been attracted to bodies of water as places for living, industry, business, and recreation.  These areas became centers of transportation water supply, and water power.  Additionally, these regions were commonly areas with fertile soils that attracted agriculture.  As these areas were developed, natural forces of flooding became a cause of damage and destruction.



Flooding is a natural and beneficial function of stream or lake systems. Floods occur when rivers, streams or lakes overflow their banks and spill onto the adjacent land area, which is called a floodplain.  Natural controls on flooding and erosion help to maintain water quality by filtering nutrients and impurities from runoff, processing organic wastes, and moderating temperature fluctuations.  Floodplains enhance biological productivity by supporting a high rate of plant growth.  People benefit from floodplains through the food they provide, the recreational opportunities they afford, and the scientific knowledge gained in studying them. 



Loss of life and property can result when people build structures and carry out other development in flood hazard areas.  Many factors can cause flooding in Ohio including: heavy and/or prolonged periods of rainfall, snowmelt, soil saturation, ground freeze, severe wind events, and insufficient drainage systems. They can occur at any time of the year, in any part of the country, and at any time of the day or night. Most lives are lost when people are swept away by flood currents, whereas most property damage results from inundation by sediment-laden water. Flood currents also possess tremendous destructive power, as lateral forces can demolish buildings and erosion can undermine bridge foundations and footings leading to the collapse of structures.


Flooding is the most frequently occurring natural disaster in Ohio and the United States. During the 20th century, floods were the number-one natural disaster in the United States in terms of the number of lives lost and property damage. In Ohio, there are many types of flooding that occur, including riverine, flash flooding, coastal flooding, and shallow flooding.  Floods damage private and public property and infrastructure in Ohio every year. 


A Base Flood is a flood that has a one percent chance of being equaled or exceeded in any given year. The base flood is also referred to as the 1% chance annual flood or one‑hundred (100) year flood. During a 30 year mortgage, there is a 26% chance of being hit with a 100 year flood (base flood) in the floodplain.  There is a 1-2% chance that the house will catch fire during the same 30 year mortgage.