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
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.