Ohio's Flood History
Floods are a natural and unavoidable fact of life along streams and rivers. Floods occur when streams overflow their banks and spill onto the adjoining land area, which is called a floodplain. Loss of life and property damage can result when people build their homes and other types of structures in the floodplain.
No area in Ohio is free from the threat of flood-producing storms. In fact, flooding occurs in Ohio every year although the location and seriousness vary according to the weather and ground conditions. Large floods in Ohio, such as those experienced in 1913,1937, 1959, 1963, 1964, 1969, 1990, 1997, and 1998 have caused the loss of many lives as well as costing billions of dollars worth of property damage.
Severe flooding occurred in June 1990 near Shadyside (Belmont County) where 26 people perished, and in July 1992 in Massieville (Ross County) in which 2 residents lost their lives.
What is Being Done About Flood Damage?
In an effort to reverse the trend of rising flood damage, local, state and federal agencies have undertaken a variety of programs that can be grouped into three general categories:
A. Keeping flood waters away from people by:
1. Constructing dams, levees and floodwalls
2. Enlarging or altering stream channels
3. Decreasing runoff through land treatment measures
B. Keeping people and buildings away from flood water through:
1. Floodplain regulations
2. Purchasing floodplain lands to discourage development
3. Flood warning systems and preparedness planning
4. Deed disclosure of flood risk
C. Reducing the cost of flood losses to individuals through:
1. Flood insurance
2. Flood disaster relief
3. Tax adjustments
The Regulatory Floodplain
The first step in planning a floodplain management program is to determine the size of the flood against which we want to be protected. From this we can determine the amount of land area that would be covered by such a flood or, in other words, the size of the floodplain that we wish to regulate. This is known as the regulatory floodplain.
The 100-year flood has become the accepted national standard for regulatory purposes. It is defined as the flood event that has a one percent chance of occurring in any given year or, on the average, occurs once in an 100-year period. This does not mean that if there is such a flood this year it will not happen again for another 100 years. There have been cases in Ohio where floods of this size have occurred within 10 years of each other.
Floodplain regulations are designed to guide floodplain development to lessen the damaging effects of floods. Floodplain regulations may be included in zoning, building codes and subdivision regulations, or they can be adopted as special purpose regulations. Ohio communities frequently adopt special purpose floodplain regulations that combine both building code and subdivision requirements.
For regulatory purposes, the floodplain is divided into two areas based on water velocity: the floodway and the flood fringe. The floodway includes the channel and adjacent floodplain area that is required to pass the 100-year flood without unduly increasing flood heights. This is the hazardous portion of the floodplain where the fastest flow of water occurs. Due to the high degree of hazard found in the floodway, floodplain regulations require that proposed floodway developments do not block the free flow of flood water as this could dangerously increase the water's depth and velocity. The flood fringe is the portion of the floodplain, outside of the floodway, that contains slow-moving or standing water. Development in the fringe will not normally interfere with the flow of water. Therefore, floodplain regulations for the flood fringe allow development to occur but require protection from flood waters through the elevation of buildings above the 100-year flood level or floodproofing buildings so that water cannot enter the structure.
ODNR Assistance in Floodplain Management
The Ohio Department of Natural Resources, Division of Water, provides technical and planning assistance to local governments and private citizens in order to reduce flood losses in Ohio. The Division's Floodplain Management Program is responsible for :
1. Promoting floodplain management in Ohio
2. Providing technical information to support floodplain regulations
3. Assisting local units of government in establishing floodplain management programs
4. Coordinating the efforts of federal, state, and local agencies involved in flood damage reduction in Ohio
5. Assisting communities to become eligible for participation in the National Flood Insurance Program
6. Assisting state and local flood-preparedness efforts
For additional information please contact:
The Ohio Department of Natural Resources
Division of Soil and Water Resources
2045 Morse Road, Bldg. B
Columbus, Ohio 43229-6693
Phone: (614) 265-6750
Fax: (614) 447-6767