The term "100-year floodplain" means to emergency preparedness officials that the odds of a flood at this level are 1 in 100 in any given year. A floodplain is an area of land that is adjacent to a river, a lake, or an ocean, and that is prone to flooding when the water level rises due to heavy rainfall, snowmelt, or storm surge.
A floodplain can have different levels of flood risk, depending on the frequency and severity of the flooding events. A 100-year floodplain is a floodplain that has a 1% chance of being flooded by a flood that has a magnitude or intensity that is expected to occur once in 100 years, or that has a return period of 100 years. A
100-year floodplain does not mean that the area is expected to be safe from flooding for at least 100 years, or that the next significant flood will hit within the next 100 years, or that the last flood of any kind to hit the area was more than 100 years ago, as these are common misconceptions or misunderstandings of the term. A
100-year floodplain means that the area has a constant and annual probability of being flooded by a 100-year flood, regardless of the past or future flooding events. Emergency preparedness officials are the authorities or the professionals that are responsible for planning, organizing, coordinating, or executing the emergency response and recovery activities in the event of a disaster, such as a flood. Emergency preparedness officials need to understand the term "100-year floodplain" and its implications, as it can help them assess the flood risk and vulnerability of the area, and develop and implement the appropriate mitigation, preparedness, response, and recovery measures for the area. References:
* [Floodplain]
* [100-year Floodplain]
* [Emergency Preparedness Officials]