Floodplain Management and Protection

A floodplain is the area adjoining a stream, river or watercourse that has been or may experience flooding in a storm event. The hazards of living on or adjacent to areas that are subject to flooding are well known. Many developed areas of Chester County are subject to periodic flooding, because they were first settled by persons who needed to be close to water for transportation and water power for mills. Development has caused flood elevations and frequency to increase over the years.

Regulations are usually located in the zoning ordinance, as an overlay district that places special controls over what is known as the 100-year floodplain. A one-hundred-year flood is calculated to be the elevation of floodwater expected to be equaled or exceeded every 100 years on average. The 100-year flood generally has a one percent chance of being equaled or exceeded in any single year. Although all Chester County municipalities have adopted zoning ordinances, they are also permitted to adopt flood management regulations as part of other municipal ordinances. Act 166 permits a municipality to adopt floodplain management regulations without adopting a zoning ordinance.

floodIn an effort to reduce the risk of loss of life and property, both Federal and State governments have established floodplain management and protection programs to reduce the impacts of floods. The Pennsylvania Flood Plain Management Act, commonly known as Act 166, was enacted in 1978 to help limit the loss of life and damage to property due to flooding, through the proper management of floodplain areas within Pennsylvania. The Act requires every municipality that is subject to flooding to participate in the National Flood Insurance Program (NFIP). The NFIP enables property owners to buy subsidized flood insurance in participating municipalities. In return for making flood insurance available at lower costs for their residents, participating municipalities are required to enact floodplain management regulations that comply with the minimum requirements of the NFIP and with regulations adopted by the Pennsylvania Department of Community and Economic Development (DCED).


Floodplain Management and Protection ordinances can be associated with the following benefits:


Floodplain Management and Protection ordinances can be associated with the following limitations:

How to Use This Tool

Municipalities that are updating their Floodplain Management and Protection regulations should consider the following:


In 2006, FEMA, the Federal Emergency Management Agency's Flood Insurance Rate Maps (FIRM) and Flood Insurance Study (FIS) in portions of Chester County were revised. This necessitated revisions to municipal ordinances to properly reference the revised FIRM and FIS so that there was no interruption of the National Flood Insurance Program (NFIP). The Pennsylvania Department of Community and Economic Development (DCED) was the liaison between FEMA and the municipalities. DCED reviewed proposed municipal ordinance language for consistency with federal and state requirements and provided feedback to the municipalities. Examples of municipal floodplain ordinances:

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