A 100-year floodplain is the area that is expected to be flooded during a 100-year, or 1-percent annual chance storm.  Floodplains in Carroll County are all located over and around streams and rivers.  The idea is that there is a 1-percent chance of a storm of that size happening each year.  Every stream has a floodplain and Carroll County regulates both the mapped Federal Emergency Management Agency (FEMA) and unmapped, non-FEMA floodplains.

FEMA floodplains in Carroll County are shown on Flood Insurance Rate Maps as either Zone A or Zone AE.  This means that FEMA has used standard engineering practices to determine that these are areas that flood from streams and rivers. 

Carroll County, the Maryland Department of the Environment, and FEMA all have requirements relating to developing within the 100-year floodplain.  Carroll County prohibits new structures from being built in the 100-year floodplain.  This includes the FEMA and non-FEMA floodplain.  There are also limitations on building additions that should be discussed with the Floodplain Manager.

All development within the 100-year floodplain (not only construction of buildings but also filling, excavation, installation of fences or sheds, etc.) requires a review by Resource Management.  There is no set distance that you can build off a stream as it depends on the stream.  Each case must be reviewed individually. 

To build a stream crossing, whether for vehicles or people, you will need to hire an engineer to determine the impact the crossing will have on the water surface elevation.  In other words, if you build a bridge or install a pipe, will it cause the floodwaters to go higher in a 100-year storm?  The impact may require information to be submitted to FEMA.  You will also need to contact the Maryland Department of the Environment (MDE) Wetlands and Waterways Division to determine what state permits are required for performing work in a stream.  Please click here for more information from MDE.

When your property was developed, an easement may have been recorded on a part of it.  Floodplain easements are recorded over and around streams.  A floodplain easement is a legally enforceable agreement between a landowner and the county or municipality to conserve the floodplain.  Some activities are allowed, such as stream restoration and tree planting, and activities that are prohibited such as causing soil disturbance or building.  These are outlined in the deed of easement that was signed by the person who created your property.  Since not all activities can be listed in a deed, approval of any activity not listed in the deed must be requested from Carroll County.