When rainfall or snowmelt intensity is greater than the land can absorb, runoff occurs. Runoff flows over the land to empty into our streams and rivers; if runoff is great enough it inundates land along streams and rivers to cause flooding. These land areas are called floodplains. Under natural conditions, flooding causes little or no damage. However, when stream courses are improperly or substantially altered, streamside trees are cut, or poorly planned floodplain development is built, damage increases substantially. Floodwaters rise higher due to filling in the floodplain, bank erosion is worsened due to greater water velocity in the constricted channel, and structures built in the flood hazard area can be threatened.
Floodplain management takes into consideration both the corrective and preventative measures that can reduce flood damage. The best approach is to simply avoid the problem by refraining from developing near rivers and streams. However, in many places development already exists within the floodplain and more active management is needed. Communities should participate in the National Flood Insurance Program (NFIP) so that structures at risk of flooding can get flood insurance. Emergency preparedness plans and early warning systems should be developed to enable people to evacuate if needed. Where rivers have already been significantly altered by past activities to the point where they have become unstable, fluvial erosion hazard (FEH) studies may be needed to determine where buildings can be safely located.
For information on flooding as a disaster type or mitigation activities, go to our emergency management page.
Floodplain Fact Sheets
The Two Rivers-Ottauquechee Regional Commission presents a series of fact sheets to help educate local officials and residents about flood hazards and floodplain management. These documents were produced by TRORC in cooperation with Vermont Law School’s Land Use Institute, and the Vermont Department of Environmental Conservation, with Samantha Riley Medlock, CFM V.L.S. ’08, as principal author.They are available for download below.
For more information about floodplain management, please visit these websites:
National Flood Insurance Program (NFIP)
Vermont Agency of Natural Resources River Management Program - Flood Hazard Management information
Connecticut River Joint Commission, River Dynamics and Erosion Guide
This guide was designed to help property owners, town planners, road agents, and decision-makers understand how rivers work. Included is a stream assessment guide to locate factors causing or resisting erosion.
Association of State Floodplain Managers
In This Section
Acid Mine Drainage
Bank Erosion & Sediment
Basin Planning
Fisheries
Floodplain Management
Good Road Maintenance
Grants
Invasive Species
Mercury
Non-Point Source Pollution
Organizations
Permits
Riparian Buffer Zones
Wastewater Treatment
Water Quality Studies
Water Supply Protection
Wetlands