When a river or stream overflows its banks, the water runs onto a floodplain. A floodplain is delineated by the flood waters. When the water recedes, the floodplain will return to terrestrial habitat.
(Floodplains and wetlands are different. Wetlands can be found in the floodplain. They serve as a buffer between the river and floodplain where smaller “periodic floods” are contained. Wetlands are wet for all or most of the year, always retaining water just under their surface.)
Flood plains give rivers and streams space to “breathe” as the water rises and overflows after heavy storms and snow melt. Because floodplains hold excess water, the water is released back into the river or stream at a slower rate, which protects the flow of the river and stream. Floodplains also act as filters. After a flood, sediment and nutrients are deposited in the floodplain instead of the river or stream.
Floodplains do more than protect our waterways, plants and wildlife. They serve people too by protecting property from flood damage. They can even save lives by preventing rapidly rushing water from entering business and residential areas.
How communities can protect floodplains
Local governments should protect floodplains by deciding what land uses to permit and encourage in their floodplains. For example, instead of building residential and commercial developments, a floodplain can be preserved or used as a public park instead. Here are some ordinances that communities can enact:
- Prohibit construction of buildings and facilities subject to floodplain water damage
- Require flood-proofing for existing buildings
- Remove flood-prone structures
- Establish construction standards for floodplain development
- Protect natural vegetative cover
- Require tree and shrub planting to prevent erosion
- Restrict dredging, filling, dumping, and/or backfilling
- Require flood insurance under the National Flood Insurance program
- Require permits to be secured from the Michigan Department of Natural Resources and the Department Environmental Quality before granting approval for any floodplain development activity
Removing dams can restore floodplains and put them back to work. Although dams are designed to keep flood water from damaging homes and businesses built on floodplains, these structures age and are not always effective against the largest floods. They also disconnect rivers from their floodplains, which harms wildlife and fish and prevents the floodplains from filtering water before releasing it back into the river or stream at a natural, slower rate.
What HRWC is doing to protect floodplains
- HRWC works with local governments to develop policies and ordinances that protect the land surrounding our waterways.
- We also led the formation of a dam operators’ network to assist dam operators in coordinating dam management to support healthier flows of the Huron River.
- We have worked with Dexter to remove a dam, have studied the dams along the river, and have developed a report on prioritizing actions our communities can take regarding local dams
What you can do to protect floodplains
Talk to your community leaders and find out what policies they support that protect people and land from flooding.
Learn about how climate change is increasing the intensity of storms and encourage your representatives to prepare for climate changes.