Information for the Media on the
Importance of Natural Floodplains

 The Natural Floodplain Functions Alliance

Floodplains are unique, natural features of the landscape.  The natural resources and functions of floodplains provide numerous economic and environmental benefits that are an immense value to the Nation.  

» Fact Sheet

» Natural Resources and Functions of Floodplains

» Links and Publication

» Contacts

» Mission, Goals, and Objectives of the Natural Floodplain Functions Alliance

Just the Facts

1. Floodplain management. The goals of floodplain management are to reduce the loss of life and property caused by floods and to protect and restore the natural resources and functions of floodplains.

2. Floodplains are beneficial.  Floodplains in their natural state provide numerous economic and environmental benefits including storing and conveying floodwaters, improving water quality, facilitating groundwater recharge, and enhancing biodiversity.  Floodplains also contain a wealth of natural resources such as wetlands and wildlife.

3. Floodplains are valuable.  A recent study found that natural floodplains provide more value per acre than any other land type. With just 2% of the land area floodplains provide 25% of all terrestrial ecosystem service benefits (these services are often referred to as environmental benefits).  See "Functions and Values of Floodplains" below for a list of the benefits.

4. What is a floodplain?  Floodplains are where land and water meet, they are low lying areas adjacent to inland and coastal waters that are occasionally and temporarily inundated during high flows.  This intermittent flooding is actually necessary for the long-term ecological integrity of floodplains and adjacent waters.  There are approximately 100 million acres of mapped floodplains in the United States.    

5. Wetlands.  Some 80% of wetlands are located in floodplains.  Wetlands are especially important as they store a significant amount of floodwater, provide critical habitats for wildlife, improve water quality, and recharge groundwater.  

6. Floods are costly.  It's been estimated that the average direct and indirect costs of flooding in the United States is between $38 and $54 billion per year.  In fact, floods have caused a greater loss of life and property and have disrupted more families and communities than all other natural disasters combined.  These costs are largely the result of unwise development in flood hazard areas and the loss of floodplain functions that naturally reduce flood damage.  

7. Floods and Climate Change.  The National Oceanic and Atmospheric Administration (NOAA) has found that there has been a significant increase in the intensity of precipitation events in most parts of the United States over the last few decades due to climate change.  Flood losses are continuing to increase as a result and greater efforts must be employed to adapt to the impacts of climate change, especially flooding.

8. Floodplains and wildlife.  Nearly 70% of wildlife species rely upon riparian areas during some point of their life cycle, riparian zones are the floodplain areas closest to the water.  

9. Damaged floodplains. In the past, a typical response to flooding was to build a "flood control" structure such as a levee or floodwall.  These structures, however, have had a significant adverse impact on the water quality and ecological integrity of rivers, as well as their adjacent floodplains, by constricting rivers and preventing floodplains from flooding.  Floodplains provide room for rivers, one acre of floodplain can store 1.5 million gallons of flood water.

10. Executive Orders. In 1977, the President signed Executive Order 11988 which required that federal projects account for the "100-year" flood (usually by elevating the structure), and the "500-year" flood for critical facilities.  In 2015, the President signed Executive Order 13690 which amended and enhanced E.O. 11988 by directing that all federal agencies use approaches to reducing flood losses that are less damaging to the environment, these are often referred to as "green infrastructure."  The Executive Order's "Implementing Guidelines" includes strong language to protect and restore the natural resources and functions of floodplains.  

11. Managing floodplains.  For regulatory purposes, the floodplain is defined as the area inundated during the flood that has a 1 % chance of occurring during any given year, often referred to as the "100-year" flood.   However, although the “100-year" flood could happen once in a hundred years, it could also happen much more frequently, some communities have experienced a "100-year" flood twice in one year.  Draining agricultural lands increases runoff, and growing communities with more hard surfaces such as roads, parking lots, and buildings prevents water from soaking into the ground sending it into rivers and streams, increasing flooding downstream. When these changes occur the "100- year flood" can happen more frequently.  National floodplain management policy balances efforts to reduce flood risks with development and private property rights.

[1] Opperman, Jeffrey, Ryan Luster, Bruce McKenney, Michael Roberts, and Amanda Wrona Meadows, 2010.  Ecologically Functional Floodplains: Connectivity, Flow Regime, and Scale.  Journal of the American Water Resources Association 46(2): 211 - 226.

Functions and Values of Floodplains

Natural floodplains provide a wide range of benefits including:

Water Resources
Storing and conveying floodwaters.
Reducing flood velocities and peaks.
Improving water quality.
Moderating temperature fluctuations.
Promoting infiltration and groundwater recharge.
Reducing frequency and duration of low stream flows.
Reducing erosion caused by floods and high tides.

Biological Resources
Providing habitats for fish and wildlife.
Enhancing biodiversity.
Creating habitats for rare and endangered species.
Maintaining ecosystem integrity.
Preserving wetland functionality.

Community Resources
Providing recreational opportunities.
Enhancing agricultural lands.
Providing "wild" natural areas for environmental education.
Preserving open space and aesthetic values.
Reducing flood damages.

For example, because of the variety of soils floodplains act as giant filters that improve water quality through physical, biological, and chemical actions.  During high water floodplains provide critical spawning habitat for fish and areas for the young to develop.  Floods also create new habitats by shifting sediments and rearranging channels.

Links and Publications

1. The Nature Conservancy: Natural Solutions for Reducing Flood Risk.

2. The Nature Conservancy: A Flood of Benefits – Using Green Infrastructure to Reduce Flood Risk.

3. American Rivers: Reconnecting Rivers to Floodplains: Returning natural functions to restore rivers and benefit communities.

4. American Water Resources Association: Shifting the Paradigm for the 21st Century: Protecting and Restoring the Natural Resources and Functions of Floodplains

5.Association of State Floodplain Managers: Natural and Beneficial Floodplain Functions: Floodplain Management - More than Flood Loss Reduction.

6. Federal Emergency Management Agency: The Natural and Beneficial Functions of Floodplains: Reducing Flood Losses by Protecting and Restoring the Floodplain Environment: A Report to Congress.

7. U.S. Environmental Protection Agency: Flood Loss Avoidance Benefits of Green Infrastructure for Stormwater Management.

8. Earth Economics: An organization that studies and reports on the economic value of natural systems. 

9. Association of State Wetland Managers: Definition of Wetland, Floodplain, Riparian "Function and Values.


» Larry Larson, Executive Director Emeritus, ASFPM, 608-828-3000;

» Jeanne Christie, Executive Director, ASWM, 207-892-3399;

» Todd Strole, The Nature Conservancy, 618-980-8624;

» Zac Christin, Earth Economics, 253-539-4801;

» John McShane, formerly FEMA and EPA, 202-546-2819,

Goals of the Natural Floodplain Functions Alliance

1. Encourage information-sharing among organizations and agencies that support restoration and conservation of natural floodplain functions and resources.

2. Use sound science to develop fair and reasonable policies and programs that support restoration and conservation of natural floodplain functions and resources.

3. Integrate natural floodplain management into broader landscape and watershed management initiatives.

4. Facilitate creation and integration of programs and policies to sustain and restore natural floodplain functions and resources.

5. Support revision or elimination of policies and programs that degrade and destroy natural floodplain functions and resources.

6. Improve communication about the importance of natural floodplain functions and resources at all levels of government.