Flood Plain Management

Floodplain Management

Floodplains by Design 2015-17 Budget Proposal

Ecology is announcing a new opportunity to submit project proposals that meet the intent of a new program designed to integrate flood hazard reduction with ecosystem benefits, and help leverage investments from other funding sources. This is not the same program as the Floodplain Management and Control 2013 Competitive Grants Program, but has similar goals.

There are two goals of the Floodplains by Design program:

  1. Promote the reduction of flood risks and floodplain ecosystem recovery while maintaining or improving agricultural production, water quality, and open space/recreation.
  2. Improve the coordination of public funding for floodplain efforts.

Preliminary proposals are due May 23, 2014. Learn more at Floodplains by Design 2015-17 Budget Proposal.

Floodplain Management and Control 2013 Competitive Grants Program

Ecology received 45 applications totaling $39,201,153 in requests for the 2013 Competitive Grant program.  Ecology Floods Staff, assisted by outside environmental experts, reviewed, rated, and ranked the applications.  Thirteen applications were the top-ranked projects and have been offered funding.  Learn more at Floodplain Management and Control Competitive Grants Program 2013.

What is a floodplain?

A floodplain is an area of relatively level land, usually bordering a lake, stream, or river that gets inundated with water from time to time.

The floodplain includes:

  • The floodway, the border area of land that normally gets inundated during annual or 10-year floods; and
  • The floodway fringe, which may get inundated during a "100-year" or "500-year" flood.

Floodplains typically support rich, diverse ecosystems, often called “riparian” zones or systems, that can contain 100 or even 1,000 times as many species as a river.

Soils in a floodplain usually are rich in nutrients from past floods and other accumulated organic matter. When it floods, these areas support thriving populations of microscopic organisms that, in turn, support a host of larger opportunistic species, especially birds.

While the production of nutrients peaks and falls away quickly, this surge of new growth endures for some time. It also makes flood plains particularly valuable for agriculture.

Historically, many towns, homes and other buildings have been built in the flood plain because:

  • It's were water is most available.
  • Floodplain land is fertile, making it attractive for farming.
  • Nearby rivers represent cheap sources of transportation and railroads were often built next to waterways.
  • Flatter land is easier to develop than hilly ears.

However, the same features that made floodplains attractive places for development also make them susceptible to flooding. To reduce costs, the federal government has developed incentives and new risk management and communication tools to minimize flood damages and maximize public awareness about flood risks. You can learn more at Floodsmart.gov.

What is floodplain management?

Floodplain management is the operation of a community program that includes corrective and preventative measures designed to reduce flood damage. These measures take a variety of forms and generally include requirements for:

  • Zoning
  • Subdivision or building
  • Special-purpose floodplain ordinances

A community’s agreement to adopt and enforce floodplain management ordinances, particularly those addressing new construction, is an important element in making flood insurance available to home and business owners. Since standard homeowners insurance doesn't cover flooding associated with storms and heavy rains for homeowners, renters, and business owners, Congress created the National Flood Insurance Program (NFIP) as a way for property owners to financially protect themselves. The program is administered by the Federal Emergency Management Agency .

Currently, more than 20,100 communities across the nation voluntarily adopt and enforce local floodplain management ordinances. These ordinances provide building standards for new and existing development designed to reduce losses from floods.

Floodplain management in Washington state

In Washington, the state coordinating agency for floodplain management is the Department of Ecology (Ecology). Ecology works with the Federal Emergency Management Agency (FEMA) and local governments to address statewide flood hazard challenges. Ecology provides grants and technical assistance to local communities to reduce losses to life and property and protect the environmental functions of flood hazard areas or flood plains.

Ecology also assists FEMA and the Washington State Military Department's Emergency Management Division by:

  • Evaluating community floodplain management programs.
  • Reviewing local floodplain ordinances.
  • Participating in statewide flood hazard mitigation planning.

Ecology's Floodplain Management team is made up of:

  • A statewide National Flood Insurance Program (NFIP) coordinator.
  • A mapping specialist in Olympia who works with FEMA and communities on amending and updating flood maps and related issues.
  • Floodplain specialists in Ecology's regional offices in Bellevue, Olympia and Spokane.


Chehalis flood photo

Chehalis Flood 2007


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Ecology's Floods homepage
Emergency flood information and more

Am I in a floodplain?
Find out in Ecology's Coastal Atlas

Publication: Living with the River

The Official Site of FEMA's National Flood Insurance Program

Staying safe in bad weather
Department of Health's fact sheets to help you prepare for the possible hazards of bad weather

King County's Flooding Services and Resources web page

Dam Safety
Ecology regulates many non-power generating dams

National Levee Policy

Chehalis Flood Authority