Chehalis River Basin Flood Control Zone District

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Frequently Asked Questions

The District is sponsoring a project that would support its goals of reducing flood risk, preserving life, preventing property damage, and protecting natural resources. The project has two related parts:

1. Flood retention facility

During major floods, the facility would store water in a temporary reservoir and slowly release it back to the river as conditions return to normal. In non-flood times, the river and its fish would move at their natural rate through outlets in the facility.

2. Improvements to the airport levee

The District is proposing to increase the height of the existing levee by four to seven feet. Additionally, 1,700 feet of Airport Road would be raised to meet the new levee height along the southern side of the airport.

Learn more here

The project would help protect basin communities from flood damage, reducing the duration and extent of severe flooding for many areas downstream. It would:

  • Cause no net loss of habitat function for fish and other aquatic species.
  • Reduce floodwater levels on over 4,000 acres.
  • Decrease flood damages to structures by up to 72%.
  • Reduce the likelihood and duration of I-5 and airport closures.
  • Save hundreds of millions of dollars by reducing damages to structures, farms, and businesses and preventing transportation interruptions. (Early estimates show savings of more than $240 million per major flood event!)

Learn more about the project.

Even if you have not personally experienced flooding, the Chehalis River Basin communities are at high risk of major and frequent flooding. In any given year, there’s a 15% chance of a major flood in the basin. Floods can happen anytime, anywhere in the basin. Ongoing climate change is expected to increase this risk.

Flooding is a natural and historic part of the Chehalis River Basin’s ecology. In the last 20 years, the Chehalis River has flooded 18 times due to severe storms in the Willapa Hills. Major floods in 2007 and 2009 shut down I-5 for several days and cost $900 million in damages to homes, farms, and businesses. In 1996, a flood forced hundreds of basin residents to evacuate their homes and take refuge in emergency shelters.

View the effects of previous floods in the photo gallery.

The Washington Department of Ecology and the United States Army Corps of Engineers are working on two separate Environmental Impact Statements (EISs). An EIS is a document that describes the project's potential benefits and impacts to aspects of the environment, including habitat, cultural resources, noise, and environmental justice. These agencies have published their draft EISs and held a public comment period in spring 2020.

The final EISs are expected in 2022. We will notify the community once the final EISs are available. Sign up for our email list to receive notifications.

In the meantime, view all submitted environmental documentation here.

Once the final EISs are available, they will be uploaded to this website in the “Resource Library” tab for public viewing.

“No net loss” means maintaining the same level of habitat function that exists in the basin today. Studies show that the District’s flood protection project can be built with no net loss of habitat function for fish and other aquatic species.

Federal and state agencies will review the District’s environmental mitigation plan. If approved, this means that all other habitat restoration work in the basin will have a net positive benefit for fish and other aquatic species.

Learn more about the District and state’s environmental efforts here.

A levee is an embankment built to prevent the overflow of a river.

Actions you can take to keep yourself and others safe include: