Flood Protection

The Strategy: Protecting Chehalis Basin from flood damage

Flooding has always been present in the Basin, but with climate change, disaster is no longer an isolated incident. The Strategy will help prepare the region for increases in the frequency and severity of future flooding through both local and large-scale flood damage reduction actions. Many of these actions will also support habitat restoration for salmon and other wildlife.

Large-scale flood damage reduction

Several options for large-scale flood damage reduction, critical for protection against predicted future catastrophic events, have been evaluated or are currently under review. Projects that have been evaluated and are no longer under consideration due to feasibility concerns include: 

  • A large-scale restorative approach to decrease flood damage by increasing the flood storage capacity of the watershed 
    • Smaller-scale restorative approaches for localized flood damage protection and habitat improvements are still under active consideration.
  • Different ideas for raising, rerouting, or walling off low-lying portions of I-5

Projects still under consideration

  • Improvements to the existing Chehalis-Centralia Airport levee
  • Expanding the existing North Shore levee to protect Aberdeen and Hoquiam
  • A flood protection dam proposed on the upper part of the Chehalis River 

Currently, the proposed Chehalis-Centralia airport levee and flood protection dam are under formal environmental review. Learn more about this proposed flood damage reduction project and the environmental review process.

Most recently, the Washington Department of Ecology released a draft Environmental Impact Statement evaluating the project’s possible and probable environmental impacts.

Local landowner and community-scale projects 

Local actions to limit flood damage are a key part of the Strategy, and will be embedded in every approach. These actions include:

  • Community Flood Assistance and Resilience actions, such as floodproofing homes, businesses, and community assets
  • Local flood mitigation projects to protect infrastructure and reduce local-scale flood damage
  • Improving flood warning systems
  • Working with willing landowners on relocating vulnerable structures and repurposing areas near rivers and streams to improve floodplain function and prevent future flood damage

More than 100 local projects to limit or avoid flood impacts on people and property and to help salmon and other at-risk aquatic species have been completed or are currently underway. 

Flood damage reduction projects

The Office of Chehalis Basin, Department of Fish and Wildlife, and the Chehalis Basin Board have been working together to perform studies and implement projects that protect communities from the effects of flooding, and to protect and enhance aquatic habitat within the basin. We have created an interactive story map that details these projects, their status, and the investment of public funds. It also highlights some of the recent work done and upcoming projects.