I-5 and the Chehalis River

The Chehalis Basin Strategy began in the Washington State Legislature as an idea to address the Basin’s challenges of extreme flooding and aquatic habitat degradation. The following information is an outline of how the Chehalis Basin Strategy was developed. Learn more about where we are today.


In 2011, as part of the capital budget (ESHB 2020, Section 1033), the Washington State Legislature required the Office of Financial Management (OFM) to prepare a report on alternative flood damage reduction projects and—in coordination with tribal governments, local governments, and state and federal agencies—to recommend priority flood hazard mitigation projects in the Chehalis River Basin for continued feasibility and design work. The William D. Ruckelshaus Center was asked by Governor Christine Gregoire’s office to support OFM in this work effort.


The OFM report was finalized in December 2012 and provided the Legislature and other decision makers with information to set the course for effective solutions to reduce the adverse impacts of flooding in the Basin and restore fish populations and other natural resources.

In November 2012, Governor Gregoire convened the Chehalis Basin Work Group, facilitated by the Ruckelshaus Center. The Work Group was comprised of six Basin representatives, including local elected officials, citizens, and tribal leaders.

2013 – Early 2015

The Governor’s Work Group oversaw a series of technical studies to support decision making on long-term, large-scale actions and implementation of smaller-scale projects to provide near-term flood damage reduction in the Basin. The Work group worked with a team of natural and water resource experts from:

  • Tribal governments
  • Washington State Department of Ecology
  • Washington Department of Fish and Wildlife
  • Washington State Conservation Commission
  • Washington Department of Natural Resources
  • Chehalis River Basin Flood Authority

Throughout the process, care was taken to analyze and describe the costs and potential impacts (positive and negative) of different flood-mitigation and aquatic species restoration projects, and combinations of these projects. The Work Group published a Recommendation Report in 2014 and proposed a series of analyses and actions which included:

  • Large-scale capital projects affecting a broad geographic area like a water retention facility, and/or improvements to protect Interstate 5;
  • Smaller-scale capital projects with more localized benefits;
  • Environmental projects to restore overall conditions, aquatic habitat, and abundance of fish in the Basin;
  • Land use management to help people already in the floodplain and reduce the potential that new development will increase flood damage; and
  • An effective flood warning and emergency response system.

The Department of Ecology is now studying the recommendations. Learn more about the 2015-2017 Chehalis Basin Strategy work effort here.