Chehalis River Basin Comprehensive Floodplain Hazard Management Plan

Lewis County, WA

Perteet was selected to lead the process to update the 2008 Chehalis River Basin Comprehensive Flood Hazard Management Plan in coordination with the Chehalis River Basin Flood Control Zone District. The intent of the plan is to identify actions to minimize flood damages at the local level, while supporting and coordinating with projects occurring at the regional and state level. The plan was developed to maximize Community Rating System points for the participating jurisdictions, which include Lewis County and the City of Chehalis. The plan incorporated the significant amount of data that exists for the basin, including Hazus results, 2D flood modeling of climate change forecasts, habitat enhancement plans, land use data to develop actions, and recommendations to reduce risk and flood damage within the County. The planning process included a hybrid approach to public outreach, as the process spanned the COVID pandemic, and included a survey, story map, and virtual meetings. The plan was adopted by the participating agencies in November 2021. The story map is currently live and can be viewed here:


  • Emergency Preparedness
  • Planning

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