Applicant's Proposal Description:
The Chehalis River Basin Flood Control Zone District (applicant) is proposing construction of a water retention facility and associated infrastructure on the main-stem Chehalis River south of the Town of Pe Ell, Washington. The facility would have capacity to provide 65,000 acre-feet of temporary flood storage during major floods, and would be constructed with a foundation to allow the future expansion of its water retention capacity. The Chehalis River would flow normally during regular conditions or small flood events. The top of the dam structure would be 1,220 feet long with a maximum structural height of up to 254 feet including 3 to 5 feet of freeboard for safety. The dam is proposed to include a 210-foot-wide emergency spillway, discharging into a 70-foot stilling basin. The applicant also proposes to raise the elevation of the Centralia-Chehalis Airport levee in Chehalis, Washington. The levee would be raised 4 to 7 feet, along with raising Airport Road 1,700 feet along the southern extent of the airport. The proposal is in pre-application status.
Links to EIS Scoping Information
NEPA Scoping Report
http://chehalisbasinstrategy.com/eis/
Special Public Notice
Notice of intent to prepare a draft environmental impact statement for the proposed Chehalis River basin flood damage reduction project
Special Public Notice
Proposed WRRDA Agreement with Chehalis River Basin Flood Control Zone District
September 28, 2018 News Release - Scoping Period Opens for EIS
Environmental review starts for Chehalis River
Technical Documents
Geotechnical Investigations Study (Landslides, roads/bridges)
Hydraulic Modeling (RiverFlow2d)
Hydrologic Modeling (Basin-wide rainfall-runoff model)
Smolt Abundance Studies
Wetland/Ordinary High Water Mark Delineation Report
Chehalis River Off-Channel Habitat Hydrologic Monitoring Project Text and Figures
Chehalis River Off-Channel Habitat Hydrologic Monitoring Project Appendices