The Post Falls Hydroelectric Development is located on the Spokane River in the Town of Post Falls, Idaho, approximately nine river miles downstream of Lake Coeur d’Alene. The development includes three separate water retaining structures designated as the North Channel Dam, Middle Channel Dam, and South Channel Dam.
The eight Tainter gates and the single 100-foot-long by 14-foot-high sector gate at the North Channel Dam provide the majority of the spillway capacity at the development, and are critical for passing flows and debris. All of the gates are classified by the FERC as Category 1 Gates (failure has significant dam safety or operational consequences). The sector gate was constructed in 1922, and the Tainter gates in 1970, with some key structural components of the gates dating back to original dam construction in 1906.
The project objectives were: perform a hands-on detailed gate inspection of the nine spillway gates at the North Channel Dam in accordance with FERC guidelines; review previous gate analysis for adequacy; review operational procedures; and make a determination of the gates’ adequacy for continued, safe operation based on the existing documentation review and inspection findings. The result of the inspections and the review of existing documentation are included in a Gate Inspection Report (GIR).
Rope access techniques were used to safely and efficiently access the gates for the hands-on inspection.