Final Environmental Assessment: Kootenai River-City of Bonners Ferry Levees. Repair of Levees for City of Bonner Ferry, Boundary County, Idaho.

摘要

The City of Bonners Ferry, Idaho (City) requested funding from the U.S. Army Corps of Engineers (Corps) to repair and stabilize the portions of the Kootenai River in and near to the city, during a flood event in May and June 2011. The high flows during this event caused damage to the levees, and caused some structures to be flooded upstream of Bonners Ferry. The Corps responded with an emergency flood-fight, adding rock to one site on the right bank, and two sites on the left bank, all downstream of the Highway 2 and 95 bridge. Upstream of the City, on the left bank, a meander channel was plugged to stem the flooding of structures at that location (Appendix A, Figures 1 and 2). It was found after the water subsided that the levee had eroded and was in need of repair adjacent to the two flood-fight sections on the left bank downstream of the bridge. Thus, the Corps intends to repair the two levee sections in the summer of 2012. The project goal is to protect the City's infrastructure and the Kootenai River by protecting the levee and reducing the potential for future erosion. In June and July 2012, another high water event led to an emergency repair on the left bank in the City of Bonners Ferry. The site of this repair coincides with one of the two sites scheduled for repair later in the summer of 2012. Work will still need to be accomplished on this site, as rock was placed only to the water line (approximately 1766 elevation); the scheduled repair requires rock placement down to approximately elevation 1143 (river bed elevation) to provide a solid foundation for the rock.