WALLA WALLA, Wash. – Visitors using the gravel trail on the south side of the federally managed section of the Mill Creek Levee System in Walla Walla, Washington, will likely encounter surveyors through the afternoon on Friday, Oct. 21, U.S. Army Corps of Engineers officials at the Mill Creek Project Office announced today.
Workers will be surveying the levee in preparation for Phase-2 of levee maintenance. While the trail will remain open during surveying activities, visitors should be aware of equipment and vehicles in the area.
Phase-2 of restoring the federally managed portion of the Mill Creek Levee System includes removing tree roots that intruded into the levee cross section from the landside slope. District Geotechnical Section engineers (levee experts) examined several test pits excavated at various points along the mile-long levee and determined removing problematic roots would require “grubbing” roughly two feet into the levee. In some locations, where tree roots have extended deeper into the levee cross section, more extensive excavation and repairs may be required.
A contract to perform Phase-2 work was awarded to KEU Inc., of Vancouver, Washington, on Sept. 14, 2016. Because of the large scope of work and a narrow timeframe to accomplish it -- between bird-nesting and flood seasons -- task-orders will be issued during multiple years to conduct work in segments.
Winter 2016-2017 Phase-2 repair work on the south levee will include an area from the division works beginning near the Mill Creek Office, progressing toward the Jones Ditch, just downstream of the wooden pedestrian bridge. Repair and maintenance work involving heavy equipment is slated to begin in early December 2016 and is anticipated to take approximately three months to complete. For visitor safety, intermittent closures of parts of Kingfisher and Whitetail trails may be required during the contract performance period. The value of task orders to be performed during Winter 2016-2017 is about $670,000.
The Walla Walla District will continue to keep the public informed of work progress and temporary impacts to visitor access. Visitors are also encouraged to look for trail-closure updates on information kiosks located at major trailheads and on the Mill Creek Project’s Facebook page www.facebook.com/millcreekdam
This maintenance is necessary to meet National Levee Safety Program requirements in accordance with Corps headquarters regulations and policies. Phase-1 work began on Oct. 8, 2015, and was completed on Dec. 31, 2015. Problematic vegetation was removed from the surface of the levee slopes and 15-feet landward from the levee’s design toe. Non-compliant vegetation on levees blocks visibility for inspections, access for maintenance, hinders flood-fighting operations, and adds uncertainty to structural performance and reliability, which increases risk to the public. The inability to inspect, maintain and flood fight typically delays emergency response and contributes to the risk of levee failure. Life safety is paramount for the Corps’ operations.
Environmental-compliance documents, maps, photos, videos and other information about this levee-maintenance project is available on the Corps’ website at www.nww.usace.army.mil/Missions/Projects/MillCreekLeveeMaintenance.aspx