WALLA WALLA, Wash. – The gravel trail on the south side of the federally managed section of the Mill Creek Levee System reopened to visitors, U.S. Army Corps of Engineers officials announced today.
Fall-Winter 2017 phase-2 repair work continues on the north levee – from about 1,500 feet upstream of the metal division works, up to the dam – requiring temporary closure of the paved trail and Rooks Park.
Safety barriers and signs are placed to alert visitors to the temporary closures and encourage public safety. A map of visitor trails which will require temporary closures to accommodate levee work activities is available on the Corps’ website at www.nww.usace.army.mil/Missions/Projects/MillCreekLeveeMaintenance.aspx. Contractors may relocate barriers as work progresses along the north levee.
The Walla Walla District will continue to announce 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.
The horse trailer parking area near the Mill Creek Project office also remains temporarily occupied as a staging and storage area for the contractor’s heavy equipment and vehicles.
Phase-2 of restoring the federally managed portion of the Mill Creek Levee System, about half of which was conducted during Winter 2016-2017, includes removing tree roots that intruded into the levee cross section from the landside slope and replacing levee material in accordance with geo-technical and design criteria. 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.
The 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 the narrow timeframe to accomplish it -- between bird-nesting and flood seasons – phase-2 work was planned to occur during multiple years. Fall-Winter 2017 phase-2 levee-repair work is anticipated to be completed in mid-December, depending upon weather and soil conditions.
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.