16-084 Mill Creek Levee phase-2 maintenance begins Thursday; trails will intermittently close for visitor safety
WALLA WALLA, Wash. – The gravel trails on the south side of the federally managed section of the Mill Creek Levee System will be intermittently closed to all visitors starting Thursday, Dec. 1, to accommodate levee-maintenance activities, U.S. Army Corps of Engineers officials announced today.
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.
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. A map of visitor trails which will require intermittent closures to accommodate levee work activities is available on the Corps’website at www.nww.usace.army.mil/Missions/Projects/MillCreekLeveeMaintenance.aspx.
Construction fencing will be placed to alert visitors to the closures and encourage public safety. Workers will be accessing the levee with heavy equipment and vehicles to remove the tree roots and recompact levee material. Foot bridges across Mill Creek will be intermittently closed as work progresses along the 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.
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 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.
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.
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