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.