MILTON-FREEWATER, Ore. – Work to repair flood damage on the Milton-Freewater levee system’s Nursery Bridge drop structure on the Walla Walla River, in Milton-Freewater, Oregon, is in progress and slated to be completed by October, according to officials with the U.S. Army Corps of Engineers, Walla Walla District (Corps).
The Nursery Bridge drop structure was constructed in 1967 to help protect the bridge from scour, allow irrigators to continue to divert water, provide for fish passage and prevent riverbed degradation from proceeding upstream. The drop structure has been damaged and repaired multiple times since it was originally installed. It was most recently damaged in 2015 during high river flows. The Milton-Freewater Water Control District, the levee sponsor, was approved for levee rehabilitation assistance under Public Law (PL) 84-99, which gives the Corps authority to undertake activities including rehabilitation of flood works threatened or damaged by flooding.
The Corps’ repair plans will help protect the structure’s gabions -- metal, cage-like boxes filled with rocks, commonly used in civil engineering projects -- by adding rip rap across the gabion mattress, downstream of the drop structure. A contract to perform the work was awarded to LKE Corp, of Washougal, Washington, for about $356,998.
The Corps conducted an environmental assessment (EA) and issued a Finding of No Significant Impact (FONSI) on April 28, 2017, for the repair project. Through its analysis and the public review, the Corps did not identify any significant environmental impacts related to implementing the proposed drop structure rehabilitation.
A requirement to plant willows as mitigation for placing rip rap was established during the draft-FONSI and EA public comment period. Members of the Milton-Freewater Boy Scout Troop 315 will assist by acquiring 275 willow cuttings to be planted downstream of the drop structure, according to John Wells, of AndersonPerry & Associates Inc., a civil engineering firm representing the levee sponsor, who is coordinating with the Corps and its contractor on this effort.
Release no. 17-092