Countyline Setback Levee

Significant flooding was affecting residences and businesses in Pacific and leading to temporarily closures of Stewart Road E due to overtopping by floodwaters. The flooding was due in part to the ongoing sedimentation in the White River; because of its gradient change, the White River near Pacific has been gradually losing channel capacity over the last several years. The goal of the Countyline Levee Setback Project was to address this loss in channel capacity and reduce flood elevations by removing 4,500 linear feet of existing levee and reconnecting the river with 121 acres of off-channel aquatic habitat. The river had been isolated from its historical floodplain at Countyline for nearly a century. A new setback levee, 6,000 feet in length, has been built and is protected by a 5,780-foot wood structure called a bio-revetment and several engineered log jams.

Parametrix provided construction management and inspection services for the removal of an existing levee and revetments, construction of a new levee with nearly continuous log bio-revetment along the existing wetland, side channels, in-water work, pile installation, engineered log structures, habitat restoration, removal of invasive plants, and restoration of native plants. Shortly after breaking ground, there was an unanticipated challenge with the discovery of contaminated soils. Parametrix supported King County and worked with the contractor to overcome this challenge and kept the project on track. We provided document control, monthly progress reports, contractor pay requests, change  management, RFIs, submittals, testing, daily observation reporting, survey, UAV (drones), special inspection, schedule analysis, QA/QC, risk assessment, and closeout.

Parametrix provided design mapping and property acquisition support. Survey services involved conventional mapping, bathymetric surveying, and LiDAR integration of over 200 acres in Pierce and King Counties, as well as processing three consecutive Boundary Line Adjustments with associated easements.

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