The West Virginia Department of Highways is using a 2-stage channel excavation concept to mitigate the hydraulic impacts of relocating U.S. Route 119. The selected highway alignment begins just north of Williamson, travels north along the Tug Fork River alignment for approximately eight miles, then veers eastward just north of Nolan, West Virginia. The river flows through a narrow valley in an area characterized by sharply ridged and steeply graded terrain. Much of the existing development lies along the floodplain of the Tug Fork. The topography of the region dictated the selection of the alignment, which includes four bridge crossings and two channel relocations of the Tug Fork. A connector roadway, proposed to link Kentucky Route 292 with the relocated U.S. Route 119 intersects the alignment between two of the proposed bridges, placing most of the connector roadway embankment within the floodplain of the river. In addition, approximately seven miles of the alignment’s roadway embankment lies within the floodplain of the river.

The goals of the project are to:

• Provide additional channel conveyance by means of flood plain modifications designed to mitigate the hydraulic impacts on the water levels upstream of the project
• Leave as much of the natural channel undisturbed as possible
• Provide additional wetlands mitigation and improve the river’s fish and wildlife habitats.

Our design meets all the above goals. In addition, the project will contribute to the improvement of the existing area surrounding the reach. Residential septic fields that drain into the river will be eliminated, channel and side slopes will be improved, bank erosion will be reduced and a tree canopy will ultimately shade the water and reduce thermal pollution. The study and monitoring of the in-stream mitigation devices will provide valuable information for the design of hydraulic and environmental mitigation projects in the future.