The Lewisville Dam Spillway Modification addresses structural stability concerns by installing dam anchors and rock anchors across the ogee weir and spillway apron slab as well as installing an upstream geomembrane blanket to prevent water flow under the spillway. The overall scope of the project includes constructing 73 post-tensioned dam anchors, installing an upstream geomembrane blanket in the approach channel of the spillway, installing 800+ rock anchors, installing an open graded drainage layer and piping, overlaying the spillway apron, and replacing the existing apron slab extension with a system involving two rows of drilled pier walls reinforced with structural steel beams and connected atop with concrete cap beams. Instrumentation to monitor structural behavior will also be installed in the post-tensioned anchors and the apron slab drainage layer.
Shimmick will complete the $76 million Lewisville Dam Spillway Modification Project, marking the final phase of improvements to the Lewisville Dam.
