Plateau Creek Pipeline Tunnels
Due to inadequate capacity and the need for increased reliability, the Ute Water Conservancy District proposed replacing the existing water supply pipeline from Jerry Creek Reservoir to the Ute Water Treatment Plant near Palisade, Colorado. The alignment for the 68,500-ft-long replacement pipeline was nominally parallel to the scenic and environmentally sensitive corridor of State Highway 65, State Highway 30, and Plateau Creek. To minimize potential environmental impacts to the creek, two sections of pipeline (10,200 ft and 3,400 ft in length, respectively) were placed in tunnels. Geology along the tunnels’ alignments consisted of sandstones, shales and siltstones; and the tunnels were mined using a 10-ft-diameter hard rock tunnel boring machine.
Lachel was involved in the development of the Plateau Creek project from the beginning. As the tunneling consultant to GEI Consultants Inc., Lachel first provided a feasibility level tunnel design and cost estimate. As the project progressed, Lachel provided the intermediate and final designs for the tunnel portions of the project. This work included developing the expected ground loads based on empirical and finite element analysis, designing the initial and final ground support systems with various classes of support to address the wide range of expected rock conditions, developing plans and specifications, and preparing the Engineer's Opinion of Probable Cost.
During construction, Lachel provided construction management services to Ute Water including resident engineering and tunnel inspection. Lachel was responsible for the administration of the contract specifications, review of construction submittals, technical support to the Owner, and interfacing with the news media on tunnel-related issues. Lachel also assisted in a Value Engineering study that saved the Owner over $1,000,000.