Plateau Creek Pipeline Tunnels

To increase water supply capacity and reliability, the Ute Water Conservancy District developed its Plateau Creek project to replace existing pipeline from Jerry Creek Reservoir to its water treatment plant near Palisade, Colorado. The alignment for the new 68,500-ft-long pipeline was nominally parallel to a scenic and environmentally sensitive corridor. Schnabel was involved with the project from its beginning.

The replacement pipeline would be developed near State Highway 65, State Highway 30, and Plateau Creek. Minimizing potential environmental impacts to the creek was important, so two sections of pipeline (10,200 ft and 3,400 ft in length) 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.

As the tunneling consultant to GEI Consultants Inc., we first provided a feasibility-level tunnel design and cost estimate. As the project progressed, we 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, we provided construction management services to Ute Water, including resident engineering and tunnel inspection. We were 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. We also assisted in a value engineering study that saved the owner over $1 million.