2014 Issue

25 ABSTRACT Over two decades, and in design and construction of 60 miles of 126- to 60-inch pipelines, Central Utah Water Conservancy District (CUWCD) and CH2M Hill have addressed a variety of movable ground risks in several aqueducts. Figure 1 shows these recently constructed aqueducts and locates key movable ground risks addressed on each. 1. 120” Olmsted Pipe at Canyon Glen Landslide 2. 120” Olmsted and 90” Alpine-1 Pipes at Slow Moving Active Landslides 3. 120” Olmsted Pipe at 2-miles of Inactive Landslides and Talus Slopes 4. 96” Spanish Fork Canyon Pipe at Recently Active Blacks Slide 5. 60” Provo Pipe: 5 mile realignment to avoid Provo bench landslides and faults 6. 60” Pioneer Crossing Pipe: 4 mile pipe in compressible soils and highway fills 7. 60” Vineyard Pipe: 7 mile pipe in compressible soils, springs and fills On each of the movable ground projects, the risks are identified and then the design and construction solutions are presented which were developed to address each risk. Each solution adds reliability to one aqueduct. Together they provide a highly reliable and redundant water delivery network. 1. 120” Olmsted Pipe at Canyon Glen Landslide Built in 1901 as a hydro- power flume, theOlmsted Flowline was rebuilt as an above ground pipe in 1948. When CUWCD acquired it for M&I use in 1987, it was failing at land- slides (Figure 2) due to a 500-year wet period. The Canyon Glen Landslide, moving up to 20 feet/ hour, swept the pipe off the hill. Because the slide remained active, and as it was cost-prohibitive to re-route the pipe around the landslide, a tunnel was chosen to be the best-fit solution. The 1 mile, 126- inch tunnel was curved into the mountain to stay in hard rock under the slide (Figures 3 & 4). By Nathaniel Jones , P.E. , Mark Breitenbach , P.E. , KC Shaw , P.E. SolvingMovable Ground Risks One at a Time in CUWCD Aqueduct Systems 1 Project Manager, CH2M-Hill, 215 South State Street, Suite 1000, Salt Lake City, UT 84111; Tel: (801) 350-5200; Fax: (801) 322-8223; E-mail: nathan.jones@ch2m.com 2 ULS Project Manager, Central Utah Water Conservancy District, 355 W University Pkwy, Orem, UT 84058, Tel: (801) 226-7105; Fax: (801) 226-7105; E-mail: Mark@cuwcd.com 3 Project Manager, Central Utah Water Conservancy District, 355 W University Pkwy, Orem, UT 84058, Tel: (801) 226-7180; Fax: (801) 226-7111; E-mail: KCShaw@cuwcd.com Figure 1. Movable ground risks to CUWCD Aqueducts in central Utah (see upper right Location Map) are located at the numbered dots in the Aqueduct Systems Map above and are listed below. Figure 2. The pipe is failing as Canyon Glen Slide starts moving. Figure 4. TBM exiting tunnel. Figure 3. The tunnel profile is below the active slide in limestone. CUWCD AQUEDUCT | continued on page 26