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I I I I Penstock Rehabilitation Summary August29,2000 I I I I I I I I I I I I I I I Description In 1948, a 412-foot long 36" diameter steel penstock was installed to convey water to the hollow- jet valves. The penstock is constructed of %-inch steel plate and coated with coal-tar epoxy on the interior and exterior. The protective coating was omitted on the exterior of the pipe where the pipe was imbedded in concrete. An expansion joint is located at the approximate center of the pipe. Manholes and 4-inch drain valves are provided at the upstream and downstream ends of the penstock. A 45-degree branch outlet is embedded in concrete at the lower end of the penstock to provide two 24-inch penstock branches that serve the hollow-jet valves, The penstock is contained in a 6.5-foot horseshoe conduit. It runs through the dam to the gate chamber and is accessed from the control house, Goals and Objectives Rehabilitation of the interior of 441 lineal feet of 36" and 24" diameter steel penstock. The Wasser coating will provide the needed protection to maintain the integrity of the penstock. At the same time, a 12" tee will be installed on the penstock to benefit M&I water users, ' D Sandblast the steel to a SP10 grade (near white blast), o Apply a Wasser MC zinc primer, o Finish with Wasser MC tar to 15 mils thickness, o Install a 12" tee on the penstock for municipal releases, .Justification During the fall 1997 inspection, it was noted that small repairs to the interior coating were necessary. During the repair, it became apparent that the coating was very brittle. During an inspection in 1999, it was noted that the coating was thin and britlle and should be replaced as soon as possible. On request from the Town of Mancos, the Mancos Rural Water Company and Mesa Verde National Park, the district will enlarge the M&I access from the present 6" line to a 12" line giving all water users the ability to pull water together, an option not currently available but necessary for the future, Next Steps The Board of Directors, having been appraised of all courses of action and having eliminated other linings and the possibility of grant money for this project, has accepted a bid of $57,000,00 from R&M Construction & Services and is now in need of financial assislance 10 cover the cosl of the lining. The district knows an additional $25,000.00 for the tap and site preparation will be needed for the job and prepared to cover this cost themselves.