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    • Mill Lake Dam Rehabilitation (2009) Mill Creek Irrigation District (MCID)

    Mill_Location.PNG

    Mill Lake Dam History

    • Earthfill dam with rock shell, originally constructed in 1912.
    • Dam located in the Selway-Bitterroot Wilderness
    • Primary purposes: Irrigation, fishing
    • Dam Height: 25 feet (approx.)
    • Dam Storage: 780 acre-feet
    • Dam Classification: High Hazard
    Mill_History.PNG

    Project History

    Since construction, the dam has had numerous rehabilitation projects, including major rehabilation in 1922, 1944, 1959, 1960, 1961, 1964, 1991 and 1992. Recently, the dam has had some serious concerns and in 2001, an emergency repair was completed and funded by a DNRC grant. In 2002, temporary slip lining of the outlet pipe occurred. In 2005, permanent slip lining was completed on the outlet pipe, funded by a DNRC grant. In 2007, a rehabilitation project (Phase I) was completed which consisted of rock berm construction, downstream dam crest edge stability construction, and AMCi® satellite alarm system. This rehabilitation was paid for by the Mill Creek Irrigation District. To complete the final phase of rehabilitation, the District looked for assistance from loans.

    Work Breakdown

    • Rock removal & stockpile
    • Slope stabilization
    • Impermeable liner installation
    • Rock installation
    • Downstream seepage filter
    • Spillway rehabilitation

    Mill_Breakdown.PNG

    Project Funding

    The total cost of the project was $603,726. To finance the project, the Mill Creek Irrigation District used the following loan program:

    • DNRC WDL: $600,000
      • Terms were at 3.5% interest for 20 years.
      • Rates were raised in preparation for the loan
      • Irrigators within the district have been satisfied with the project; lots of smaller irrigators, therefore, cost increases haven’t been impractical
      • Temporary loan was needed due to allowing contractor to purchase materials because of the tight construction window
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    Project Status & Results

    • The final phase was completed in 2009
    • No water storage occurred in 2009 due to drawdown
    • 90 day work schedule
    • Working inside the wilderness required close coordination with the USFS, additional permitting and environmental analysis
    • Have a well thought out plan-of-attack prior to construction to demonstrate project knowledge and means and methods of construction at a remote work site

     

    Project Partners

           Owner: Mill Creek Irrigation District

           Lead Design Engineer: Hydrometrics

           Prime Contractor: Land Tech Montana Inc.

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