McMillen Jacobs has performed construction and design-build work for Idaho Power on a wide range of projects. Example projects include the following.
- Upper Salmon Spillway Repairs (Phases 1, 2, 3)
McMillen Jacobs completed repairs to the Upper Salmon Spillways on the Snake River to fix significant cracking and failures to the entire shell of the concrete piers of the spillway, near the embed trunnion pins, and the overhead bridge column supports. Work also included removal and replacement of limit switches on the existing radial gates. McMillen Jacobs served as the Prime Construction Firm and self-performed repairs.
- Reconstruction of Thousand Springs Snowbank Bridge
Hagerman, Idaho. McMillen Jacobs was retained to reconstruct the existing bridge that leads to the Thousand Springs Power Plant. The existing bridge remained open to traffic throughout the construction period. Our team provided traffic control to ensure public safety throughout the construction period. We installed two 40-ft long, 2-ft diameter heavy walled HDPE pipe to divert the stream flow around the disturbed streambed during the work in order to comply with permitting requirements along with the necessary energy dissipation required for discharge at the end of the diversion pipe.
- Upper Salmon Emergency Intake Canal Concrete Repairs
The canal was in a state of disrepair and was experiencing spalled and crumbling concrete. Full-depth cracking that had led to extensive leaking, considerable erosion, and loss of backfill due to burrowing animals. Idaho Power was unable to operate the canal at maximum capacity because of the conditions of the canal wall crest, requiring the urgency of the corrective action. McMillen Jacobs’ crews performed emergency repairs to the crest of the intake canal. Repairs were required to both the south canal walls accessible by road, as well as the north canal walls that could only be accessed for repair by boat. Logistics required that concrete was pumped over an active 120-foot canal.
- Bliss Tailrace Repairs, Bliss, Idaho
Our team provided structural repairs by resurfacing rock to concrete in deteriorated areas. Safety and time were key components as there were extremely hazardous conditions for both McMillen Jacobs employees performing this work and Idaho Power employees performing their normal maintenance activities on the power plant. We implemented a stringent safety program due to extremely hazardous conditions. McMillen Jacobs was able to fabricate a rolling, cantilevered scaffolding to access the leading edge of the tailrace and set formwork and temporary safety rails while the repairs were performed. Elements include saw cutting concrete and rolling cantilevered scaffolding over water.
- Lower Malad Tainter Gate Replacement Project
Idaho Power Company sought a contractor to replace two tainter gates at their Lower Malad Diversion Spillway. An inspection of the two wood-faced tainter gates at the Lower Malad Diversion Dam found that the gate steel frames had shallow pitting and minor section losses throughout with more severe section losses at and in the vicinity of the upper three arm-to-girder connections, including areas of 100 percent section loss. Construction involved establishing safe access to the gate bays, newly fabricated stops logs with temporary bulkheads upstream, newly fabricated gates, inspection and turndown of existing trunnions, disassembly and demolition of the existing gate structure, installation of a new gate, and testing and closeout.
- Bliss Dam Concrete Repairs
McMillen Jacobs served as the General Contractor to self-perform the concrete repairs at Bliss Dam. Specific locations involved four areas: tailrace repairs, powerhouse deck repairs, intake deck and north access repairs and spillway repair. This project included a variety of concrete repairs, including spalled concrete, 2,400 feet of epoxy injection grouting, cast-in-place concrete, and installation of miscellaneous metals. We worked closely with the operators to mitigate any interruptions to existing power generation.
- Brownlee Dam Debris Boom Project
McMillen Jacobs provided construction services for the procurement, assembling, and installation of a Worthington Tuffboom Debris Boom system for both the forebay pool as well as the tailrace channel. The 32 precast lake anchors in the forebay weigh 50,000 pounds each and are connected to mooring lines and buoys and stretched across the span of the reservoir (2,700 linear feet) to protect the intake from debris. The forebay lake anchors are also connected to rock anchors on the Idaho and Oregon shores of the reservoir. McMillen Jacobs also installed a single span boater safety boom at the tailrace below the dam. It spanned approximately 500 linear feet across the river and was connected to drilled rock anchors located on each shore.