Wanapum Dam Spillway Recovery and Mitigation

Columbia River, near Beverly, Washington: Emergency project in response to a horizontal fracture discovered in monolith 4, approximately 65' in length.

Project Details

Emergency project to repair a horizontal fracture in Monolith 4 of the Wanapum Dam on the Columbia River. When the crack was discovered February 24, 2014, the forebay was lowered approximately 26 feet below its normal operating level due to dam safety concerns. The lowered forebay impacted fish passage, reduced power generation by 50%, had significant cultural and recreational impacts, and necessitated costly shoreline monitoring. The Kuney led JV mobilized March 14, 2014 as the General Contractor, with the task of working with an integrated team of the PUD and its design team to engineer and implement the repairs as quickly as possible. A project of this magnitude would normally take years just to design, but in this case the team was able to design and construct all repairs in just 16 months, with full pool raise achieved in just over 12 months.

Project specs

  • Location: Columbia River, near Beverly, Washington
  • Owner: Grant County PUD
  • Timeframe: 2014 - 2015
  • Size: $55 Million
  • Fish Ladder modifications: Kuney’s first task was to modify fish ladders exits into fish slides, to allow safe passage in spite of the lower water level.
  • Upstream: Dam stabilization was implemented via 35 steel anchor tendons (3 per pier), +/- 250 ft long, installed into the top of dam down into bedrock, utilizing Kuney's floating plant and 150 ton crane staged in the forebay.
  • Downstream: Bulkheads were installed to dewater affected spillways for repairs. Over 50 steel bars were drilled into the damaged spillways and a new ogee surface poured in place.


  • 2015 Best Energy / Industrial Project - Engineering News Record (ENR)
  • 2015 Build Northwest Award for Construction Excellence - Inland NW AGC