This week, the U.S. Army Corps of Engineers Nashville District awarded a $109,450,000 contract to American Bridge Company for the Wolf Creek Dam Spillway Gates Replacement Project. The project is fully funded by the Disaster Relief Supplemental Appropriations Act of 2022.
Replacement is needed because a Spillway Radial Gate Evaluation Design Document Report in 2016 revealed the 10 spillway tainter gates are subject to overstress due to trunnion friction issues. Trunnion friction is the force generated around the trunnion pin during a gate lifting operation. It is caused by the bearing of the trunnion pin against the gates’ trunnion hub and bushing, which is the rotating point of the gate. In addition, the gates and lifting equipment have been in operation since the dam was completed for full beneficial use in 1952.
The scope of this contract includes fabrication of 10 new spillway tainter gates; removal of existing gates and lifting machinery equipment required to operate the gates; and installation of the new gates and lifting machinery equipment.
Capt. Joseph R. Cotton, Nashville District project manager, said the contractor will systematically replace each gate. The contractor is limited to three inoperable gates at any period of time, always leaving seven operable gates. As an additional risk reduction measure, only one gate bay will be open at any given time during construction. Replacement of gates will only occur between June and November each year, which is considered the dry season, when there is a lower lake level and less risk for flooding.
This replacement project will ensure the authorized flood-risk-reduction capabilities of this project will be realized for many years to come. During construction, “the key takeaway is that public safety is our top priority,” Cotton said. “Corps of Engineers’ water managers will maintain lake levels within current parameters agreed upon with the Southeastern Power Administration and the public will not experience significant drawdowns of the lake elevation. The most distinguishable change to reservoir levels during the construction period, may be a lower peak summer pool from 723 feet to closer to 720 feet. This adjustment would lower project risk during construction while still falling within current operating targets.”
Cotton said it will initially take some time for the contractor to begin fabricating the new gates, so he doesn’t expect significant construction impacts in the near term to traffic crossing the dam on Highway 127. As the project proceeds later in 2023, the Corps of Engineers plans to communicate any road closures and impacts with signage, news releases, and posts on Lake Cumberland’s Facebook page at http://www.facebook.com/lakecumberland.
“The Corps of Engineers will do everything possible in the planning and execution phases of the project to reduce traffic impacts to local businesses and residents,” Cotton added. “We will strive to minimize impacts to Highway 127. Typical temporary road closures will only affect one lane but there may be short periods when both lanes of traffic may be closed.”
The contractor will have to modify the bridge substructure to accommodate replacement of the 10 spillway tainter gates, which are 37-feet high and 50-feet wide, and to access lifting machinery equipment. This includes wire rope and drum setup, and replacement of high and low-speed gear boxes, 10 horsepower electric motor, bull and pinion gears, and the machinery base on each gate pier.
American Bridge Company, part of the Southland Holdings LLC group of companies, specializes in construction of new bridges, bridge rehabilitation and maintenance, complex structures, and marine construction. Its headquarters is located in Coraopolis, Pennsylvania.
The replacement of the spillway tainter gates and lifting machinery equipment will not affect the operation of the dam’s six hydroelectric generating units, which have an estimated annual energy output of 800,000,000 kilowatt-hours of hydropower.
Paving of the roadway across Wolf Creek Dam is also expected sometime during the summer of 2023, but is not related to this project.