Tennessee Valley Authority
Blue Ridge Dam Rehabilitation
To help ensure public safety and meet more rigorous dam safety standards, TVA is rehabilitating Blue Ridge Dam. This work began in July 2010 and is expected to be complete in early summer 2012.
May 1, 2012 — TVA will continuing holding the water level in Blue Ridge Reservoir at approximately 1,672 feet (its current elevation) at least through the end of July 2012. This means the reservoir will remain below normal summer pool for this year.
Blue Ridge Dam is safe and stable. There is no change in the dam’s ability to hold water.
Because public safety is TVA’s number one priority, we are being overly cautious and holding the reservoir at this level after we saw unexpected ground movement on March 7, 2012. This movement occurred during the completion of the two-year Blue Ridge Dam rehabilitation project.
To ensure long-term dam safety, we are conducting significant monitoring, testing and analysis on the earlier ground movement at the dam. Holding the reservoir steady provides TVA consistent conditions for collecting the data necessary to complete a full engineering evaluation. It removes the variable of fluctuating water pressure against the dam from monitoring readings. This will allow us to determine if additional long-term stability work is necessary before completing the dam rehabilitation project.
This project includes three components:
- Installing a new liner in the penstock (the underwater pipe that carries water from the reservoir to the turbines in the powerhouse), which was damaged when the reservoir was refilled after construction in 1931
- Stabilizing the intake tower at its base
- Stabilizing the upstream face of the dam
- Stabilizing the downstream face of the dam
The penstock phase of the project required a deep drawdown of Blue Ridge Reservoir to an elevation 1620 to 1630 feet above sea level. Workers then opened the penstock from above, allowing for increased demolition of the existing penstock before installing a new penstock liner.
The penstock repair has been completed. The new penstock liner should eliminate the need for deep drawdowns that formerly were required every five years to inspect the penstock.
Project milestones
- Completed deep drawdown
- Completed low level boat access ramp at Blue Ridge Marina
- Installed erosion controls and dewatering system at penstock excavation site
- Inspected and cleaned the penstock
- Installed equipment to position the new liner inside the penstock
- Installed a new liner in the penstock
- Installed anchors to stabilize the water intake tower
- Removed old riprap from upstream face of dam; completed grading
- Placed layers of sand, crushed rock, and new riprap on the upstream face of the dam
- Re-armored the upstream face of the dam.
- Completed two retaining walls to hold the material that will be added to the downstream face of the dam
Next steps
Work to stabilize the dam’s intake tower and improve the dam’s upstream face is complete. Work is now in progress to place an estimated 258,000 tons of material on the downstream side of the dam.
“We are pleased with the smooth and safe progress we have made," says Blue Ridge Project Engineer Jeff Brown. "We are moving forward on the remainder of the project with a focus on safety for our workers, the public and the environment."