Work on Third Dam is winding down. Workers there are beginning to move equipment out of the Logan Canyon dam site Thursday.
LOGAN – Dan Barton, lead substation technician for Logan City Power and Light, said they should finish the construction on Third Dam in November.
“We should have everything wrapped up in a couple of months,” Barton said. “We had some delays but, should finish right on schedule.”
The work included replacing the surge tank, sluice gate spillway, gatehouse and other necessary improvements.
The only major thing left is the slurry trench and clean up. A slurry trench is constructed underground to impede groundwater flow and to control groundwater remediation problems.
“When the dam is finished and the site is cleaned-up we will start the sediment removal,” Barton said. “We’ve had a mountain of red tape along the way. It has been amazing.”
He said it’s been crazy to watch the number of inspections along the way and they’ve had no major issues.
There have been inspections by the U.S. Forest Service (who owns the dirt), Utah Department of Transportation (who owns the road next to the dam), and the Federal Energy Regulatory Commission (who oversees the project).
The Army Corps of Engineers, Utah Dam Safety, U.S. Fish and Wildlife, Utah Division of Wildlife Resources, Utah Division of Water Resources and the State Historical Preservation Office all have a chance to inspect the work being done.
The Logan River Trail detour will soon be removed and the public will be able to resume using the trail as soon as the construction is complete.
The dam was built over 100 years ago and wasn’t built with the scrutiny there is today.
The issues that slowed the project was the old gate house which had to be torn down and they built a slightly bigger building made of concrete.
“The old gates were made out of wood boards and were dangerous. The new gates will be controlled by a bladder that uses air, similar to the one (Utah State University) built at First Dam.
“The hydroelectric generator was built in the early 1900’s and was upgraded to its current state around 1920. Until now, nothing had been done to it since then.”
Stantec, an international engineering firm was contracted for the work on the dam. They have a photo taken around 1904 of some men standing on the dam. From the picture, it seems the dam was built with rock boulders covered with concrete.
Gerber Construction, out of Salt Lake, is doing the actual construction. The Logan office of JUB Engineers is also involved in the Third Dam renovation.
Third Dam is a diversion dam that takes water from the river and pushes it into a 72-inch pipe that feeds water to the turbines at the second dam’s generating plant.
Logan City Light and Power derives its electricity from many sources. Along with two hydro turbines on the Logan River, they also have a natural gas turbine and a solar farm. The city also buys power from other outside sources.