Dam work delayed to late December

POST FALLS — The boat launch near Avista Utilities' South Channel Dam at Post Falls will close for the season Monday, Nov. 2, but construction on the dam will continue.

"We expect the dam will be operational by the end of December with the landscaping, including the new overlook, to be completed by fall of next year," said Debbie Simock, Avista spokeswoman.

The completion will be a year later than originally planned. Among the delays in the project were the permit process, a redesign of the temporary dam that allowed employees to work on the permanent structure, erosion and unstable rock above the construction work area.

"There was an additional delay caused by a problem with the hoists that lift and close the spill gates," Simock said.

The previous South Channel Dam was 108 years old and one of three dams that Avista owns on the Spokane River at Post Falls. The South Channel Dam is not used to generate power, but helps lower lake and river levels during the spring runoff season. The North Channel Dam was upgraded in 2004 and the Middle Channel Dam was upgraded in 2012.

The $13.5 million South Channel project has included constructing a temporary dam just upstream from the permanent structure to allow workers to perform upgrades. The concrete of the structure was repaired, the spillway gates and manual equipment were replaced and the original 1906 concrete gate frames were removed.

The project is being funded by rate-payers as part of Avista’s capital improvement program. The project is on budget despite the yearlong delay.

"It is amazing to see the difference in the structure with the new concrete, gates and hoists," Simock said.

The area between the temporary dam and the permanent dam now has water as normal.

"The (temporary) dam is in the early stages of being removed, with that work expected to be completed by mid-December," Simock said. "At this stage, removal involves a large crane lifting sacks from the water and moving them to the fenced area near the office trailer. There the sacks are loaded in a dump truck and removed from the site. Once the coffer dam is removed, we will be able to open the new gates as needed."

Simock said the site will be returned as close as possible to its original state when all work is completed.

A new ADA-accessible overlook will be constructed for viewing the dam and landscaping with native vegetation. Construction is expected to start in the spring of 2016 and wrap up in the fall.

"This work will not impact the recreation season next year," Simock said.

A new staging area has been completed near the boat launch to make it easier for those launching or loading their boats.

The launch is typically closed each year in early to mid-November due to weather conditions and dropping water levels.

The boat launch must remain closed for safety reasons whenever water is spilled through gates at the Post Falls Dam, which can be the case for much of the fall through spring. Generally, the ramp re-opens in the late spring or early summer, depending on inflows into Lake Coeur d’Alene.

As a result of Avista’s annual drawdown of the lake, Spokane River levels above the dam will be about 2.5 feet below the summer full pool elevation of 2,128 feet on Nov. 2.

Water levels may drop by as much as 5 additional feet by the end of January. Levels are subject to change due to weather conditions.

People can access waterflow information at avistautilities.com/waterflow or by calling 769-1357.

The recorded information is provided to advise shoreline property owners, commercial and recreational users of changes in the lake and river elevation levels that may affect plans for water use.