Albeni Falls Dam spillway gate removed

OLDTOWN — The U.S. Army Corps of Engineers has decided to remove the defective spill gate at the Albeni Falls Dam to sustain current Lake Pend Oreille levels and mitigate potential flood risk on the shorelines nearby.

USACE staff removed the spill gate late Tuesday, May 14, and reduced the powerhouse flow in an attempt to achieve the desired total water outflow for the lake’s predicted elevation. Powerhouse flows were reduced during the removal to regulate the total flow increase to 5,000 cubic feet per second and the gate was removed without incident, said USACE public affairs specialist Nicole Celestine. 

Celestine said that the removal was deemed a better option than moving multiple gates around to regulate lake levels.

It is unclear at this point whether the defective gate will undergo repairs and will be put back in place or whether the gate will be replaced altogether. USACE did not immediately respond to requests for comment on how long the dam would be operating with one less gate while staff figure out the best option going forward.

“Current hydrologic modeling indicates maintaining current Lake Pend Oreille elevation until late May might be necessary,” she added. “Officials are monitoring real-time weather, streamflow trends and updating modeling predictions daily.”

Once lakeshore flood risk passes, USACE will operate to meet normal summer pool elevations as quickly as possible. Even with lower-than-normal snowpack recorded in the basin, there still is significant uncertainty in the inflow forecasts both in terms of total volume and snowpack runoff timing, she said. 

“We need to keep storage space available to guard against the potential for rain or snow events that can lead to sudden spring high inflows,” said Albeni Falls Dam operating project manager Amanda Smith. “The basin is extremely large so there is a lot to consider when monitoring the conditions. These rain events can happen in any year, so we are being cautious during refill operations.”

Staff are closely monitoring upstream storage projects, streamflow, snowpack and weather forecasts, and officials are adjusting operations as conditions allow.

To receive email notifications for Albeni Falls Dam outflow changes, email uppercolumbiawm@usace.army.mil and request to be added.