DOVER — The Bonneville Power Administration pulled back the curtain slightly Wednesday on its controversial proposal to fluctuate the level of Lake Pend Oreille.

Officials from BPA told the Pend Oreille Basin Commission that this winter’s deeper drawdown elevation could provide more flexibility in managing the hydroelectric system as more constraints are added to protect fish species in the Columbia Basin.

“We see an opportunity this year to tap into that flexibility,” said Holly Harwood, a fish operations policy and planning official for BPA. “We have a limited amount of flexibility in the way we use the system.”

That means water could be stored and released as regional power demands dictate, according to BPA, a federal agency which markets electric power in the region.

The U.S. Army Corps of Engineers drafted Lake Pend Oreille to 2,051 feet above sea level for the second consecutive year partly because the population of spawning kokanee was too small to justify a higher winter pool, which provides more spawning habitat.

Corps officials said Wednesday they have no choice but to consider the request by BPA.

“The corps has to take a look at the proposal,” said Joe Summers, operations manager for the Albeni Falls Dam on the Pend Oreille River.

Summers said a decision on the BPA request is still under review.

Meanwhile, concerns over a fluctuating lake level continue to pile up.

Those concerns include further shoreline erosion; damage to marinas, docks and water intakes; sedimentation; further spread of aquatic invasive species; impacts to cold and warm-water fish species; and effects to downstream hydroelectric projects such as the Box Canyon Dam in Pend Oreille County, Wash.

Heightening frustration with the request are vague assurances from the corps that a proper environmental analysis of the request is being done.

There is a 1983 environmental impact statement and Summers said there was further environmental review on Albeni Falls Dam operations in the mid-1990s and several years after that. He said a corps ice specialist is also considering potential impacts.

“The evaluation of potential impacts is happening, if you will, behind closed doors,” basin Commissioner Brent Baker pointed out.

There are also doubts that a meaningful study can be done by the time the corps makes its decision.

The Idaho Department of Fish & Game is not taking a position on the BPA request, although it has agreed to help monitor shoreline erosion. But a staff mitigation biologist for Fish & Game said she still hasn’t seen the all specifications for the proposed monitoring.