The spawning behavior of kokanee this year will dictate how fast and how far north Idaho's Lake Pend Oreille will be drawn down.

Technical Management Team members on Wednesday agreed to an Albeni Falls Dam operational plan aimed at dropping the reservoir to its winter minimum control elevation of 2,051 feet by Nov. 15. TMT's federal, state and tribal members discuss day-to-day federal Columbia/Snake river hydro system operations that might benefit fish listed under the Endangered Species Act.

In this case it is threatened bull trout, which feed on Lake Pend Oreille's diminished population of kokanee. Manipulations of the reservoir level have been employed in recent years in an attempt to improve spawning conditions for kokanee and ultimately help rebuild the population.

In anticipation of the decision, flows through Albeni Falls' turbines were pushed from about 16,000 cubic feet per second last week to 27 kcfs. The lake elevation as measured at the powerhouse dropped from 2,060.38 to 2,058.05 during the first six days of October.

This week's "System Operations Request" for the deep drawdown was submitted by the Idaho Department of Fish and Game and the U.S. Fish and Wildlife Service based on a decision tree that tells them how Pend Oreille's water might best be used. The USFWS is responsible for protecting the listed bull trout. The IDFG would also like see a kokanee rebound that would allow a reopening of that popular lake fishery.

Those agencies and dam operators -- the U.S. Army Corps of Engineers -- want to execute the relatively quick drawdown while minimizing or eliminating the need to spill at Albeni Falls Dam, and without exceeding state maximum total dissolved gas standards at Albeni Falls or downstream projects. Spill can boost TDG to levels that are unhealthy for fish.

"We're pushing it as much as we can without forcing them (downstream dams) to spill," said the Corps' Ken Brettmann. The idea is to flush as much water early to assure attainment of the 2,051 goal even if rain events push up river levels and give the system more water to deal with. If precipitation is light the outflows could later be decreased, or the goal reached early.

The Nov. 15 goal itself is early. Kokanee spawning has started earlier than the norm during the past two years (Nov. 8 instead of the more typical Nov. 20), and the large size of individual adult kokanee this year indicates possible early spawning in 2008 as well, the SOR says.

A 2,055-feet upper elevation has been targeted since the kokanee operations began in 1996. That level has been achieved in two of the past three years. In 2006-2007 the reservoir was drawn down almost to 2,052 because of the early arrival kokanee spawners and because of an experiment intended to dewater the redds of earlier spawning lake trout.

If kokanee spawning is in progress prior to Nov. 15 and occurs in locations and shallower depths that are deemed vulnerable to being dewatered, the SOR asks that the Corps, with 5 days of notification, stop the drawdown activities even if the 2,051 elevation has not been reached.

And if a few spawners show up early with the intent to spawn in deeper water, the Corps may be asked to speed up the drawdown, said the IDFG's Russ Kiefer said.

Kiefer said that if the only management consideration was the resident fish, the lake would be drawn down to the minimum once every four years. That limits the spawning area for kokanee but allows wave action to clean sediment from gravels that are favored nesting sites.

"Keeping Lake Pend Oreille higher after a winter of draw down has been shown to enhance kokanee egg-to-juvenile survival," according to the SOR. "The higher lake level inundates shoreline areas that were previously exposed to wave action, and provides an abundance of good, clean spawning habitat."

It is a good year for a deep drawdown because the IDFG expects a low number of spawning female kokanee – about 30,000 – so less spawning area is needed. And a return to a 2,055 level next year will allow a bigger spawning class to enjoy clean gravel.

"IDFG lake surveys indicate an increase in the sub-adult kokanee population that should be ready to spawn next fall," the SOR says.

"We think we've got them past the real critical size range for predation," Kiefer said of the hope that those sub-adults survive another year.

This year also seemed favorable because the three-month forecast calls for an equal chance of below average, above average or average precipitation in the Pacific Northwest.

"Providing the additional flow augmentation from Lake Pend Oreille in years with below or average November -- January precipitation may help provide river flows below Bonneville Dam that are more advantageous for chum salmon spawning before increased flows from winter flood control drafts at upstream reservoirs arrive," the SOR says. Flows from Albeni Falls and elsewhere in the system are called on to maintain river levels in the lower Columbia that allow chum access to their spawning grounds.

"Three decades of annual deep drawdown during the winter months are believed to be a contributing factor to the large declines in kokanee abundance, and are more recently exacerbated by the combined predation effects of lake trout and rainbow trout," the SOR says. "Both populations of predators are being intensively researched and managed to reduce their impacts on kokanee abundance."

Lake Pend Oreille provided the state's largest kokanee fishery with an average of more than 1 million harvested each year from 1952 through 1966 in 522,692 angler hours annually.

From 1966 to1985 the catch declined steadily, hitting a low of 71,208 harvested in 1985, according to IDFG research. Much of the decline was blamed on deep drawdowns for flood control and power production. The fishery has been closed since 2000.

While kokanee numbers have fallen the numbers of predatory lake and rainbow trout have risen. With lake levels that provide favorable spawning conditions, biologists are seeing more kokanee fry emerging from the gravels but most are being picked off before they emerge by predators. The IDFG estimates that in 2006, predatory fish ate about 551,000 pounds of kokanee.