Draining Diamond Lake to kill millions of tui chubs is out, but explosives remain an option for ridding the lake of the unwanted fish and the ecological harm they cause there, authorities said.

Umpqua National Forest officials said Wednesday in Medford that they’ve pulled the plug on the lake-draining option, tossing it into a pile of 20 other options that won’t be analyzed in an environmental study.

The specter of running a 4-inch pipe 14 miles from Diamond Lake in Douglas County down Lake Creek to Lemolo Lake for two years at a cost of about $41 million just didn’t pencil out as viable, study leaders said.

"It’s too expensive and too risky for the ecology of Lake Creek," said Sherri Chambers, who heads a multi-agency look at the lake’s dilemma. "The pipeline would be vulnerable to fire, vandalism and earthquakes."

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That leaves six options for a Draft Environmental Impact Statement the Forest Service and other agencies are preparing to study the cost, feasibility, and the social and environmental impacts of completely or partially ridding the lake of its 40 million chubs.

Options include the possibility of using explosives to shock the fish to death, much like poachers once used dynamite to blow salmon out of a river hole.

"Demolition experts say it’s possible, but I haven’t been able to find where it’s been applied at this scale," Chambers said. "But I’m still exploring that option."

Wednesday’s meeting in Medford was what Chambers called "a project report" on the draft study to see if the public believes the range of alternatives is adequate to ferret out the best solution for the problem at the high Cascade lake.

About 30 people attended the meeting, mostly asking questions about the alternatives or stumping for the government’s preferred alternative — using the chemical rotenone to kill off all the fish, then restocking with trout for anglers.

"The rotenone, to me, seems to be the most feasible to fix 100 percent of the problem," said Bob Dunn, a Central Point resident who has owned a summer cabin at Diamond Lake since 1966. "It’s just what hoops do (agencies) have to jump through to get it done?"

But others, like angler Raymond Patterson of Central Point, asked instead for massive mechanical removal of chubs, then stocking of predatory brown trout to keep chub numbers to less-troublesome levels.

"The brown trout will be able to keep the chub under control, instead of killing it and wait for it to happen again," Patterson said. "You’d save millions of dollars."

Discovered in 1992 and likely introduced illegally by an angler using them as bait, the chubs have overrun the lake and now represent 92 percent of the lake’s biomass.

The chubs out-compete trout for food and space, and they eat so much zooplankton that they trigger toxic algae blooms that have led to swimming closures each of the past three summers because of health risks.

Along with the rotenone, mechanical removal and explosive alternatives, others now up for study include using chemicals less lethal to the lake’s frogs and other "nontargeted species" or using an aggressive fish-stocking program to reduce chub numbers. A no-action alternative rounds out the list.

The draft is due in March, with the final decision expected next May. No work would be done without a separate push for state and federal funds for the project, and appeals also could stall the process, Umpqua Forest Supervisor Jim Caplan said.

Caplan, who will make the ultimate call on the lake’s future, said there is "near- unanimous" support for improving the lake’s water quality.

"Where we differ somewhat is in the way to do it and whether we should restock it," Caplan told the crowd. "That’s good. We need to be challenged on our ideas."

A similar meeting in planned tonight in Roseburg.

Reach reporter Mark Freeman at 776-4470, or e-mail mfreeman@mailtribune.com