Lo Do In The Lakes And Rivers

[Danoinark]

From the Baxter Bulletin, Mountain Home

River dissolved oxygen plummets

FRANK WALLIS • Bulletin Staff Writer • October 27, 2008

Water at the bottom of U.S. Army Corps of Engineers reservoirs in the White River Basin is dangerously devoid of oxygen right now, according to Jeff Williams, Arkansas Game and Fish Commission biologist and head of the Arkansas Trout Program.

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The opening of tubine vents and partial loading of generators in USACE dams on the White, North Fork and Little Red rivers has apparently helped the fish to thrive, said Williams.

Anglers and river watchers said Thursday that lots of trout are being caught, including a few trophies.

Williams says without help from weather, a fish kill is likely in upper reaches of the tailwaters that flow from the three dams.

Earlier this month, Williams ordered stocking restrictions on the three rivers. Dissolved oxygen levels range from a record low of three milligrams per liter (mgl) from Greers Ferry Lake into the Little Red River to current levels of 3.9-4.6 mgl from Bull Shoals and Norfork lakes.

Six milligrams per liter is the Arkansas Department of Environmental Quality's minimum standard for oxygen levels in Arkansas waters, said Williams. The stocking restriction will continue until dissolved oxygen levels begin to climb without help from turbine vents and partial loading of generators inside the dams, he said.

Hatchery production from the state's trout hatchery on the Little Red River near Mammoth Spring and the National Fish Hatchery at the Norfork Dam will be introduced to the White River at points starting near Rim Shoals and downstream to Guion, Williams said. No trout will be stocked to the North Fork of the White River upstream from Rose's Trout Dock. No trout will be stocked within a 10-mile stretch of the Little Red River downstream from Greers Ferry Dam. The tailwaters gain oxygen content as the streams flow, said Williams. The upper 24 miles of the White River tailwaters are most affected by the low oxygen phenomenon that occurs at varying levels of intensity each year between July and November, said Williams.

"In Bull Shoals we have some of the lowest dissolved oxygen levels we have seen in the last eight years, and the lowest on record in Greers Ferry," said Williams. The biologist said dissolved oxygen is also well off the minimum standard of 6 mgl in waters coming from Beaver Lake Dam.

Williams said Thursday that river watchers had observed a few dead trout but not in extraordinary numbers that could be attributable to low oxygen.

Fishing guide Jerry McCoy of Bull Shoals said Thursday he was aware of the stocking restriction, but he had seen no evidence of trout suffering from low oxygen in the fish he and his clients are catching.

"A client caught an eight pound brown Saturday evening and it fought like a tiger," said McCoy. "We're catching lots of fish and their bellies are full of sowbugs."

Williams said the catch is a good sign that the opening of vents and partial loads on generators to whip oxygen into the waters is helping to raise dissolved oxygen levels, said Williams. Those measures alone, though, won't be enough to save the trout without help from cooler weather to stir lake waters, Williams said.

The biologist said what's happening in the lakes now is the outcome of water stratified in the lakes starting in July with warm water stuck on top and the coldest water at the bottom of lake. An abundance of sunlight on the surface of lake supports plankton and other organisms that grow and die and fall to the bottom where they decompose and consume whatever small levels of oxygen is available. A gigantic volume of organic matter that washed into the lakes in March and April floods provided more nutrients for the annual bloom of alga and other aquatic plants.

Williams sad hydrogen sulfide is a byproduct of the process that creates a smell similar the smell of rotten eggs particularly in Lake Norfork. The smell of hydrogen sulfide was prominent inside the National Trout Hatchery at Norfork on Friday. Williams said the water supply to the hatchery is siphoned from Norfork Lake.

"Fish become lethargic. They loose their appetite. They loose weight. Enough time in that environment they will die," said Williams.

The best immediate remedy for the problem is cold weather to cool the lakes' surface waters.

In the absence of cold air, the best man-made remedy is a fore-bay oxygen diffusing system developed by the Tennessee Valley Authority that introduces liquid oxygen to the late through a series of hoses that perform much like a garden "soaker" hose, said Williams.

The agreement between AG&FC, USACE and Southwestern Power Administration (SWPA) to open vents and partially load generators is the outcome of a meeting of the Arkansas Dissolved Oxygen Committee. A representative from each entity is represented on the committee.

Williams said SWPA officials asked TVA experts to study Arkansas lakes in 1996 with a view toward identifying a permanent fix for the low dissolved oxygen problem. The fore-bay technology was recommended by TVA.

George Peters, president of North Arkansas Fly Fishers, said Thursday he's optimistic fore-bay diffusers will eventually be put to work on Arkansas lakes. Peters said he and champion fly angler John Wilson have three times this year been invited to the state capital by Gov. Mike Beebe to discuss ways to correct the dissolved oxygen problems and to pay for oxygen diffusers. High ranking officials from SWPA, USACE and AG&FC have also been a part of those meetings, Peters said.

"I'm more than encouraged, said Peters. "Gov. Beebe didn't have to call these conferences, but he did. He has said again and again he wants to solve the problem."

A diffuser on Norfork Lake will cost an estimated $10 million and $3 million a year to operate.

The fishing tourism impact for northern Arkansas is about $168-million each year, Peters said.

fwallis@baxterbulletin.com

[DoveTail]

At a cost of $10 million to install and $3 million annual expenses may explain why Table Rock let some water out at ZERO DO levels. I guess Arkansas has a much larger river system where they see how important the fishing industry is, so a minor expense compared to the total boost to the economy.

[Fishhand]

Good information. Thanks for the article Dano. That paragraph about the hydrogen sulfide explains the odor down at Taney.

It's kind of wild that we've had so much rain this year yet the D.O. levels in some tailwaters are at their lowest levels in years. Going into the months of Fall, I was thinking the exact opposite. I hate to say it, but, bring on the COLD weather.