Drought Accelerates Summer at Kentucky, Barkley Lakes: As Weather Heats Up, Lake Levels Go Down, Leading to Stratification.

By Steve Vantreese, The Paducah Sun, Ky.

Jun. 24– — Not only is it stacking up to be a long, hot summer on Kentucky Lake and Lake Barkley, it looks like it’s going to be one in the big lakes.

Drought conditions are moderate in western Kentucky and worse to the east from which the Tennessee and Cumberland river systems flow. With summer brand new officially, Kentucky and Barkley lakes already are experiencing conditions that could be typical of mid-summer.

“We’re about a month ahead on hot, dry weather,” said Paul Rister, Western District fisheries biologist for the Kentucky Department of Fish and Wildlife Resources. “We are in conditions that are normal for July or August.”

Most specifically, the big sister lakes’ flow rate, the speed with which water passes through them, has become plodding because of the lack of abundant water in both river systems.

The drought also is seen in water elevations. Lately, the lakes have been approximately a foot lower than the normal summer pool level, 359 feet above sea level.

Rister said lower flow rates and a decline of current lead to the phenomenon of stratification in more areas of the lakes — the layering of water in temperature bands, cooler water settling to the lowest levels, warmer water toward the surface.

With little current to mix the water, stratification sets up potential problems with oxygen content, he said.

“An example of what’s happening is when you go swimming in the lake and you hit a cool spot with your feet while your upper body is in water that’s a lot warmer,” Rister said. “On a bigger scale, that’s what happens in parts of the lakes.”

Rister said the stratified water in hot weather tends to be markedly lower in dissolved oxygen in the depths.

Recent oxygen monitoring found no problems in deep main lake areas, but samplers found less than desirable oxygen levels in the mouth of the bay at Taylor Creek, site of Kentucky Dam Village State Resort Park.

“We ran some deep trot lines recently to take some catfish for testing, and the fish we hooked down in 50 feet of water died overnight,” Rister said. “There was enough oxygen for fish to go in there and feed, but the fish we hooked couldn’t leave and there wasn’t enough oxygen for them to survive overnight.”

Rister said even increasing temperatures and protracted low flow rates are unlikely to ecologically harm the lakes.

“When oxygen levels get low in places, fish just move to where conditions are better,” Rister said. “It will probably make fish more sluggish. And fishing will likely be sluggish, too. We’ve had a creel clerk out there, and he’s reporting that the fishing already is pretty tough.”

Bob Sneed, chief of water management of the Corps of Engineers’ Nashville District office, said Lake Barkley presently shows no significant water quality problems, but he expects harder times as the summer wears on.

“There may be issues with water temperatures and oxygen levels,” Sneed said. “We’re probably going to see water temperatures of 90 degrees or better. The temperatures and oxygen levels probably are going to stress some things.”

While Lake Barkley, like Kentucky Lake, hosts no species that can survive only in chilly water, Sneed said, fish like striped bass that prefer cooler water may warrant some concern.

Rister said there have been no fish kills attributable to the advanced summer condition.

“There have been some kills of corbicula, the little Asian clams, but that’s fairly typical for summer,” Rister said. “Some people have thought it was mussels dying, but these are the little bitty exotic clams. I’ve heard no reports of native mussels dying.”

Dr. David White, director of Murray State University’s Hancock Biological Station on Kentucky Lake, said conditions presently only look like normal — except that they’re more normal for mid-summer.

“Oxygen levels are getting lower in deeper parts of the lake, but nothing that poses a problem so far,” White said.

He said the advanced summer traits of the lake, however, do make it appear that the reservoir could be flirting with an extreme drought.

“Current adds to turbidity, and with the low flow we’ve had, it minimizes turbidity,” White said. “The most unusual thing we’ve seen is how clear the lake is. The clear water is helping the weed beds grow in the bays.”

White said lake users can have access to lake condition monitoring at the biological station by seeing the Web site www.murraystate.edu/qacd/cos/hbs/wq.cfm.

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Copyright (c) 2007, The Paducah Sun, Ky.

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