Ken Cooke, Water Watch coordinator for the state Division of Water, said today the herbicide spraying on dry land around Silver Lake couldn't be blamed for a major fish kill in the lake last week.

He said there was no evidence the chemical reached the water.

Kerry Prather, district fisheries biologist for the Kentucky Department of Fish and Wildlife Resources, sprayed "an approved aquatic herbicide" on vegetation around the lake, but not in the water, four days before the July 4-5 fish kill.

Prather has a small business not associated with his state government job, and was hired by some individual property owners close to the lake.

The Silver Lake Homeowners Association, however, didn't pay for the spraying, according to David Lawhorn, treasurer of the association.

"I treated creeping water primrose, which was on dry land," Prather said last week. "Nothing was sprayed in the water. It was a product called Reward. The active ingredient is Diquat, an approved aquatic herbicide.

"This is a terrible concidence and I can see where people would think (the spraying and the fish kill are related). But they're not related."

Prather said the fish kill was a natural occurrence due to oxygen depletion in the lake.

Cooke said there are "any number of factors that can cause oxygen depletion in a lake such as Silver Lake."

Those include the warm temperatures and low water caused by drought conditions; mixing of the water after a recent storm, stirring up low oxygen waters along the bottom; an increase of turbidity in the water causing a reduction in photosynthesis, and an increase in chemical oxygen demand from soil iron oxidizing.

"Aquatic herbicides have been used for years to control invasive weeds, without such fish kills," Cooke said. "What we have here is a "perfect storm' of sorts, a lot of factors contributing to low oxygen levels in the lake."

If residents around Silver Lake would like information on how to monitor the water for oxygen levels, "Kentucky Water Watch would be glad to provide them with equipment and training to run dissolved oxygen tests," Cooke said.

The tests take about 15 minutes to perform and are best done early in the morning when oxygen levels are lowest, Cooke said.

"The group may also consider aeration measures such as fountains or bubble diffusers," he said. "Of course these can cost a lot to install and they have to be maintained. That would require a subscription fee from the neighbors and a dedicated management team.

"But considering the value of that lake, and its impact on the values of the surrounding property, I think it would be worthwhile."

Former Franklin County Magistrate Howard Dawson, a resident of Silverlake Boulevard, said Wednesday the "vultures did an excellent job of cleaning things up. The smell was bad for about three days, but the odor is gone now.

"I believe 400 to 500 fish died. But I think the lake was overpopulated and this was nature taking care of itself to some extent."