Marion Reservoir team prepares for explosion of zebra mussels

Marion Reservoir may may not be able to avoid in the years ahead a beach scene like this one at El Dorado State Lake.

The discovery of zebra mussels won?t have an immediate impact on activity at Marion Reservoir?except for the U.S. Army Corps of Engineers team charged with preparing for their inevitable population growth.

?The short answer is we?re going to learn to live with them at the reservoir,? Neal Whitaker, reservoir project manager, told the 40 or so people at an informational meeting Thursday.

?Next year you?re probably not going to see any yet,? he told them. ?The year after that, 2010, we?re going to begin seeing them.?

The growth of zebra mussels will have an impact on recreational users of the lake.

?The way they?ll probably be impacted is the way they swim or wade?they?ll have to wear shoes so they don?t get their feet cut,? Whitaker said, because of the mussels? sharp shells.

?If you get a large infestation, sometimes the boat ramps become slick,? he added. ?Other than that, people who use boats aren?t going to be greatly impacted.?

Whitaker said the recent discovery will have a significant effect on agency staff, though.

?It?s going to mean additional work and additional money,? he said.

The primary issue is that zebra mussels attach themselves to hard surfaces in cumulative fashion.

?We?re going to have to go around and scrape all of our regulatory buoys every year, or a couple of times a year,? he said. ?The delineation lines at our beaches will have to be scraped so the kids don?t cut themselves on the sharp shells that are attached to that.

?Our boat docks may have to be removed and scrapped every year, too? Whitaker added.

The one area zebra mussels won?t affect the operation of the reservoir is flood control.

?The motors we use to lift the gates, and all the cabling and such, (the mussels) can?t get heavy enough to affect our ability to open the gates,? Whitaker said.

Until now, it?s been the practice of the Corps to bring in a crane once every five years to maintain the gates. Now the process will be more burdensome.

?In the future when we do that, we?ll use a power washer to clean the mussels off of (the gates),? Whitaker said. ?If we get a big infestation, we may have to move that inspection up to every three years rather than every five years.?

The biggest cause for concern, Whitaker said, is keeping the two water intakes along the concrete area of the dam from becoming clogged with zebra mussels. The 24-inch wide intakes, about 40 feet deep, are the exit points for putting water into the distilling basin and furnishing water to the pump house for Hillsboro and the valve house for Marion.

?There are solutions?they?ve been around for 20 years in the Great Lakes, where there are untold water intakes,? he said. ?So the technology is there to address the problem. The question is finding out what works best here and what?s going to be cost-effective here.?

Despite the sobering predictions for what lies ahead, Whi?taker said at least three factors work in the reservoir?s favor.

?For one, we found them at the reservoir earlier than they?ve been found anywhere else in the state, so we bought ourselves a year or so of time,? he said.

?The second thing is that drum (fish) eat mussels, and drum tend to congregate in the winter right in front of the intakes?so that?s in our favor.

?The third thing that is in our favor is that this fall we?ve received permission for a lake-level draw-down program,? Whitaker said. ?We?ll drop the lake two feet between January, February and March.?

The draw-down will expose the mussels living in the top two feet of water surface.

?We won?t knock them out (entirely), but those that are shallower then two feet will be killed,? he said.

As a timely coincidence, the draw-down request had been initiated prior to the discover of the zebra mussels as a way to help the fisheries at the lake.

?Normally there?s a year lag time between the time you propose something and the time it?s implemented,? Whitaker said. ?But John (Stein, fish biologist with the Kansas Department of Wildlife and Parks) had the foresight to ask for this water draw-dawn program a year ago, so it?s a done deal.?

It remains to be seen how an infestation of zebra mussels will affect the blue-green algae bloom that has affected the reservoir over the past five years.

?It wasn?t an issue this year,? Whitaker said of the bloom. ?We didn?t have to close any of the swimming beaches. It wasn?t much of an issue last year, although I think we did have a couple of beach closings.?

Generally, the presence of zebra mussels is thought to exacerbate an algae bloom problem because they feed on the plankton that tends to cloud the water. Clear water enhances algae growth.

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