Draining of Apple Valley lake yields limited benefit

  • Article by: LAURIE BLAKE , Star Tribune
  • Updated: July 19, 2014 - 6:36 PM

Long Lake saw a reduction in an invasive weed but just a small gain in water quality after the draining and winter freeze.

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Curly-leaf pondweed can form in thick mats on a lake’s surface, complicating paddling and blocking light to other plants. When it dies, it promotes green algae.

When Apple Valley decided to drain Long Lake last winter in an attempt to revive its water quality and fight an invasion of curly-leaf pondweed, the key question was: Would the weather cooperate?

Boy, did it ever.

One of the coldest winters on record gave the pondweed turions (a version of roots) buried in the lake bed the desired hard, killing freeze.

The result?

The lake is not cleared of pondweed but the concentration is reduced, said Jeff Kehrer, natural resources director for Apple Valley.

The weed is still growing in the lake in similar locations as in the past “but in much lighter levels,’’ Kehrer said.

He considers the drawdown a success. But many residents say it did not deliver the improvement in water quality they were hoping for.

“I do think the clarity of the water was improved, especially in the early spring.” said Paul Habegger, president of the Long Lake Watershed Association. “And I do think that the curly-leaf pondweed came up later than it usually does. We were giddy for a while, thinking that this thing really worked.

“But it came back and came back with a vengeance.’’

The pondweed may have been knocked back. But that brought light into the lake that allowed other weeds to grow, Habegger said.

“Is the overall aesthetic and quality of the lake better? I think most people would say no. I think the weather conditions [for the drawdown] were perfect, and if we didn’t hit a home run now, that proves it’s not a panacea.’’

The lake is choked with so much algae and other weeds that a paddleboat can’t cut through it, said Greg Johnson who has lived on Long Lake for 10 years.

“I propose that we chemically knock it out,’’ Johnson said.

A lot of people on the lake do want to use chemicals, but that may not be as simple as it sounds, Habegger said. Permits would be needed from the state. And residents ringing the lake would face some cost.

The next step is to come up with a new five-year plan and chemicals may figure into that, Habegger said.

Kehrer said testing of the lake water will continue over the summer and a plant survey in the fall will determine if wanted native plants benefited from the draining.

One lake to another

Apple Valley drained the 37-acre Long Lake in September. The water was piped under Pilot Knob Road into adjoining Farquar Lake.

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