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Lake Hickory is having fewer problems with aquatic weeds and algae, according to state water quality studies.
An invasion of parrotfeather weed, which limited boating and threatened the supply of drinking water six years ago, is under control, a state water quality staff member says. And algae is no longer causing complaints of foul odors and bad-tasting water, said Kevin Greer, assistant public services director for the city of Hickory.
Greer credited better efforts at reducing the amount of runoff heading to Lake Hickory as an important step in reducing algae. Runoff may be carrying fewer nutrients, which feed algae growth, he said.
Erosion control in Catawba County and counties upstream from Lake Hickory has helped, said Greer, who reported recently to the Hickory City Council on the state studies.
The construction of more low-lying areas called rain gardens has slowed the rush of storm water, allowing it to soak into the ground rather than pour into the reservoir. Rain gardens, like one built behind Lowe's home improvement store in the Viewmont section of Hickory, are important in controlling runoff from large parking lots that cannot absorb rainwater.
Nutrient levels in Lake Hickory have not worsened, even through the area is becoming more developed with homes, where the fertilizers used on lawns end up in the lake. "I think people are getting smarter and are using less fertilizer," Greer said.
Lake Hickory has not had a problem with the invasive aquatic weed parrotfeather in two years, Greer said. The plant is a native of South America and is sold for use in ornamental fish ponds. No one is knows for sure how it got into the lake.
Duke Power biologists spotted a 2- to 3-acre growth of parrotfeather in Lake Hickory in 2001 and alerted the state. By 2003, the weed covered 125 acres.
The weed was so thick near the U.S. 321 bridge in 2003 that boaters could not reach the nearby marina. Hickory was concerned the acres of weeds would clog the pipe that carries water from Lake Hickory to the city's water treatment plant. Dense growth of parrotfeather can provide breeding grounds for mosquitoes and worsen water quality and fish habitat.
In 2004, 2006 and 2007, the city and the state shared the cost of spraying the herbicide Komeen, which has been successful in stopping parrotfeather, said Rob Emens, an environmental specialist in the weed program of the N.C. Division of Water Resources.
"It was amazing we could get it under control so quickly," Emens said.
Some weeds have washed downstream and rooted in Lookout Shoals Lake, where they have been largely controlled with sterile grass carp that were introduced by the state. The carp eat the weed.
Emens says there is a potential for parrotfeather to return to Lake Hickory. It and other weeds are spread by boaters, who could bring it from other lakes on their trailers or propellers. In an attempt to halt the spread, the state has posted signs at boat launching ramps urging boaters to throw away any "hitchhikers" - aquatic weeds.
Aquatic plants will quickly outgrow ornamental ponds, and owners should dispose of the extra in a compost pile or garbage can. Do not toss aquatic weeds into the lake, Emens said.
