Lake Waccamaw State Park attacks hydrilla

Lake Waccamaw State Park, with the help of a consortium of state agencies and experts, began an intensive treatment this week for an infestation of the aquatic weed hydrilla.

Contractors spread flurodine granules a few hundred yards of the lake's northwest shoreline.
Contractors spread flurodine granules a few hundred yards from the lake’s northwest shoreline.

Contractors in a pair of small boats began spreading a granular form of the chemical fluridone near the lake’s northwest shoreline in hopes of attacking the week just as it emerges for a hot-weather growth spurt. The affected area is near the largest of two public boat ramps on Lake Waccamaw. The application poses no danger to swimmers, boaters or others in contact with the lake’s waters.

Hydrilla is a submersed aquatic plant that can create nearly impenetrable mats of stems and leaves on a lake’s surface. An invasive species from central Africa, hydrilla impedes recreational use of waterways, crowds out native vegetation and can ultimately harm fish and other aquatic species. That’s particularly worrisome at Lake Waccamaw, which is home to about 50 species of fish and mollusks. Many are rare or endangered and some are endemic, occurring nowhere else.

Hydrilla’s spread is often attributed to boats that are trailered from lake to lake, and an educational campaign has begun to encourage boaters to repeatedly wash their craft, especially boat propellers, after use.

Residents on the 8,938-acre lake and local officials were as alarmed as park rangers when hydrilla was noticed there in 2011, since the Carolina bay lake is an economic engine in the rural community and a backdrop for the homes of many retirees. Researchers from North Carolina State University mapped the infestation at more than 900 acres. Left unchecked, the infestation could spread to about 1,500 acres within a year and to about 5,700 acres within three years.

Hydrilla can crowd out native species such as these water lilies.
Hydrilla can crowd out native species such as these water lilies.

The Town of Lake Waccamaw and Columbus County contributed $50,000 each toward the $196,660 cost of the initial treatment, matched by funds from the Department of Environment and Natural Resources. Other treatments may be necessary this summer, and certainly will be required over the next several years. Estimates of the cost range as high as $500,000 each year.

The response to the infestation is being coordinated by a Lake Waccamaw Technical Advisory Committee, with representatives from seven state and federal agencies as well as other stakeholders. The committee considered a range of treatment options, such as the introduction of grass carp, but determined that chemical application was the most appropriate considering the lake’s rare, endemic species. This is the first recorded hydrilla infestation of a Carolina bay lake. Lake Waccamaw is the largest of these natural bay lakes in southeastern North Carolina and holds the status of National Natural Landmark.

2 thoughts on “Lake Waccamaw State Park attacks hydrilla

  1. Residential and farm properties line the boundaries of the lake. Are the property owners aware their landscaping behaviors are fertilizing plant growth in the lake?

  2. EdC

    A few corrections:
    1) Hydrilla verticillata is generally considered to be a Eurasian species, though there may be populations in Africa (not sure about Central Africa though).

    2) Hydrilla was confirmed in the lake in October 2012, when residents had inquired with the Division of Water Resources about the Southern Naiad populations in the lake.

    3) NC State mapped the infestation at just over 600 acres, not 900 (the actual area of treatment).

    In response to cazz, I’m not aware of any farm properties on the lake. Shoreline properties are either private/residential or state-owned.

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