Input on hydrilla sought following release of corps' assessment

May. 13, 2013 @ 04:24 PM

Public input is being sought on a recently released Environmental Assessment of the Kerr Reservoir prepared by the U.S. Army Corps of Engineers.

The plan identifies and evaluates environmental impacts associated with management actions proposed as part of the John H. Kerr Reservoir Aquatic Vegetation Management Program (AVMP) on the reservoir and contiguous water bodies.

Due to concern for the increased occurrence of hydrilla, the corps contracted N.C. State University to survey the reservoir for the presence of aquatic vegetation.

“They take this really high tech sonar machine, and they go all the way around the shore, maybe 50 feet out from the shore,” said Paul McKenzie, Vance County Cooperative Extension agent. “They can look at the sonar and see whether or not there’s any aquatic weeds coming up from the bottom.

“They create a map that shows where the aquatic weeds or plants are.”

Findings from the sonar map revealed hydrilla was the most prevalent invasive species found, infesting approximately 698 acres in 2011, and 888 acres in 2012, mainly in Little Nutbush Creek and the Nutbush Creek portion of the reservoir known as the Nutbush Creek Arm.

“Ninety percent or more is the hydrilla,” McKenzie said. “The percentage increase is pretty significant.”

A management plan will be used to ensure maintenance of a health and sustainable native aquatic vegetation population, and to address recent increases in occurrence of invasive vegetation, primarily hydrilla.

According to the environmental assessment, the purpose of the AVMP would be to serve as a planning tool ensuring that management actions for control of aquatic vegetation are undertaken after consideration of available information, and in coordination with stakeholders.

To date, actions addressing hydrilla have included public education efforts intended to prevent spread, surveys and monitoring to document extent, and limited herbicide treatments.

Herbicide treatments were undertaken by the corps of engineers, the N.C. Division of Parks and Recreation, and licensed herbicide applicators contracted by shoreline permit holders beginning in 2010. These treatments in areas around public boat ramps and private floating docks have had limited success resulting in localized temporary reduction in the amount of hydrilla.

Based on the increasing acreage presented in the environmental assessment, it was determined efforts have not been effective in limiting the spread or the increase in adverse effects of hydrilla.

The AVMP includes an action plan that would be updated annually. The action plan details proposed objectives, actions and responsibilities under the following action items: chemical control, biological control, hand removal, native aquatic vegetation, survey and monitoring, public education and enforcement.

“They’re anticipating to continue to allow people on the lake to hire private contractors in the area around the docks,” McKenzie said. “The products they use for those treatments are very safe, and there’s little if any effect on fish or the environment.

“There’s no hazards as far as swimming.”

McKenzie feels the corps of engineers’ action plan proposed under the AVMP, which includes stocking the lake with grass carp, seems reasonable. Grass carp will eat vegetation in all areas of the lake, while chemical control and herbicides would be targeted to high-use areas only.

“They are looking at the grass carp, which is a very effective method to control hydrilla, and the grass carp are raised in such a way that they cannot reproduce,” McKenzie said. “So, it’s not like you’re introducing a new species in the water that’s going to take over.

“They can’t reproduce so you have to do periodic restocking.”

In a written statement, Frank Timberlake, lead public affairs person for the Kerr Lake Park Watch, expressed the demand for public input.

“We want the corps to take more of an ownership role in trying to control hydrilla in Kerr Lake,” Timberlake said. “People who have already been impacted or soon will be impacted by the noxious kudzu of the lake should make their opinions, their research and information known to the government.”

Individuals have the option to mail or email written comments no later than May 31, and can both get information and make comments at usace.army.mil.com.

Written comments regarding the environmental assessment can be sent to Robert Dennis, 1930 Mays Chapel Road, Boydton, VA, 23917; or to jhkerr@usace.army.mil. Phone contact with Dennis can be made by calling (434) 738-6101, ext. 160.


Contact the writer at abentley@hendersondispatch.com.