Susan L. Sprecher, Ph.D
U. S. Army Engineer Waterways Experiment Station
Tennessee Valley Authority's (TVA) recent decision to reinstate aquatic weed control in a reservoir in Alabama ("TVA Agrees to Destroy Guntersville Lake's Weeds," The Huntsville Times, July 29, 1998) means that extensive cooperative WES-TVA research will once again be put to use on a problem that has refused to go away. TVA's decision to reinstate its long-standing and well-managed aquatic herbicide program was credited to efforts of local officials and residents who worried that infestations of nuisance exotics like Eurasian watermilfoil (Myriophyllum spicatum) would hurt the health of the lake as well as tourism and economic development. During the past decade, scientists from the Chemical Control Technology Area of the US Army Corps of Engineer's Aquatic Plant Control Research Program (APCRP) have worked with TVA under the Joint Agency Guntersville Project (JAGP) to determine optimal management practices for USEPA-approved aquatic herbicides. Herbicide concentrations able to eliminate invasive weeds with minimal impact to native plants, fish and invertebrates were verified in field studies, along with samplings that showed largemouth bass were not affected by herbicide applications.
When the TVA's consistent aquatic vegetation management plan was dropped in 1995, once targeted weeds did not stand still. Favorable conditions of water depth, light, sediment substrate and nutrients allowed the highly competitive and noxious Eurasian watermilfoil to choke Lake Guntersville. The years without weed control have left this northeast Alabama reservoir threatened by take-over, where boat lanes have to be cut through the weed mass to allow movement from the shore to deeper water. When a recent public opinion survey indicated that 60 percent of the people polled supported the use of aquatic herbicides, TVA agreed to re-evaluate its weed management plan. Information from herbicides studies conducted under JAGP will be used in formulating a consistent and effective plan for the future.
Technology Transfer Products:
Burns, E.R., Turner, E.G., and Getsinger, K.D. (1994). "Summary of field evaluations of herbicides on Guntersville Reservoir," Proceedings, 28th Annual Meeting, APCRP. Miscellaneous Paper A-94-2, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS, 260-262.
Getsinger, K.D., Turner, E.G. and Madsen, J.D. (1992). "Field evaluation of the herbicide triclopyr for managing Eurasian watermilfoil," Information Exchange Bulletin A-92-3, Aquatic Plant Control Research Program, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS.
Webdate: Dec 1998