LGA Plan 2008

Lake Gaston Association

Recommended Lake Gaston Management Plan

Lake Gaston is heavily utilized not only by lakeside property owners, but by anglers, boaters, and other visitors.  Vegetation management activities have the potential to significantly affect (1) access to outdoor activities such as swimming, boating, skiing, and angling, (2) property values in and around the lake, (3) local businesses, (4) the county tax base, (5) water quality, (6) the environmental health of the system, and (7) tourism.

Hydrilla is a highly invasive aquatic weed, able to propagate by fragmentation, and through tuber and turion production.  The Lake Gaston Association (LGA) recommends the use of triploid grass carp as the primary effort to control and/or eradicate the federally listed noxious aquatic weed hydrilla in Lake Gaston.  Herbicide treatments will be used to supplement grass carp based on available funding.

The vegetated** acreage of hydrilla in Lake Gaston has fluctuated annually, but has remained around 3,500 acres.  Areas previously treated with herbicides have never been hydrilla free and therefore the infested** acreage is likely to be greater than 8,000 acres since hydrilla has been observed growing at a depth of 20 feet.  “Since 2000, hydrilla has colonized waters as deep as 15 feet, which would include 40% of the lake or a potential total acreage of 8,120 acres” (John Madsen’s assessment for 2004, 2005, and 2006)”.

 No infested lake has ever successfully controlled hydrilla with herbicides alone.  Herbicides are expensive.  They are potentially dangerous, and therefore must be applied by a licensed applicator in accordance with the label.

          Therefore, the LGA recommends stocking grass carp at a rate of 15 fish per vegetated acre of hydrilla, based on the Fall Total Lake Survey plus that acreage privately treated with contact herbicide.  That the grass carp are a minimum of 12 inches in length and be widely distributed in several coves from bridges which would facilitate off loading.  That future stocking be based on a total of 15 fish per vegetated acre until hydrilla is controlled without the excessive use of herbicides.  The stocking rate should then be reduced 5 fish per vegetated acre and released in the areas where hydrilla is prevalent.

     Herbicide treatment using public money will consist of only systemic herbicide treatments on hydrilla in coves where success of reducing the tuber count is achievable and multiple year treatments be applied to these coves in order to eliminate tuber count.   Contact herbicide and algaecides using public money would be limited to public boat ramps, dry fire hydrants, and other invasive vegetation (i.e., Eurasian watermilfoil, Brazilian elodea, Lyngbya, etc).  Since Eurasian watermilfoil is not the preferred food of grass carp, aggressive treatment of these areas with contact herbicide is recommended. 

** Definitions used in this plan:

Vegetated:  The biomass of actively growing plants.

Infested:     The area where there are known hydrilla tubers.

Acre:          Unit of land measure equal to 43,560 sq ft (about an area 208 ft x 208 ft).

Fall survey:  The vegetated acreage of all aquatic plants in Lake Gaston

Lake Gaston Association

www.Weeds@LakeGastonAssoc.com