Developing an Effective Vegetation Management Program at Boone Lake Exeter, RI

1. Developing an Effective Vegetation Management Program at Boone LakeExeter, RI

3. DEVELOPMENT OF A COMPREHENSIVE AQUATIC VEGETATION MANAGEMENT PLAN LAKE ASSESSMENT * Water Quality * Biology * Watershed * Morphometry EVALUATION OF MANAGEMENT TECHNIQUES * Effectiveness * Environmental Effects * Compatibility with Other Uses * Cost * Social Acceptability MANAGEMENT OBJECTIVES * Fisheries/Wildlife * Recreation * Aesthetics FINAL DESIGN & PERMITTING IMPLEMENTATION MONITORING PUBLIC EDUCATION

4. 2009 AQUATIC PLANT SURVEY TASKS • Aquatic vegetation identification and distribution mapping. • Qualitative shoreline and overall site assessment. • Evaluate the feasibility of potential aquatic vegetation management/control strategies. • Develop a recommended management program.

5. DOMINANT AQUATIC VEGETATION • Diverse plant assemblage – 10 different species of submersed and floating-leaf plant species observed. • Greatest abundance of native plant growth observed in shallow water areas < 6 feet deep. • Sparse to dense beds of non-native variable milfoil found throughout shoreline.

8. Variable WatermilfoilMyriophyllum heterophyllum • Acidic waters • 7-10 pairs of leaflets • Vegetative propagation

9. Common ReedPhragmites australis • Emergent wetland plant • Common around salt marshes, highway drainage swales and lake shorelines • Highly invasive

10. FISH, WILDLIFE & NATIVE PLANTS Displacement of native plants Displacement of endangered, threatened or rare aquatic plants Habitat loss for fish & wildlife Change in spawning site availability Change in fish distribution Reduction in feeding success of predatory fish Reduction of open-water WATER QUALITY Temperature & oxygen fluctuations Increased phosphorus (nutrient) loading Alteration in plant and algae communities Accelerated eutrophication rates POTENTIAL IMPACTS OF EXOTIC OR INVASIVE PLANTS Source: A report from the Milfoil Study Committee on the Use of Aquatic Herbicides to Control Eurasian Watermilfoil in Vermont. VTDEC, March 1993

11. POTENTIAL IMPACTS OF EXOTIC OR INVASIVE PLANTS (continued) RECREATION • Risk of swimmer entanglement • Reduced access for boating & fishing • Reduced aesthetics LOCAL COMMERCE & REAL ESTATE • Reduced property taxes • Declining property values • Renters fail to return for a second season • Slowed business for marinas, etc. • Declining attendance at lakefront beaches and parks Source: A report from the Milfoil Study Committee on the Use of Aquatic Herbicides to Control Eurasian Watermilfoil in Vermont. VTDEC, March 1993

12. RECOMMENDED MANAGEMENT GOALS/OBJECTIVES • Control and prevent further expansion of non-native and invasive variable watermilfoil. • Improve access for recreational activities (fishing, boating, wildlife viewing, etc.). • Preserve diverse native plant assemblage, including: low-growing submersed species, and floating-leaved water lilies to provide fish and wildlife habitat

13. In-Lake Management Techniques Different Approaches • Physical/Manual • Mechanical • Biological • Chemical Determining Which One to Use • Program goals and objectives • Accurate plant identification • Environmental constraints • Social acceptability • Cost

14. SMALL INFESTATIONS • Bottom Barriers • Hand Pulling Suction Harvesting

15. LARGE INFESTATIONS • Mechanical Harvesting or Raking NOT RECOMMENDED

16. Drawdown (limited benefit)

17. CHEMICAL TREATMENT • Navigate (2,4-D) • Reward (Diquat) • Renovate (Triclopyr) • Sonar (Fluridone) FACTORS FOR HERBICIDE SELECTION… • Target species • Size & configuration of treatment area • Selectivity desired or required • Water uses • Flow considerations • Timing • Cost

18. What are the risks? Herbicide Toxicity • Risk = Toxicity x Exposure • Products registered by EPA under FIFRA, also registered in each State • 20 active ingredients for aquatics in 1976 – now only 8 • No aquatic herbicides have a swimming restriction on the label; however, closure on day of treatment is recommended • Use of lake water for drinking or for irrigation will be restricted following treatment

19. Available Aquatic Herbicides

20. METHODS OF APPLICATION

21. Formulation: Granular (BEE) Mode of Action: Systemic – auxin mimic, inhibits cell division in new tissue and stimulates growth of existing tissue Environmental Fate: Hydrolysis, microbial degradation, photolysis Water Use Restrictions: Drinking < 70 ppb, Irrigation < 100 ppb Advantages: fairly selective for broad-leaf (dicot) species, multiple year control, effective for spot-treatments Limitations: prohibited in water supply watershed areas, negative public perception Plants Controlled: Milfoil, Water Chestnut, Waterlilies, Watershield Navigate (2,4-D)

22. Reward (Diquat) • Formulation: Liquid • Mode of Action: Contact – interferes with photosynthesis • Environmental Fate: Sediment absorption, photolysis • Water Use Restrictions: Drinking 1-3 days, Irrigation 1-5 days, Watering Livestock 1 day • Advantages: Rapid action effective for partial lake or shoreline treatments • Limitations: Annual control does not kill roots • Plants Controlled: Milfoil, Curlyleaf Pondweed, Elodea, Hydrilla, Coontail, Pondweeds, Naiad, Duckweed, Bladderwort, Algae

23. Congamond Lakes – Southwick MA • Town operated mechanical harvesters for years • 2000 – complete littoral zone infestation of Eurasian watermilfoil • 2001 – Whole-lake (450 acres) Sonar herbicide treatment • 2002-2009 – spot-treatments of 20-35 acres per year to control curlyleaf pondweed and Eurasian watermilfoil

24. Lower Suncook Lake – Barnstead, NH • Variable watermilfoil infestation • Reward (diquat) treatment in 2002 only provided seasonal control • Association coordinated a grant funded research project and worked with legislators to get 2,4-D approved • Treated 132 acres with 2,4-D in 2004, surveys and treatment guided by GPS

25. Briggs Marsh – Little Compton, RI • Phragmites infestation around this coastal freshwater pond • Initiated Rodeo herbicide spot-treatments in 1997 • Treated with Airboat, but pond breaches to ocean regularly • Switched to Argo track-driven amphibious vehicles • Infestation reduced to maintenance levels

26. Recommended ProgramBoone Lake – 2010 • Finalize aquatic plant management approach ASAP • File RI DEM Pesticide Permit January • Pre-treatment vegetation survey May • Reward (Diquat) herbicide application for the control of variable watermilfoil Late May - Mid June • Spot-treatment of phragmites September • Late-season vegetation survey September • Project completion report Nov.-Dec.

27. ESTIMATED PROGRAM COSTS - 2010 Permitting • File pesticide permit application with DEM $200 Herbicide Treatment • Diquat treatment of up to 20 acres for the control of milfoil and thinning of native species $4,875 • Glyphosate/Imazapyr spot-treatment of phragmites $650 Monitoring and Reporting • Pre and post-treatment surveys and year-end reporting $750 TOTAL RECOMMENDED PROJECT BUDGET FOR 2010 $6,475

28. Thank You!