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

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

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.

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.

heterophyllum Variable Watermilfoil Myriophyllum heterophyllum Acidic waters 7-10 pairs of leaflets Vegetative propagation

Common Reed Phragmites australis Emergent wetland plant Common around salt marshes, highway drainage swales and lake shorelines Highly invasive

POTENTIAL IMPACTS OF EXOTIC OR INVASIVE PLANTS 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 Source: A report from the Milfoil Study Committee on the Use of Aquatic Herbicides to Control Eurasian Watermilfoil in Vermont. VTDEC, March 1993

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

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

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

SMALL INFESTATIONS Bottom Barriers Bottom Barriers Hand Pulling Suction Harvesting Hand Pulling Suction Harvesting

LARGE INFESTATIONS Mechanical Harvesting or Raking Mechanical Harvesting or Raking NOT RECOMMENDED

Drawdown (limited benefit) Drawdown (limited benefit)

–Navigate (2,4-D) –Reward (Diquat) –Renovate (Triclopyr) –Sonar (Fluridone) CHEMICAL TREATMENT FACTORS FOR HERBICIDE SELECTION… Target speciesTarget species Size & configuration of treatment areaSize & configuration of treatment area Selectivity desired or requiredSelectivity desired or required Water usesWater uses Flow considerationsFlow considerations TimingTiming CostCost

Herbicide Toxicity Risk = Toxicity x Exposure Risk = Toxicity x Exposure Products registered by EPA under FIFRA, also registered in each State Products registered by EPA under FIFRA, also registered in each State 20 active ingredients for aquatics in 1976 – now only 8 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 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 Use of lake water for drinking or for irrigation will be restricted following treatment What are the risks?

Available Aquatic Herbicides TRADE NAME ACTIVE INGREDIENT MANUFACTURER Aqua-Kleen / Navigate 2,4-D Cerexagri / Applied Biochemists Aquathol K EndothallCerexagriwww.cerexagri.com Komeen / Nautique CopperSePROwww.sepro.com RenovateTriclopyrSePROwww.sepro.com RewardDiquatSyngentawww.syngentaprofessionalproducts.com Rodeo & generics Glyphosate Dow AgroSciences SonarFluridoneSePROwww.sepro.com HabitatImazapyrBASFwww.vmanswers.com

METHODS OF APPLICATION

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

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

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

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

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

Recommended Program Boone Lake – 2010 Finalize aquatic plant management approachASAP File RI DEM Pesticide PermitJanuary Pre-treatment vegetation surveyMay Reward (Diquat) herbicide application for the control of variable watermilfoilLate May - Mid June Spot-treatment of phragmitesSeptember Late-season vegetation surveySeptember Project completion reportNov.-Dec.

ESTIMATED PROGRAM COSTS 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

Thank You!