Controlling Submerged Aquatic Vegetation

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Controlling Submerged Aquatic Vegetation

• Aquatic Plant Management in Chautauqua Lake

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Introduction Background

• Small, naturally formed lake
• Southwestern corner of NYS
• History of aquatic vegetation overgrowth
• problems with Eurasian milfoilweed
• curly leaf pondweed
• impending threat from Hydrilla

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Setting

• Two basins
• North Basin - mesotrophic
• overgrowth not a big problem
• South Basin - eutrophic
• naturally shallow
• heavy siltation
• naturally rich in nutrients

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Other sources of eutrophication

• Importance of Agriculture
• economic impact
• source of pollution
• nitrogen, phosphates, pesticides
• Tourism
• effort to control vegetation for recreation
  purposes
• recreation may contribute to overgrowth
• Rural Character
• septic systems

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Setting

• Environmental Stewardship
• Chautauqua Watershed Conservancy
• Chautauqua Lake Association
• Local Waterfront Revitalization Planning
• federally funded program
• survey data - SAV is the 1 issue

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Methods

• Several different methods
• Differing issues
• price
• effectiveness
• level of government involvement

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Dredging

• Method
• Drag bottom of lake
• remove sediment
• remove rooted vegetation
• Effective removal of all vegetation, including
  non-target species
• Expensive
• Question of spoils

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Harvesting

• Methodology
• cut vegetation above roots
• remove refuse onto barges
• Somewhat effective
• fragments left behind
• must be repeated during growing season
• Expensive
• about 100,000/summer
• compost material to offset cost?

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Arguments against harvesting

• Decline in fish population
• Continued harvesting could prevent stable
  recovery
• habitat issues
• fish get caught

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Herbicides

• Methodology
• apply chemicals at specific times during growing
  season to prevent overgrowth
• Aquathol-K, Sonar
• Effective when used properly
• Mid-range price
• about 50,000/summer

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Arguments against herbicides

• Public health issues
• use of fish for food
• swimming
• Lag time between application and effectiveness
• short growing season
• Possibility of fish kills
• oxygen reduction

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Legislation Infrastructure

• Direct government involvement
• septic pumping
• greenbelt planning
• Planning projects
• increase sewer coverage
• No interest from planning department

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Education Programs

• Purpose is two-fold
• personal impacts on the watershed
• familiarity with other environmental issues
• Lakescaping Programs
• Lawn Maintenance Workshops

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Biological Controls

• Methodology
• introduce natural predators to the environment
• Effective if used properly
• Low cost with little impact on the ecosystem

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Application

• Harvesting herbicides both used
• Biological Controls are the up and coming method
  of choice

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Biological Controls

• Role of Cornell University Chautauqua County
  Cornell Cooperative Extension
• Use of aquatic moths and weevils

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• Addition of moths and weevils has damaged milfoil
  populations
• study is ongoing
• augmentation of population this month
• continued maintenance of population

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• Plan is feasible as a long term alternative for
  SAV management
• cost effective
• 50,000 for initial study
• 10,000 committed to insect production
• less costly than chemicals or harvesting
• Environmental impacts are lessened

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Conclusions

• Chautauqua County has found viable plan for SAV
  control
• cost effective
• environmentally sound
• acceptable to the social atmosphere