Aquatic Pesticide Monitoring Program
Non-Chemical Aquatic Plant Control
A New Research Program
Nicole David
Ben K. Greenfield
Geoff Siemering
Aquatic Pesticide Monitoring Program
Background
• Increased permitting requirements for chemical
pesticide application after Talent decision
• Increased costs for pesticide permitting:
reevaluate control methods
• Specified in SWRCB/Waterkeepers legal settlement
• Chemical monitoring program
• Non-chemical alternatives program
Chemical Program Objectives
Gather basic sampling data for SWRCB
• Refine sampling, analytical, and toxicity
protocols
• Identify and fill gaps in pesticide knowledge
base
• Develop monitoring plan handbook
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Pesticide User Groups
1. Irrigation supply systems
2. Drinking water reservoirs
3. Exotic weed control (canals and coastal)
4. Mosquito abatement
5. Flood and storm water control
6. Recreational impoundments (golf courses,
parks, etc)
Target Aquatic Pesticides
Selected by Science Advisory Committee based on toxicity
and extent used.
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Copper sulphate
Acrolein
Glyphosate
Fluridone
Methoprene
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Diquat dibromide
Malathion
2,4-D
Triclopyr
Monitoring Techniques
• Chemical Monitoring
• Water Quality Parameters
– Conductivity, pH, Temp.,
– Water
TSS, Alkalinity, [Ca],
– Sediment
[Mg], [Na], DOC, DO,
– Porewater
Hardness
– Tissue
• Sediment Quality Parameters
• Toxicity Testing
– Grain size, Nitrate, %
solids, TN, TOC, SEM– Water: EPA 3 species
AVS (for Cu sites)
– Sediment: H. azteca
– Tox TIE (by tox labs)
Non-Chemical Alternatives Program
Objectives
1. Conduct thorough cost-effectiveness evaluations
of non-chemical aquatic plant control options
2. Identify additional non-chemical methods for
CA waters
3. Produce guidebook to help managers determine
best control options
Identify additional non-chemical approaches
for California waters
• Interviews with weed-control experts nationwide to make
sure CA isn't missing out on effective methods
• Demonstration Projects with potentially promising methods
for specific water body types
Available Methods
• Biological methods
• Insects
• Grass Carp
• Physical methods
• Mechanical Harvesting and Cutting
• Rotovation
• Weed Rollers
• Suction Dredging
• Bottom Barriers
• Manual Removal
• Water Drawdown
• Sediment Excavation/Chaining
Biological Control
Sterile Grass Carp
• Feeds on aquatic plants
• Non-selective
• Works best in small ponds
Insects
• Reduce plant growth and seed production
• Establishment might be difficult
• Plant specific
Mechanical Control
Mechanical Harvesting/ Mechanical Cutting
• Cuts plants several feet below water surface
• Immediate but short-term results
• Impact on fish and invertebrates
• Risk of spreading invasive plants
Rotovation
• Barge-mounted rototilling machine
• Dislodges plant root crowns
Weed Rollers
• Metal cylinder attached to dock
• Rolls in 270 degree arc
• Compresses plants and soil
• Disturb bottom dwelling organisms
and fish
Suction Dredging
• Diver-operated pump system
• Suction plants and roots from sediment
• Plant material is collected on the boat
• Slit curtain can be used to control
turbidity
Bottom Barriers
• Semi-permanent materials laid over plant bed
• Eliminate sunlight
• Loss of habitat for benthic organisms
Manual Removal
• Removes entire root crown
• Labor intensive
Water Level Drawdown
• Dewatering water body by releasing water via
dam or weir or pump
• Requires water level control structures
Excavation
• Removes plants and surface sediment
• Viable for storm water and irrigation canals
• Increased turbidity downstream
Preliminary Interview results
• Results from interviews with experts from 11 states
in draft Technical Memo
• California is in the loop. Most available approaches and
technologies have been attempted in California waters
• Method improvements have mostly been restricted by
a lack of funding.
Mechanical Shredding Demonstration Projects
Mechanical shredding without removal
• Comparing to chemical treatment at similar location and
control site
• Cost effectiveness comparison
• Invertebrate community
bioassessment
• Impact on water chemistry
• Possibility of trace metal
analysis
Demonstration Projects
• Preliminary plan - Mechanical shredding of water hyacinth
(Eichhornia crassipes) in Delta sloughs.
Demonstration Projects
Fish Study Objectives
• Direct measurements of water chemistry before
and after mechanical harvesting operations.
• Quantification of removed fish and fish species.
Deliverables
• First Year’s Summary Report already available.
• Phase 2 data analysis and report for chemical project:
Beginning of 2004
• Data analysis and report for non-chemical
demonstration projects
Mechanical Shredding: Mid 2004
Fish Study: Beginning of 2004
Conclusion
In many weed management situations a mix of
techniques, possibly including non-chemical and
chemical methods will be the most appropriate approach.