Aquatic Pesticide Monitoring Program

Non-Chemical Aquatic Plant Control

A New Research ProgramNicole David

Ben K. GreenfieldGeoff Siemering

Aquatic Pesticide Monitoring ProgramBackground

• 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

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

• Copper sulphate• Acrolein• Glyphosate• Fluridone• Methoprene

• Diquat dibromide • Malathion • 2,4-D • Triclopyr

Selected by Science Advisory Committee based on toxicity and extent used.

Monitoring Techniques

• Chemical Monitoring– Water– Sediment– Porewater– Tissue

• Toxicity Testing– Water: EPA 3 species– Sediment: H. azteca– Tox TIE (by tox labs)

• Water Quality Parameters– Conductivity, pH, Temp.,

TSS, Alkalinity, [Ca], [Mg], [Na], DOC, DO, Hardness

• Sediment Quality Parameters– Grain size, Nitrate, %

solids, TN, TOC, SEM-AVS (for Cu sites)

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 organismsand 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 beforeand 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 2004Fish Study: Beginning of 2004

ConclusionIn many weed management situations a mix of techniques, possibly including non-chemical and chemical methods will be the most appropriate approach.