Washington State Department of AgricultureWashington State Department of Agriculture

Evaluation of Streamside Vegetation and its Role in Reducing Pesticide Loading to Streams

Natural Resources Assessment Section (NRAS)Joel Demory, Kelly McLain

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About NRAS

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•WSDA Natural Resource Assessment SectionGoal: Protect endangered species and water quality

while maintaining agricultural productivity

•Activities: Research, collaboration, outreach, and policy

•Our main projects:-Ambient Surface Water Monitoring-Pesticide Use Data Collection-Agricultural Land Use Mapping-Special Projects

-Targeted Monitoring

Collaborative Effort

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Targeted Monitoring:• Met with NMFS Pesticide BiOp staff to

discuss targeted monitoring design.

• Study Objective: Determine how effective streamside vegetation is at reducing pesticide loading to streams

Whatcom County WA:• Changes in pesticide use

– new pest pressure (SWD)• Presence of natural and planted riparian

vegetation vs no vegetation FT1 (Vegetated Site)

Collaborative Effort

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In 2014, NRAS Partnered with:• NMFS (NOAA)• EFED (EPA)• Whatcom Conservation

District• Washington State Red

Raspberry Commission• Washington State Blueberry

Commission• Agronomists with Whatcom

Farmers Co-Op

• Aerial applicators• SDIMT (Pesticide

Registrants)

What are Hedgerows?

• Generally 15 ft wide (from ordinary high water mark) • 3 rows of plantings, 5 feet apart• Use early succession shrubs (grow very quickly)• Some maintenance required 1-1.5 summers before plants

become established• Minimal encroachment on cropping area

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Hedgerows Continued

• Variety of native species available that are not hosts for SWD• Design can be tailored to meet the needs and goals of the

producer• Low installation and maintenance cost • Alternative solution for weed control in ditches• Ditches need to be dredged far less often

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Win-Win Situation for Everyone

Benefits for Producers:– Continued use of malathion and other BiOp chemicals– Get credit and acknowledgment for having voluntary

mitigation in place– Identify vegetation planting options that are low-cost, low

maintenance, and quick growing– “reduced set of no-spray buffers or not have to follow the no-

spray buffer requirements” (NMFS draft BiOp)– Move away from “one size fits all buffers”

Environmental and WQ benefits:– Lowers in-stream temperatures– Reduces nutrient loading from runoff and erosion

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Study Design

• Control Sites - without dense woody vegetation• Vegetated Sites - with dense woody vegetation - 4 to 10 meters wide

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• Monitored applications at– 2 control sites– 3 vegetated sites (1

hedgerow, 2 natural vegetation)

• Monitored 8 total events– 4 control– 4 vegetated

• Collected site specific and event specific data

• Stream & Vegetation characteristics

• Weather conditions Site Layout at UD1 (Control Site)

Study Design

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• Sites - divided into 6 equally spaced transects– Data Collected

• Instream– Geometry– Shading– Habitat– Gen. Water Chem

• Vegetation– Width– Height– Canopy cover– Species composition

Study Design• Evaluating Off-Target Chemical Movement

– Depositional Samples• Field edge• Vegetation edge• Water

– Water Samples• Standing water

– Grab samples collected at each transect before and after• Flowing water

– Automated Water Samplers – upstream & downstream» 100mL subsamples – every 6 min.

• 4 - 400mL composite samples collected every 24 min. – Weather Station

• Wind speed & direction• Temperature• Humidity• Solar Radiation

– Logged every – 30 sec 10Downstream at FM2 (Vegetated Site)

Transect Layout – UD2

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Transect Layout – UD1

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Transect Layout – FT1

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Depositional Samplers

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Site Comparison

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Averages for Field and Vegetation Measurements

Site Type Mean Vegetated Sites

Mean Control Sites

Canopy Angle (°) 71.79 0

Instream Canopy Cover (%) 85.76 45.72

In Vegetation Canopy Cover (%) 95.62 0

Bankfull Width (m) 6.66 4.86

Buffer Width (m) 6.61 n/a

Buffer Height (m) 5.72 n/a

Water to Veg Distance (m) 8.22 2.84

Veg to Field Distance (m) 8.3 3.59

Upstream of FM2 (Vegetated Site)

Site Comparison

16Error Bars Represent One Standard Deviation *Two-Sided Sites

5.9 7.4

12.9 14.619.4

0

2

4

6

8

10

12

14

16

18

20

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UD1* UD2 FM1 FM2 FT1*

Control Vegetated

Dist

ance

(m)

Average Distance from Field-edge to Water

*

Preliminary Water Results

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Site Type Samples Event Sample Type Average (µg/L) Max (µg/L) detections

Control UD1

1Grab – Before < 0.05 < 0.05 0 of 6

Grab – After 4.14 7.1 7 of 7

2Grab – Before 0.08 0.21 3 of 6

Grab – After 3.45 7.8 6 of 6

Vegetated FM1 1Composite - Upstream 0.05 0.064 1 of 4

Composite – Downstream 0.06 0.069 3 of 4

Vegetated FM2

1Composite - Upstream < 0.05 < 0.05 0 of 4

Composite – Downstream 0.07 0.11 2 of 4

2Composite - Upstream < 0.05 < 0.05 0 of 4

Composite – Downstream < 0.05 < 0.05 0 of 4

Vegetated FT1 1

Grab – Before < 0.05 < 0.05 0 of 6

Grab – After 0.14 0.28 6 of 6

Composite - Upstream 0.09 0.13 3 of 4

Composite – Downstream 0.27 0.29 4 of 4

ESLOC: 1.65 µg/L

Preliminary Deposition Results

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3,158

1,430

1,035

3,509

21139

0

500

1000

1500

2000

2500

3000

3500

4000

Field edge Vegetation edge Water

Mal

athi

on (µ

g/m

2 )

Median Malathion Deposition

Control

Vegetated

Relationship Between Deposition Canopy Cover

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Supplemental Slides

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54%

73%

94%88%

99%

0

20

40

60

80

100

UD1 UD2 FM1 FM2 FT1

Control Vegetated

Perc

ent R

educ

tion

Median Percent Reduction from Field Edge to Water

Future Steps

In-depth Data Analysis:

QA analysis

Spatial analysis

Model comparison

Statistical analysis to assess

the relationship between

deposition, weather, and

vegetation characteristics

21Transect 1 at UD2 (Control Site)

Acknowledgements

• Blueberry Producers in Whatcom• Aaron Bagwell, Whatcom Farmers Co-Op• Kyle Blackburn and Essential Flight Ops, LLC• Tony Hawkes, Scott Hecht, Cathy Laetz, and Thomas Hooper, David

Baldwin, NMFS Pesticide BiOp team• Washington Blueberry and Red Raspberry Commissions• Steve Thun and Rick Jordan, Pacific Agricultural Labs• EFED staff - EPA Office of Pesticide Programs• Bernalyn McGaughey and staff, Compliance Services International• Spray Drift Issue Management Team members, Crop Life America• Heather Hansen, Washington Friends of Farms and Forests• John Hanzas, Stone Environmental• Paul Whatling, Cheminova• Harold W. Thistle, USDA Forest Service• Tim Bargar, U.S. Geological Survey• Vince Hebert, Washington State University 22

Questions?

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