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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