Drift and Runoff Reduction Measures and Associated Points

Choose and implement mitigation options from the table below that achieve an equal or greater number of points for drift and/or runoff per the instructions in the Bulletin. Mitigation options can be added together to achieve the required number of drift and/or runoff points.

Drift Measures	Estimated % reduction loading	Points	Runoff/drainage Measures	Estimated % reduction loading	Points
No Spray Drift Buffers^{1, 2, 3}: Ground: 10 meters 20 meters 50 meters Air blast: 10 meters 20 meters 50 meters Aerial Medium or coarser droplets (ASABE S641): 20 meters 50 meters 75 meters 100 meters Finer droplets (< Medium ASABE S641): 20 meters 50 meters 75 meters 100 meters	90 95 98	70 75 80	Vegetated filter strip^{5, 9}: 5 meters 10 meters 20 meters Inter row	40 65 80	20 45 60
	80 95 99	60 75 80		50	30
	70 87 91 94	50 65 70 75	Vegetated ditches⁵	50	30
	42 66 75 80	20 45 55 60	Vegetated ditches⁵	50	30
Spray Drift Reduction Technology⁴	Varies	Varies	Runoff Reduction Technology⁴	Varies	Varies
Granular treatment, Drip Chemigation	99	80	Water control structures⁵: Edge of field In-field	40 50	20 30
Spot Applications <0.1 A⁶	99	80	Spot Applications <0.1A⁶	99	80
Riparian Hedgerow⁷	30	10	No-till or reduced tillage⁵	50	30
Riparian Hedgerow⁷	30	10	Retention pond^5,10	75	55
Participation in recognized stewardship program⁴	Varies	Varies	Participation in recognized stewardship program⁴	Varies	Varies
Functional riparian system alongside water ways, > 10 meters wide⁸	99	80	Functional riparian system alongside water ways, > 10 meters wide⁸	99	80
¹AgDrift Tier 1 Ground Boom – point deposition estimates compared to field edge (1 m buffer): low boom, very fine to fine distribution, 50th percentile distribution. ²AgDrift Tier 1 Orchard Airblast - point deposition estimates for sparse orchard compared to field edge (1m buffer). ³AgDrift Tier 1 Aerial – point deposition estimates compared to field edge (1 meter buffer)- Medium assumed VDM = 254 µm, Finer droplets assumed VDM = 137 µm. ⁴Requires NMFS review for efficacy, e.g. recent proposal for consideration of sprinkler chemigation needs NMFS review of supporting materials. ⁵Alix et al. 2017 ⁶Spot applications are applications to small distinct areas, typically using hand-held wand and backpack sprayer. Estimated reductions assumed a median field size of 0.278 km2 (Yan and Roy 2016). ⁷Washington State Department of Agriculture riparian vegetation pilot study ( Hancock et al. 2019); 27-36% reduction in spray drift observed. ⁸informed by USDA National Resource Conservation Service (NRCS) Conservation Buffers (NRCS 2000) and USDA NRCS practice standards for riparian forest buffer and riparian herbaceous cover (Ac. 390 and 391, available at: Conservation Practice Standards) ⁹ Consider Natural Resource Conservation Service, “Conservation Practice Standard: Filter Strip Code 393” US Department of Agriculture, 2016 (Conservation Practice Standard: Filter Strip Code 393 pdf) ¹⁰ Retention pond or other closed system capable of retaining runoff from treated area, such as those that may be employed for culturing cranberries or rice.