R18-2-410. Visibility Protection 

A. For any new major source or major modification subject to the provisions of this Chapter, no 

permit or permit revision under this Article shall be issued to a person proposing to construct or 

modify the source unless the applicant has provided: 

1. An analysis of the anticipated impacts of the proposed source on visibility in any Class I areas 

which may be affected by the emissions from that source; and 

2. Results of monitoring of visibility in any area near the proposed source for such purposes and 

by such means as the Director determines is necessary and appropriate. 

B. A determination of an adverse impact on visibility shall be made based on consideration of all 

of the following factors: 

1. The times of visitor use of the area; 

2. The frequency and timing of natural conditions in the area that reduce visibility; 

3. All of the following visibility impairment characteristics: 

a. Geographic extent, 

b. Intensity, 

c. Duration, 

d. Frequency, 

e. Time of day; 

4. The correlation between the characteristics listed in subsection (B)(3) and the factors 

described in subsections (B)(1) and (2). 

C. The Director shall not issue a permit or permit revision pursuant to this Article or Article 3 of 

this Chapter for any new major source or major modification subject to this Chapter unless the 

following requirements have been met: 

1. The Director shall notify the individuals identified in subsection (C)(2) within 30 days of 

receipt of any advance notification of any such permit or permit revision under this Article. 

2. Within 30 days of receipt of an application for a permit or permit revision under this Article 

for a source whose emissions may affect a Class I area, the Director shall provide written 

notification of the application to the Federal Land Manager and the federal official charged with 

direct responsibility for management of any lands within any such area. The notice shall: 

a. Include a copy of all information relevant to the permit or permit revision under this Article, 

b. Include an analysis of the anticipated impacts of the proposed source on visibility in any area 

which may be affected by emissions from the source, and 

c. Provide for no less than a 30-day period within which written comments may be submitted. 

3. The Director shall consider any analysis provided by the Federal Land Manager that is 

received within the comment period provided in subsection (C)(2). 

a. Where the Director finds that the analysis provided by the Federal Land Manager does not 

demonstrate to the satisfaction of the Director that an adverse impact on visibility will result in 

the area, the Director shall, within the public notice required under R18-2-330, either explain the 

decision or specify where the explanation can be obtained. 

b. When the Director finds that the analysis provided by the Federal Land Manager 

demonstrates to the satisfaction of the Director that an adverse impact on visibility will 

result in the area, the Director shall not issue a permit or permit revision under this Article 

for the proposed major new source or major modification.
4. When the proposed permit decision is made, pursuant to R18-2-304(J), and available for 

public review, the Director shall provide the individuals identified in subsection (C)(2) with a 

copy of the proposed permit decision and shall make available to them any materials used in 

making that determination. 

Historical Note 

Adopted effective May 14, 1979 (Supp. 79-1). Former Section R9-3-410 renumbered 

without change as Section R18-2-410 (Supp. 87-3). Section R18-2-410 renumbered to R18-

2-610, new Section R18-2-410 adopted effective November 15, 1993 (Supp. 93-4).

Historical Note

Former Section R18-2-610 renumbered to R18-2-612; new Section R18-2-610 adopted by 

final rulemaking at 6 A.A.R. 2009, effective May 12, 2000 (Supp. 00-2). Amended by 

exempt rulemaking at 13 A.A.R. 4326, effective November 14, 2007 (Supp. 07-4). 

Amended by exempt rulemaking at 18 A.A.R. 137, effective December 29, 2011 (Supp. 

11-4). Subsection (A) corrected at the request of the Department, Office File No. M12-

133, filed April 5, 2012 (Supp. 11-4).

R18-2-612. Definitions for R18-2-613

1. “Access restriction” means restricting or eliminating public access to noncropland with signs 

or physical obstruction.

2. “Aggregate cover” means gravel, concrete, recycled road base, caliche, or other similar 

material applied to noncropland.

3. “Artificial wind barrier” means a physical barrier to the wind.

4. “Bed row spacing” means increasing or decreasing the size of a planting bed area to reduce 

the number of passes and soil disturbance by increasing plant density.

5. “Best management practice” means a technique verified by scientific research, that on a 

case-by-case basis is practical, economically feasible, and effective in reducing PM10 

emissions from a regulated agricultural activity.

6. “Chemical irrigation” means applying a fertilizer, pesticide, or other agricultural chemical 

to cropland through an irrigation system.

7. “Combining tractor operations” means performing two or more tillage, cultivation, planting, 

or harvesting operations with a single tractor or harvester pass.

8. “Commercial farm” means 10 or more contiguous acres of land used for agricultural 

purposes within the boundary of the Yuma PM10 nonattainment area.

9. “Commercial farmer” means an individual, entity, or joint operation in general control of a 

commercial farm.

10. “Conservation irrigation” means the use of drips, sprinklers, or underground lines to 

conserve water, and to reduce the weed population, the need for tillage, and soil 

compaction.

11. “Conservation tillage” means types of tillage that reduce the number of passes and the 

amount of soil disturbance.

12. “Cover crop” means plants or a green manure crop grown for seasonal soil protection or 

soil improvement.
13. “Critical area planting” means using trees, shrubs, vines, grasses, or other vegetative cover 

on noncropland.

14. “Cropland” means land on a commercial farm that:

a. Is within the time-frame of final harvest to plant emergence;

b. Has been tilled in a prior year and is suitable for crop production, but is currently fallow; 

or

c. Is a turn-row.

15. “Cross-wind ridges” means soil ridges formed by a tillage operation.

16. “Cross-wind strip-cropping” means planting strips of alternating crops within the same 

field.

17. “Cross-wind vegetative strips” means herbaceous cover established in one or more strips 

within the same field.

18. “Equipment modification” means modifying agricultural equipment to prevent or reduce 

particulate matter generation from cropland.

19. “Limited activity during a high-wind event” means performing no tillage or soil preparation 

activity when the measured wind speed at six feet in height is more than 25 mph at the 

commercial farm site.

20. “Manure application” means applying animal waste or biosolids to a soil surface.

21. “Mulching” means applying plant residue or other material that is not produced onsite to a 

soil surface.

22. “Multi-year crop” means a crop, pasture, or orchard that is grown, or will be grown, on a 

continuous basis for more than one year.

23. “Night farming” means performing regulated agricultural activities at night when moisture 

levels are higher and winds are lighter.

24. “Noncropland” means any commercial farmland that:

a. Is no longer used for agricultural production;

b. Is no longer suitable for production of crops;

c. Is subject to a restrictive easement or contract that prohibits use for the production of 

crops; or

d. Includes a private farm road, ditch, ditch bank, equipment yard, storage yard, or well 

head.

25. “Permanent cover” means a perennial vegetative cover on cropland.

26. “Planting based on soil moisture” means applying water to soil before performing planting 

operations.

27. “Precision farming” means use of satellite navigation to calculate position in the field, to 

reduce overlap during field operations, and allow operations to occur during nighttime and 

inclement weather, thus generating less PM10.

28. “Reduce vehicle speed” means operating farm vehicles or farm equipment on unpaved 

farm roads at speeds not to exceed 20 mph.

29. “Reduced harvest activity” means reducing the number of harvest passes using a 

mechanized method to cut and remove crops from a field.

30. “Regulated agricultural activity” means a commercial farming practice that may produce 

PM10 within the Yuma PM10 nonattainment area.

31. “Residue management” means managing the amount and distribution of crop and other 

plant residues on a soil surface.
32. “Sequential cropping” means growing crops in a sequence that minimizes the amount of 

time bare soil is exposed on a field.

33. “Surface roughening” means manipulating a soil surface to produce or maintain clods.

34. “Synthetic particulate suppressant” means a manufactured product such as lignosulfate, 

calcium chloride, magnesium chloride, and polyacrylamide, an emulsion of a petroleum 

product, and an enzyme product that is used to control particulate matter.

35. “Tillage and harvest” means any mechanical practice that physically disturbs cropland or 

crops on a commercial farm.

36. “Tillage based on soil moisture” means applying water to soil before or during tillage, or 

delaying tillage to coincide with precipitation.

37. “Timing of a tillage operation” means performing tillage operations at a time that will 

minimize the soil’s susceptibility to generate PM10.

38. “Transgenic crops” means the use of genetically modified crops such as “herbicide ready” 

crops, which reduces the need for tillage or cultivation operations, and reduces soil 

disturbance.

39. “Track-out control system” means a device to remove mud or soil from a vehicle before 

the vehicle enters a paved public road.

40. “Tree, shrub, or windbreak planting” means providing a woody vegetative barrier to the 

wind.

41. “Watering” means applying water to noncropland.

42. “Yuma PM10 nonattainment area” means the Yuma PM10 planning area as defined in 40 

CFR 81.303, which is incorporated by reference in R18-2-210.

Historical Note

New Section R18-2-612 renumbered from R18-2-610 at 6 A.A.R. 2009, effective May 12, 

2000 (Supp. 00-2). Former Section R18-2-612 renumbered to R18-2-614; new Section 

R18-2-612 made by final rulemaking at 11 A.A.R. 2210, effective July 18, 2005 (Supp. 

05-2).