Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L E N V I R O N 

A P P E N D I X A

Technical Memorandum: Latest Revisions of the 

Windblown Dust Study 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L A-1 E N V I R O N 

Appendix A 

Technical Memorandum: Latest Revisions of the 

Windblown Dust Study

Appendix A presents the September 20, 2005 Technical Memorandum from ENVIRON detailing 

the final revised results of ENVIRON’s Imperial Valley Fugitive Dust Emissions Inventory. First, a 

brief background of the original study is presented, followed by a discussion of the issues and 

concerns associated with the results presented in the original Final Report (ENVIRON, 2004). 

Finally, the revised analyses and windblown dust emission results are presented. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L A-2 E N V I R O N 
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D R A F T F I N A L A-3 E N V I R O N 
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D R A F T F I N A L A-4 E N V I R O N 
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D R A F T F I N A L A-5 E N V I R O N 
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D R A F T F I N A L A-6 E N V I R O N 
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D R A F T F I N A L A-7 E N V I R O N 
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D R A F T F I N A L A-8 E N V I R O N 
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D R A F T F I N A L A-9 E N V I R O N 
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D R A F T F I N A L A-10 E N V I R O N 
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D R A F T F I N A L A-11 E N V I R O N 
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D R A F T F I N A L A-12 E N V I R O N 
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D R A F T F I N A L A-13 E N V I R O N 
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D R A F T F I N A L A-14 E N V I R O N 
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D R A F T F I N A L A-15 E N V I R O N 
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D R A F T F I N A L A-16 E N V I R O N 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L E N V I R O N 

A P P E N D I X B 

Entrained and Windblown Emission From Unpaved Roads 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L B-1 E N V I R O N 

Appendix B 

Entrained And Windblown Emissions From Unpaved Roads

Appendix B presents the assumptions and calculations to determine the entrained and windblown 

dust emissions from unpaved roads in Imperial County, including city and County roads, canal 

roads that line the irrigation canals and drainage ditches, farm roads and roads on federal lands, 

such as BLM and USFS roads. 
Technical Memorandum: Regulation VIII BACM Analysis 

D R A F T F I N A L B-2 

Summary of PM10 emissions - tons/dayEntrained

Current CARB 2003 Notes

city/county 26.64 16.84 higher ADT on high ADT county roads (if 10 ADT per CARB, ems = 13.62, ems cocanal 31.56 12.78 1993 SIP: 3,128 mi canals; 1,682 mi canal roads / Current: 3156 mi canal; 6,312 mfarm 1.41 1.41 Using latest but unpublished ARB methodBLM/USFS 1.39 2.28 Using 1993 road mileage; ARB may have grown road milesTotal 61.00 33.31Windblown

Current CARB 2003 Notes

city/county 7.82 5.9 Consistentcanal 16.76 73.50 Using ARB emission factor significantly reduces estimated emissions compared to farm 6.01 -- Not in ARB inventoryBLM/USFS 0.37 -- Not in ARB inventoryTotal 30.95 79.40NOTES:All entrained unpaved road dust estimates using new ARB emission factor of 2 lbs PM10/VMT (previous 2.27 or higher)Canal road entrained dust assumes 5 ADT for all roads on an average day (as in 1993 SIP)..
Technical Memorandum: Regulation VIII BACM Analysis 

D R A F T F I N A L B-3 

Unpaved Road Emissions - From Vehicle TravelAnnual Emissions =VMT*EF= road miles* passes/day*day/year* lbPM10/VMT

EF 2 lbPM10/VMT

365 day/year

REF (Emission Factor): CARB methodology, Section 7.10: Unpaved Road Dust (Non-Farm Roads); August 1997, p. 1

Unpaved Road Characteristics

Length of roads 

with varying 

vehicle miles 

traveled (miles)

passes/day Emissions (tons/day)

total county 1,354 -- --

< 50 vehicles/day 1,137 10 11.37

>50 vehicles/day 217 70 15.19

city roads 7.5 10 0.075

city and county total 1,361.5 -- --

REF: Imperial County Public Works and Imperial County CitiesImperial County Public Works water and blade about 16 mi/day of unpaved roadsEstimated Emissions

tons/day tons/year

2004 PM10 emissions 

assuming 10 passes/day 

for all roads

13.62 4,969.48

2004 PM10 emissions 

adjusted for vehicle travel 26.64 9,721.78

REF: CARB methodology*current emissions estimate (2002) for vehicle travel on CARB website is 6,147 tons/year or 16.84 tons/day

Variables
Technical Memorandum: Regulation VIII BACM Analysis 

D R A F T F I N A L B-4 

Unpaved Road Emissions - From Windblown DustAnnual Emissions (tons PM10/yr) = a*I*C*K*L*V*(PM10 ratio)*(acres of road)Variables

a 0.038 dimensionless

I 86 tons/acre/year

C 1.274

K 1.0

L 0.32

V 1

PM10 ratio 0.5

365 day/year

0.666 tons PM10/acre/yr

Unpaved Road Characteristics

Length of roads 

with varying 

vehicle miles 

traveled (miles)

Width of roads 

(ft) Acreage of roads Emissions (tons/day)

total county 1,354 26 4,267.2 --

< 50 vehicles/day 1,137 26 3,583.3 6.54

>50 vehicles/day 217 26 683.9 1.25

city roads 7.5 20 18.2 0.03

city and county total 1,361.5 -- 4,285.3 --

REF (Road lengths): Imperial County Public Works and Imperial County Cities

REF (Road widths): State Implementation Plan for Imperial County, 1993, Table C-2: Unpaved Roads Data

Imperial County Public Works water and blade about 16 mi/day of unpaved roadsEstimated Emissions

tons/day tons/year

2004 PM10 emissions 7.82 2,854.67

REF: CARB methodology

*current emissions estimate (2002) for windblown dust on CARB website is 2,153.5 tons/year or 5.9 tons/day

Ratio of PM10 to TSP

Estimated emission factor

REF: CARB methodology, Section 7.13: Windblown Dust - Unpaved Roads; August 1997, p. 2 (definitions) & Table 2 (values)

dimensionless

Surface Roughness FactorUnsheltered Field Width FactorVegetative Cover FactorEstimated quantity of the total eroded material actually suspended to airSoil ErodibilityClimatic Factor
Technical Memorandum: Regulation VIII BACM Analysis 

D R A F T F I N A L B-5 

Unpaved Canal Road Emissions - From Vehicle TravelAnnual Emissions =VMT*EF= road miles* passes/day*day/year* lbPM10/VMT

EF 2 lbPM10/VMT

365 day/year

REF (Emission Factor): CARB methodology, Section 7.10: Unpaved Road Dust (Non-Farm Roads); August 1997, p. 1

Mileage from Imperial Irrigation District Website

Lateral canals 1,438 mi

Main canals 230 mi

All-American Canal 82 mi

Drainage ditches 1,406 mi

Total 3,156 mi

Total assuming roads 

on both sides of the 

canals

6,312 mi

REF: Imperial Irrigation DistrictAssume that each canal road has the same passes per dayEstimated Emissions

tons/day tons/year

0.133 0.84 307

1 6.31 2,3042 12.62 4,6085 31.56 11,519

10 63.12 23,039

REF: CARB methodology*current emissions estimate (2002) on CARB website is 4,664.7 tons/year or 12.78 tons/dayVariables

2004 county & city PM10 emissions passes/day
Technical Memorandum: Regulation VIII BACM Analysis 

D R A F T F I N A L B-6 

Unpaved Canal Road Emissions - From Windblown DustAnnual Emissions (tons PM10/yr) = a*I*C*K*L*V*(PM10 ratio)*(acres of road)Variables

a 0.038 dimensionless

I 86 tons/acre/year

C 1.274

K 1.0

L 0.32

V 1

PM10 ratio 0.5

365 day/year

0.666 tons PM10/acre/yr

REF: CARB methodology, Section 7.13: Windblown Dust - Unpaved Roads; August 1997, p. 2 (definitions) & Table 2 (values)

Mileage from Imperial Irrigation District Website

Length (mi) Width (ft) Acreage

Lateral canals 1,438 12 2,092

Main canals 230 12 335

All-American Canal 82 12 119

Drainage ditches 1,406 12 2,045

Total 3,156 12 4,591

Total assuming roads 

on both sides of the 

canals

6,312 12 9,181

REF (Canal lengths): Imperial Irrigation DistrictREF (Road widths): State Implementation Plan for Imperial County, 1993, Table C-2: Unpaved Roads Data

Estimated emissions

tons/day tons/yr

Total assuming roads 

on both sides of the 

canals

16.76 6,116

Unsheltered Field Width FactorEstimated quantity of the total eroded material actually suspended to air

Estimated emission factor

Soil ErodibilityClimatic FactorSurface Roughness Factor

dimensionless

Vegetative Cover FactorRatio of PM10 to TSP
Technical Memorandum: Regulation VIII BACM Analysis 

D R A F T F I N A L B-7 

Unpaved Farm Roads - From Vehicle TravelAnnual Emissions= VMT/acre*acre*(lbPM10/VMT/year)Variables

EF 2 lbPM10/VMT/year

4.375 VMT/acre

365 days/year

REF: CARB methodology, Section 7.11: Unpaved Road Dust - Farm Roads; August 1997, p. 1 (EF) & Table 1 (VMT/acre)

Farm Acreage for Imperial County

Field Crops 376,292Veggie and Melon 94,602Fruit and Nut 6,975Seed and Nursery 64,252

Total 542,121

REF: http://imperialcounty.net/ag/Crop%20&%20Livestock%20Reports/Crop%20&%20Livestock%20Report%202003.pdf

Estimated Emissions

tons/day tons/year

2003 estimate for 

unpaved farm road 

emissions

6.50 2,372

*2003 Emissions inventory on CARB website = 514.65 ton/year or 1.41 tons/day

1.41 tons/day

As agreed by CARB (Patrick Gaffney), the emissions from unpaved farm roads will be reported as 1.41 tons/day, until the new methodology for this source can be applied to the latest per crop acreage.NOTE: On 9/30/05, CARB indicated that this methodology has been replaced by a newer unpublished methodology. See note at bottom of page.

2003 Imperial County 

Agricultural Crop and 

Livestock Report

acres
Technical Memorandum: Regulation VIII BACM Analysis 

D R A F T F I N A L B-8 

Unpaved Farm Roads - From Windblown DustAnnual Emissions (tons PM10/yr) = a*I*C*K*L*V*PM10*(acres of road)Variables

a 0.038 dimensionless

I 86 tons/acre/year

C 1.274

K 1.0

L 0.32

V 1

PM10 ratio 0.5

365 day/year

0.666 tons PM10/acre/yr

REF: CARB methodology, Section 7.13: Windblown Dust - Unpaved Roads; August 1997, p. 2 (definitions) & Table 2 (values

Estimated Area of Farm Roads

2,263 mi

12 ft

3,292 acre

REF: State Implementation Plan for Imperial County, 1993, Table C-2: Unpaved Roads Data

Estimated Emissions

tons/day tons/yr

2004 PM10 emissions 6.01 2,192.72

dimensionless

Area of Unpaved RoadsEstimated quantity of the total eroded material Soil ErodibilityClimatic FactorUnsheltered Field Width FactorWidth of Farm roads Total Area of Unpaved Roads

Estimated emission factor

Surface Roughness FactorVegetative Cover FactorRatio of PM10 to TSPTotal miles of farm roads
Technical Memorandum: Regulation VIII BACM Analysis 

D R A F T F I N A L B-9 

Unpaved Roads in BLM and US Parks and Forests - From Vehicle TravelAnnual Emissions =VMT*EF= road miles* passes/day*day/year* lbPM10/VMTVariables

EF 2 lbPM10/VMT

365 day/year

REF (Emission Factor): CARB methodology, Section 7.10: Unpaved Roads (Non-Farm Roads); August 1997, p. 1

Miles of Road

BLM 114 mi

US Parks and Forests 26 mi

Total 139 mi

REF: CARB methodology, Section 7.10: Unpaved Roads (Non-Farm Roads); August 1997, Table 1

Estimated Emissions for BLM

tons/day tons/year

10 1.14 414.28

REF: CARB methodology*current estimation by CARB (2003) for BLM roads is 657 ton/year or 1.8 tons/dayEstimated Emissions for US Parks and Forests

tons/day tons/year

10 0.26 94.54

REF: CARB methodology*current estimation by CARB (2003) for US Parks and Forest roads is 175.2 ton/year or 0.48 tons/dayEstimated Emissions for BLM, US Parks and Forests

tons/day tons/year

10 1.39 508.81

REF: CARB methodology

passes/day 2004 PM10 emissions passes/day 2004 PM10 emissions passes/day 2004 PM10 emissions 
Technical Memorandum: Regulation VIII BACM Analysis 

D R A F T F I N A L B-10 

Unpaved Roads in BLM and US Parks and Forests - From Windblown DustAnnual Emissions (tons PM10/yr) = a*I*C*K*L*V*PM10*(acres of road)Variables

a 0.038 dimensionless

I 86 tons/acre/year

C 1.274

K 1.0

L 0.32

V 1

PM10 ratio 0.5

365 day/year

0.666 tons PM10/acre/yr

REF: CARB methodology, Section 7.13: Windblown Dust - Unpaved Roads; August 1997, p. 2 (definitions) & Table 2 (values

Acres of Road

Miles of roads Width (ft) Acreage

BLM 114 12 165.09

US Parks and Forests 26 12 37.67

Total 139 12 202.76

REF (Road miles): CARB methodology, Section 7.10: Unpaved Roads (Non-Farm Roads); August 1997, Table 1

REF (Road widths): State Implementation Plan for Imperial County, 1993, Table C-2: Unpaved Roads Data

Estimated Emissions

tons/day tons/yr

BLM 0.30 109.98

US Parks and Forests 0.07 25.10

Total 0.37 135.07

Climatic FactorSurface Roughness Factor

Estimated emission factor

Unsheltered Field Width Factor dimensionlessVegetative Cover FactorRatio of PM10 to TSPEstimated quantity of the total eroded material actually suspended to airSoil Erodibility
Technical Memorandum: Regulation VIII BACM Analysis 

D R A F T F I N A L B-11 

Determination of PR 805 applicability

road type miles windblown emissions % windblown emissions entrained emissions % entrained emissions

county < 50 vehicles/day 1,137 6.54 26.2 11.37 19.1county >50 vehicles/day 217 1.25 5.0 15.19 25.5city roads 7.5 0.03 0.1 0.075 0.1canal roads 6,312 16.76 67.2 31.56 53.0federal 139 0.37 1.5 1.39 2.3TOTAL 7,813 24.95 100.00 59.59 100.00Percent ApplicableApplicable Roads are county >50 & canal >20 ADTPercent of canal roads with >20 ADTcanal >20 ADT 0.5%A = (county >50 + 0.005*canal)/Total% Applicable Road Emissions

A

Windblown 5.3%Entrained 26%
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L E N V I R O N 

A P P E N D I X C 

Detailed Comparative Analysis for Significant Sources
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-1 E N V I R O N 

Appendix C 

Detailed Comparative Analysis for Significant Sources

Appendix C presents a detailed comparative analysis for sources above the DM level: unpaved 

roads and areas, disturbed areas, and agricultural sources. It begins with general requirements of 

the proposed Regulation VIII amendments related to visible dust emissions and stabilized surfaces 

for these sources (e.g., PAR 800, PR 804, PR 805, and PR 806). Next, the comparative analysis for 

each specific significant source is presented. The analysis includes a discussion of the stringency of 

the applicability thresholds and requirements for each source, a comparison of that stringency to the 

most stringent thresholds and/or requirements adopted in other serious PM10 non-attainment areas, 

and if the threshold and/or requirement is not as stringent as the most stringent, a justification is 

presented based on Imperial County conditions. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-2 E N V I R O N 

FUGITIVE DUST CATEGORY: GENERAL 

SUBCATEGORY: VISIBLE DUST EMISSIONS 

Proposed Imperial Requirements:

• Limit visible emissions to not more than 20% opacity 

o All non-exempt sources (Ref: PAR 800) 

o Construction / demolition (de minimis source) (Ref : PR 801, Section E.1) 

o Bulk materials (de minimis source) (Ref : PR 802, Section E.1) 

o Open areas (significant source) (Ref : PR 804, Section E.1) 

o Unpaved roads and traffic areas (significant source) (Ref : PR 805, Section E.1) 

• Test methods in Appendix A and B shall be used to determine compliance with the Reg VIII rules 

(Ref: PAR800, Section G) 

SJV Requirements:

• Limit visible emissions to not more than 20% opacity (Ref: R8021,Sect. 5.0; R8031, Sect 5.0; R8041, 

Sect. 5.7.2; R8051, Sect. 5.0; R8061, Sect. 5.2; R8071, Sect. 5.1; and 8081, Sect. 5.0) 

• Opacity based on six vehicles, two readings per vehicle for unpaved surfaces and minimum 12 

observations, spaced 15 seconds apart, for other sources. (Ref: R8011, Appendix A, Sections 1 and 2) 

South Coast Requirements:

• No visible emissions across property line. (Ref: R403(d)(1)) 

Maricopa County Requirements:

• Limit visible emissions to not more than 20% opacity (Ref R310, Sect. 301) 

• Opacity for dust generating activities based on minimum 12 observations, spaced 15 seconds apart 

(Ref: R310, Section 501.1(a)) 

• Opacity for unpaved parking lots and unpaved haul/access roads based on six vehicles, two readings 

per vehicle (Ref: R310, Section 501.1 (a) and (b)) 

Clark County Requirements

• Limit visible emissions to not more than 20% opacity (Ref: AQR Section 91.2.1.4; AQR Section 

92.2.1.3; AQR Section 93.2.1.5; AQR Section 94.5.3) 

• Opacity based on six vehicles, two readings per vehicle for unpaved surfaces And minimum 12 

observations, spaced 15 seconds apart, for other sources. (Ref AQR Section 91.4.1.1 and AQR 

Section 94 AQR Section 94.5.3) 

• Opacity based on six vehicles, two readings per vehicle for unpaved surfaces And minimum 12 

observations, spaced 15 seconds apart, for other sources. (Ref AQR Section 91.4.1.1 and AQR 

Section 94.9.1) 

• Limit construction visible emissions to not more than 100 yards (Ref: AQR Section 94.5.2(a)) 

• Proposed: Limit VDE to 100 feet; and not cross property line 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-3 E N V I R O N 

Discussion:

Imperial County is proposing the same opacity limits and test methods used in other areas, except South 

Coast, which appears less stringent than other areas. There are likely to be situations where opacity may 

be more stringent (especially in large construction sites where heavy dust plumes may no longer be 

visible by the time they reach the property line) and other circumstances where opacity may be less 

stringent (especially on smaller dust-producing sites, and with intermittent plumes.) For time-averaged 

situations (i.e., non-road/vehicle related dust emissions), to assure that most stringent conditions are in 

place, a combination of the two approaches is warranted. Clark County requires both opacity limits and a 

100-yard visible emission distance limit for construction activities. Construction emissions in Imperial 

County are below the DM level, and thus justification as “most stringent” is not required. 

Imperial County is proposing the same opacity limits and test methods used by San Joaquin Valley that 

have been accepted by EPA as “most stringent” in its May 26, 2004 approval of the San Joaquin Valley 

PM10 SIP1

. 

 

1

 Federal Register Vol. 69, No. 102; p.30035; May 26, 2004. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-4 E N V I R O N 

FUGITIVE DUST CATEGORY: GENERAL 

SUBCATEGORY: DEFINITION OF STABILIZED SURFACE 

Proposed Imperial County Requirements:

• Any disturbed surface are or open bulk storage pile that is resistant to wind blown fugitive dust 

emissions. A surface is considered to be stabilized if it meets at least one of the following conditions 

specified in below or as determined by test methods outlined in Appendix B. 

1. Visible crust; or 

2. Threshold frictional velocity of 100 cm/sec or greater; or 

3. Flat vegetative cover of at least 50% that is attached or rooted vegetation; or unattached 

vegetative debris lying on the surface with a predominant horizontal orientation (not subject to 

wind movement); or 

4. Standing vegetative cover over 30% that is attached or rooted 

5. A standing vegetative cover of at least 10% that is attached or rooted with a predominate vertical 

orientation where the TFV is at least 43 centimeters per second when corrected for non-erodible 

elements 

6. A surface greater than or equal to 10% of non-erodible elements such as rocks, stones, or hardpacked clumps of soil 

(Ref: 800 C.28) 

Test methods:

• Materials used for chemical/organic stabilization of soils, including petroleum resins, asphaltic 

emulsions, acrylics, and adhesives shall not violate State Water Quality Control Board standards for 

use as a soil stabilizer. Any material prohibited for use as dust suppressant by EPA, the ARB, or 

other applicable law, rule, or regulation is also prohibited under Regulation VIII. (Ref: PR801, 

Section F) 

• Use of hygroscopic materials may be prohibited by the ICAPCD in areas lacking sufficient 

atmospheric moisture of soil for such materials to effectively reduce fugitive dust emissions. The 

atmospheric moisture of soil is considered to be sufficient if it meets the application specifications of 

the hygroscopic product manufacturer. Use of such materials may be approved in conjunction with 

sufficient wetting of the controlled area. (Ref: PR801, Section F) 

• Any use of dust suppressants or gravel pads, and paving materials such as asphalt or concrete for 

paving, shall comply with other applicable District Rules. (Ref: PR801, Section F) 

• Test methods in Appendix A and B shall be used to determine compliance with the Regulation VIII 

rules (Ref PAR800, Section G) 

SJV Requirements:

• Any disturbed surface that is resistant to wind blown fugitive dust and meets at least one of the 

following conditions: 

1. A visible crust 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-5 E N V I R O N 

2. A threshold friction velocity of 100 cm/sec or greater 

3. A vegetative cover of at least 50% that is attached or rooted 

4. Unattached horizontal vegetative cover of at least 50% and wind-movement resistant 

5. Vertical, rooted vegetation with at least 30% cover, or 10% cover where the soil threshold friction 

velocity is at least 43 cm/sec 

6. A surface that is at least 10% covered with non-erodible materials (Ref: R8011, Section 3.58) 

South Coast Requirements:

• Stabilized surface means any previously disturbed surface area or open storage pile which, through 

the application of dust suppressants, shows visual or other evidence of surface crusting and is 

resistant to wind driven 

• Fugitive dust and is demonstrated to be stabilized; (Ref: R403, (C)(28)) 

Maricopa County Requirements:

• Must meet at least one of the following standards: 

1. Maintain a visible crust 

2. Maintain a threshold friction velocity of 100 cm/sec or greater 

3. Maintain standing (rooted, vertical) vegetative cover of at least 30%, or 10% cover where the soil 

threshold friction velocity is at least 43 cm/sec 

4. Maintain flat (rooted or horizontal debris not subject to wind movement) of at least 50% 

5. Maintain a cover of at least 10% with non-erodible materials 

6. Comply with specially-approved alternative method 

(Ref: R310, Section 302.3) 

Clark County Requirements:

• Stabilization standards: 

1. Establish visible crust 

2. Establish cover of at least 20% with non-erodible materials 

3. Establish soil threshold friction velocity of at least 100 cm/sec 

4. Comply with specially-approved alternative method 

Discussion:

Imperial County is proposing the same stabilized surface definition and requirements as used in the San 

Joaquin Valley, which are comparable to the requirements used in all other areas, except South Coast. 

The exception is that Clark County has established a more stringent requirement if non-erodible materials 

are used to establish a stabilized surface, namely, that a more restrictive 20% minimum covering 

(compared to 10% in San Joaquin Valley, Maricopa County and proposed IC Regulation VIII) is required. 

However, inclusion of a 20% minimum non-erodible material coverage as a control option in Clark 

County does not mean its inclusion is necessary for Regulation VIII to be demonstrated as BACM for this 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-6 E N V I R O N 

category. Clark County’s limit was based on local observations at areas where the soil was significantly 

pulverized as the result of significant amounts of traffic.2

 Imperial County does not have similar areas 

experiencing such high levels of growth and commuters “trailblazing” unpaved roads across open areas. 

Thus, this limit was based on specific Clark County conditions and should not be applied to Imperial 

County. 

Taken together, the applicable limits and requirements in the definition of a stabilized surface provide 

equivalent stringency and can be considered as stringent as the most stringent limits and requirements. 

The exact same provisions in San Joaquin Valley were approved as BACM by EPA3

 in 2004 

 

2

 September 26, 2005 telephone conversation with Rodney Langston, Clark County Department of Air Quality 

Management 

3

 Federal Register Vol. 69, No. 102; p.30035; May 26, 2004. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-7 E N V I R O N 

FUGITIVE DUST CATEGORY: UNPAVED ROAD DUST 

SUBCATEGORY: LIMITS FOR APPLICABILITY 

Proposed Imperial County Requirements:

• Unpaved Haul/ Access Roads: All roads (Ref: PR805, Section E.1) 

• Unpaved Roads: 50 or more average daily vehicle trips (Ref: PR805, Section E.2) 

• New Unpaved Roads: All new unpaved roads except for those that meet the definition of a 

Temporary Unpaved Road (Ref: PR805, Section E.3) 

• Canal Roads: 20 or more ADT (Ref: PR805, Section E.4) 

SJV Requirements:

• 26 annual average vehicle daily trips or more (Ref: R8061, Section 5.2.1) 

South Coast Requirements:

• For meeting standards of rule: 

o more than 50’ wide at all points, or 

o are not within 25’ of property line, or 

o more than 20 vehicle trips per day (Ref: R403(g)(2)(B)(iii)) 

• For treating unpaved roads: 

o All roads greater than the average ADT of all unpaved roads within its jurisdiction, up to a set 

number of miles by 2006 (Ref: R1186(d)(4)) 

Maricopa County Requirements:

• 150 vehicles or more per day (Ref: R310.01, Section 304) 

Clark County Requirements:

• For new unpaved roads, there is no VDT limit (Ref AQR Section 91.2.1) 

• For existing unpaved roads (prior to June 22, 2000), the control measures apply to roads with 150 or 

more vehicles per day. 

Discussion:

Imperial County’s proposed limit is 50 or greater ADVT. The Imperial County 50 ADVT or more limit is 

more stringent than either Maricopa County of Clark County. Both Maricopa and Clark County have a 

significant number of unpaved roads with greater than 150 ADT; hence their rules target those roads. The 

provisions of the South Coast rule, tied to average levels of VDT, is generally less restrictive than in other 

jurisdictions. 

The proposed ADT limit for unpaved city and county roads in IC Regulation VIII is less stringent than 

SJV’s limit of 26 ADVT. However, the percentage of unpaved city / county roads with greater than 26 

ADT in San Joaquin Valley is 12% (90 out of 750 miles) compared to 16% of Imperial County roads with 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-8 E N V I R O N 

greater than 50 ADT (217 out of 1361.5 miles).4 Thus, proposed Regulation VIII is the most stringent. 

Proposed Regulation VIII will require the treatment of over 217 miles of unpaved city and county roads, 

compared with 90 miles of city and county roads that must be treated in San Joaquin Valley under their 

regulation 8061. (For comparison, the population in Imperial County is about 150,000 people, compared 

to over 3,200,000 in the San Joaquin Valley.) A discussion of the implementation schedule for PR 805 

for county and city unpaved roads, compared to the implementation schedule of other serious nonattainment areas, is presented in the next section, Unpaved Road Dust / Control Requirements. 

Only Imperial County has proposed a separate, lower threshold for canal roads, and 20 ADT is below any 

other unpaved road threshold. Proposed Regulation VIII is the most stringent. 

 

4

 EPA’s Technical Support Document for the San Joaquin Valley, California 2003 PM-10 Plan and 2003 PM-10 

Plan Amendments., p. 31. January 27, 2004. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-9 E N V I R O N 

FUGITIVE DUST CATEGORY: UNPAVED ROAD DUST 

SUBCATEGORY: CONTROL REQUIREMENTS 

Proposed Imperial County Requirements:

• For road segments with 50 or more average daily vehicle trips (ADVT), limit VDE to 20% opacity 

and comply with the requirements of a stabilized unpaved road surface by application and/or 

maintenance of at least one of the following control requirements (Ref: PR805, Section E.2). AND 

For canal roads with 20 or more average daily vehicle trips (ADVT), limit VDE to 20% opacity and 

comply with the requirements of a stabilized unpaved road surface by application and/or maintenance 

of at least one of the following control requirements (Ref: PR805, Section E.4) 

a) Pave (Ref: PR805, Section F.1.a) 

b) Apply chemical stabilization as directed by product manufacturer to control dust on unpaved 

roads (Ref: PR805, Section F.1.b) 

c) Apply and maintain gravel, asphalt, or other material of low silt content of a depth of 3 or more 

inches (Ref: PR805, Section F.1.c) 

d) Apply water one ore more times daily (Ref: 805, section F.1.d) 

e) Permanent road closure (Ref: PR805, Section F.1.e) 

f) Restrict unauthorized vehicle access (Ref: PR805, Section F.1.f) 

g) Any other method that limits VDE to 20% opacity and meets conditions of a stabilized unpaved 

road (Ref: PR805, Section F.1.g) 

• For city and county roads, implementation of E.2 shall be done on the schedule, and according to the 

requirements of Section E.7, which requires the treatment of 10% (on average) of applicable unpaved 

city and county roads per year for the year 2006 though 2015. 

• Within an urban area, construction of any new unpaved road is prohibited unless it meets the 

definition of a “temporary unpaved road” and is stabilized in accordance with Rule 800 requirements. 

Temporary unpaved roads are for supporting temporary or periodic activity and cannot be used more 

than 6 months in any consecutive 3-year period. (Ref: PR805, Section E.3) 

SJV Requirements:

• For unpaved roads with greater than 26 annual average vehicle trips per day, limit VDE to 20% 

opacity and implement at least one of the following control measures: 

a) apply water 

b) apply uniform layer of washed gravel 

c) apply chemical/organic dust suppressant 

d) use vegetative materials 

e) pave 

f) use any other approved method to limit VDE to 20% opacity and meets the condition of a 

stabilized unpaved road (Ref: R8061, Section 5.2.1) 

• As option to above, obtain Fugitive PM10 Management Plan (Ref: ibid, Section 5.2.1) 

a) Must achieve at least 50% control efficiency (Ref: R8011, Section 7.0) 

b) Must specify location, length, and area of unpaved traffic areas (Ref: ibid, 7.5.2) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-10 E N V I R O N 

c) Description of traffic conditions (vehicle trips per unit time; types of vehicles) 

(Ref: ibid, 7.5.3) 

d) Description of control measures used and application details (Ref: ibid, 7.5.4) 

e) Description of expected resulting road surface condition (Ref: ibid, 7.5.5) 

• Within an urban area, the construction of any unpaved road is prohibited unless the road meets the 

definition of a temporary unpaved road (Ref: ibid, Section 5.2.2) 

• Cities and counties shall treat an average of 20% of applicable roads per year form 2006 through 

2010, to a cap of 5 miles per year per jurisdiction. A statement of financial hardship can be submitted 

if a jurisdiction cannot afford to meet the requirements of this section.. (Ref R8061, Section 5.2.3). 

South Coast Requirements:

• Annually treat unpaved public roads beginning in 1998 and continuing for each of 8 years thereafter 

by implementing one of the following (Ref: R1186(d)(4)): 

a) Pave at least one mile with typical roadway material (Ref: ibid, (d)(4)(A)) 

b) Apply chemical stabilizers to at least two miles to maintain stabilized surface 

(Ref: ibid, (B)) 

c) Take at least one of the following on at least three miles of road surface: 

i. Install signage at 1⁄4 mile intervals limiting speed to 15 mph 

ii. Install speed control devices every 500 feet 

iii. Maintain roadway in a manner which limits speed to 15 mph (Ref:, ibid, (C)) 

• Apply at least one BACM to unpaved roads at active operations (Ref: R403(d)(2)) 

a) Pave (Ref: R403 Handbook, BACM (F)) 

b) Use chemical stabilizers (Ref: ibid, (G)) 

c) Apply water (Ref: ibid, (H)) 

d) Reduce speed limits to 15 mph (Ref: ibid (I)) 

e) Reduce vehicular trips, target at least 60% (Ref: ibid, (J)) 

f) Apply gravel to depth of 4 inches (Ref: ibid, (K)) 

Maricopa County Requirements:

• For 150 vehicles or more per day, implement at least one of the following BACM 

(Ref: R310.01, Section 304): 

a) Pave 

b) Apply dust suppressants 

c) Uniformly apply and maintain surface gravel 

(Ref: ibid, Section 304.1) 

• For existing roads, BACM, as above, must be implemented by: 

a) June 10, 2000 for more than 250 vehicle trips 

b) June 10, 2004 for more than 150 vehicle trips 

(Ref: ibid, 304.2) 

• BACM must meet the following standards: 

a) Limit VDE to 20% opacity 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-11 E N V I R O N 

b) Do not equal or exceed 0.33 oz/ft2, or 

c) Do not exceed 6% silt content 

(Ref: ibid, 304.3) 

Clark County Requirements:

• Implement one control measure on 1/3 of unpaved roads with 150+ VDT by June 1, 2001 (Ref: AQR 

Section 91.2.1.1(a)) 

• Implement one control measure on 2/3 of unpaved roads with 150+ VDT by June 1, 2002 (Ref: ibid, 

(b)) 

• Implement one control measure on all unpaved roads with 150+ VDT by June 1, 2003 (Ref: ibid, (c)) 

• For any unpaved road with newly found levels of 150+ VDT, implement one control measure within 

365 days (Ref: ibid, (d)) 

• For unpaved roads with less than 150 VDT, maintain stabilized surface standards within 365 days of 

determination of non-stabilized surface (Note: this is not a SIP measure, Ref: ibid, (e)) 

• No new unpaved roads are to be constructed in public thoroughfares after June 22, 2000 (Ref: AQR 

Section 91.2.1.2) 

• Applicable control measures are as follows: 

a) Pave 

b) Apply dust palliatives to meet stabilization standards 

(Ref: ibid, 91.2.1.3) 

• Stabilization standards: 

a) Limit VDE to 20% opacity 

b) Do not equal or exceed 0.33 oz/ft2

, or 

c) Do not exceed 6% silt content 

(Ref: ibid, 91.2.1.4) 

Discussion:

Proposed Regulation VIII and requirements in all serious non-attainment areas except South Coast require 

compliance with the 20% opacity standard for unpaved roads; Proposed Regulation VIII is as stringent as 

the most stringent for this requirement. In addition, all areas except South Coast specify the 

implementation of at least one control requirement to comply with the requirements of a stabilized 

surface. Clark and Maricopa County do not allow watering as a control option, but only require 

implementation on roads with greater than 150 ADT. As noted by EPA5

, the inclusion of a control option 

or requirement does not mean it is necessary for a proposed regulation to meet BACM, as long as other 

applicable limits combine provide adequate stringency. In this case, the applicability and control 

requirements combine provide adequate stringency. 

 

5

 Federal Register Vol. 69, No. 102; p.30019; May 26, 2004. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-12 E N V I R O N 

Proposed Regulation VIII prohibits the construction of new unpaved roads in urban areas. This is as 

stringent as the San Joaquin Valley and Clark County regulations. (Clark County regulations are only in 

effect in the non-attainment area, which is predominantly urban, and not in the surrounding rural and 

federal lands. Hence, the prohibition on new unpaved roads is essentially a prohibition on new unpaved 

roads in urban areas.) 

The control options in Proposed Regulation VIII and in San Joaquin Valley’s regulations are the same, 

and thus equally stringent (although as seen in the discussion of Unpaved Roads: Limits of Applicability, 

proposed Regulation VIII applies to a greater percentage and absolute mileage of unpaved roads). 

Although the compliance schedule for city and county roads appears more stringent for San Joaquin (20% 

per year), that only equates to 18 miles per year, compared to almost 22 miles per year for Imperial 

County (10% of 217 miles). In addition, San Joaquin caps at 5 the number of miles that require treatment 

per year per urban areas. San Joaquin also allow cities and/or counties to submit a statement of financial 

hardship if they cannot met the rule requirements. The San Joaquin Valley regulations have been 

approved as BACM by EPA6

. For all of these reasons, proposed Regulation VIII limits and requirements 

are as stringent as the most stringent in other serious non-attainment areas. 

 

6

 Federal Register Vol. 69, No. 102; p.30035; May 26, 2004. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-13 E N V I R O N 

FUGITIVE DUST CATEGORY: UNPAVED PARKING LOTS/STAGING AREAS 

SUBCATEGORY: APPLICABILITY 

Proposed Imperial County Requirements:

• Unpaved traffic areas larger than one (1) acre and with 75 or more average vehicle trips per day shall 

comply with one or more of the requirements of Section F.3 so as to limit VDE to 20% opacity (Ref: 

PR805, Section E.4) 

SJV Requirements:

• Areas with AVDT of 50 or more (areas with less than 50 AVDT are exempt) (Ref: R8071, Section 

4.1) 

• Agricultural sources exempt from Rule 8081 are also exempt from R8071. 

South Coast Requirements:

(Note: South Coast does not have rule language specifying this category. It is presumed that Rule 403 

provisions for either unpaved roads, or disturbed surface areas would apply.) 

Maricopa County Requirements:

• Over 100 vehicles entering or parking (Ref: R310.01, Section 303) 

Clark County Requirements:

• No minimum vehicle limit specified for parking lots. (Ref: AQR, Section 92.2.1) 

• No minimum vehicle limit specified for staging areas (Ref: AQR Section 94 Handbook, CST 17) 

Discussion:

Clark County has no minimum vehicle limit for parking lots or staging areas. Maricopa has a 

100 vehicle threshold. San Joaquin exempts traffic areas with less than 50 annual average daily 

trips and agricultural traffic area sources exempt from R8071 (e.g., traffic area less than 1.0 acre 

and more than one mile from an urban area, or with less than 50 AADT or less than 150 VDT if 

intermittently used). EPA has adjudged the San Joaquin rule as BACM7 based on the adequacy 

of their cost-effectiveness analyses of potential lower thresholds. 

Proposed Regulation VIII has a higher threshold for ADVT than San Joaquin and a 1 acre size 

threshold. According to the 1993 Imperial Valley PM10 SIP, there are only 200 acres of nonfarm traffic areas (compared to 13,700 acres of non-farm unpaved roads) and speed in these 

areas are significantly less than on the roads themselves.. There is no information at this time on 

the levels of usage (e.g. ADVT), size, or current controls for these unpaved traffic areas. Some 

 

7

 EPA’s Technical Support Document for the San Joaquin Valley, California 2003 PM-10 Plan and 2003 PM-10 

Plan Amendments., p. 34-5. January 27, 2004 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-14 E N V I R O N 

are subject to conditional use permits (CUPs) from local jurisdictions. Imperial County believes 

that, similar to San Joaquin, a detailed cost-effectiveness analysis will indicate that the coverage 

provide by proposed Regulation VIII meets BACM. ICAPCD is conducting additional survey 

work and will prepare a cost-effectiveness analysis to justify the proposed thresholds. If the 

analysis indicates that more stringent thresholds are cost-effective, amendments to PR805 will be 

prepared. 

(Although agricultural unpaved traffic areas are exempt from PR 805, any size traffic area for an 

agricultural operation with more than 40 acres total must implement controls, per PR 806.) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-15 E N V I R O N 

FUGITIVE DUST CATEGORY: UNPAVED PARKING LOTS/STAGING AREAS 

SUBCATEGORY: REQUIREMENTS 

Proposed Imperial County Requirements (unpaved traffic areas):

For unpaved traffic areas larger than one (1) acre and with 75 or more average vehicle trips per day shall 

comply with one or more of the requirements of Section F.3 (listed below) so as to limit VDE to 20% 

opacity: 

• Pave or (Ref: PR805, Section F.3.a) 

• Apply chemical stabilizers (Ref: PR805, Section F.3.b) 

• Apply and maintain gravel, recrushed/recycled asphalt or other material of low silt content to a depth 

greater than 3 inches (Ref: PR805, Section F.3.c) 

• Wetting. Apply water one or more times daily (Ref: PR805, Section F.3.d) 

SJV Requirements:

• For days with 50 or more vehicle trips, limit VDE to 20% opacity and implement at least one of the 

following control measures: 

o apply water 

o apply uniform layer of washed gravel 

o apply chemical/organic dust suppressant 

o use vegetative materials 

o pave 

o use any other method to limit VDE to 20% opacity (Ref: R8071, Section 5.1.1) 

• For days with 100 or more vehicle trips: 

o limit VDE to 20% opacity 

o comply with requirements for stabilized surface 

o implement at least one of the following control measures: 

 apply water 

 apply chemical/organic dust suppressant 

 apply roadmix 

 pave 

 use any other method that results in stabilized surface (Ref: ibid, Section 5.1.2) 

• On each day that 25 or more VDT with 3 or more axles will occur on an unpaved vehicle/equipment 

traffic area, the owner/operator shall limit VDE to 20% opacity and comply with the requirements of 

a stabilized unpaved road by the application and/or re-application/maintenance of at least one of the 

control measures specified sections 5.1.1.1 through 5.1.1.6 (Ref: R8071, Section 5.1.3). 

• On each day when a special event will result in 1,000 or more vehicles that will travel/park on an 

unpaved area, the owner/operator of the unpaved area to be traveled/parked upon must notify the 

District at least 48 hours in advance when such a special event will occur. During the duration of the 

special event vehicle travel/parking, the owner/operator shall limit VDE to 20% opacity and comply 

with the requirements of a stabilized unpaved road by the application and/or reapplication/ 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-16 E N V I R O N 

maintenance of water or chemical/organic dust stabilizers/suppressants in accordance with the 

manufacturer’s specifications (Ref: R8071, Section 5.1.4). 

• As option to above, obtain Fugitive PM10 Management Plan (Ref: ibid, Section 5.2.1, 5.2.2, and 5.2.3) 

 Must achieve at least 50% control efficiency (Ref: R8011, Section 7.0) 

 Must specify location, length, and area of unpaved traffic areas (Ref, ibid, 7.5.2) 

 Description of traffic conditions (vehicle trips per unit time; types of vehicles) 

(Ref: ibid, 7.5.3) 

 Description of control measures used and application details (Ref: ibid, 7.5.4) 

 Description of expected resulting road surface condition (Ref: ibid, 7.5.5) 

South Coast Requirements:

(No specific rule language for this category. See measures for “Unpaved Roads” for presumed applicable 

BACM.) 

Maricopa County Requirements:

• If utilized less than 35 days per year, use one of following: 

a) Apply dust suppressants to maintain stabilized surface 

b) Apply and maintain gravel to maintain stabilized surface 

(Ref: R310.01, Section 303, and 303.1) 

• If utilized at least 35 days per year: 

a) Add option, to above, to pave 

(Ref: ibid; also R310, Table 1, 1B,2B,3B) 

Clark County Requirements:

• For unpaved parking lots, use one of following: 

a) Pave 

b) Apply dust palliatives to maintain stabilized surface 

c) Apply dust palliatives to travel lanes, and apply gravel to a depth of two inches in the parking 

areas to maintain stabilized surface (Ref: AQR Section 92.2.1 and 92.2.1.2) 

• If parking lot is used intermittently, less than 35 days per year, and the lot was in existence prior to 

June 22, then application may be limited to period of use (Ref; ibid, 92.2.1 and 92.2.1.1) 

• For staging areas: 

o Limit size of staging areas (Ref AQR, Section 94 Handbook, CST 17-1) 

o Apply water (Ref: ibid, CST 17-2) 

o Apply dust palliative (Ref: ibid, CST 17-3) 

o Limit vehicle speeds to 15 mph (Ref: ibid, CST 17-4) 

o Limit ingress and egress points (Ref: ibid, CST 17-5) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-17 E N V I R O N 

Discussion:

Maricopa County requires the stabilization or paving of all traffic areas, regardless of usage. 

Watering is not an option. Clark County requires the paving or stabilization of unpaved traffic 

areas, unless the area is only used infrequently. In that case, stabilization only has to occur 

during use times. Watering is not an option. 

Proposed Regulation VIII and San Joaquin Valley rules allow the use of daily watering as a 

control option; thus, Regulation VIII includes an option that is less stringent, based on the 

relative control effectiveness of watering compared to stabilization, gravelling and paving. 

However, proposed Regulation VIII still requires compliance with the opacity limit 

However, in SJV for sites on days with more than 100 trips, the surface must comply with 

stabilized surface requirements, and for areas on days with more than 25 VDT from vehicles 

with 3 or more axles or if over 1000 vehicles are anticipated, there are special control 

requirements (generally re-application of stabilizers or water) for those days. Imperial County 

commits to assessing the need and cost-effectiveness of these specific single day provisions and 

preparing amendments to PR 805, if necessary. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-18 E N V I R O N 

FUGITIVE DUST CATEGORY: UNPAVED ROADS 

SUBCATEGORY: CANAL ROADS 

Proposed Imperial County Requirements:

• For Canal Roads with 20 or more ADT (Ref: PR805, Section E.3) 

a) Stock Triploid Grass carp in canals to reduce maintenance vehicle trips along Canal Banks to 

mechanically remove aquatic weeds or (Ref: PR805, Section F.2.a) 

b) Install remote control delivery gates to eliminate manual gate operation by maintenance personnel 

or (Ref: PR805, Section F.2.b) 

c) Implement Silt removal program to delay grading of spoil piles deposited after cleaning 

operations or (Ref: PR805, Section F.2c) 

d) Permanent road closure or (Ref: PR805, Section F.2d) 

e) Convert open canals to pipeline or (Ref: PR805, Section F.2.e) 

f) Line canals to eliminate maintenance for silt/week control or (Ref: PR805, Section F.2.f) 

g) Initiate canal bank surface maintenance (Ref: PR805, Section F.2.g) 

SJV Requirements:

(No requirements specified.) 

South Coast Requirements:

(No requirements specified.) 

Maricopa County Requirements:

(No requirements specified.) 

Clark County Requirements:

(No requirements specified.) 

Discussion:

Canal roads are unpaved roads used by the Imperial Irrigation District to maintain the irrigation canal 

network. San Joaquin has identified private canal roads in its inventory but does not anticipate that these 

private canal roads have traffic levels that meet the 26 ADT threshold for unpaved road controls and does 

not specify additional canal road requirements such as the ones in proposed Regulation VIII. Thus, these 

requirements are the most stringent for this source. (NOTE: These requirements are in addition to the 

general unpaved road requirements for unpaved roads that canal roads are also subject to. See also 

Unpaved Roads: Applicability and Unpaved Roads: Control Requirements.) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-19 E N V I R O N 

FUGITIVE DUST CATEGORY: DISTURBED OPEN AREAS 

SUBCATEGORY: APPLICABILITY 

Proposed Imperial County Requirements:

• 0.5 acres or larger in urban areas, or 3.0 acres or more in rural areas; and contains at least 1,000 

square feet of disturbed surface area (Ref: PR804, Section B) 

SJV Requirements:

• This rule applies to any open area having 0.5 acres or more within urban areas, or 3.0 acres or more 

within rural areas; and contains at least 1000 square feet of disturbed surface area (R8051, Section 

2.0). 

South Coast Requirements:

• No limit 

Maricopa County Requirements:

Unclear: Rule 310, Section 102 exempts disturbed open areas which are not located at sources requiring 

“any permit under these rules.” However, most open areas will not have need for permits. Section 303 

requires a dust control plan (presumed to be what is referred to in Section 102 as a “permit”), for all 

sources that involve earthmoving operations of 0.10 acres or greater. Since soil disturbances can occur 

for reasons other than earthmoving, for example, off-road vehicle traverses, it appears that many 

disturbed open areas, vacant lots, etc, may be exempt under these rules. 

Clark County Requirements:

• 5,000 square feet or larger (non-agricultural) (Ref: AQR Section 90.1.2 and 90.2.1) 

Discussion:

The most stringent applicability is South Coast Rule 403, which has no minimal level (although the 

related control requirements are less stringent than other serious non-attainment areas) Clark County 

AQR Section 90 which has a 5,000 square foot (approx. 1/9 acre) minimum level for all types of open 

areas and vacant lots. Imperial County and SJV applicability thresholds are the same. EPA adjudged8

 the 

SJV thresholds as meeting the stringency test and qualifying for BACM since over 98%of the total parcel 

acreage is in parcels of 3 acres or greater. For Imperial County, more than 99.5% of the total parcel 

acreage is in parcels of 3 acres or greater9

. Hence, proposed Regulation VIII applicability threshold is 

more stringent than SJV’s applicability threshold, which has already been determined to be BACM. 

 

8

 EPA’s Technical Support Document for the San Joaquin Valley, California 2003 PM-10 Plan and 2003 PM-10 

Plan Amendments., p. 37-38. January 27, 2004. 

9

 Imperial County Assessors Office parcel data, 2001. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-20 E N V I R O N 

FUGITIVE DUST CATEGORY: DISTURBED OPEN AREAS 

SUBCATEGORY: CONTROL MEASURES 

Proposed Imperial County Requirements:

• Limit open areas to VDE of 20% opacity (Ref: PR804, Section E.1) 

• Prevent unauthorized vehicle access by posting “No Trespassing” signs or installing physical barriers 

such as fences, gates, posts, and/or appropriate barriers to prevent access (Ref: PR804, Section E.2) 

• Apply and maintain water or dust suppressant to all unvegetated areas (Ref: PR804, Section F.1.a) 

• Establish vegetation on all previously disturbed areas (Ref: PR804, Section F.1.b) 

• Pave, apply gravel, chemical stabilizers/suppressants (Ref: PR804, Section F.1.c) 

SJV Requirements:

• Apply water/dust suppressants to unvegetated areas sufficient to limit VDE to 20% opacity (Ref: 

R8051, Table 8051-1, A1) 

• Establish vegetation to limit VDE to 20% opacity (Ref: ibid, A2) 

• Pave, apply gravel, apply stabilizers to limit VDE to 20% opacity (Ref: ibid, A3) 

• Upon evidence of trespass, post “no trespass” signs or install barriers to prevent access to area (Ref: 

ibid, B) 

South Coast Requirements:

• Apply chemical stabilizers (Ref: R403 Handbook, BACM (Q)) 

• Water with sufficient frequency to establish a surface crust (Ref: ibid, (R)) 

• Establish (drought-resistant) vegetation as quickly as possible (Ref: ibid, (T)) 

Maricopa County Requirements:

• Restore vegetative ground cover and soil characteristics similar to native Conditions (Ref: R310, 

Table 1, 1E) 

• Pave, apply gravel, apply stabilizer to meet stabilized standards (Ref: ibid, 2E) 

• Establish vegetation to meet stabilized standards (Ref: ibid, 3E) 

• Stabilized standards, one of the following (Ref: R310, Section 302.3): 

o Maintain visible crust 

o Maintain threshold friction velocity of 100 cm/sec or greater 

o Maintain flat vegetation, not subject to wind movement, of at least 50% 

o Maintain standing (rooted, vertical) vegetation of at least 30% 

o Maintain standing (rooted, vertical) vegetation of at least 10% where the soil threshold friction 

velocity is 43 cm/sec or greater 

o Maintain cover of non-erodible elements of at least 10% 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-21 E N V I R O N 

Clark County Requirements:

• Upon evidence of soil disturbance by motor vehicles, prevent trespass, parking, and access by 

installing barriers, curbs, fences, gates, posts, signs, shrubs, and trees. (Ref: AQR Section 

90.2.1.1(a)) 

• Apply gravel or chemical stabilizers to meet one of stabilization standards (Ref: ibid, (b)) 

• Stabilization standards (Ref: AQR Section 90.2.1.2) 

o Establish visible crust 

o Establish cover of non-erodible elements of at least 20% 

o Establish threshold friction velocity of 100 cm/sec or higher 

Discussion:

Proposed Regulation VIII and SJV requirements are identical. Maricopa County and Clark County have 

established soil stabilization standards for determining the effectiveness of the control measures. (With 

respect to the stabilization standards, see General: Definition of a Stabilized Surface above.) EPA has 

approved the SJV regulations as BACM10, and the proposed Regulation VIII requirements are as stringent 

as the most stringent requirements in other serious non-attainment areas 

 

10 Federal Register Vol. 69, No. 102; p.30035; May 26, 2004. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-22 E N V I R O N 

FUGITIVE DUST CATEGORY: WINDBLOWN DUST 

SUBCATEGORY: DEFINITIONS 

Proposed Imperial County Requirements:

Not defined 

SJV Requirements:

Reference to wind blown dust is only included within the definition of “stabilized surface: any disturbed 

surface area or open bulk storage pile that is resistant to wind blown fugitive dust.” (Ref: R8011, Section 

3.56). There is no specific definition of “wind blown fugitive dust.” 

South Coast Requirements:

• Includes a definition for “wind-driven fugitive dust” as being “any visible emissions from any 

disturbed surface area which is generated by wind action alone.” (Ref: R403(c)(29) 

• High wind conditions are specified as wind gusts in excess of 25 mph (Ref: R403(h)(2)(A)) and wind 

gust defined as maximum instantaneous wind speed (Ref: R403(c)(30)) 

Maricopa County Requirements:

• Includes a definition of wind blown dust as being “visible emissions from any disturbed surface area 

which are generated by wind action alone (Ref: R310, Section 233) 

• Includes a definition of wind event: “when the 60-minute average wind speed is greater than 25 mph” 

(Ref: ibid, 234) 

Clark County Requirements:

No definitions specified 

Discussion:

This section is provided for information purposes, since the “definition” of wind blown dust is not a 

control measure. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-23 E N V I R O N 

FUGITIVE DUST CATEGORY: DISTURBED AREAS 

SUBCATEGORY: WINDBLOWN DUST 

Proposed Imperial County Requirements:

No specific requirements, except for construction and earthmoving activities during wind events. See 

description in Appendix B concerning Construction/Windblown Dust. 

SJV Requirements:

No specific requirements, except for construction and earthmoving activities during wind events. See 

description in Appendix B concerning Construction/Windblown Dust. 

South Coast Requirements:

For large operations, implementing one of the following contingency measures exempts the 

owner/operator from certain rule provisions: 

• If operations remain inactive for not more than four consecutive days, apply water and chemical 

stabilizers in sufficient concentration to maintain a stabilized surface for six months (Ref: R403, 

Table 3, 0B) 

• Apply chemical stabilizers prior to wind event (Ref: ibid, 1B) 

• Apply water 3 times per day; if evidence of wind driven fugitive dust, increase watering to 4 times 

per day (Ref: ibid, 2B) 

• Establish vegetative ground cover within 21 days after active operations have ceased (Ref: ibid, 3B) 

Maricopa County Requirements:

• Apply gravel or dust suppressants (Ref: R310, Table 2, 1B) 

• Apply water 3 times per day; if evidence of wind driven fugitive dust, increase watering to 4 times 

per day (Ref: ibid, 2B) 

Clark County Requirements:

(No specific wind requirements, however, the general requirements for disturbed surface areas include 

provisions which are intended to reduce windblown dust: 

• Prevent access to limit soil disturbance (Ref: AQR Section 94 Handbook, CST 11) 

• Stabilize soil, using dust palliative or vegetation to maintain stabilized surface 

(Ref: ibid, CST 11-4 and 11-5) 

• Pave or apply surface rock to maintain stabilized surface (Ref: ibid, CST 11-6)) 

Discussion:

There are no specific exemptions for wind events in the proposed Regulation VIII amendments. PR803 

opacity and stabilization requirements apply regardless of wind speed. This is the most stringent 

requirement, since there are not exemptions from Regulation VIII provisions because of high winds 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-24 E N V I R O N 

It should be noted that for construction activities (which are not a significant source), there is an 

exemption from the 20% opacity requirement (PR801, Section D.2). To qualify for the exemption, the 

operator must either cease operations, water or apply dust suppressants once per hour, or maintain a 12% 

soil moisture content by watering. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-25 E N V I R O N 

FUGITIVE DUST CATEGORY: AGRICULTURAL OPERATIONS – CROP FARMS 

SUBCATEGORY: CONSERVATION (OR BEST) MANAGEMENT PRACTICES 

Proposed Imperial County Requirements:

For owner/operators of agricultural operation sites greater than or equal to 40 acres, implement at least 

one of the following in each category: 

• Land preparation and cultivation (Ref: PR806, Section E.1): 

a) alternative till 

b) bed/row size spacing 

c) chemical/fertigation 

d) combined operations 

e) conservation irrigation 

f) conservation tillage 

g) cover crops 

h) equipment changes/technological improvements 

i) fallowing land 

j) integrated pest control 

k) mulching 

l) night farming 

m) non tillage/chemical tillage 

n) organic practices 

o) precision farming 

p) transgenic crops 

• Harvesting (Ref: PR806, Section E.2): 

a) bailing/large bails 

b) combined operations 

c) equipment changes/technological improvements 

d) green chop 

e) hand harvesting 

f) fallowing land 

g) nigh harvesting 

i) no burning 

j) pre-harvesting soil preparation 

k) shed packing 

l) shuttle system/large carrier 

• Unpaved farm roads and traffic areas (Ref: PR806, Section E.3 and E.4): 

a) chips/mulches, organic materials, polymers, road oil and sand 

b) gravel 

c) paving 

d) restricted access 

e) speed limit 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-26 E N V I R O N 

f) track-out control 

g) water 

h) wind barrier 

SJV Requirements:

SJVAPCD Rule 4550 requires the submittal of a conservation management plan for sites with more than 

100 acres with 1 conservation management practice (CMP) for each category: 

• Land preparation and cultivation: same as Imperial County with addition of floor management (nut 

crops), time of planting and transplanting (some vegetable crops) options. 

• Harvest: same as Imperial County with addition of continuous tray/D.O.V. (dry fruit crops) fallowing 

land; and floor management (nut crops) options. 

• Unpaved farm roads and traffic areas: same as Imperial County with the addition of mechanical 

pruning (tree and vine crops) option. 

South Coast Requirements:

For agricultural operations within the South Coast Air Basin, with combined disturbed surface area of 10 

acres or more, the standards of Rule 403 apply after July 1, 1999 unless Best Management Practices as 

delineated in the Rule 403 Agricultural Handbook are implemented. (Ref: R403(h)(1)) 

Best Management Practices as described in the Agricultural Handbook are as follows: 

a) Active conservation practices 

1) Ensure adequate soil moisture so that VDE do not exceed 100 feet 

2) Irrigate or bed fields as soon as feasible 

3) Utilize conservation tillage practices 

4) Apply mulch or other materials to help bind soil 

b) Inactive conservation practices 

1) Comply with local dust ordinances relating to agricultural operations 

2) Establish cover crops that maintain a minimum 60% ground cover 

3) Maintain crop residues at a minimum 60% ground cover as determined by line-intersection 

method 

4) Conduct surface roughening by bedding, rough disking, or tillage that leaves stable clods 

5) Alternate strips of row crops with wind-resistant crops 

6) Establish tree or shrub windbreaks at right angles to prevailing winds 

7) Establish ridge plantings by normal tillage and planting equipment at a right angle to the 

prevailing winds 

8) Plant or maintain perennial or annual plants as a vegetative wind barrier by planting throughout a 

field at a right angle to the prevailing wind 

c) Farm yard areas 

1) Establish or maintain sufficient vegetation to prevent wind driven dust 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-27 E N V I R O N 

2) Use water or dust suppressants to bind soils 

3) Apply surface improvements (gravel, paving, etc) 

4) Reduce disturbed areas by at least 50% 

d) Trackout conservation practices 

1) Pave or apply dust suppressants on unpaved road connections with public paved roads, preferably 

to a distance of 100 feed from the paved road 

2) Use trackout prevention devices 

3) Avoid turning tractors and other farm machinery on public pave roads if soil will be dropped on 

the road. If material is dropped, clean the road at the conclusion of the activity 

e) Unpaved road conservation practices 

1) Reduce vehicle speeds to a maximum of 15 mph 

2) Restrict public access to private roads by using signage or obstructions 

3) Apply water, dust suppressants, mulch or other materials to unpaved roads prior to heavy use 

periods 

4) Improve heavily used roads by paving, applying gravel or recycled road base material 

f) Storage pile conservation practices 

1) Enclose with a three-sided barrier equal to height of pile 

2) Water sufficiently to prevent wind driven fugitive dust 

3) Apply chemical stabilizers 

4) Cover with tarps, plastic, or other materials 

(Ref: Guide to Agricultural PM10 Dust Control Practices, dated June 1999) 

Maricopa County Requirements:

In May 2000, the Agricultural BMP Committee adopted the agricultural PM10 general permit, which 

became effective by rule on May 12, 2000 (Arizona Administrative Code [AAC], R18-2- 610 and 611). 

The Committee identified 34 BMPs that focus on feasible, effective, and common sense practices while 

minimizing negative economic impacts on local agriculture. (These BMPs were based on the BMPs in 

the South Coast Agricultural Handbook). The general permit requires that a commercial farmer 

implement at least one BMP to control PM10 for each of the following three categories: tillage and 

harvest, non-cropland, and cropland. The general permit requires a commercial farmer to comply by 

December 31, 2001. 

Clark County Requirements:

(No requirements for this source) 

Discussion:

The South Coast Rule 403 subjects agricultural operations to a long list of best management practice 

choices, which encompass many of the requirements for non-agricultural sources. Although 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L C-28 E N V I R O N 

implementation and documentation of BMP is considered “voluntary,” failure to do so subjects the 

owners/operators to the basic standards of the rule, which include VDE beyond the property line, 

implementation of at least one BACM for each fugitive dust source, upwind-downwind limit of 50 μg/m3

of PM10, and trackout control requirements. The Arizona requirements were based on the South Coast 

BMPs. The San Joaquin requirements were developed after the BACM analysis performed for the 

SJVAPCD 2003 PM10 SIP and after extensive rule development. 

ICAPCD CMPs apply to farm sites with 40 or more acres, which represent 90% of farm land in Imperial 

County. By comparison, San Joaquin Valley requires CMPs at site greater than 100 acres, which 

represents about 91% of farm land in San Joaquin Valley. Thus, the farm site limit is equally stringent 

compared to the most stringent threshold. 

The proposed ICAPCD CMP requirements are similar to the requirements in San Joaquin Valley, 

Maricopa County and South Coast, and are directly based on the San Joaquin Valley requirements that 

were approved by EPA11 as meeting the BACM requirements. The Proposed Imperial County 

requirements are specifically based on the San Joaquin requirements and are of similar stringency; thus, 

they are as stringent as the most stringent requirements for this source. 

 

11 Federal Register Vol. 69, No. 102; p.30035; May 26, 2004 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

A P P E N D I X D 

Detailed Comparative Analysis for Sources Below the DM Level 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-1 E N V I R O N

Appendix D 

Detailed Comparative Analysis for Sources Below the DM Level

Appendix D presents a detailed comparative analysis for sources below the DM level: construction / 

demolition activities, bulk material, track-out, paved roads, cattle feedlots, BLM and BP sources, 

and weed abatement. These sources do not require a comparative analysis and this material is 

presented for information purposes only. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-2 E N V I R O N 

FUGITIVE DUST CATEGORY: CONSTRUCTION 

SUBCATEGORY: PRE-EARTHMOVING OPERATIONS 

Proposed Imperial Requirements:

Construction and Earthmoving sites shall comply with the following requirements: 

• Pre-water site sufficient to limit VDE to 20% opacity (Ref: PR801, Section F.1.a.1) 

• Phase work to reduce the amount of disturbed surface area at any one time (Ref: PR801, Section 

F.1.a.2) 

SJV Requirements:

• Pre-water in sufficient amount to limit VDE to 20% opacity (Ref: R8021, Table 8021-2, A1) 

• Phase work to reduce disturbed surface area (Ref: R8021, Table 8021-2, A2) 

South Coast Requirements:

• Apply water to increase soil moisture content to depth of proposed cut (Ref R403 Handbook, BACM 

Control Measure A) 

• Grade each phase separately to coincide with construction phase (Ref: ibid, 

• BACM A-2(1)) 

• If full grading, apply chemical stabilizers to graded areas where construction will not begin for more 

than 60 days after grading (Ref: ibid, BACM A-2(2)) 

Maricopa County Requirements:

• Pre-water to depths of cuts (Ref R310, Table 1, 1D) 

• Phase work to reduce the amount of disturbed surface areas (Ref: ibid, Table 1, 2D) 

Clark County Requirements:

• Presoak soils to depths of cuts (AQR Section 94 Handbook, CST 07) 

• Presoak with water and surfactant mixture in soils with high emission potential (Ref: ibid, CST 07-7) 

• Include phasing details as part of Dust Control Permit and Dust Control Mitigation Plan (Ref, ibid, 

GEN 01) 

Discussion:

Imperial County and SJV are of similar stringency. Clark and Maricopa counties require pre-watering to 

the depth of the cut. 

For phased earthmoving or construction, the requirements appear to be equally stringent. Emission 

reductions can be reduced by limiting the area of disturbed soils to the minimum necessary for the 

construction project. The success of such limitation is dependent upon the degree of specificity, i.e., it 

would be difficult to determine if the phasing is actually minimizing the disturbed surface conditions 

unless such information is provided in advance. The Clark County requirements for providing such 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-3 E N V I R O N 

details are considered more stringent than the Imperial County and SJV requirements because such 

phasing details are not part of the Imperial County or SJV Dust Control Plan submittals. 

The Clark County provision of using a mixture of water and chemical stabilizers for resoaking soils with 

high emissions potential is questionable regarding reducing emissions. Chemical stabilizers tend to help 

form surface soil crusts, which minimize dust emissions from activities on the surface. If grading is done 

to levels below the surface, there is unknown value as to the ability of such chemicals to have an effect on 

subsurface soils. Thus it cannot be determined if such measures have greater dust-reducing capabilities. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-4 E N V I R O N 

FUGITIVE DUST CATEGORY: CONSTRUCTION 

SUBCATEGORY: EARTHMOVING OPERATIONS 

Proposed Imperial Requirements:

• Construction and Earthmoving sites shall comply with the following requirements: Apply water or 

chemical stabilization as directed by product manufacturer to limit VDE to 20% opacity; or (Ref: 

PR801, Section F.1.b.1) 

• Construct and maintain wind barriers to limit VDE to 20% opacity (Ref: PR801, Section F.1.b.2) 

• Apply water or chemical stabilization to unpaved/haul access roads and unpaved vehicle equipment 

areas sufficient to limit VDE to 20% opacity (Ref: PR801, Section F.1.b.1) 

SJV Requirements:

• Apply water or chemical stabilizers/dust suppressants, in conjunction with optional wind barriers, to 

limit VDE to 20% opacity (Ref: R8021, Table 8021-2, B1 and B2) 

South Coast Requirements:

• General VDE conditions apply (See FD Category, Visible Dust Emissions) 

• Maintain soil moisture content (by applicable ASTM Method D-2216) minimum of 12% (Ref: R403, 

Table 2, 1(a)) 

• Conduct watering to limit VDE from exceeding 100 feet (Ref, ibid, (1a-1) and (1c)) 

Maricopa County Requirements:

• Apply water or dust suppressants to limit VDE to 20% opacity (Ref: R310, Table 1, 3D) 

• Apply water to maintain soil moisture at a minimum 12% (by applicable ASTM Method D-2216-98) 

(Ref: R310, Table 1, 4D) 

• Construct 3-5 foot high wind barriers, with 50% or less porosity, adjacent to roadways or urban areas, 

and meet either VDE or soil moisture limits. (Ref: ibid, 5D) 

• For one acre or larger, if water is used, operate water truck or similar water application system on 

disturbed surfaces (Ref: ibid, 1M) 

Clark County Requirements:

(Note: Clark County does not have a specific section for earthmoving. Two activities which are specified 

include cut-and-fill operations and backfilling operations. Control measures are summarized from those 

activities.) 

• General VDE conditions apply (See FD Category, Visible Dust Emissions) 

• Apply water to maintain soil moisture (Ref: AQR Section 94 Handbook, CST 01) 

• Apply water or dust suppressant immediately following activity (Ref, ibid, CST 01- 6, CST 07-5 and 

CST 07-6) 

• When loading soils, minimize height from loader bucket, and empty bucket slowly (Ref: ibid, CST 

01-7 and CST 01-8) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-5 E N V I R O N 

Discussion:

The South Coast and Maricopa 12% soil moisture content requirement option is deemed more stringent 

than the VDE limit alone because this is a distinct action to minimize emissions. The Proposed Imperial 

County requirements are as stringent as the SJV requirements. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-6 E N V I R O N 

FUGITIVE DUST CATEGORY: CONSTRUCTION 

SUBCATEGORY: INACTIVE DISTURBED LAND 

Proposed Imperial County Requirements:

• Restrict vehicle access (Ref: PR801, Section F.1.c.1) 

• Apply water or chemical stabilization sufficient to comply with conditions of a stabilized surface. If 

an area ≥ 0.5 acres of disturbed surface area remains unused for ≥ 7 days, the area must comply with 

the conditions for a stabilized surface (Ref: PR801, Section F.1.c.2) 

SJV Requirements:

• Restrict vehicle access (Ref: R8021, Table 8021-2, C1) 

• Apply water/dust suppressants to meet stabilized surface definition; if area is greater than 0.5 acres 

and inactive more than 7 days, then must comply with definition of stabilized surface (Ref, ibid, C2) 

South Coast Requirements:

• Apply chemical stabilizers within 5 days of completion of grading (Ref: R403, Table 2, (2c)) 

• Apply water to at least 80% of inactive disturbed area on a daily basis when there is evidence of 

windblown dust (Ref: ibid, (3a)) 

• Establish vegetative ground cover within 21 days after active operations cease. 

• Must be of sufficient density within 90 days to expose less than 30% of the disturbed area (Ref: ibid, 

(3c)) 

Maricopa County Requirements:

• For weekends, holidays, and after-hours: 

o Apply water/dust suppressants to maintain stabilized surface (Ref, R310, Table 1, 6D) 

o Establish vegetative ground cover to maintain stabilized surface (Ref: ibid, 7D and 11D) 

o Restrict vehicle access (Ref: ibid, 8D) 

• For longer-term stabilization (must be done within 8 months) 

o Restore vegetation similar to natural conditions to maintain stabilized surface 

(Ref: ibid, 9D) 

o Pave, apply gravel or dust suppressant (presumably to road surfaces) to maintain stabilized 

surface (Ref: ibid, 10D) 

Clark County Requirements:

• Prevent access to limit soil disturbance (Ref: AQR Section 94 Handbook, CST 11) 

• Stabilize soil, using dust palliative or vegetation to maintain stabilized surface (Ref: ibid, CST 11-4 

and 11-5) 

• Pave or apply surface rock to maintain stabilized surface (Ref: ibid, CST 11-6) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-7 E N V I R O N 

Discussion:

Although other approaches may have more specificity in control measures, the effect of maintaining a 

stabilized surface in the Imperial County and SJV rules is deemed equivalent to other rules. However, 

Maricopa County does not specify a de minimis acreage, and hence the requirement for longer-term 

stabilization is deemed more stringent than the Imperial County or SJV rules which establishes a de 

minimis level of 0.5 acres. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-8 E N V I R O N 

FUGITIVE DUST CATEGORY: CONSTRUCTION ACTIVITIES 

SUBCATEGORY: DEMOLITION 

Proposed Imperial Requirements:

• All persons who own or operate a Construction/Earthmoving Site shall comply with requirements of 

Section F.1 so as to limit VDE to 20% opacity (Ref: PR801, Section E.1.a) 

SJV Requirements:

• Apply water to limit VDE to not more than 20% opacity (Ref: R8021,5.1.1, 5.1.2) 

• Apply dust suppressants to limit VDE to not more than 20% opacity (Ref, ibid, 5.1.3) 

• Handling, storage, and transport of bulk materials on-site or off-site resulting from the demolition or 

razing of buildings shall comply with the requirements specified in Rule 8031 (Bulk Materials) (Ref, 

ibid, 5.1.4) 

• Movement/handling must meet requirements for bulk materials (Ref: ibid, 5.1.5) 

• Trackout prevention must comply with Rule 8041 (Ref: ibid, 5.1.6) 

South Coast Requirements:

• Demolition must meet same requirements as other applicable dust-producing operations 

1) No visible emissions beyond property line (Ref: R403(d)(1)) 

2) Must apply one or more BACM (Ref: R403(d)(2) 

3) Upwind-downwind PM10 levels must not exceed 50μg/m3

 (Ref: R403(d)(4)) 

4) Must meet trackout requirements (Ref: R403(d)(5)) 

Maricopa County Requirements:

• Demolition must meet same requirements as other applicable dust generating operations 

1) Visible dust emissions must not exceed 20% opacity (Ref: R310, Sect. 301) 

2) Must implement one primary and one contingency control measure (Ref: R310, Sect. 304.3(a)) 

Clark County Requirements

• For implosion: 

1) Limit blasting to time periods when wind direction is away from closest residential areas, 

occupied buildings, and major roadways. 

2) Limit blasting times to between 8:00 am and 4:30 pm 

3) Stabilize soils prior to blasting 

4) Stabilize soils and debris after blasting 

5) Do not blast when wind speeds occur or are forecast to occur 

6) Restrict vehicles to paved or stabilized surfaces 

(Ref: AQR Section 94 Handbook, CST 08) 

• For mechanical/manual demolition: 

1) Stabilize erodible surfaces 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-9 E N V I R O N 

2) Stabilize surfaces where support equipment will operate 

3) Stabilize loose soil and demolition debris (Ref: AQR Section 94 Handbook, CST 09) 

4) Stabilize surfaces where support equipment will operate 

5) Stabilize loose soil and demolition debris (Ref: AQR Section 94 Handbook, CST 09) 

Discussion:

These requirements vary from general restrictions, such as, South Coast and Maricopa County, to specific 

requirements, as in Imperial County, San Joaquin Valley, and Clark County. While the specifics of 

opacity limits are likely to be equivalent to the general restrictions of South Coast and Maricopa County, 

the specific measures in the Clark County regulations appear to be more stringent in preventing 

unintended violations of the opacity limit. For example, it may never be known until after a demolition 

blast has actually occurred that there is an opacity violation. By specifying actions, such as stabilizing 

surface before and after blasting, and not allowing blasting when wind speeds exceed 25 miles per hour, 

there is at least a more proactive effort to minimize dust generation. Limiting the hours and wind 

direction conditions for approved blasting does not result in lower emissions, but rather is responsive to 

potential public impacts. As such, from an emissions standpoint, these are not deemed to be more 

stringent control measures. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-10 E N V I R O N 

FUGITIVE DUST CATEGORY: CONSTRUCTION/EARTH MOVING 

SUBCATEGORY: WINDBLOWN DUST 

Proposed Imperial County Requirements:

For exemption from the 20% opacity limit requirements during wind events, an operation must implement 

one of the following: 

• Cease dust generating activities for the duration of the wind event. If operations cease for the 

remainder of the day, stabilization measures must be implemented.(Ref: PR801, D.2.a) 

• Apply water/dust suppressant once per hour (Ref: ibid, D.2.b) 

• Apply water to maintain minimum 12% soil moisture content (Ref: ibid, Table D.2.c) 

• Construct fences 3-5 feet high with 50% or less porosity, and must be done in conjunction with 

another measure, as above (Ref: ibid, D.2.d) 

SJV Requirements:

• Cease all outdoor construction activities if fugitive dust exceeds 20% opacity (Ref: Rule 8021, 

Section 5.4.1) 

• Continue to operate water trucks when outdoor construction halted unless unsafe to do so (Ref: ibid, 

Section 5.4.2) 

South Coast Requirements:

For exemption from the visible dust over the property line and unwind / downwind monitoring 

requirements, during wind events an operation must: 

• For earthmoving: 

o Cease all active operations (Ref R403, Table 1, 1A) 

o Apply water to soil not more than 15 minutes prior to moving such soil 

(Ref: ibid, 2A) 

• For unpaved roads at construction sites: 

o Apply chemical stabilizers prior to wind event (Ref: R403, Table1, 1C) 

o Apply water twice per hour during active operations (Ref: ibid, 2C) 

o Stop all vehicular traffic (Ref: ibid, 3C) 

Maricopa County Requirements:

As an affirmative defense for opacity exceedence enforcement action, during wind events an operation 

must do one of the following: 

• Cease dust generating activities for the duration of the wind event. If operations cease for the 

remainder of the day, stabilization measures must be implemented. 

(Ref: R310, Table 20.a.1) 

• Apply water/dust suppressant once per hour (Ref: ibid, Table 20.a.2) 

• Apply water to maintain minimum 12% soil moisture content (Ref: ibid, Table 20.a.3) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-11 E N V I R O N 

• Construct fences 3-5 feet high with 50% or less porosity, and must be done in conjunction with 

another measure, as above (Ref: ibid, Table 20.a.4) 

Clark County Requirements:

• Cease all construction activities if fugitive dust exceeds 20% opacity and visible plume caused by 

winds cannot be controlled (Ref: AQR Section 94 Handbook, Gen 03) 

• Continue to operate water trucks unless hazardous to do so (Ref: ibid, Gen 03, 2) 

Discussion:

The proposed Imperial County requirements are based on the South Coast and Maricopa County 

regulations. The South Coast rule creates an exemption for property line and upwind/downwind 

exceedences if wind event controls are implemented. The Maricopa County rule states that opacity 

violations in high winds are still violations, but that the imposition of wind event controls is an 

affirmative defense for the operator. In the proposed Imperial County regulations, there is an exemption 

from the 20% opacity requirement (PR801, Section D.2). To qualify for the exemption, the operator must 

either cease operations, water or apply dust suppressants once per hour, or maintain a 12% soil moisture 

content by watering. Imperial County requirements are as stringent as the rules in these two areas. (It 

should be noted that all other PR801 requirements, including stabilization, are in force during wind events 

also.) Clark County and SJV allow fewer control options, and thus could be considered more stringent. 

South Coast is the only agency to have specific requirements for unpaved roads at construction sites. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-12 E N V I R O N 

FUGITIVE DUST CATEGORY: CONSTRUCTION 

SUBCATEGORY: DUST CONTROL PLAN: APPLICABILITY 

Proposed Imperial County Requirements:

All persons who own or operate a construction site greater than 10 acres in a residential development or 

greater than 5 acres for a non-commercial development shall submit a Dust Control Plan to the APCO. 

(Ref: R801, Section E.2.c). 

NOTE: All construction/demolition sites and earthmoving activities, except at existing single family 

homes, is required to comply with the BACM requirements of PR 801. 

SJV Requirements:

• Size: 10 acres or larger for residential areas and 5 acres or larger for non-residential (Ref: R8021, 

Section 6.3.1) 

• Earth movement: 2,500 cubic yards or more on at least 3 days (Ref: R8021, Section 6.3.1) 

South Coast Requirements:

Prior to April 2004, South Coast Rule 403 required dust control plans for sites greater than 100 acres or 

more than 10,000 cubic yards of daily earth movement. In the April 2004 amendments, South Coast 

removed all plan limits and requirements, instead requiring that all sites greater than 50 acres or with 

daily earth movement of 5,000 cubic yards or more meet additional requirements for large operations. 

These sites do not need to submit a plan, but they must submit a large operation notification. (Ref: R403, 

(e)) 

Maricopa County Requirements:

• Size: 0.10 acres or larger (Ref: R310, Section 303) 

• Certain permitted activities which have any dust generating activities (Ref: ibid, Section 303.3) 

Clark County Requirements:

• Dust Control Permit 

o Size: 0.25 acres or smaller 

o Demolition projects 1000 square feet or greater 

o Trenching operations 100 feet in length or greater 

• Dust Mitigation Plan 

o Size: 0.25 to 10 acres 

• Site-Specific Dust Control Mitigation Plan 

o Size: 10 acres or larger 

(Ref: AQR Section 94 Handbook, DCP 01) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-13 E N V I R O N 

Discussion:

Dust control plans, per se, do not reduce emissions. However, to the extent that dust control management 

efforts on the part of the operator, and oversight and compliance efforts on the part of the agency are 

substantially enhanced, it can be presumed that a greater degree of dust control implementation and 

adherence to standards ultimately result in lower fugitive dust emissions. On that basis, dust control plans 

(permits) can be evaluated as a BACM. 

As far as size is concerned, Maricopa County, and Clark County have much more stringent requirements 

than does SJV and the South Coast and the proposed Imperial County requirements. (It should also be 

noted that Clark County allows less detailed dust control permits/plans for sites less than 10 acres.) South 

Coast no longer requires dust control plans for large operations (>50 acres), but does require that such 

sites submit a large operation notification and meet specific rule standards. The effect of overall 

emissions reductions needs to include the elements of the plan in addition to size. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-14 E N V I R O N 

FUGITIVE DUST CATEGORY: CONSTRUCTION 

SUBCATEGORY: DUST CONTROL PLAN: REQUIREMENTS 

Proposed Imperial County Requirements:

• Retain a copy of the Dust Control Plan at the project site. (Ref: R801, Section F.2.a) 

• Comply with the requirements of the approved Dust Control Plan. (Ref: R801, Section F.2.b) 

• The Dust Control Plan shall include (Ref: R801, Section F.2.c): 

1. Name, address, phone numbers 

2. Plot Plan 

3. Total area of land surface disturbed, estimated daily throughput volume of earthmoving in cubic 

yards, and total area in acres of the entire project site 

4. The start and end dates of the project. 

5. Actual and potential sources of fugitive dust emissions on the site and the location of bulk 

material handling and storage areas, paved and unpaved roads, entrances and exits where Track 

Out/Carry Out may occur, and traffic areas 

6. Specifications of dust suppressants to be applied. 

7. Specific surface treatments and/or control measures utilized to control Track Out/Carry Out 

8. The Dust Control Plan should describe all fugitive dust control measures to be implemented 

before, during, and after any dust generating activity. 

SJV Requirements:

• Information on owner/operator (Ref: R8021, Section 6.3.6.1) 

• A location plot plan (Ref: ibid, Section 6.3.6.2) 

• Project size (Ref: ibid, Section 6.3.6.3) 

• Start and end dates of soil disturbing activities (Ref: ibid, Section 6.3.6.4) 

• Identification of all sources of fugitive dust (Ref: ibid, Section 6.3.6.5) 

• Information on dust suppressants to be used (Ref: ibid, Section 6.3.6.6) 

• Details of measures to control trackout (Ref: ibid, Section 6.3.6.7) 

• Description of all fugitive dust control measures to be implemented before, during, after any dust 

generating activity (Ref: ibid, Section 6.3.8) 

South Coast Requirements:

Prior to April 2004, South Coast Rule 403 required dust control plans for sites greater than 100 acres or 

more than 10,000 cubic yards of daily earth movement. In the April 2004 amendments, South Coast 

removed all plan limits and requirements, instead requiring that all sites greater than 50 acres or with 

daily earth movement of 5,000 cubic yards or more meet additional requirements for large operations. 

These sites do not need to submit a plan, but they must submit a large operation notification. (Ref: R403, 

(e)) and comply with Table 2 and 3 dust control measures. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-15 E N V I R O N 

Large operation requirement includes:

• Large Operation Notification (not a Plan), with annual renewal submittal containing: 

o Information on owner/operator (Ref: R403 (f)(3)(A)) 

o A description of site including a map (Ref: ibid, (f)(3)(B)) 

• Project signage with contact information 

• Trained dust control supervisor is required and must be identified 

Maricopa County Requirements:

• Information on person conducting dust generating operations (Ref: R310, Section 304.1) 

• Project drawing (Ref: ibid, Section 304.2) 

• Identification of one primary and one contingency control measure from Table 1 for each source of 

fugitive dust (Ref: ibid, Section 304.3a) 

• Number of vehicles traveling on unpaved haul/access roads (Ref: ibid, Section 304.3c) 

• Information on dust suppressants and frequency of application (Ref: ibid, Section 304.4) 

• Details of measures to control trackout (Ref: ibid, Section 304.5) 

Clark County Requirements:

• Complete application for permit 

• Provide project vicinity and assessors parcel maps 

• Include best management practices as detailed in Section 94 Handbook 

• If greater than 50 acres, trained dust control monitor is required 

• Key construction project class required to take dust control class 

• Signage required 

• Dust control plans must be provided to all contractors and subcontractors (Ref: AQR Section 94 

Handbook, DCP 01) 

Discussion:

The proposed Imperial County requirements are based on the SJV requirements and are of similar 

stringency. Clark County has the most detailed requirements in the sense that their Best Management 

Practices Handbook provides the most detailed set of dust control options for specified sources of dust 

generating activities. That is not to say that more options can result in fewer emissions, but the more 

options available, the more guidance is provided to dust generating activities in the selection of 

appropriate combinations of control measures. Clark County is also the most progressive in being 

proactive to control dust emissions by requiring training of key construction personnel and also requiring 

a trained dust monitor for operations, which are larger than 50 acres. 

In April 2004, South Coast removed its large operation plan requirements, now requiring a simple 

notification and adherence to Table 1 and Table 2 dust control measures. For large operations, South 

Coast now requires an on-site trained monitor also. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-16 E N V I R O N 

FUGITIVE DUST CATEGORY: BULK MATERIALS 

SUBCATEGORY: HANDLING/STORAGE 

Proposed Imperial County Requirements:

Handling/Transfer 

• Spray with water prior to handling and/or at transfer points; or (Ref: PR802, Section F.1.a) 

• Apply and maintain chemical stabilizer; or (Ref: PR802, Section F.1.b) 

• Protect from wind erosion by sheltering or enclosing the operation and transfer line (Ref: R02, 

Section F.1.c) 

Storage 

• Cover bulk materials stored outdoors with tarps, plastic, or other suitable material and anchor in a 

manner that prevents the cover from being removed; or (Ref: PRR802, Section F.2.a) 

• Construct and maintain wind barriers with less than 50% porosity; or (Ref: PRR802, Section F.2.b) 

• Utilize a 3-sided structure with a height at least equal to the height of the storage pile and with less 

than 50% porosity. (Ref: PRR802, Section F.2.c) 

SJV Requirements:

• Water or stabilize to limit VDE to 20% opacity (Ref 8031, 5.3, A1) 

• Store in accordance with definition for stabilized surface (Ref, ibid, B1) 

• Cover outdoor materials with tarps, plastic, etc (Ref, ibid, B2) 

• Use wind barriers to limit VDE to 20% plus water/stabilize (Ref, ibid, A2 and B3) 

• Utilize a 3-sided structure with a height at least equal to the height of the storage pileand with less 

than 50% porosity (Ref, ibid, B4) 

South Coast Requirements:

• Use chemical stabilizers (Ref R403, Table 2, 5a) 

• Water 80% surface area on windy days (Ref, ibid, 5b) 

• Use temporary coverings (Ref, ibid, 5c) 

• Use 3-sided enclosures, less than 50% porosity to height of pile (Ref, ibid, 5d) 

• Fully enclose (Ref R403 Handbook, pg 6-4, (L)) 

• Alter load-in, load-out procedures (Ref, ibid, (O)) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-17 E N V I R O N 

Maricopa County Requirements:

• Water to limit VDE to 20% opacity (Ref R310, Table 1, 1F) 

• Cover with tarps, plastic, etc. (Ref, ibid, 2F) 

• Apply water to maintain minimum 12% soil moisture or 

o 70% optimum soil moisture content (Ref, ibid, 3F) 

• Meet requirements for stabilized surface (Ref, ibid, 4F) 

• Construct wind barriers (with less than 50% porosity), storage silos, or 

o 3-sided enclosures to height of pile and length, distance restrictions (Ref, ibid, 4F) 

Clark County Requirements:

• Must stabilize stockpiles 

• Must not be over 8 feet high if within 100 yards of occupied building 

• Must have water access to top of pile if higher than 8 feet 

• Avoid steep slopes 

• Apply water during stocking, loading, unloading (high emission potential soils) 

(Ref Section 94 Handbook, CST-18) 

Discussion:

The proposed Imperial County requirements are of similar stringency as the SJV requirements. Other 

items do not necessarily result in reduced emissions, such as Clark County’s requirement for limiting pile 

height near an occupied building. The Maricopa County 12% minimum soil moisture content may be 

useful if opacity measurements are difficult to determine due to intermittent nature of dust plumes. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-18 E N V I R O N 

FUGITIVE DUST CATEGORY: BULK MATERIALS 

SUBCATEGORY: TRANSPORT 

Proposed Imperial County Requirements:

• Completely cover or enclose all Haul Truck loads of Bulk Material (Ref: PR802, Section F.3.a) 

• Haul trucks transporting aggregates shall not be required to cover loads if loads remains six inches 

from upper area of container (Ref: PR802, Section F.3.b) 

• Cargo compartments are to be constructed and maintained so that no spillage and loss of bulk 

material can occur (Ref: PR802, Section F.3.c) 

• Cargo compartment should be cleaned and/or washed at delivery site after removal of bulk material 

(Ref: PR802, Section F.3.d) 

SJV Requirements:

• Limit vehicle speed such that VDE does not exceed 20% (Ref: R8031, Table 8031-1, C1) 

• Maintain at least 6 inches freeboard when crossing paved public access road (Ref: ibid, C2 and D3) 

• Apply water to top of load to limit VDE to 20% opacity (Ref: ibid, C3) 

• Cover haul trucks with tarps or other suitable cover (Ref: ibid, C4) 

• Clean interior of truck before leaving site (Ref: R8031, Table 8031-1, D1) 

• Prevent spillage from holes and openings in floor, side, or tailgate (Ref: ibid, D2) 

South Coast Requirements:

• Cover haul vehicles (R403 Handbook, BACM, (D)) 

• Use bottom-dumping vehicles when feasible (Ref: ibid, (E)) 

• Maintain minimum 6 inches freeboard in high wind conditions (Ref: R403, Table 1, (2E)) 

Maricopa County Requirements:

• Maintain at least 3” freeboard (Ref: R310, Table 1, 1G and 7G) 

• Prevent spillage from holes and openings in floor, side, or tailgate (Ref: ibid, 2G and 8G) 

• Prevent trackout (Ref: ibid, 3G) 

• Limit on-site vehicle speed to 15 mph (Ref: ibid, 4G) 

• Apply water to top of load to limit VDE to 20% opacity (Ref: ibid, 5G) 

• Cover haul trucks with tarps or other suitable closure (Ref: ibid, 6G) 

• Clean interior of truck before leaving site (Ref: ibid, 9G) 

Clark County Requirements:

• Use tarps or other suitable enclosures on haul trucks (Ref: AQR Section 94 Handbook, CST 13-1) 

• Maintain 3-6 inches of freeboard (Ref: ibid, CST 13-2) 

• Check belly-dump truck seals and remove trapped rocks to prevent spillage (Ref: ibid, CST 13-3) 

• Clean wheels and undercarriage before leaving site (Ref: ibid, CST 13-4) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-19 E N V I R O N 

• Limit on-site vehicle speeds to 15 mph (Ref: ibid, CST 13-5) 

• Keep optimum soil moisture when handling material (Ref: ibid, CST 13-6) 

• When loading material: 

• Stabilize to meet VDE requirements (Ref: ibid, CST 22 

• Empty loader bucket slowly (Ref: ibid, CST 22-1) 

• Minimize drop height (Ref: ibid, CST 22-2) 

Discussion:

Proposed Imperial County requirements are very similar to Maricopa County and SJV, with the 

exceptions that the six-inch freeboard requirement is more stringent than the three-inch requirement of 

Maricopa County and Imperial County does not require a vehicle speed limit or require water to be 

applied to the top of the load. Imperial County is considered at least equally stringent as other BACM for 

this category with the exception that Clark County has specified BACM for loading material into the 

transport trucks. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-20 E N V I R O N 

FUGITIVE DUST CATEGORY: BULK MATERIALS 

SUBCATEGORY: OUTDOOR CHUTE/CONVEYOR 

Proposed Imperial County Requirements:

• Spray with water prior to handling and/or at transfer points; or (Ref: PR802, Section F.1.a) 

• Apply and maintain chemical stabilizer; or (Ref: PR802, Section F.1.b) 

• Protect from wind erosion by sheltering or enclosing the operation and transfer line (Ref: R02, 

Section F.1.c) 

SJV Requirements:

• Fully enclose chute or conveyor (Ref: R8031, Table 8031, E1) 

• Operate water spray to wet materials to limit VDE to 20% opacity (Ref: ibid, E2) 

• Wash conveyed materials to remove PM10 to limit VDE to 20% opacity (Ref: ibid, E3) 

South Coast Requirements:

(No equivalent requirements under Rule 403) 

Rule 1157, PM10 Emission Reductions from Aggregate and Related Operations, requires that the operator 

of a facility/operation using a conveyor shall apply dust suppressants or other dust control methods at the 

conveyor including all transfer points where materials are released as necessary to meet the performance 

standards in subparagraph (d)(1)(A), which are opacity and plume requirements. 

Maricopa County Requirements:

(No equivalent requirement under Rule 310) 

Clark County Requirements:

(No equivalent requirement under AQR Section 94) 

Discussion:

SJV and South Coast (aggregate operations only) are the only agency to specify requirements for 

conveyor/chute movement of bulk materials. Imperial County is proposing similar requirements. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-21 E N V I R O N 

FUGITIVE DUST CATEGORY: BULK MATERIALS/STORAGE PILES 

SUBCATEGORY: WINDBLOWN DUST 

Proposed Imperial County Requirements:

There are no specific exemptions for wind events in the proposed Regulation VIII amendments, thus no 

requirements are specified. 

SJV Requirements:

(No specific requirements) 

South Coast Requirements:

• Apply water twice per hour (Ref: R403, Table 1, 1D) 

• Install temporary coverings (Ref: ibid, 2D) 

Maricopa County Requirements:

• Apply water twice per hour (Ref: R310, Table 2, 3B) 

• Cover with tarps, plastic, or other material to prevent wind from removing coverings 

(Ref: ibid, 4B) 

Clark County Requirements:

(No specific requirements for windblown emissions.) 

Discussion:

There are no specific exemptions for wind events in the proposed Regulation VIII amendments. This is 

the most stringent requirement. The measures for both South Coast and Maricopa County are basically 

identical. Thus, the most stringent measures for high-wind exemptions call for watering twice per hour or 

using appropriate coverings. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-22 E N V I R O N 

FUGITIVE DUST CATEGORY: CARRYOUT AND TRACKOUT 

SUBCATEGORY: WHEN TO REMOVE TRACKOUT, CLEAN-UP METHODS 

Proposed Imperial County Requirements:

All sites that are subject to Regulation VIII where carry-out or track-out has occurred on public roads or 

the paved shoulders of a paved public road. 

• Rapidly clean up, by the end of each workday, any Bulk Material tracked out or carried out onto a 

Paved Road surface. (Ref: PR803, Section F.1.a) 

SJV Requirements:

• Remove trackout at end of workday (non-urban areas and if trackout is less than 50 feet (Ref: R8041, 

Section 5.1) 

• For all urban areas, construction projects greater than 10 acres in rural areas, remove immediately if 

trackout exceeds 50 feet. (Ref: R8041, 5.4 & 5.5) 

• Methods: 

o Manual sweeping (Ref: R8041, Section 5.7.1) 

o Rotary brush/broom with sufficient wetting to limit VDE to 20% opacity (Ref: ibid, 5.7.2) 

o Operating PM10-efficient street sweeper with 80% efficiency per SCAQMD R1186 (Ref: ibid, 

5.7.3) 

o Flushing with water in areas without curbs and gutters and without violating NPDES 

requirements. 

South Coast Requirements:

• Remove any trackout greater than 25 feet immediately and at the end of the work day (Ref 

R403(d)(4)) 

• For sites greater than 5 acres or 100 cubic yards import / export, a trackout device or other trackout 

prevention measure is required. 

Maricopa County Requirements:

• Remove trackout at end of workday 

• Remove ASAP if trackout exceeds 50 feet (Ref R308.3(b)(1) and (2)) 

• Methods 

o Operate street sweeper or wet broom with sufficient water at speeds recommended by 

manufacturer (Ref: R310, Table 1, 1H) 

o Manual sweeping (Ref: ibid, 2H) 

Clark County Requirements:

• Clean trackout from streets daily 

• Remove ASAP if trackout exceeds 50 feet (Ref Section 94 Handbook, CST 19) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-23 E N V I R O N 

Discussion:

South Coast’s Rule 403 requires trackout cleanup immediately for any trackout greater than 25 feet; it is 

the most stringent requirement. SJV, Clark County and Maricopa are of similar stringency. SJV and 

Maricopa County specify measures to clean up trackout after it has occurred. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-24 E N V I R O N 

FUGITIVE DUST CATEGORY: CARRYOUT AND TRACKOUT 

SUBCATEGORY: PREVENTION 

Proposed Imperial County Requirements:

All sites with access to a paved road and with ≥ 150 vehicle trips per day, or ≥20 vehicle trips per day by 

vehicles with ≥ 3 axles shall: 

• In addition to F.1.a, all sites shall install one or more Track-Out Prevention Devices or other APCO 

approved track out control devices or wash down system at access points where unpaved traffic 

surfaces adjoin paved roads; or (Ref: PR803, Section F.1.b) 

• In addition to F.1.a, all sites shall apply and maintain paving, chemical stabilization, or at least 3 inch 

depth of gravel for a distances of 50 or more consecutive feet at access points where unpaved roads 

adjoin paved roads (Ref: PR803, Section F.1.c) 

SJV Requirements:

For sites with more than 150 AVT or 20 or more AVT by vehicles with three or more axles: 

• Install trackout control device at all access points to public roads (Ref: R8041, Section 5.8.1) 

• Use approved procedure with equivalent or greater level of control (Ref: ibid, Section 5.8.2) 

South Coast Requirements:

For sites greater than 5 acres or daily import/export greater than 100 cubic yards: 

• Pave, gravel, or chemically stabilize road surface from point of intersection with public paved road to 

distance of at least 100 feet by 20 feet wide (Ref R403, Table 3, (1)) 

• Install trackout control device from point of intersection with public paved road to distance of at least 

25 feet by 20 feet wide (Ref: ibid, (2)) 

Maricopa County Requirements:

• Install grizzly or wheel wash system at all access points (Ref: R310, Table 1, 1J) 

• At all access points, install gravel pad at least 50’ long, 30’ wide, and 6” deep (Ref: ibid, 2J) 

• Pave from point of intersection with public paved road to distance of at least 100 feet by 20 feet wide. 

(Ref: ibid, 3J) 

Clark County Requirements:

• Pave construction roadways as early as possible (Ref: AQR Section 94 Handbook, 

(CST 19-1) 

• Install gravel pads at least 3” deep by 30 feet wide by 50 feet long (or the length of (longest haul truck 

if greater than 50 feet). Use 1” to 3” rough diameter gravel 

o or crushed rock and maintain effectiveness (Ref: ibid, CST 19-2) 

Install wheel shakers if gravel pads are not effective (Ref: ibid, CST 19-3) 

o Install wheel washer if gravel pads and wheel shakers not effective (Ref: ibid, CST 19-4) 

• All exiting traffic must be routed over selected track out controls (Ref, ibid, CST 19) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-25 E N V I R O N 

Discussion:

Proposed Imperial County requirements are similar to those of SJV, although less stringent than South 

Coast, Clark County and Maricopa County requirements. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-26 E N V I R O N 

FUGITIVE DUST CATEGORY: PAVED ROAD DUST 

SUBCATEGORY: NEW/MODIFIED ROADS 

Proposed Imperial County Requirements:

Applies to both public and private roads (Ref: PR805, Section F.4) 

• New paved roads or modifications to existing paved roads with projected average daily vehicle trips > 

500 vehicles shall construct paved shoulder of 4 ft (500-3000 vehicle trips) or 8 ft (> 3000 vehicle 

trips) (Ref: PR805, Section F.4.a) 

• In lieu of F.4.1, a curbing adjacent to and contiguous with the travel lane or paved shoulder or road 

may be constructed (Ref: PR805, Section F.4.b) 

• In lieu of F.4.1, intersections, auxiliary entry lanes and auxiliary exit lanes may be constructed 

adjacent to and contiguous with the roadway Ref: PR805, Section F.4.c) 

• New paved road construction or modifications to an existing paved road that are required to comply 

with CEQA and NEPA determinations regarding environmental, cultural, archeological, historical, or 

other considerations adddressed in such documents, are exempt from the paved shoulder width 

requirements specified in Section F.4.a. (Ref: PR805, Section F.4.d) 

• For Paved Roads with projected annual average daily vehicle trips of 500 or more are constructed, or 

modified with medians, the medians shall be constructed with paved shoulders having a minimum 

width of four feet adjacent to the traffic lanes unless: (Ref: PR805, Section F.4.e) 

o The medians of roads having speed limits set at or below 45 mph are constructed with curbing; or 

(Ref: PR805, Section F.4.e.1) 

o The medians are landscaped and maintained with grass or other vegetative ground cover to 

comply with the definition of Stabilized Surface. (Ref: PR805, Section F.4.e.2) 

SJV Requirements:

Applies to both public and private paved roads (Ref: R8061, Section 5.1.1) 

• Paved shoulders required for all roads with average daily vehicle trips (ADVT) of 500 or more. 

• If ADVT is 500-3000, then average width is 4 feet. If ADVT is greater than 3000, then average 

width is 8 feet. (Ref: R8061, Section 5.1.1.1) 

• Curbing adjacent to and contiguous with paved lane or shoulder can be used in lieu of shoulder width 

requirements (Ref: ibid, Section 5.1.1.2) 

• Intersections, auxiliary entry and exit lanes may be constructed adjacent to and contiguous with paved 

roadway in lieu of shoulder requirements (Ref: ibid, Section 5.1.1.3) 

• If ADVT is 500 or greater, and medians are part of the roadway, then medians are to be constructed 

with minimum 4-foot shoulder widths adjacent to traffic lanes (Ref: ibid, Section 5.1.1.5) 

• Where speed limits are below 45 mph, medians are to be constructed with curbing (Ref: ibid, Section 

5.1.1.5.1) 

• Medians are to be landscaped to meet stabilized surface requirements (Ref: ibid, Section 5.1.1.5.2) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-27 E N V I R O N 

• As an option to shoulder paving or vegetation requirements, oils or chemical dust suppressants can be 

used, according to the specified widths, and must be maintained to limit VDE to 20% opacity (Ref: 

ibid, Section 5.1.2) 

South Coast Requirements:

Applies to both public and private paved roads (Ref R1186(e)(1)): 

• For ADVT of 500 or more, curbing or paved shoulders required: 

o For ADVT 500-3000, shoulder width of at least 4 feet 

o For ADVT greater than 3000, shoulder width of at least 8 feet 

o (Ref: ibid, (e)(1)(A)) 

• For medians with ADVT of 500 or more, pave median area with typical roadway materials, unless 

speed limits less than 45 mph; or medians are landscaped with ground cover and there is curbing; or 

medians are treated with chemical stabilizers to maintain stabilized surface (Ref: ibid, (e)(1)(B)) 

*Contingency notification pertains to certain findings by EPA regarding lack of attainment or rate of 

progress. 

Maricopa County Requirements:

(Note: Maricopa County regulations do not specify requirements for new/modified paved roads; however 

this element is contained in State Legislation and specific commitments by local jurisdictions.) 

• Applicability not specified, but appears to apply to public paved roads: 

• A.R.S. 9-500.04(3) and 49-474.01(4), also known as SB1427 (1998) requires cities, towns and 

counties in a specified area to develop and implement plans to stabilize targeted unpaved roads, 

alleys, and unpaved shoulders on targeted arterials beginning January 1, 2000. The plans must address 

performance goals and reporting requirements. 

• In addition, Maricopa County and 17 local jurisdictions have committed to additional measures to 

stabilize unpaved roads, including paving, graveling, curbs and gutters, and vegetation. 

Clark County Requirements:

• Applies to both public and private paved roads (Ref: AQR Section 93.2.1): 

• Paved travel section must have 4 feet of paved or stabilized shoulder on each side (Ref: AQR Section 

93.2.1.1) 

• If shoulder is not paved, it must be stabilized with dust palliative or gravel to prevent trackout onto 

paved road section (Ref: ibid) 

• Adjacent, contiguous curbing can be used in lieu of shoulder requirements (Ref: ibid, 93.2.1.2) 

• If medians are used, one of the following apply: 

o curbing 

o solid paving across medial 

o use of dust palliative to meet stabilization standards 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-28 E N V I R O N 

o use of rock or landscaping on median to prevent trackout (Ref: ibid, 93.2.1.4) 

• If roads are constructed not in conformance with these requirements, reconstruction must be 

completed within one calendar year. (Ref: ibid, 93.2.1.6) 

Discussion:

The Maricopa County requirements appear to apply more toward the reduction of unpaved road surfaces 

than to specifications for construction of new/modified roads to minimize trackout from shoulders and 

medians. The Imperial County provisions are similar to the South Coast and SJV. Hence, Imperial 

County, SJV, and South Coast requirements appear to be more stringent than Maricopa County. As for 

Clark County, shoulder stabilization is set at four feet, whereas Imperial County and SJV have an 8-foot 

requirement for roads with ADVT greater than 3000. Thus, the Imperial County and SJV requirements 

are most stringent for paved roads with this level of ADVT. On the other hand, Clark County has no 

minimum level of ADVT for stabilizing shoulders, thus it is more stringent than the SJV requirements for 

ADVT levels less than 500. For ADVT of 500 to 3000, the stringency is equivalent. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-29 E N V I R O N 

FUGITIVE DUST CATEGORY: PAVED ROAD DUST 

SUBCATEGORY: EROSION CLEAN-UP 

Proposed Imperial County Requirements:

(No specific requirements for this category) 

SJV Requirements:

(No specific requirements for this category) 

South Coast Requirements:

• Remove material from public paved roads within 72 hours of being notified of such accumulation 

(Ref: R1186(d)(1)) 

Maricopa County Requirements:

• Remove deposits from any (public and private) roadway within 24 hours of identification of such 

condition, by using appropriate control measures to limit VDE to 20% opacity (Ref: R310.01 Section 

306.1a and 306.2) 

• Material disposal must not result in causing new source of fugitive dust (Ref: ibid, 306.1b) 

Clark County Requirements:

(No specific requirements for this category) 

Discussion:

The most stringent requirement (from a time standpoint) was established by Maricopa County with a 

requirement for treatment of such material on the paved road surface within 24 hours of identification. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-30 E N V I R O N 

FUGITIVE DUST CATEGORY: PAVED ROAD DUST 

SUBCATEGORY: STREET SWEEPING 

Proposed Imperial County Requirements:

(No specific requirements for this category) 

SJV Requirements:

(No specific requirements for this category) 

South Coast Requirements:

• Certified PM10-efficient street sweepers must be used by governmental agencies or their street 

sweeping contractors where the contract date, purchase date, or lease date is after January 1, 2000. 

(Ref: R1186(d)(2)) 

• Certified sweepers are to be used for all routine street sweeping except those with curbs, paved road 

shoulders greater than 4 feet width, not within 1000 feet of an unpaved road, and provided 

documentation of such is provided. (Ref: R1186(d)(2) and (i)(3)) 

• Certified sweepers are to be maintained according to manufacturers specifications (Ref: ibid, (d)(3)) 

Maricopa County Requirements:

(No specific rule requirements for routine street sweeping, however the Revised Serious Area PM10 SIP 

[Feb, 2000] contains certain commitments to test the feasibility of using PM10-efficient street sweepers, 

along with commitments from several local jurisdictions to utilize such sweepers according to a proposed 

implementation schedule.) 

Clark County Requirements:

• Any operator who utilizes street sweeping equipment or contracts for street sweeping services must, 

after January 1, 2001, acquire or contact to acquire PM10-efficient street sweeping equipment (Ref: 

AQR Section 93.2.2) 

Washoe County

(Note: Regulation adopted on Feb 27, 2002) 

• Any governmental agency which conducts street sweeping or contract for street sweeping services, 

must purchase or lease PM10-efficient certified street sweepers on or after February 1, 2002. (Ref: 

R040.032, Section A2 and C1) 

• Certified street sweepers must be operated and maintained according to manufacturer’s specifications 

(Ref: ibid, C2) 

Routine street sweeping must be conducted a minimum of once per month (Ref: ibid, C4) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-31 E N V I R O N 

Discussion:

PM10-efficient street sweepers, as determined by South Coast Rule 1186 test method, can capture the finer 

particles. Since South Coast, Washoe County, and Clark County have rule provisions to employ PM10-

efficient street sweepers for routine street sweeping, these are considered to be most stringent. 

As noted in the SJVUAPCD “BACM/BACT and RACM/RACT Demonstration for Sources of PM10 and 

PM10 Precursors in the San Joaquin Valley Air Basin,” (dated April 28, 2003), “use of these units will 

result in safety problems on freeways and rural roads in flat terrain.” The overwhelming majority of 

roads in Imperial County are freeways or rural roads in flat terrain. 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-32 E N V I R O N 

FUGITIVE DUST CATEGORY: FEEDLOTS AND RELATED OPERATIONS 

SUBCATEGORY: CONTROL MEASURES 

Proposed Imperial County Requirements:

ICAPCD Rule 420 requires any person using or operating a Livestock Feed Yard to acquire and maintain 

a "Livestock Feed Yard Certificate." Application, fee and renewal requirements for such a certificate are 

substantially the same as those set out in Regulation II for permits, except as provided. An application for 

a Livestock Feed Yard certificate shall include a written plan designed to effectively control Dust. Such 

Dust control plan shall contain the following: 

• Procedures for assuring Manure at all times is maintained at a moisture factor 

• between 20% and 40%, in the top three inches (3") in occupied pens. 

• An outline of Manure management practices, including standards and time tables for manure removal, 

designed to effectively control Dust and to prevent adverse public health conditions. 

SJV Requirements:

For feedlot operations with more than 190 cows, SJVAPCD Rule 4550 requires the submittal of a 

conservation management plan with 1 conservation management practice (CMP) for each category: 

• Pens / Manure Handling: 

o Sprinkle 

o Frequent scraping and/or removal of manure 

o Fibrous layer in working areas 

o Pull-type manure harvesting equipment 

o Shade for animals 

• Overall Management / Feeding: 

o Bulk materials control 

o Feeding near dusk 

o Wet feed during mixing 

o Place wet material in feedwagon first 

o Downwind shelterbelts / boundary trees 

• Unpaved roads and traffic areas: 

o Dust suppressants 

o Gravel 

o Access restriction 

o Speed reduction 

o Pavement 

o Trackout control 

o Appropriate equipment and vehicles 
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South Coast Requirements:

For livestock operations of 10 acres or larger: 

• Cease hay-grinding activities between 2 and 5 pm if visible emissions extend more than 50 feet from 

the source (Ref: R1186(d)(5)) 

• Treat all unpaved access connections and unpaved feed lane access areas with pavement, gravel to a 

depth of four inches, or asphaltic road base (Ref: R1186(d)(6)) 

• Rule 1127 requires choosing a best management practice for dust: 

o Scrape or harrow before 9 am only unless the moisture content of the manure is greater than 20% 

throughout the corral, as determined by an moisture meter in accordance with paragraph(h)(1); 

OR 

o Clear corrals such that an even surface of compacted manure remains on top of the soil and do not 

scrape down to soil level; OR 

o Water corral before manure removal to reduce dust through increased surface moisture. This 

measure is not required for lactating cows. 

Maricopa County Requirements:

For commercial feedlots and commercial livestock areas: 

• Apply dust suppressants to limit VDE to 20% opacity (Ref R310.01, Section 305.1a), or 

• Apply and maintain surface gravel to limit VDE to 20% opacity (Ref: ibid, 305.1b), or 

• Install shrubs and/or trees within 50 to 100 feet of animal pens to limit VDE to 20% opacity (Ref: 

ibid, 305.1c) 

Clark County Requirements:

(No specific requirements for feedlots.) 

Discussion:

For livestock and feedlots, Imperial County’s requirements for the feedlots themselves can be considered 

most stringent since they require a specific moisture level be maintained in the feedlots. SJV, South 

Coast and Maricopa County have taken steps to reduce emissions, mainly from disturbed surfaces. South 

Coast has a de minimis size of 10 acres, whereas Maricopa County does not specify a minimum size. 

Hence the application of measures to control dust from unpaved roads and access areas is more stringent 

in Maricopa County. South Coast has provisions for hay grinding activity, which is not contained in 

Maricopa County. 
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FUGITIVE DUST CATEGORY: BUREAU OF LAND MANAGEMENT (BLM) AND BORDER 

PATROL (BP) AREAS AND ACTIVITIES 

SUBCATEGORY: REQUIREMENTS 

Proposed Imperial County Requirements:

The BLM shall prepare a Dust Control Plan that includes the following: (Ref: PAR800, Section F.5): 

• Stipulate that all new authorizations for stationary emission sources obtain all necessary permits and 

satisfy all applicable SIP provisions, including project- or activity- specific BACM; 

• A summary of: the total miles of BLM roads that are paved, paved with unpaved shoulders, and 

unpaved roads with 50 or more vehicle trips per day, including length and level of usage of each such 

road; the priority for control of road segments based on annual and episodic (e.g. event) usage; the 

plans for control of PM10 emissions from these roads; the location and extent (e.g. acreage) of open 

areas disturbed by legal and illegal recreational use; the priority for control of these open areas based 

on annual and episodic (e.g. event) usage; and the plans for control of PM10 emissions from these 

areas. 

o BLM must demonstrate in its Dust Control Plan that unpaved roads, parking, and open areas are 

controlled pursuant to the applicability and requirements of Rules 804 and 805 except where 

measures are demonstrated by BLM to be prohibited by federal or state laws, regulations, or 

approved plans concerning wilderness preservation and species management and recovery. 

o Where compliance with any control measure in Rules 804 and 805 is prohibited pursuant 

to F.5.b.1, the Dust Control Plan must discuss and commit to implement other possible 

control measures, such as vehicle speed limits.

o The Dust Control Plan must describe all PM-10 control measures that will be implemented, such 

as restricted use areas, stabilization of unpaved traffic areas and current RAMP measures, to 

reduce PM10 emissions during off-road events and/or competitions on public land and include all 

those measures that are feasible and not prohibited by the laws, regulations and plans described in 

F.5.b.1 

• Use BLM-standard road design and drainage specifications when maintaining existing roads or 

authorizing road maintenance and new road construction; and 

• Include public educational information on PM10 emissions with BLM open area literature and on 

information signs in heavily used areas. 

The BP shall prepare a Dust Control Plan that includes the following fugitive dust control measures 

(Ref: PAR800, Section F.5): 

• Stipulate that all new authorizations for stationary emission sources obtain all necessary permits and 

satisfy all applicable SIP provisions, including project-or activity- specific BACM; 

• Implement alternatives to tire-dragging for monitoring of immigration across the U.S.-Mexico border; 

and 
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• Control dust emissions from certain roads and routes as identified through general BP planning. 

SJV Requirements:

(No specific requirements for this category) 

South Coast Requirements:

(No specific requirements for this category) 

Maricopa County Requirements:

(No specific requirements for this category) 

Clark County Requirements:

(No specific requirements for this category) 

Discussion:

Unpaved roads and disturbed open areas are considered significant sources of PM10 in Imperial County. 

There are unpaved roads in the lands administered by BLM and the USFS; entrained and windblown dust 

from these roads is 1.8 tons/day, less than 2% of the 92 tons/day for all unpaved roads. Almost all of the 

unpaved roads on BLM and USFS lands have traffic levels under the Rule 805 threshold of 50 ADT. Of 

the over 2,666,600 acres in Imperial County over 77% is scrubland, barren land, or sand dunes. Most of 

this land is administered by BLM and the USFS. Except for areas used by the military or lands set aside 

for OHV use, most of the land is disturbed only by wind, water, and native animals. The lack of 

“destination” national or state parks, low County population density, general remoteness, and high 

summer temperatures minimizes man-made disturbances on most of this land. The exception to this is 

special off-roading events held in the dune areas. These special events occur 5 to 10 times per year, for a 

few days each. The BLM Dust Control Plan in PAR 800 requires control measures for these special 

events, even if annual or average day usage does not meet the thresholds in Rules 804 and 805. 

The only Imperial County significant sources on BLM lands are unpaved roads and disturbed open areas. 

In addition, PAR 800 only exempts the recreational use of public lands (e.g., OHVs, all-terrain vehicles, 

trucks, cars, motorcycles, motorbikes or motorbuggies), not other dust-producing activities such as 

construction, etc. The BLM Dust Control Provisions make clear that any stationary source activity must 

meet all applicable SIP provisions, including project- or activity-specific BACM. Thus, the focus of the 

Dust Control Plan provisions are on unpaved road and disturbed open area sources related to the 

recreational use of public lands. 

BLM sources are considered separate from the general dust source categories; this is in recognition of the 

special federal purposes of these agencies (e.g., habitat preservation and compliance with other areaspecific environmental laws) and the inconsistency of requiring certain traditional dust control methods 

on these sources (e.g., vegetating disturbed dune areas approved for off-highway vehicle recreational 

use.). Many restrictions apply to actions on federal lands that have special purposes, such as habitats, 

national monuments and preserves. Common dust control measures, such as chemical stabilization and 
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D R A F T F I N A L D-36 E N V I R O N 

paving would not be allowed if it endangered native wildlife or affected habitats. BLM is required to 

determine if a proposed dust control project conforms with the approved land use plan terms and 

conditions, as required by CFR 1610.5. Examples of such laws and plans include the federal Endangered 

Species Act, the California Desert Protection Act, the California Desert Conservation Area Plan and 

related tiered plans( e.g. the Yuha Basin ACEC Management Plan, Yuha Desert Habitat Management 

Plan, Yuha Desert Management Plan, Imperial San Dunes Recreation Area Management Plan (RAMP), 

Algodones Dunes Habitate Management Plan, Flat-tailed Horned Lizard Rangewide Strategy and 

Recovery Plan for Bighorn Sheep in the Peninsular Ranges, CA). 

BLM also must meet the requirements of NEPA for its projects. BLM is the appropriate lead agency for 

both NEPA and conformity determinations for dust control projects on BLM lands; mandating Rule 804 

and 805 requirements without consideration of NEPA and conformity issues could unnecessarily involve 

ICAPCD in these issues and potentially delay implementation of proposed dust control programs. 

Mandating PR 804 and 805 could also put BLM in the position of either violating an ICAPCD rule or 

potentially requiring a finding of overriding concerns for a given Environmental Assessment. 

Furthermore, any action on the use of the BLM lands has been highly litigious. Were ICAPCD to 

unilaterally impose requirements on BLM, it is possible that litigation and a temporary suspension of 

those rules while the litigation is resolved will occur. Thus, proposed Regulation VIII establishes a 

separate control program for the BLM lands, rather than imposing general Regulation VIII requirements 

on them on a dust source by dust source basis. ICAPCD believes that this is the most appropriate way to 

reduce emissions from federal sources. 

ICAPCD and BLM have worked together on previous dust control programs, including the inclusion of 

PM10 control measures in the RAMP. BLM has also included PM10 prevention and mitigation measures 

based on its Environmental Assessment of its road and trail maintenance activities related to Border 

Patrol activities. Appendix F is the Environmental Assessment for this project. It is an example of the 

detailed environmental analysis required for projects on BLM lands and the use of the NEPA process to 

identify and implement PM10 prevention and mitigation measures. 
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FUGITIVE DUST CATEGORY: WEED ABATEMENT ACTIVITIES 

SUBCATEGORY: REQUIREMENTS 

Proposed Imperial County Requirements:

(No specific requirements for this category) 

SJV Requirements:

There are no specific requirements for weed abatement, other than in the definition for “earthmoving 

activities.” However, in the “applicability” section of Rule 8021, weed abatement actions are not 

specifically identified. It can be presumed that the following actions apply: 

• Pre-activity 

o Pre-water to limit VDE to 20% opacity (Ref 8021, Table 8021-2) 

o Phase work to reduce amount of disturbed surface area (Ref: ibid) 

• During Active Operations 

o Apply water to limit VDE to 20% opacity (Ref: ibid) 

• Stabilization During Periods of Inactivity 

o Restrict vehicle access to area 

o Apply water or chemical stabilizers to meet conditions of a stabilized surface (Ref: ibid) 

South Coast Requirements:

• Such activities subject to standards of Rule 403, unless: 

a) Mowing or cutting is used, instead of discing, and maintains stubble at least three inches above 

the soil (Ref R403(h)(1)(H)(i)) 

b) If discing is used, there is a determination of a potential fire hazard 

(Ref: ibid, (ii)) 

• After discing, requirement for taking action on disturbed surface areas apply 

(Ref: ibid) 

Maricopa County Requirements:

• For weed abatement by discing or blading: 

o Pre-water and take post-discing actions (Ref: R310, Section 308.8 & Table 1, 1K) 

o Apply water during activity and take post-discing actions (Ref: ibid, 2K) 

o Post-discing/blading actions to meet requirement for stabilized surface: 

a) pave 

b) apply gravel 

c) apply water 

d) apply dust suppressant 

(Ref: ibid, 3K) 

e) establish vegetative ground cover (Ref: ibid, 4K) 
Technical Memorandum: Regulation VIII BACM Analysis October 2005 

D R A F T F I N A L D-38 E N V I R O N 

Clark County Requirements:

• If discing or blading is used on lots greater than 5000 square feet, then all of the following apply: 

a) apply water before discing/blading 

b) apply water during activity 

c) implement one of the following for stabilized surface: 

i) pave 

ii) apply water 

iii) apply dust palliative 

(Ref: AQR Section 90.2.2 and 90.2.2.1) 

Discussion:

The SJV requirements are somewhat vague in the sense that the only mention of weed abatement is in the 

definition of “earthmoving activities” without any further specificity for actions specific to weed 

abatement. In other approaches, Clark County and Maricopa County are very similar, except that 

Maricopa County does not have a de minimis area, and so it is considered to be more stringent in this 

case. South Coast goes one extra step in preventing soil disturbance by encouraging cutting or mowing in 

preference to discing.