CALIFORNIA AIR RESOURCES BOARD

SIP COMPLETENESS CHECKLIST

(Electronic Format)

*** TO BE COMPLETED BY DISTRICT AND RETURNED TO ARB ***

All rules submitted to the EPA as State Implementation Plan (SIP) revisions must be supported by certain information and 

documentation for the rule packages to be deemed complete for review by the EPA. Rules will not be evaluated for 

approvability by the EPA unless the submittal packages are complete. To assist you in determining that all necessary 

materials are included in rules packages sent to the ARB for submittal to the EPA, please fill out the following form and 

include it with the rule package you send ARB. See the ARB's Guidelines on the Implementation of the 40 CFR 51, 

Appendix V, for a more detailed explanation than is provided here. Adopted rules and rule amendments should be checked 

against U.S. EPA's Guidance Document for Correcting Common VOC & Other Rule Deficiencies (Little Blue Book, August 

21, 2001) to ensure that they contain no elements which will result in disapproval by EPA.

District: Imperial County APCD

Rule No: 800

Rule Title: General Requirments For Control of Fine Particulate Matter (PM10)

Date Adopted or Amended: November 8, 2005

ADMINISTRATIVE MATERIALS

Note: All documents should be in electronic format. Items that have signatures, initials, or stamps may be scanned.

Not

Attached Attached N/A

COMPLETE COPY OF THE RULE: Provide an unmarked copy of the entire rule 

as adopted or amended by your District Board.

UNDERLINE AND STRIKEOUT COPY OF THE RULE: If an amended rule, 

provide a complete copy of the rule indicating in underline and strikeout format 

all language which has been added, deleted, or changed since the rule was last 

adopted or amended.

COMPLETE COPY OF THE REFERENCED RULE(S): For any rule which

includes language specifically referencing another rule, a copy of that other rule 

must also be submitted, unless it has already been submitted to EPA as part 

of a previous SIP submittal.

PUBLIC NOTICE EVIDENCE: Include a copy of the local newspaper clipping 

certification(s), stating the date of publication, which must be at least 30 days 

before the hearing. As an alternative, include a copy of the actual published 

notice of the public hearing as it appeared in the local newspaper(s). In this 

case, however, enough of the newspaper page must be included to show the 

date of publication. The notice must specifically identify by title and number 

each rule adopted or amended.

RESOLUTION/MINUTE ORDER: Provide the Board Clerk certified resolution or 

minute order. This document must include certification that the hearing was 

held in accordance with the information in the public notice. It must also list 

the rules that were adopted or amended, the date of the public hearing, and a 

statement of compliance with California Health and Safety Code Sections

40725-40728 (Administrative Procedures Act).

PUBLIC COMMENTS AND RESPONSES: Submit copies of written public 

comments made during the notice period and at the public hearing. Also

submit any written responses prepared by the District staff or presented to the 

District Board at the public hearing. A summary of the public comments and 

responses is adequate. If there were no comments made during the notice 

period or at the hearing, please indicate N/A to the left.
5/1/2002

CALIFORNIA AIR RESOURCES BOARD

SIP COMPLETENESS CHECKLIST

(Electronic Format)

TECHNICAL MATERIALS

Note: All documents and forms should be in electronic format.

Not

Attached Attached N/A

RULE EVALUATION FORM: See instructions for completing the Rule Evaluation 

Form and the accompanying sample form.

NON-EPA TEST METHODS: Attach all test methods that are referenced in your 

rule that do not appear in 40 CFR 51, 60, 61, 63, or have not been previously 

submitted to EPA. EPA methods used in other media such as SW846 for solid 

waste are not automatically approved for air pollution applications. Submittal of 

test methods that are not EPA-approved should include the information and 

follow the procedure described in Region 9’s “Test Method Review & Evaluation 

Process.”

MODELING SUPPORT: Provide if appropriate. In general, modeling support is 

not required for VOC and NOx rules to determine their impacts on ozone levels. 

Modeling is required where a rule is a relaxation that affects large sources (>

100 TPY) in an attainment area for SO2, directly emitted PM10, CO, or NOx 

(for NO2 purposes). In cases where EPA is concerned with the impact on air 

quality of rule revisions which relax limits or cause a shift in emission patterns 

in a nonattainment area, a reference back to the approved SIP will be sufficient 

provided the approved SIP accounts for the relaxation and provided the approved 

SIP used the current EPA modeling guidelines. If current EPA modeling

guidelines were not used, then new modeling may be required.

ECONOMIC AND TECHNICAL JUSTIFICATION FOR DEVIATIONS FROM EPA 

POLICIES: The District staff report or other information included with the

submittal should discuss all potential relaxations or deviations from RACT, 

RACM, BACT, BACM, enforceability, attainment, RFP, or other relevant EPA 

requirements. This includes, for example, demonstrating that exemptions or 

emission limits less stringent than the presumptive RACT (e.g., a CTG) meet 

EPA’s 5 percent policy, and demonstrating that all source categories exempted 

from a RACM/BACM rule are de minimus according to EPA’s RACM/BACM 

policy.

ADDITIONAL MATERIALS: Provide District staff reports and any other

supporting information concerning development of the rule or rule changes. This 

information should explain the basis for all limits and thresholds contained in 

the rule.
CALIFORNIA AIR RESOURCES BOARD

APCD/AQMD RULE EVALUATION FORM – Page 1

(Electronic Format)

I. GENERAL INFORMATION

District: Imperial County Air Pollution Control District

Rule No(s): Rule 800 Date adopted/Amended/Rescinded: Amended November 8, 2005

Rule Title(s): General Requirements For Control of Fine Particulate Matter (PM-10)

Date Submitted to ARB: March 30, 2006

If an Amended Rule, Date Last Amended (or Adopted): November 25, 1996

Is the Rule Intended to be Sent to the U.S. EPA as a SIP Revision? Yes No (If No, do not complete remainder of form)

District Contact: Reyes Romero Phone Number: (760) 482-4606 E-mail Address: reyesromero@imperialcounty.net

Narrative Summary of New Rule or Rule Changes: New Rule Amended Rule

Rule 800 is the first of a series of seven rules which together form Regulation VIII, Fugitive Dust Control. On August 

11, 2004 the Imperial County was redesignated as a "serious"non attainment area for PM10. This rule, as an 

integral part of regulation VIII, was amended to help fullfill the requirement of Best Available Control Measures 

(BACM.) Rule 800 applies at any active operation and/or man-made condition or practice with the potential to 

generate fugitive dust (PM10.) This rule is the general requirements section of Regulation VIII. It includes 

definitions, record implementation, compliance and test methods. 

Pollutant(s) Regulated by the Rule (Check): ROG (NOx) SO2

 (CO) PM TAC (name):

II. EFFECT ON EMISSIONS

Complete this section ONLY for rules that, when implemented, will result in quantifiable changes in emissions. Attach reference(s) for emission 

factor(s) and other information. Attach calculation sheet showing how the emission information provided below was determined.

Net Effect on Emissions: Increase Decrease N/A

Emission Reduction Commitment in SIP for this Source Category: N/A

Inventory Year Used to Calculate Changes in Emissions: N/A Area Affected: N/A

Future Year Control Profile Estimate (Provide information on as many years as possible):

N/A
CALIFORNIA AIR RESOURCES BOARD

APCD/AQMD RULE EVALUATION FORM - Page 2

(Electronic Format)

Baseline Inventory in the SIP for the Control Measure: N/A

Emissions Reduction Commitment in the SIP for the Control Measure: N/A

Revised Baseline Inventory (if any): N/A

Revised Emission Reduction Estimate (if developed): N/A

Note that the district’s input to the Rule Evaluation Form will not be used as input to the ARB’s emission forecasting and 

planning.

III. SOURCES/ATTAINMENT STATUS

District is: Attainment Nonattainment Split

Approximate Total Number of Small (<100 TPY) Sources Affected by this Amendment: N/A

Percent in Nonattainment Area: N/A%

Number of Large (> 100 TPY) Sources Controlled: N/A Percent in Nonattainment Area: N/A%

Name(s) and Location(s) (city and county) of Large (> 100 TPY) Sources Controlled by Rule (Attach additional sheets as 

necessary): N/A

IV. EMISSION REDUCTION TECHNOLOGY

Does the Rule Include Emission Limits that are Continuous? Yes No

If Yes, Those Limits are in Section(s) of the Rule.

Other Methods in the Rule for Achieving Emission Reductions are: 

V. OTHER REQUIREMENTS

The Rule Contains:

Emission Limits in Section(s): Work Practice Standards in Section(s): 

Recordkeeping Requirements in Section(s): H Reporting Requirements in Section(s): H
5/1/2002

CALIFORNIA AIR RESOURCES BOARD

APCD/AQMD RULE EVALUATION FORM - Page 3

(Electronic Format)

VI. IMPACT ON AIR QUALITY PLAN

 No Impact Impacts RFP Impacts attainment

Discussion: Rule 800 is an administrative rule. This rule includes definitions, record implementation, compliance and test 

methods.
Imperial County Air Pollution Control District DRAFT Rule 800

October 7, 2005

1

RULE 800. GENERAL FUGITIVE DUST REQUIREMENTS FOR CONTROL OF FINE 

PARTICULATE MATTER (PM-10) 

(Adopted 10/10/94; revised 11/25/96; revised -------------)

A. General Description

The purpose of this regulation is to reduce the amount of fine Particulate Matter (PM-10) 

entrained in the ambient air as a result of emissions generated from anthropogenic 

(man-made) Fugitive Dust (PM-10) sources generated from within Imperial County by 

requiring actions to prevent, reduce, or mitigate PM-10 emissions. This Regulation 

contains EPA required Reasonably Available Control Measures (RACM) to be included 

in the Imperial County Air Pollution Control District (APCD) Non-Attainment Area Plan

for attaining the National Ambient Air Quality Standards for PM-10. The Rules

contained within this Regulation have been developed pursuant to United States

Environmental Protection Agency guidance for Serious PM10 Non Attainment Areas. 

B. Applicability

The requirements of this rule Regulation shall apply to any Active Operation, and/or 

man-made or man-caused condition or practice capable of generating Fugitive Dust (PM10) as specified in this Regulation except those determined exempt as defined in Part E of 

this Rule Regulation. The definitions, exemptions, requirements, administrative 

requirements recordkeeping requirements, and test methods set forth in this rule are 

applicable to all the rules under Regulation VIII (Fugitive Dust Requirements) of the 

Rules and Regulations of the Imperial County Air Pollution Control District.

C. Definitions

For the purpose of this Regulation, the following terms are defined:

C.1 ACTIVE OPERATION: Activities capable of generating Fugitive Dust (PM-10) 

conducted for industrial, commercial, state, federal, city, county or special district 

purposes and their contractors, including but not limited to, Earthmoving 

Activities, Construction activities, Unpaved Roads, Track-Out/Carry-Out, Bulk 

Material storage and transport, Unpaved Haul/Access Roads.

C.2 AGGREGATE MATERIALS: Consists of sand, Gravel, quarried stone and/or 

rock fragments that are typically used in Construction. Aggregates may be 

natural, artificial or recycled.

C.3 ANEMOMETRS: Are devices used to measure wind speed and direction in

accordance with manufacturer’s performance standards, maintenance and

calibration criteria.
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C.4 ANNUAL AVERAGE DAILY VEHICLE TRIPS: annual average 24-hour total 

of all vehicles counted on a road.

C.25 APCD: The Imperial County Air Pollution Control District.

C.36 APCO: The Imperial County Air Pollution Control Officer. 

C.7 AVERAGE VEHICLE TRIPS PER DAY: Means the average number of vehicles 

that cross a given point surface during a specific 24-hour period as determined by 

the most recent Institute of Transportation Engineers trip generation manual, tube 

counts, or observations. 

C.8 BLM: The Bureau of Land Management.

C.9 BP: The United States Border Patrol.

C.410 BULK MATERIAL: Earth, rock, Silt, sediment, sand, Gravel, soil, fill,

Aggregate, dirt, mud, debris, and other organic and/or inorganic material

consisting of or containing Particulate Matter with five percent or greater Silt 

content. For the purpose of this Regulation, the Silt content level is assumed to be 

5 percent or greater, unless the Person responsible for the Active Operation

conducts the applicable laboratory tests and demonstrate that the Silt content is 

less than 5 percent. Active Operations seeking to determine if the Silt content is 

less than five percent are required to conduct the laboratory analysis in

accordance with ASTM method C-136-a (Standard Test Method for Sieve

analysis of Fine and Coarse Aggregates), or other equivalent test methods

approved by EPA, ARB, and the APCD. Attachment A is ASTM method C-136, 

attachment B is ASTM method D-75 for sampling aggregate material.

C.511 CANAL BANK: A rise of land on either side of an irrigation canal.

C.612 CHEMICAL STABILIZATION/SUPPRESSION: A means of Fugitive Dust

(PM-10) control implemented to mitigate PM-10 emissions by applying

petroleum resins, asphaltic emulsions, acrylics, adhesives, or any other materials 

approved for use by the California Air Resources Board (CARB), U.S.

Environmental Protection Agency (U.S. EPA) and/or the APCO.

C.13 CONSTRUCTION: Any on-site mechanical activities preparatory to or related to

the building, alteration, rehabilitation, or demolition of an improvement on real 

property, including, but not limited to, land clearing, excavation related to

construction, land leveling, grading, cut and fill grading, and the erection or 

demolition of any structure. As used in Regulation VIII, a construction site may 

encompass several contiguous parcels, or may encompass only a portion of one 
Imperial County Air Pollution Control District DRAFT Rule 800

October 7, 2005

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parcel, depending on the relationship of the property boundaries to the actual 

construction activities.

C.714 DESIGNATED REPRESENTATIVE: The agent for a Person. The Designated 

Representative shall be responsible for and have the full authority to implement 

RBACM on behalf of the Person.

C.15 EARTHMOVING ACTIVITIES: The use of any equipment for an activity that 

may generate Fugitive Dust emissions, including, but not limited to, cutting and 

filling, grading, leveling, excavation, trenching, loading or unloading of Bulk 

Materials, demolishing, drilling, adding to or removing bulk of materials from 

open storage piles, weed abatement through disking, and back filling.

C.816 FUGITIVE DUST: The Particulate Matter entrained in the ambient air which is 

caused from man-made and natural activities such as, but not limited to,

movement of soil, vehicles, equipment, blasting, and wind. This excludes

Particulate Matter emitted directly in the exhaust of motor vehicles or other fuel 

combustion devices, from portable brazing, soldering, or welding equipment, pile 

drivers, and stack emissions from stationary sources.

C.917 GRAVEL: Gravel travelways shall have a three (3) inch minimum depth

Stabilized Surface. The travelway shall have a relative compaction of not less 

than 90% 95% as determined by Test Method No. California 216 of State of 

California, Business and Transportation Agency Department of Transportation, 

and conforming to the following grading:

3⁄4” Maximum

Sieve Designation Percent Passing

1 1⁄2"1” 100

3/4"3⁄4” 85-95 90-100

#4 55-75 35-60

#30 25-45 10-30

#200 15-25* 2-9

*(with <5% Silt)

Reference: County of Imperial Department of Public Works Standard S-1101.

 California Department of Transportation Standard Specification 

 Section 26/class II Aggregate Base

C.1018HAUL/ACCESS ROAD: Any on-site road used for commercial, industrial,

institutional, and/or governmental traffic, excluding Haul/Access Roads used for 

agricultural operations. 

C.1119HAUL TRUCK: Any fully or partially open-bodied licensed motor vehicle used 

for transporting Bulk Material for industrial or commercial purposes.
Imperial County Air Pollution Control District DRAFT Rule 800

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C.1220IMPLEMENT OF HUSBANDRY: An unlicensed vehicle which is used

exclusively in the conduct of Agricultural Operations. An Implement of

Husbandry does not include a vehicle if its existing design is primarily for the 

transportation of persons or property on a highway, unless specifically designated 

as such by some other provision of the Vehicle Code of California.

C.21 NON-RESIDENTIAL AREA: Any unpaved vehicle and equipment traffic area 

operated at any commercial, manufacturing or government sites. 

C.22 MODIFIED PAVED ROAD:Any Paved Road that is widened or improved so as 

to increase traffic capacity. This term does not include road maintenance, repair, 

chip seal, pavement or roadbed rehabilitation that does not affect roadway

geometrics, or surface overlay work.

C.23 OFF-FIELD AGRICULTURAL SOURCE: Any Agricultural Source or activity at 

an Agricultural Source that falls into one or more of the following categories:

C.23.a Outdoor handling, storage and transport of Bulk Material;

C.23.b Paved Road;

C.23.c Unpaved Road; or

C.23.d Unpaved Traffic Area.

C.1324OFF-ROAD VEHICLE: Any nonstationary device, powered by an internal

combustion engine or motor, used primarily off the highways to propel, move, or 

draw persons or property including any device propelled, moved, or drawn

exclusively by human power, and used in, but not limited to, any of the following 

applications: marine vessels, construction/farm equipment, utility and lawn and 

garden equipment, off-road motorcycles, and off-highway vehicles.

C.25 ON-FIELD AGRICULTURAL SOURCE: Any Agricultural Source or activity at 

an Agricultural Source that is not an Off-Field Agricultural Source, including (but 

not limited to) the following:

C.25.a Activities conducted solely for the purpose of preparing land for the 

growing of crops or the raising of fowl or animals, such as brush or timber 

clearing, grubbing, scraping, ground excavation, land leveling, grading, 

turning under stalks, disking, or tilling;

C.25.b Drying or pre-cleaning of agricultural crop material on the field where it 

was harvested;
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C.25.c Handling or storage of agricultural crop material that is baled, cubed, 

pelletized, or long-stemmed, on the field where it was harvested, and the 

handling of fowl or animal feed materials at sites where animals or fowl 

are raised;

C.25.d Disturbances of cultivated land as a result of fallowing, planting,

fertilizing or harvesting.

C.26 OPEN AREA: Any of the following described in Subsection C.26.a through 

C.26.c of this rule. For the purpose of this rule, vacant portions of residential or 

commercial lots and contiguous parcels that are immediately adjacent to and 

owned and/or operated by the same individual or entity are considered one open 

area. An open area does not include any Unpaved Traffic Area as defined in this 

rule.

C.26.a An un-subdivided or undeveloped land adjoining a developed (or partially 

developed) residential, industrial, institutional, governmental, or

commercial area.

C.26.b A subdivided residential, industrial, institutional, governmental, or

commercial lot, which contains no approved or permitted building or 

structures of a temporary or permanent nature.

C.26.c A partially developed residential, industrial, institutional, governmental, or 

commercial lot and contiguous lots under common ownership.

C.1427PARTICULATE MATTER: Any material, except uncombined water, which

exists in a finely divided form as a liquid or solid at 60 degrees F and one 

atmosphere pressure.

C.1528PAVED ROADS:An improved street, highway, alley, public way, that is covered 

by concrete, asphaltic concrete, or asphalt.

C.1629PERSON: Any individual, public or private corporation, partnership, association, 

firm, trust, estate, municipality, or any other legal entity whatsoever which is 

recognized by law as the subject of rights and duties, who is responsible for an 

Active Operation.

C.17 PHYSICAL STABILIZATION: A means of dust control implemented to

mitigate PM-10 emissions by applying vegetation, Gravel, recrushed/recycled 

asphalt or any other materials or methods specified for use by U.S. EPA, CARB 

and/or the APCO.
Imperial County Air Pollution Control District DRAFT Rule 800

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C.1830PM-10: Particulate Matter with an aerodynamic diameter smaller than or equal to 

a nominal 10 microns as measured by the applicable State and Federal reference 

test methods. 

C.19. REASONABLY AVAILABLE CONTROL MEASURE (RACM): A technique, 

practice, or procedure as identified in Section I of this Regulation that is used to 

prevent or minimize the generation, emission, entrainment, suspension and/or 

airborne transport of Fugitive Dust (PM-10). 

C.31 RECREATIONAL USE: the recreational use of public lands covered by the most 

recent BLM dust control plan.

C.2032SILT: Any Aggregate Material with a particle size less than 75 micrometers in 

diameter as measured by a No. 200 sieve as defined in ASTM D-2487 

(attachment C, subsection 3.1.4 and as tested by ASTM-C-136 or other equivalent 

test methods approved by EPA, ARB, and the APCD. (attachment A).

C.33 STABILIZED SURFACE: Any disturbed surface area 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 this 

Section and as determined by the test methods specified in Appendix B of this 

rule:

C.33.a A visible crust; or

C.33.b A threshold friction velocity (TFV) for disturbed surface areas corrected 

for non-erodible elements of 100 centimeters per second or greater; or

C.33.c A flat vegetative cover of at least 50 percent that is attached or rooted 

vegetation; or unattached vegetative debris lying on the surface with a 

predominant horizontal orientation that is not subject to movement by

wind; or

C.33.d A standing vegetative cover of at least 30 percent that is attached or rooted 

vegetation with a predominant vertical orientation; or

C.33.e A standing vegetative cover that is attached or rooted vegetative with a 

predominant vertical orientation that is at least 10 percent and where the 

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

elements; or

C.33.f A surface that is greater than or equal to 10 percent of non-erodible 

elements such as rocks, stones, or hard-packed clumps of soil.
Imperial County Air Pollution Control District DRAFT Rule 800

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C.34 Stabilized Unpaved Road: Any Unpaved Road or unpaved vehicle/equipment 

traffic area surface which meets the definition of Stabilized Surface as determined 

by the test method in Appendix B, Section C of this rule, and where VDE is 

limited to 20% opacity.

C.35 TACTICAL TRAINING: Training conducted by the U.S. Department of Defense, 

the U.S. military services, or its allies for combat, combat support, combat service 

support, tactical or relief operations. Examples include but are not limited to 

munitions training.

C.36 TEMPORARY UNPAVED ROAD: Any Unpaved Road surface which is created 

to support a temporary or periodic activity and the use of such road surface is 

limited to vehicle access for a period of not more than six months during any 

consecutive three-year period. 

C.37 THRESHOLD FRICTION VELOCITY (TFV): The corrected velocity necessary 

to initiate soil erosion as determined by the test method specified in Appendix B, 

Section D, of this rule. The lower TFV, the greater the propensity for fine 

particles to be lifted at relatively low wind speeds.

C.2138TRACK-OUT/CARRY-OUT: Any and all Bulk Materials that adhere to and 

agglomerate on the exterior surfaces of motor vehicles and/or equipment

(including tires) and excluding Implements of Husbandry and that may then fall 

onto the pavement.

C.2239TRACK-OUT PREVENTION DEVICE: A vibrating or tire spreading device to 

dislodge mud, dirt and/or debris from the tires and undercarriage of motor

vehicles A Gravel pad, grizzly, wheel wash system, or a paved area, located at the 

point of intersection of an unpaved area and a Paved Road that prevents or 

controls Track-Out.

C.2340UNPAVED ROADS: Streets, alley ways, or roadways that are improved and 

maintained and that are not covered by one of the following: concrete, asphaltic 

concrete, asphalt, or other similar materials specified by the U.S.EPA, CARB 

and/or the APCO. 

C.41 UNPAVED TRAFFIC AREA: Any nonresidential area that is:

C.41.a Not covered by asphalt, recycled asphalt, asphaltic concrete, concrete, or 

concrete pavement, and

C.41.b Used for fueling and servicing; shipping, receiving and transfer; or

parking or storing equipment, haul trucks, vehicles, and any conveyances.
Imperial County Air Pollution Control District DRAFT Rule 800

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C.42 VDE: Visible dust emissions. Dust emissions that are visible to an observe r.

C.2443VMT: Vehicle miles traveled. 

C.44 WIND GUST: Is the maximum instantaneous wind speed as measured by an 

anemometer.

D. Compliance Schedule

D.1 Existing sources subject to this Regulation shall comply with its requirements no 

later than 90 days after its adoption date.

D.2 New sources subject to this Regulation shall comply with its requirements prior to 

initiation of activity.

D.3 The BLM and BP shall each comply with the following compliance schedule:

D.3.a Submit a draft dust control plan addressing all applicable portions of this 

Regulation including section F.5 within three (3) months of the adoption 

date of this rule, to which the APCO shall respond within 60 days;

D.3.b Submit a final dust control plan addressing all APCO comments within 

two (2) months after receiving APCO’s comments, which the APCO shall 

transmit to CARB and U.S. EPA for 45-day review and comment;

D.3.c Implement all final dust control plan elements within six (6) months of 

submittal; and

D.3.d Submit an updated dust control plan every two calendar years by the 

procedures described in D.3.a to D.3.c. The updated plans shall be 

transmitted to the District no later than 90 days after the end of the 

calendar year and, in addition to information required of the initial plan, 

shall include a summary of actions taken to prevent or mitigate PM10 

emissions during the previous two years.

E. Exemptions 

The following activities are exempt from provisions of this Regulation:

E.1 Actions required by the Federal or State Endangered Species Act or any order 

issued by a court or governmental agency.

E.2 Off-Field Agricultural Sources necessary to minimize or respond to adverse

effects on agricultural crops caused during freezing temperatures as declared by 
Imperial County Air Pollution Control District DRAFT Rule 800

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the National Weather Service.

Any operation already under Air Pollution Control District permit with

requirements for PM-10 control, provided the control of fugitive PM-10 

emissions is at least as stringent as required by this Regulation.

E.3 Agricultural operations including the growing, harvesting, tilling, cultivating and 

post harvesting of crops, or the raising of animals, fowl, or bees excepting the 

vehicle transportation, and vehicle hauling or other movement of the crops,

animals, fowl or bees resulting from such operations and ingress to and egress 

from Paved Roads.

E.43 Non-routine or emergency maintenance of flood control channels and water 

spreading basins.

E.5 Paved and unpaved driveways serving single family residential dwellings.

E.64 Any emergency operation and/or law enforcement activities performed to ensure 

public health and safety. Emergency activities lasting more than 30 days shall be 

subject to this Regulation, except where compliance would limit the effectiveness 

of the emergency activity performed to ensure public health and safety.

E.7 Outdoor storage or handling of organic or inorganic fertilizer, grains, seed and 

feed) which would be damaged by wetting.

E.85 Blasting operations permitted by the California Division of Industrial Safety. 

Other activities performed in conjunction with blasting are not exempt from

complying with the provisions of this rule.

E.96 The Recreational Use of public lands covered by the most recent BLM dust 

control plan that complies with Rule 800, including but not limited to Off-Road 

Vehicles, all-terrain vehicles, trucks, cars, motorcycles, motorbikes or

motorbuggies.

E.7 Military training activities conducted by the Department of Defense including but 

not limited to: (1) military Tactical Training, (2) maintenance, repair, and removal 

of targets and munitions associated with military Tactical Training, (3) open areas 

on active military ranges, including but not limited to designated impact areas, 

landing zones, and bivouac areas. Other activities performed in conjunction with 

military Tactical Training are not exempt from complying with the provisions of 

this rule.

F. General Requirements

F.1 Materials used for Chemical Stabilization of soils, including petroleum resins, 
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asphaltic emulsions, acrylics, and adhesives shall not violate State Water Quality 

Control Board standards for use as a soil stabilizer. Materials accepted by the 

California Air Resources Board (ARB) and the United States Environmental 

Protection Agency (EPA), and which meet State water quality standards, shall be 

considered acceptable to the ICAPCD.

F.2 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.

F.3 Use of hygroscopic materials may be prohibited by the APCD 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.

F.4 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.

F.5 Bureau of Land Management (BLM) Requirements

The BLM shall prepare a dust control plan to minimize PM10 emissions for 

sources under the control of BLM. The dust control plan shall include at a 

minimum the following:

F.5.a A stipulation that all new authorizations for point and area stationary

emission sources obtain all necessary permits and satisfy all applicable 

SIP provisions, including project- or activity- specific BACM;

F.5.b A summary of: the total miles of BLM roads that are paved, paved with 

unpaved shoulders, and unpaved roads with 50 or more average 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 PM-10 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; the plans for control of PM-10 

emissions from these areas;

F.5.c 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 
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species management and recovery.

F.5.d Where compliance with any control measure in Rules 804 and 805 is 

prohibited pursuant to F.5.c, the dust control plan must discuss and 

commit to implement other possible control measures, such as vehicle 

speed limits.

F.5.e 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.c;

F.5.f Use BLM-standard road design and drainage specifications when

maintaining existing roads or authorizing road maintenance and new road 

construction; and

F.5.g Include public educational information on reducing PM-10 emissions with 

BLM open area literature (e.g. identification of restricted areas and/or 

applicable speed limits) and on related information signs in heavily used 

areas.

F.6. Border Patrol (BP) Requirements

The BP shall prepare a dust control plan designed to minimize PM10 emissions 

from sources under the control of the BP. The dust control plan shall include 

those dust control measures found in Rules 804 and 805 that are not inconsistent 

with the BP’s authority and/or mission. The dust control plan shall include the 

following fugitive dust control measures:

F.6.a A stipulation that all new authorizations for point and area stationary 

emission sources obtain all necessary permits and satisfy all applicable 

SIP provisions, including project-or activity- specific BACM;

F.6.b Implement alternatives to tire-dragging that result in fewer PM10

emissions, when such alternatives are consistent with the monitoring of 

immigration across the U.S.-Mexico border; and

F.6.c Control dust emissions from certain Unpaved Roads and routes owned or 

operated by the BP as identified through general BP planning consistent 

with Rule 805 unless those dust control measures are demonstrated to be 

inconsistent with BP authority and/or mission.
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F. Requirements

F.1 Any Person who engages in any Active Operations identified in Section F of this 

rule shall provide for the implementation and maintenance of applicable RACMs, 

unless the implementation of such RACM endangers or could endanger the health 

or safety of the public.

F.2 Track Out/Carry Out: Any Person who causes the deposition of Bulk Material by 

tracking out or carrying out onto a Paved Road surface shall apply one or more 

applicable RACM to prevent or mitigate such deposition.

F.3 Unpaved Haul/Access Roads: No Person shall cause, suffer or allow the

operation, use, or maintenance of any Unpaved Haul/Access Road of more than 

1⁄2 mile in length at any work site without applying one or more appropriate so as 

to affect at least 15% of the total road surface(s) or apply one or more RACM so 

as to achieve a level of control that is equivalent to 100% control of emissions 

from 15% of the total unpaved surface(s).

F.4 Unpaved Roads: All Persons who cause, suffer or allow the operation, use or 

maintenance of any Unpaved Road, greater than 3/4 mile in length, and with 

20.0 or more average VMT per mile per day shall apply one or more appropriate 

RACM as to affect at least 15% of the total road surface(s) or apply one or more 

RACM so as to achieve a level of control that is equivalent to 100% control of 

emissions from 15% of the total unpaved surface(s).

 F.5 Bulk Material Handling: No Person shall cause, suffer, allow or engage in any 

Bulk Material handling operation including, but not limited to, storage, stacking, 

loading, unloading, conveying and reclaiming of Bulk Material, for industrial or 

commercial purposes without applying one or more appropriate RACM.

F.6 Material Transport: No Person shall cause, suffer, allow or otherwise engage in 

the transportation of Bulk Materials for industrial or commercial purposes,

without applying one or more appropriate RACM.

F.7 Haul Trucks: No Person shall cause, suffer, allow or otherwise engage in the use 

or operation of any Haul Truck, for industrial or commercial purposes, of

transporting or storing Bulk Material without applying one or more appropriate 

RACM.

G. Administrative Requirements

G.1 Test Methods

G.1.a Determination of VDE Opacity
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Opacity observations to determine compliance with VDE standards shall 

be conducted in accordance with the test procedures for “Visual

Determination of Opacity” as described in Appendix A of this rule. 

Opacity observations for sources other than unpaved traffic areas (e.g., 

roads, parking areas) shall be conducted per Section B of Appendix A and 

shall require 12 readings at 15-second intervals.

G.1.b Determination of Stabilized Surface

Observations to determine compliance with the conditions specified for a 

stabilized surface, in any inactive disturbed surface area, whether at a 

work site that is under construction, at a work site that is temporarily or 

permanently inactive, or on an open area and vacant lot, shall be

conducted in accordance with the test methods described in Appendix B of 

this rule. If a disturbed surface area passes any of the specified tests, then 

the surface shall be considered stabilized.

G.1.c Determination of Soil Moisture Content

Soil moisture content shall be determined by using ASTM Method D2216-

98 (Standard Test Method for Laboratory Determination of Water

[Moisture] Content of Soil and Rock by Mass), or other equivalent test 

methods approved by the EPA, ARB, and the APCO.

G.1.d Determination of Silt Content for Bulk Materials

Silt content of a Bulk Material shall be determined by ASTM Method 

C136a (Standard Test Method for Sieve Analysis of Fine and Coarse 

Aggregates), or other equivalent test methods approved by EPA, ARB, 

and the APCD.

G.1.e Determination of Silt Content for Unpaved Roads and Unpaved

Vehicle/Equipment Traffic Areas

Silt Content for Unpaved Roads and Unpaved Traffic Areas shall be 

determined by using Section C of Appendix B of this Rule or other 

equivalent test methods approved by EPA, ARB, and the APCO.

G.1.f Determination of Threshold Friction Velocity (TFV)

TFV shall be determined by using Section D of Appendix B of this Rule 

or other equivalent test methods approved by EPA, ARB, and the APCO.
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G. Record of Control Implementation

Any Person engaged in any Active Operation subject to this Regulation VIII shall 

maintain records of RACM sufficient to establish location, type and date of treatment. 

Records shall be maintained and be readily accessible for two years after the date of each 

entry and shall be provided to the APCD upon request and shall be open for inspection 

during unscheduled audits during normal business hours.

Persons who opt for the equivalency control in sections F.3 and/or F.4 must keep records 

to include equivalency formulas or factors with at least one sample calculation.

H. Record of Control Implementation

Any Person subject to the requirements of this rule shall compile and retain records that 

provide evidence of control measure application and compliance with this rule (i.e., 

receipts and/or purchase records). Such Person shall describe, in the records, the type of 

treatment or control measure, extent of coverage, and date applied. For control measures 

which require multiple daily applications, recording the frequency of application will 

fulfill the recordkeeping requirements of this rule (i.e., water being applied three times a 

day and the date) Records shall be maintained and be readily accessible for two years 

after the date of each entry and shall be provided to the APCD upon request.

HI. Violations

Failure to comply with any of the provisions of this Regulation shall constitute a violation 

of this Regulation. Failure to comply with the provisions of an APCO approved dust 

control plan shall also constitute a violation of this Regulation. Regardless of whether an 

APCO approved dust control plan is being implemented or not, or whether a Person 

responsible for an Active Operation(s) is complying with an approved dust control plan, 

the Person is still subject to the requirements of Regulation VIII at all times.

I. Reasonably Available Control Measures for Fugitive Dust (PM-10)

I.1 UNPAVED HAUL AND ACCESS ROADS:

I.1.a Pave.

I.1.b Apply Physical/Chemical Stabilization as directed by product

manufacturer to control dust on Unpaved Roads.

I.1.c Apply Gravel, recrushed/recycled asphalt or other material of low Silt 

(<5%) content to a depth of three or more inches. 
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I.1.d Wetting. Apply water one or more times daily.

I.1.e Permanent road closure.

I.1.f Reduce vehicle speeds by 50%.

I.1.g Reduce vehicle trips by 50%.

I.2 UNPAVED ROADS:

I.2.a Pave.

I.2.b Apply Physical/Chemical Stabilization, as directed by product

manufacturer to control dust on Unpaved Roads. 

I.2.c Apply Gravel, recrushed/recycled asphalt or other material of low Silt 

(<5%) content to a depth of three or more inches. 

I.2.d Reduce vehicle speeds by 50% .

I.2.e Reduce number of vehicle trips by 50%.

I.2.f Wetting. Apply water one or more times daily. 

I.2.g Stocking of Triploid Grass Carp in canals to reduce maintenance vehicle 

trips along Canal Banks to mechanically remove aquatic weeds.

I.2.h Installation of remote control delivery gates to eliminate manual gate 

operation by maintenance personnel in vehicles along Canal Banks.

I.2.i Implement policies and training to emphasize: 

I.2.i.1 regulated use of field-side Canal Banks for agricultural

equipment parking/storage and agricultural commodity storage;

I.2.i.2 reduced speed along Canal Banks;

I.2.i.3 minimal use of Canal Banks for access to canal gate structures;

I.2.i.4 when feasible, restrict vehicle travel along Canal Bank to one 

side (opposite of field-side Canal Bank).

I.2.j Implement Silt removal program to emphasize delaying grading of spoil 
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piles deposited on Canal Bank after cleaning operations until the next 

cleaning operation to eliminate vehicle access to Canal Bank.

I.2.k Permanent road closure.

I.2.l Conversion of open canals to pipeline.

I.2.m Lining canals to eliminate maintenance for Silt/weed control.

I.2.n Canal Bank surface maintenance.

I.3 TRACK OUT/CARRY OUT:

I.3.a Rapidly clean up, within 48 hours of deposition, any Bulk Material

tracked out or carried out onto a Paved Road surface. 

I.3.b Install one or more Track-Out Prevention Devices or other APCO

approved track out control device or wash down system at access points 

where unpaved traffic surfaces adjoin Paved Roads.

I.3.c Pave, Chemically Stabilize, or Gravel (using Gravel or other low Silt 

(<5%) content material), 50 or more consecutive feet at access points 

where Unpaved Roads adjoin Paved Roads.

I.4 BULK MATERIAL HANDLING/TRANSFER:

I.4.a Spray with water 15 minutes prior to handling and/or at points of transfer.

I.4.b Chemical/Physical Stabilization.

I.4.c Protect from wind erosion by sheltering or enclosing the operation and 

transfer line.

I.5. MATERIAL TRANSPORT/HAULING:

I.5.a Completely cover or enclose all Haul Truck loads of Bulk Material. 

I.5.b Haul Trucks transporting loads of Aggregate Materials shall not be

required to cover their loads if the load, where it contacts the side, front, 

and back of the cargo container area remains six inches from the upper 

area of the container area, and if the load does not extend, at its peak, 

above any part of the upper edge of the cargo container area (As defined in 

Section 23114 of the California Vehicle Code for both public and private 

roads).
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I.5.c The cargo compartment(s) of all Haul Trucks are to be constructed and 

maintained so that no spillage and loss of Bulk Material can occur from 

holes or other openings in the cargo compartment's floor, side, and/or 

tailgate. Seals on any openings used to empty the load including, but not 

limited to, bottom-dump release gates and tailgates to be properly

maintained to prevent the loss of Bulk Material from those areas.

I.5.d The cargo compartment of all Haul Trucks are to be cleaned and/or 

washed at delivery site after removal of Bulk Material.

J. Calexico/Mexicali Cross-Border Source Apportionment Study

A PM-10 monitoring program was completed in 1993 along the border between Imperial 

Valley California and the Mexicali Valley, Baja California, Mexico to determine the 

major contributors to PM-10 and to determine how much was contributed by transport 

across the international boundary. This study was funded by the U.S. Environmental 

Protection Agency and conducted by the University of Nevada, Desert Research Institute 

Energy and Environmental Engineering Center. This study is expected to be published in 

final form by the end of the first quarter of 1995. The Imperial County Air Pollution 

Control District (ICAPCD) will conduct a workshop on the study within thirty days of the 

formal publication date for the purpose of receiving public input on the results and 

recommendations contained therein. The comments received at that workshop and this 

Regulation will be reviewed by APCD staff and recommendations forwarded to the 

ICAPCD Board of Directors.

K. RACM implementation

Reasonably Available Control Measure (RACM) implemented since the date of adoption 

of the State Implementation Plan (SIP) for PM-10 in the Imperial Valley (September 28, 

1993) can be included as a portion of any amount of PM-10 control required in this 

Regulation.
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APPENDIX A

Visual Determination of Opacity

SECTION A Test Method For Unpaved Roads and Unpaved Traffic Areas

SECTION B Test Method For Time-Averaged Regulations

SECTION A TEST METHOD FOR UNPAVED ROADS AND UNPAVED TRAFFIC 

AREAS

A. Opacity Test Method. The purpose of this test method is to estimate the percent opacity of 

Fugitive Dust plumes caused by vehicle movement on Unpaved Roads and Unpaved 

Traffic Areas. This method can only be conducted by an individual who has current

certification as a qualified observer.

A.1 Step 1: Stand at least 16.5 feet from the fugitive dust source in order to provide a 

clear view of the emissions with the sun oriented in the 140° sector to the back. 

Following the above requirements, make opacity observations so that the line of 

vision is approximately perpendicular to the dust plume and wind direction. If 

multiple plumes are involved, do not include more than one plume in the line of 

sight at one time.

A.2 Step 2: Record the Fugitive Dust source location, source type, method of control 

used, if any, observer’s name, certification data and affiliation, and a sketch of the 

observer’s position relative to the Fugitive Dust source. Also, record the time, 

estimated distance to the Fugitive Dust source location, approximate wind direction, 

estimated wind speed, description of the sky condition (presence and color of

clouds), observer’s position to the Fugitive Dust source, and color of the plume and 

type of background on the visible emission observation form both when opacity 

readings are initiated and completed.

A.3 Step 3: Make opacity observations, to the extent possible, using a contrasting

background that is perpendicular to the line of vision. Make opacity observations 

approximately 1 meter above the surface from which the plume is generated. Note 

that the observation is to be made at only one visual point upon generation of a 

plume, as opposed to visually tracking the entire length of a dust plume as it is 

created along a surface. Make two observations per vehicle, beginning with the 

first reading at zero seconds and the second reading at five seconds. The zerosecond observation should begin immediately after a plume has been created above 

the surface involved. Do not look continuously at the plume but, instead, observe 

the plume briefly at zero seconds and then again at five seconds.

A.4 Step 4: Record the opacity observations to the nearest 5% on an observational 

record sheet. Each momentary observation recorded represents the average opacity 
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of emissions for a 5-second period. While it is not required by the test method, 

EPA recommends that the observer estimate the size of the vehicles which generate 

dust plumes for which readings are taken (e.g. mid-size passenger car or heavy-duty 

truck.) and take the approximate speeds the vehicles are traveling when the readings 

are being taken.

A.5 Step 5: Repeat Step 3 (Section A.3. of this appendix) and Step 4 (Section A.4. of 

this appendix) until you have recorded a total of 12 consecutive opacity readings. 

This will occur once six vehicles have driven on the source in your line of

observation for which you are able to take proper readings. The 12 consecutive 

readings must be taken within the same period of observation but must not exceed 1 

hour. Observations immediately preceding and following interrupted observations 

can be considered consecutive.

A.6 Step 6: Average the 12 opacity readings together. If the average opacity reading 

equals 20% or lower, the source is in compliance with the opacity standard

described in the applicable rule.

SECTION B TEST METHOD FOR VISUAL DETERMINATION OF OPACITY OF

EMISSIONS FROM SOURCES FOR TIME-AVERAGED REGULATIONS

B. Applicability. This method is applicable for the determination of the opacity of emissions 

from sources of visible emissions for time-averaged regulations. A time-averaged 

regulation is any regulation that requires averaging visible emission data to determine the 

opacity of visible emissions over a specific time period.

B.1 Principle. The opacity of emissions from sources of visible emissions is determined 

visually by a qualified observer who has received certification.

B.2 Procedures. A qualified observer who has been certified shall use the following 

procedures for visually determining the opacity of emissions.

B.2.a Position. Stand at a position at least 5 meters from the Fugitive Dust 

source n order to provide a clear view of the emissions with the sun

oriented in the 140° sector to the back. Consistent as much as possible 

with maintaining the above requirements, make opacity observations from 

a position such that the line of sight is approximately perpendicular to the 

plume and wind direction. The observer may follow the Fugitive Dust 

plume generated by mobile earthmoving equipment, as long as the sun 

remains oriented in the 140° sector to the back. As much as possible, if 

multiple plumes are involved, do not include more than one plume in the 

line of sight at one time.

B.2.b Field Records. Record the name of the site, Fugitive Dust source type 
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(i.e., pile, material handling (i.e., transfer, loading, sorting)), method of 

control used, if any, observer’s name, certification data and affiliation, 

and a sketch of the observer’s position relative to the Fugitive Dust source. 

Also, record the time, estimated distance to the Fugitive Dust source 

location, approximate wind direction, estimated wind speed, description of 

the sky condition (presence and color of clouds,) observer’s position

relative to the fugitive dust source, and color of the plume and type of the 

background on the visible emission observation form when opacity

readings are initiated and completed.

B.2.c Observations. Make opacity observations, to the extent possible, using a 

contrasting background that is perpendicular to the line of sight. For

storage piles, make opacity observations approximately 1 meter above the 

surface from which the plume is generated. For extraction operations and 

the loading of haul trucks in open-pit mines, make opacity observations 

approximately one meter above the rim of the pit. The initial observation 

should begin immediately after a plume has been created above the

surface involved. Do not look continuously at the plume, but instead 

observe the plume momentarily at 15-second intervals. For Fugitive Dust 

from Earthmoving equipment, make opacity observations approximately 1 

meter above the mechanical equipment generating the plume.

B.2.d Recording Observations. Record the opacity observations to the nearest 

5% every 15 seconds on an observational record sheet. Each momentary 

observation recorded represents the average opacity of emissions for a 15-

second period. If a multiple plume exists at the time of an observation, do 

not record an opacity reading. Mark an “x” for that reading. If the 

equipment generating the plume travels outside of the field of observation, 

resulting in the inability to maintain the orientation of the sun within the 

140° sector or if the equipment ceases operating, mark an “x” for the 15 –

second interval reading. Readings identified as “x” shall be considered 

interrupted readings.

B.2.e Data Reduction For Time-Averaged Regulations. For each set of 12 or 24 

consecutive readings, calculate the appropriate average opacity. Sets must 

consist of consecutive observations, however, readings immediately

preceding and following interrupted readings shall be deemed consecutive 

and in no case shall two sets overlap, resulting in multiple violations.
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APPENDIX B

Determination of Stabilization

SECTION A Test Methods for Determining Stabilization

SECTION B Visible Crust Determination

SECTION C Determination of Silt Content for Unpaved Roads and Unpaved

Vehicle/Equipment Traffic Areas

SECTION D Determination of Threshold Friction Velocity

SECTION E Determination of Flat Vegetative Cover

SECTION F Determination of Standing Vegetative Cover

SECTION G Rock Test Method

SECTION A TEST METHODS FOR DETERMINING STABLIZATION

The test methods described in Section B through Section G of this appendix shall be used 

to determine whether an area has a Stabilized Surface. Should a disturbed area contain 

more than one type of disturbance, soil, vegetation, or other characteristics, which are 

visibly distinguishable, test each representative surface separately for stability, in an area 

that represents a random portion of the overall disturbed conditions of the site, according 

to the appropriate test methods in Section B through Section G of this appendix, and 

include or eliminate it from the total size assessment of disturbed surface area(s)

depending upon test method results.

SECTION B VISIBLE CRUST DETERMINATION

B.1 Where a visible crust exists, drop a steel ball with a diameter of 15.9 millimeters (0.625 

inches) and a mass ranging from 16-17 grams from a distance of 30 centimeters (one 

foot) directly above (at a 90° angle perpendicular to ) the soil surfa ce. If blowsand is 

present, clear the blowsand from the surfaces on which the visible crust test method is 

conducted. Blowsand is defined as thin deposits of loose uncombined grains covering 

less than 50% of a site which have not originated from the representative site surface 

being tested. If material covers a visible crust, which is not blowsand, apply the test 

method in Section D of this appendix to the loose material to determine whether the 

surface is stabilized.

B.2 A sufficient crust is defined under the following conditions: once a ball has been dropped 

according to section B.1 of this appendix, the ball does not sink into the surface, so that it 

is partially or fully surrounded by loose grains and, upon removing the ball, the surface 

upon which it fell has not been pulverized, so that loose grains are visible.

B.3 Drop the ball three times within a survey area that measures 1 foot by 1 foot and that 

represents a random portion of the overall disturbed conditions of the site. The survey 
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area shall be considered to have passed the Visible Crust Determination Test if the results 

of at least two out of the three times that the ball was dropped, met the criteria in section 

B.2 of this appendix. Select at least two other survey areas that represent a random 

portion of the overall disturbed conditions of the site, and repeat this procedure. If the 

results meet the criteria of section B.2 of this appendix for all of the survey areas tested, 

then the site shall be considered to have passed the Visible Crust Determination Test and 

shall be considered sufficiently crusted.

B.4 At any given site, the existence of a sufficient crust covering one portion of the site may 

not represent the existence or protectiveness of a crust on another portion of the site. 

Repeat the visible crust test as often as necessary on each random portion of the overall 

conditions of the site for an accurate assessment.

SECTION C DETERMINATION OF SILT CONTENT FOR UNPAVED ROADS AND

UNPAVED VEHICLE/EQUIPMENT TRAFFIC AREAS

The purpose of this test method is to estimate the silt content of the trafficked parts of 

Unpaved Roads and Unpaved vehicle/equipment Traffic Areas. The higher the Silt 

content, the more fine dust particles that are released when vehicles travel on Unpaved 

Roads and Unpaved vehicle/equipment Traffic Areas.

C.1 Equipment:

C.1.a. A set of sieves with the following openings: 4 millimeters (mm), 2mm, 1mm, 

0.5mm and 0.25 mm, a lid, and collector pan.

C.1.b A small whisk broom or paintbrush with stiff bristles and dustpan 1 ft. in width 

(the broom/brush should preferably have one, thin row of bristles no longer than 

1.5 inches in length.)

C.1.c A spatula without holes.

C.1.d A small scale with half-ounce increments (e.g., postal/package scale.)

C.1.e A shallow, lightweight container (e.g., plastic storage container.)

C.1.f A sturdy cardboard box or other rigid object with a level surface.

C.1.g A basic calculator.

C.1.h Cloth gloves (optional for handling metal sieves on hot, sunny days.)

C.1.i Sealable plastic bags (if sending samples to a laboratory.)

C.1.j A pencil/pen and paper.

C.2 Step 1: Look for a routinely traveled surface, as evidenced by tire tracks. Only collect 

samples from surfaces that are not damp due to precipitation or dew. This statement is 

not meant to be a standard in itself for dampness where watering is being used as a 

control measure. It is only intended to ensure that surface testing is done in a

representative manner. Use caution when taking samples to ensure personal safety with 

respect to passing vehicles. Gently press the edge of a dustpan (1 foot in width) into the 

surface four times to mark an area that is 1 square foot. Collect a sample of loose surface 
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material into the dustpan, minimizing escape of dust particles. Use a spatula to lift 

heavier elements such as gravel. Only collect dirt/Gravel to an approximate depth of 3/8 

inch or 1 cm in the 1 square foot area. If you reach a hard, underlying subsurface that is 

<3/8 inch in depth, do not continue collecting the sample by digging into the hard 

surface. In other words, you are only collecting a surface sample of loose material down 

to 1 cm. In order to confirm that samples are collected to a 1cm depth, a wooden dowel 

or other similar narrow object at least one-foot in length can be laid horizontally across 

the survey area while a metric ruler is held perpendicular to the dowel. (Optional: At this 

point, you can choose to place the sample collected into a plastic bag or container and 

take it to an independent laboratory for silt content analysis. A reference to the procedure 

the laboratory is required to follow is at the end of this section.)

C.3 Step 2: Place a scale on a level surface. Place a lightweight container on the scale. Zero 

the scale with the weight of the empty container on it. Transfer the entire sample 

collected in the dustpan to the container, minimizing escape of dust particles. Weigh the 

sample and record its weight.

C.4 Step 3: Stack a set of sieves in order according to the size openings specified above, 

beginning with the largest size opening (4mm) at the top. Place a collector pan

underneath the bottom (0.25mm) sieve.

C.5 Step 4: Carefully pour the sample into the sieve stack, minimizing escape of dust 

particles by slowly brushing material into the stack with a whiskbroom or brush. On 

windy days, use the trunk or door of a vehicle as a wind barrier. Cover the stack with a 

lid. Lift up the sieve stack and shake it vigorously up and down and sideways for at least 

1 minute.

C.6 Step 5: Remove the lid from the stack and disassemble each sieve separately, beginning 

with the top sieve. As you remove each sieve, examine it to make sure that all of the 

material has been sifted to the finest sieve through which it can pass (e.g., material in 

each sieve (besides the top sieve that captures a range of larger elements) should look the 

same size.) If this is not the case, re-stack the sieves and collector pan, cover the stack 

with the lid, and shake it again for at least 1 minute. You only need to reassemble the 

sieve(s) that contain material, which require further sifting.

C.7 Step 6: After disassembling the sieves and collector pan, slowly sweep the material from 

the collector pan into the empty container originally used to collect and weigh the entire 

sample. Take care not to minimize escape of dust particles. You do not need to do 

anything with material captured in the sieves – only the collector pan. Weigh the 

container with the materials from the collector pan and record its weight.

C.8 Step 7: If the source is an unpaved road, multiply the resulting weight by 0.38. If the 

source is an Unpaved vehicle/equipment Traffic Area, multiply the resulting weight by 

0.55. The resulting number is the estimated silt loading. Then, divide the total weight of 
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the sample you recorded earlier in Step 2 (Section C.4) and multiply by 100 to estimate 

the percent Silt content.

C.9 Step 8: Select another two routinely traveled portions of the Unpaved Road or Unpaved 

vehicle/equipment Traffic Area and repeat this test method. Once you have calculated 

the silt loading and percent silt content of the 3 samples collected, average your results 

together.

C.10 Step 9: Examine Results. If the average silt loading is less than 0.33 oz/ft2, the surface is 

STABLE. If the average silt loading is greater than or equal to 0.33 oz/ft2, then proceed 

to examine the average percent Silt content. If the source is an Unpaved Road and the 

average percent Silt content is 6% or less, the surface is STABLE. If the source is an 

unpaved parking lot and the average percent Silt content is 8% or less, the surface is 

STABLE. If your field test results are within 2% of the standard (for example, 4%-8% 

Silt content on an Unpaved Road) it is recommended that you collect 3 additional

samples from the source according to Step 1 (section C.2) and take them to an

independent laboratory for Silt content analysis.

C.11 Independent Laboratory Analysis: You may choose to collect samples from the source, 

according to Step 1 (section C.2) and send them to an independent laboratory for Silt 

content analysis rather than conduct the sieve field procedure. If so, the test method the 

laboratory is required to use is: “Procedures For Laboratory Analysis for Surface/Bulk 

Dust Loading Samples,” (Fifth Edition, Volume 1, Appendix C.2.3 “Silt Analysis,”

1995,) AP-42, Office of Air Quality Planning & Standards, U.S. Environmental

Protection Agency, Research Triangle Park, North Carolina.

SECTION D DETERMINATION OF THRESHOLD FRICTION VELOCITY (TFV)

For disturbed surface areas that are not crusted or vegetated, determine threshold friction 

velocity (TFV) according to the following sieving field procedure (based on a 1952 

laboratory procedure published by W.S. Chepil).

D.1 Obtain and stack a set of sieves with the following openings: 4 millimeters (mm), 2 mm, 

1 mm, 0.5 mm, and 0.25 mm or obtain and stack a set of standard/commonly available 

sieves. Place the sieves in order according to size openings, beginning with the largest 

size opening at the top. Place a collector pan underneath the bottom (0.25 mm) sieve. 

Collect a sample of loose surface material from an area at least 30 cm by 30 cm in size to 

a depth of approximately 1 cm using a brush and dustpan or other similar device. Only 

collect soil samples from dry surfaces (i.e. when the surface is not damp to the touch). 

Remove any rocks larger than 1 cm in diameter from the sample. Pour the sample into 

the top sieve (4 mm opening) and cover the sieve/collector pan unit with a lid. Minimize 

escape of particles into the air when transferring surface soil into the sieve/collector pan 

unit. Move the covered sieve/collector pan unit by hand using a broad, circular arm 

motion in the horizontal plane. Complete twenty circular arm movements, ten clockwise 
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and ten counterclockwise, at a speed just necessary to achieve some relative horizontal 

motion between the sieves and the particles. Remove the lid from the sieve/collector pan 

unit and disassemble each sieve separately beginning with the largest sieve. As each 

sieve is removed, examine it for loose particles. If loose particles have not been sifted to 

the finest sieve through which they can pass, reassemble and cover the sieve/collector pan 

unit and gently rotate it an additional ten times. After disassembling the sieve/collector 

pan unit, slightly tilt and gently tap each sieve and the collector pan so that material 

aligns along one side. In doing so, minimize escape of particles into the air. Line up the 

sieves and collector pan in a row and visibly inspect the relative quantities of catch in 

order to determine which sieve (or whether the collector pan) contains the greatest 

volume of material. If a visual determination of relative volumes of catch among sieves 

is difficult, use a graduated cylinder to measure the volume. Estimate TFV for the sieve 

catch with the greatest volume using Table 1 of this appendix, which provides a

correlation between sieve opening size and TFV.

Table 1. Determination of Threshold Friction Velocity (TFV)

Tyler Sieve No. ASTM 11

Sieve No.

Opening

(mm)

TFV

(cm/s)

5 5 4 135

9 10 2 100

16 18 1 76

32 35 0.5 58

60 60 0.25 43

Collector Pan --- --- 30

D.2 Collect at least three soil samples which represent random portions of the overall

conditions of the site, repeat the above TFV test method for each sample and average the 

resulting TFVs together to determine the TFV uncorrected for non erodible elements. 

Non-erodible elements are distinct elements, in the random portion of the overall

conditions of the site, that are larger than 1 cm in diameter, remain firmly in place during 

a wind episode, and inhibit soil loss by consuming Section of the shear stress of the wind. 

Non-erodible elements include stones and bulk surface material but do not include flat or 

standing vegetation. For surfaces with non-erodible elements, determine corrections to 

the TFV by identifying the fraction of the survey area, as viewed from directly overhead, 

that is occupied by non-erodible elements using the following procedure. Select a survey 

area of 1 meter by 1 meter that represents a random portion of the overall conditions of 

the site. Where many non-erodible elements lie within the survey area, separate the nonerodible elements into groups according to size. For each group, calculate the overhead 

area for the non-erodible elements according to the following equations: 
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Average Dimensions =

(Average Length) x ( Average Width) Eq. 1

Overhead Area =

(Average Dimensions) x (Number of Elements) Eq. 2

Total Overhead Area =

Overhead Area Of Group 1 + Overhead Area of Group 2 (etc)

Eq. 3

Total Frontal Area =

Total Overhead Area/2 Eq. 4

Percent Cover of Non-Erodible Elements =

(Total Frontal Area/Survey Area) x 100 Eq. 5

Note: Ensure consistent units of measurements (e.g., square meters or square inches when 

calculating percent cover).

Repeat this procedure on an additional two distinct survey areas that represent a random 

portion of the overall conditions of the site and average the results. Use Table 2 of this 

appendix to identify the correction factor for the percent cover of non-erodible elements. 

Multiply the TFV by the corresponding correction factor to calculate the TFV corrected 

for non-erodible elements.

Table 2. Correction Factors for Threshold Friction Velocity

Percent Cover of Non-Erodible Elements Correction Factor

Greater than or equal to 10% 5

Greater than or equal to 5% and less than 10% 3

Less than 5% and greater than or equal to 1% 2

Less than 1% None

SECTION E DETERMINATION OF FLAT VEGETATIVE COVER

Flat vegetation includes attached (rooted) vegetation or unattached vegetative debris 

lying on the surface with a predominant horizontal orientation that is not subject to 

movement by wind. Flat vegetation, which is dead but firmly attached, shall be

considered equally protective as live vegetation. Stones or other aggregate larger than 1 
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centimeter in diameter shall be considered protective cover in the course of conduction 

the line transect test method. Where flat vegetation exists conduct the following line 

transect test method.

E.1 Line Transect Test Method. Stretch a 100 foot measuring tape across a survey area that 

represents a random portion of the overall conditions of the site. Firmly anchor both ends 

of the measuring tape into the surface using a tool such as a screwdriver, with the tape 

stretched taut and close to the soil surface. If vegetation exists in regular rows, place the 

tape diagonally (at approximately a 45° angle) away from a parallel or perpendicular 

position to the vegetated rows. Pinpoint an area the size of a 3/32 inch diameter brazing 

rod or wooden dowel centered above each 1 foot interval mark along one edge of the 

tape. Count the number of times that flat vegetation lies directly underneath the

pinpointed area at 1 foot intervals. Consistently observe the underlying surface from a 

90° angle directly above each pinpoint on one side of the tape. Do not count the 

underlying surface as vegetated if any portion of the pinpoint extends beyond the edge of 

the vegetation underneath in any direction. If clumps of vegetation or vegetative debris 

lie underneath the pinpointed area, count the surface as vegetated, unless bare soil is 

visible directly below the pinpointed area. When 100 observations have been made, add 

together the number of times a surface was counted as vegetated. This total represents 

the percent of flat vegetations cover (e.g., if 35 positive counts were made, then

vegetation cover is 35%.) If the survey area that represents a random portion of the 

overall conditions of the site is too small for 100 observations, make as many

observations as possible. Then multiply the count of vegetated surface areas by the 

appropriate conversion factor to obtain percent cover. For example, if vegetation was 

counted 20 times within a total of 50 observations, divide 20 by 50 and multiply by 100 

to obtain a flat vegetation cover of 40%.

E.2 Conduct the line transect test method, as described in section E.1 of this appendix, an 

additional two times on areas that represent a random portion of the overall conditions of 

the site and average results. 

SECTION F DETERMINATION OF STANDING VEGETATIVE COVER.

Standing vegetation includes vegetation that is attached (rooted) with a predominant 

vertical orientation. Standing vegetation, which is dead but firmly rooted, shall be 

considered equally protective as live vegetation. Conduct the following standing

vegetation test method to determine if 30% cover or more exists. If the resulting percent 

cover is less than 30% but equal to or greater than 10%, then conduct the test in Section 

D; “Determination Of Threshold Friction Velocity (TFV,) of this appendix in order to 

determine if the site is stabilized, such that the standing vegetation cover is equal to or 

greater than 10%, where threshold friction velocity, corrected for non-erodible elements, 

is equal to or greater than 43cm/second.

F.1 For standing vegetation that consists of large, separate vegetative structures (e.g., shrubs 
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and sagebrush,) select a survey area that represents a random portion of the overall 

conditions of the site that is the shape of a square with sides equal to at least 10 times the 

average height of the vegetative structures. For smaller standing vegetation, select a 

survey area of three feet by three feet.

F.2 Count the number of standing vegetative structures within the survey area. Count 

vegetation, which grows in clumps as a single unit. Where different types of vegetation 

exist and/or vegetation of different height and width exists, separate the vegetative 

structures with similar dimensions into groups. Count the number of vegetative

structures in each group within the survey area. Select an individual structure within 

each group that represents the average height and width of the vegetation in the group. If 

the structure is dense (e.g., when looking at it vertically from base to top there is little or 

zero open air space within its perimeter,) calculate and record its frontal silhouette area, 

according to Equation 6 of this appendix. Also, use Equation 6 of this appendix to 

estimate the average height and width of the vegetation if the survey area is larger than 

nine square feet. Otherwise, use the procedure in section F.3 of this appendix to calculate 

the frontal silhouette area. Then calculate the percent cover of standing vegetation

according to Equations 7, 8, and 9 of this appendix.

Frontal Silhouette Area =

(Average Height) x (Average Width) Eq. 6

Frontal Silhouette Area Of Group=

(Frontal Silhouette Area Of Individual Vegetative Structure) x 

(Number Of Vegetation Structures Per Group)

Eq. 7

Total Frontal Silhouette Area =

Frontal Silhouette Area Of Group 1 + Frontal Silhouette Area Of 

Group 2 (etc.)

Eq. 8

Percent Cover Of Standing Vegetation =

(Total Frontal Silhouette Area/Survey Area) x 100 Eq. 9

Percent Open Space =

[(Number Of Circled Gridlines Within The Outlined Area 

Counted That Are Not Covered By Vegetation/Total Number Of 

Gridline Intersections Within The Outlined Area) x 100]

Eq.10

Percent Vegetative Density =

100 – Percent Open Space Eq. 11

Vegetative Density =

Percent Vegetative Density/100 Eq. 12

Frontal Silhouette Area =

[Max. Height x Max. Width] x [Vegetative Density/.04]o.5 Eq. 13
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Note: Ensure consistent units of measurement (e.g., square meters or square inches when 

calculating percent cover.)

F.3. Vegetative Density Factor. Cut a single, representative piece of vegetation (or

consolidated vegetative structure) to within 1cm of surface soil. Using a white paper grid 

or transparent grid over white paper, lay the vegetation flat on top of the grid (but do not 

apply pressure to flatten the structure.) Grid boxes of 1 inch or 1⁄2 inch squares are 

sufficient for most vegetation when conducting this procedure. Using a marker or pencil, 

outline the shape of the vegetation along its outer perimeter, according to Figure B, C, or 

D of this appendix, as appropriate. (Note: Figure C differs from Figure D primarily in 

that the width of vegetation in Figure C is narrow at its base and gradually broadens to its 

tallest height. In Figure D, the width of the vegetation generally becomes narrower from 

its midpoint to its tallest height.) Remove the vegetation, count and record the total 

number of gridline intersections within the outlined area, but do not count gridline 

intersections that connect with the outlined shape. There must be at least 10 gridline 

intersections within the outlined area and preferably more than 20, otherwise, use smaller 

grid boxes. Draw small circles (no greater than a 3/32 inch diameter) at each gridline

intersection counted within the outlined area. Replace the vegetation on the grid within 

its outlined shape. From a distance of approximately 2 feet directly above the grid, 

observe each circled gridline intersection. Count and record the number of circled 

gridline intersections that are not covered by any piece of the vegetation. To calculate 

percent vegetative density, use Equations 10 and 11 of this appendix. If percent

vegetative density is equal to or greater than 30, use an equation (one of the equationsEquations 16, 17, or 18 of this appendix) that matches the outline used to trace the 

vegetation (Figure B, C, or D) to calculate its frontal silhouette area. If percent

vegetative density is less than 30, use Equations 12 and 13 of this appendix to calculate 

the frontal silhouette area.

Figure B. Cylinder

Frontal Silhouette Area = Maximum Height x Maximum Width Eq.16
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Figure C. Inverted Cone

Frontal Silhouette Area = Maximum Height x 1⁄2 Maximum Width Eq. 17

Figure D. Upper Sphere

Frontal Silhouette Area = (3.14 x Maximum Height x 1⁄2 Maximum Width)/2 Eq.18

SECTION G ROCK TEST METHOD

The Rock Test Method, which is similar to Section D, Test Methods For StabilizationDetermination Of Threshold Friction Velocity (TFV) of this appendix, examines the 

wind-resistance effects of rocks and other non-erodible elements on disturbed surfaces. 

Non-erodible elements are objects larger than 1 centimeter (cm) in diameter that remain 

firmly in place even on windy days. Typically, non-erodible elements include rocks, 

stones, glass fragments, and hardpacked clumps of soil lying on or embedded in the 

surface. Vegetation does not count as a non-erodible element in this method. The 

purpose of this test method is to estimate the percent cover of non-erodible elements on a 

given surface to see whether such elements take up enough space to offer protection 

against windblown dust. For simplification, the following test method refers to all nonerodible elements as ‘rocks.”

G.1 Select a 1 meter by 1 meter survey area that represents the general rock distribution on 
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the surface. A 1 meter by 1 meter area is slightly greater than a 3 foot by 3 foot area. 

Mark-off the survey area by tracing a straight, visible line in the dirt along the edge of a 

measuring tape or by placing short ropes, yard sticks, or other straight objects in a square 

around the survey area.

G.2 Without moving any of the rocks or other elements, examine the survey area. Since 

rocks >3/8 inch (1cm) in diameter are of interest, measure the diameter of some of the 

smaller rocks to get a sense of which rocks need to be considered.

G.3 Mentally group the rocks >3/8 inch (1cm) diameter lying in the survey area into small, 

medium, and large size categories. Or, if the rocks are all approximately the same size, 

simply select a rock of average size and typical shape. Without removing any of the 

rocks from the ground, count the number of rocks in the survey area in each group and 

write down the resulting number.

G.4 Without removing rocks, select one or two average-size rocks in each group and measure 

the length and width. Use either metric units or standard units. Using a calculator, 

multiply the length times the width of the rocks to get the average dimensions of the 

rocks in each group. Write down the results for each rock group.

G.5 For each rock group, multiply the average dimensions (length times width) by the number 

of rocks counted in the group. Add the results from each rock group to get the total rock 

area within the survey area.

G.6 Divide the total rock area, calculated in section G.5 of this appendix, by two (to get 

frontal area.) Divide the resulting number by the size of the survey area (make sure the 

units of measurement match,) and multiply by 100 for percent rock cover. For example, 

the total rock area is 1,400 square centimeters divide 1,400 by 2 to get 700. Divide 700 

by 10,000 (the survey area is 1 meter by 1 meter, which is 100 centimeters by 100 

centimeters or 10,000 centimeters) and multiply by 100. The result is 7% rock cover. If 

rock measurements are made in inches, convert the survey area from meters to inches (1 

inch = 2.54 centimeters.)

G.7 Select and mark-off two additional survey areas and repeat the procedures described in 

section G.1 through section G.6 of this appendix. Make sure the additional survey areas 

also represent the general rock distribution on the site. Average the percent cover results 

from all three survey areas to estimate the average percent of rock cover.

G.8 If the average rock cover is greater than or equal to 10%, the surface is stable. If the 

average rock cover is less than 10%, follow the procedures in section G.9 of this 

appendix.

G.9 If the average rock cover is less than 10%, the surface may or may not be stable. Follow 

the procedures in Section D.3 Determination Of Threshold Friction Velocity (TFV) of 
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this rule and use the results from the rock test method as a correction (i.e., multiplication) 

factor. If the rock cover is at least 1%, such rock cover helps to limit windblown dust. 

However, depending on the soil’s ability to release fine dust particles into the air, the 

percent rock cover may or may not be sufficient enough to stabilize the surface. It is also 

possible that the soil itself has a high enough TFV to be stable without even accounting 

for rock cover.

G.10 After completing the procedures described in Section G.9 of this appendix, use Table 2 of 

this appendix to identify the appropriate correction factor to the TFV, depending on the 

percent rock cover.
Imperial County Air Pollution Control District Rule 800

800-1

RULE 800 GENERAL REQUIREMENTS FOR CONTROL OF FINE PARTICULATE

MATTER (PM-10) 

(Adopted 10/10/94; revised 11/25/96; revised 11/08/2005)

A. General Description

The purpose of this regulation is to reduce the amount of fine Particulate Matter (PM-10) 

entrained in the ambient air as a result of emissions generated from anthropogenic 

(man-made) Fugitive Dust (PM-10) sources generated from within Imperial County by 

requiring actions to prevent, reduce, or mitigate PM-10 emissions. The Rules contained 

within this Regulation have been developed pursuant to United States Environmental 

Protection Agency guidance for Serious PM10 Non Attainment Areas. 

B. Applicability

The requirements of this rule shall apply to any Active Operation, and/or man-made or 

man-caused condition or practice capable of generating Fugitive Dust (PM-10) as 

specified in this Regulation except those determined exempt as defined in Part E of this

Rule. The definitions, exemptions, requirements, administrative requirements

recordkeeping requirements, and test methods set forth in this rule are applicable to all 

the rules under Regulation VIII (Fugitive Dust Requirements) of the Rules and

Regulations of the Imperial County Air Pollution Control District.

C. Definitions

For the purpose of this Regulation, the following terms are defined:

C.1 ACTIVE OPERATION: Activities capable of generating Fugitive Dust (PM-10),

including but not limited to, Earthmoving Activities, Construction activities,

Unpaved Roads, Track-Out/Carry-Out, Bulk Material storage and transport,

Unpaved Haul/Access Roads.

C.2 AGGREGATE MATERIALS: Consists of sand, Gravel, quarried stone and/or 

rock fragments that are typically used in Construction. Aggregates may be 

natural, artificial or recycled.

C.3 ANEMOMETRS: Are devices used to measure wind speed and direction in

accordance with manufacturer’s performance standards, maintenance and

calibration criteria.

C.4 ANNUAL AVERAGE DAILY VEHICLE TRIPS: annual average 24-hour total 

of all vehicles counted on a road.

C.5 APCD: The Imperial County Air Pollution Control District.

C.6 APCO: The Imperial County Air Pollution Control Officer.
Imperial County Air Pollution Control District Rule 800

800-2

C.7 AVERAGE VEHICLE TRIPS PER DAY: Means the average number of vehicles 

that cross a given point surface during a specific 24-hour period as determined by 

the most recent Institute of Transportation Engineers trip generation manual, tube 

counts, or observations. 

C.8 BLM: The Bureau of Land Management.

C.9 BP: The United States Border Patrol.

C.10 BULK MATERIAL: Earth, rock, Silt, sediment, sand, Gravel, soil, fill,

Aggregate, dirt, mud, debris, and other organic and/or inorganic material

consisting of or containing Particulate Matter with five percent or greater Silt 

content. For the purpose of this Regulation, the Silt content level is assumed to be 

5 percent or greater, unless the Person responsible for the Active Operation

conducts the applicable laboratory tests and demonstrate that the Silt content is 

less than 5 percent. Active Operations seeking to determine if the Silt content is 

less than five percent are required to conduct the laboratory analysis in

accordance with ASTM method C-136-a (Standard Test Method for Sieve

analysis of Fine and Coarse Aggregates), or other equivalent test methods

approved by EPA, ARB, and the APCD.

C.11 CANAL BANK: A rise of land on either side of an irrigation canal.

C.12 CHEMICAL STABILIZATION/SUPPRESSION: A means of Fugitive Dust

(PM-10) control implemented to mitigate PM-10 emissions by applying

petroleum resins, asphaltic emulsions, acrylics, adhesives, or any other materials 

approved for use by the California Air Resources Board (CARB), U.S.

Environmental Protection Agency (U.S. EPA) and/or the APCO.

C.13 CONSTRUCTION: Any on-site mechanical activities preparatory to or related to 

the building, alteration, rehabilitation, or demolition of an improvement on real 

property, including, but not limited to, land clearing, excavation related to

construction, land leveling, grading, cut and fill grading, and the erection or 

demolition of any structure. As used in Regulation VIII, a construction site may 

encompass several contiguous parcels, or may encompass only a portion of one 

parcel, depending on the relationship of the property boundaries to the actual 

construction activities.

C.14 DESIGNATED REPRESENTATIVE: The agent for a Person. The Designated 

Representative shall be responsible for and have the full authority to implement 

BACM on behalf of the Person.

C.15 EARTHMOVING ACTIVITIES: The use of any equipment for an activity that 

may generate Fugitive Dust emissions, including, but not limited to, cutting and 

filling, grading, leveling, excavation, trenching, loading or unloading of Bulk 
Imperial County Air Pollution Control District Rule 800

800-3

Materials, demolishing, drilling, adding to or removing bulk of materials from 

open storage piles, weed abatement through disking, and back filling.

C.16 FUGITIVE DUST: The Particulate Matter entrained in the ambient air which is 

caused from man-made and natural activities such as, but not limited to,

movement of soil, vehicles, equipment, blasting, and wind. This excludes

Particulate Matter emitted directly in the exhaust of motor vehicles or other fuel 

combustion devices, from portable brazing, soldering, or welding equipment, pile 

drivers, and stack emissions from stationary sources.

C.17 GRAVEL: Gravel travelways shall have a three (3) inch minimum depth

Stabilized Surface. The travelway shall have a relative compaction of not less 

than 95% as determined by Test Method No. California 216 of State of California, 

Business and Transportation Agency Department of Transportation, and

conforming to the following grading:

3⁄4” Maximum

Sieve Designation Percent Passing

1” 100

3⁄4” 90-100

#4 35-60

#30 10-30

#200 2-9

Reference: California Department of Transportation Standard Specification 

 Section 26/class II Aggregate Base

C.18 HAUL/ACCESS ROAD: Any on-site road used for commercial, industrial,

institutional, and/or governmental traffic. 

C.19 HAUL TRUCK: Any fully or partially open-bodied licensed motor vehicle used 

for transporting Bulk Material for industrial or commercial purposes.

C.20 IMPLEMENT OF HUSBANDRY: An unlicensed vehicle which is used

exclusively in the conduct of Agricultural Operations. An Implement of

Husbandry does not include a vehicle if its existing design is primarily for the 

transportation of persons or property on a highway, unless specifically designated 

as such by some other provision of the Vehicle Code of California.

C.21 NON-RESIDENTIAL AREA: Any unpaved vehicle and equipment traffic area 

operated at any commercial, manufacturing or government sites. 

C.22 MODIFIED PAVED ROAD:Any Paved Road that is widened or improved so as 

to increase traffic capacity. This term does not include road maintenanc e, repair, 

chip seal, pavement or roadbed rehabilitation that does not affect roadway

geometrics, or surface overlay work.
Imperial County Air Pollution Control District Rule 800

800-4

C.23 OFF-FIELD AGRICULTURAL SOURCE: Any Agricultural Source or activity at 

an Agricultural Source that falls into one or more of the following categories:

C.23.a Outdoor handling, storage and transport of Bulk Material;

C.23.b Paved Road;

C.23.c Unpaved Road; or

C.23.d Unpaved Traffic Area.

C.24 OFF-ROAD VEHICLE: Any nonstationary device, powered by an internal

combustion engine or motor, used primarily off the highways to propel, move, or 

draw persons or property including any device propelled, moved, or drawn

exclusively by human power, and used in, but not limited to, any of the following 

applications: marine vessels, construction/farm equipment, utility and lawn and 

garden equipment, off-road motorcycles, and off-highway vehicles.

C.25 ON-FIELD AGRICULTURAL SOURCE: Any Agricultural Source or activity at 

an Agricultural Source that is not an Off-Field Agricultural Source, including (but 

not limited to) the following:

C.25.a Activities conducted solely for the purpose of preparing land for the 

growing of crops or the raising of fowl or animals, such as brush or timber 

clearing, grubbing, scraping, ground excavation, land leveling, grading, 

turning under stalks, disking, or tilling;

C.25.b Drying or pre-cleaning of agricultural crop material on the field where it 

was harvested;

C.25.c Handling or storage of agricultural crop material that is baled, cubed, 

pelletized, or long-stemmed, on the field where it was harvested, and the 

handling of fowl or animal feed materials at sites where animals or fowl 

are raised;

C.25.d Disturbances of cultivated land as a result of fallowing, planting,

fertilizing or harvesting.

C.26 OPEN AREA: Any of the following described in Subsection C.26.a through 

C.26.c of this rule. For the purpose of this rule, vacant portions of residential or 

commercial lots and contiguous parcels that are immediately adjacent to and 

owned and/or operated by the same individual or entity are considered one open 

area. An open area does not include any Unpaved Traffic Area as defined in this 

rule.

C.26.a An un-subdivided or undeveloped land adjoining a developed (or partially 
Imperial County Air Pollution Control District Rule 800

800-5

developed) residential, industrial, institutional, governmental, or

commercial area.

C.26.b A subdivided residential, industrial, institutional, governmental, or

commercial lot, which contains no approved or permitted building or 

structures of a temporary or permanent nature.

C.26.c A partially developed residential, industrial, institutional, governmental, or 

commercial lot and contiguous lots under common ownership. 

C.27 PARTICULATE MATTER: Any material, except uncombined water, which

exists in a finely divided form as a liquid or solid at 60 degrees F and one 

atmosphere pressure.

C.28 PAVED ROADS:An improved street, highway, alley, public way, that is covered 

by concrete, asphaltic concrete, or asphalt.

C.29 PERSON: Any individual, public or private corporation, partnership, association, 

firm, trust, estate, municipality, or any other legal entity whatsoever which is 

recognized by law as the subject of rights and duties, who is responsible for an 

Active Operation.

C.30 PM-10: Particulate Matter with an aerodynamic diameter smaller than or equal to 

a nominal 10 microns as measured by the applicable State and Federal reference 

test methods. 

C.31 RECREATIONAL USE: The use of motorized vehicles on public lands.

C.32 RURAL: Areas not classified as urban constitute “rural.”

C.33 SILT: Any Aggregate Material with a particle size less than 75 micrometers in 

diameter as measured by a No. 200 sieve as defined in ASTM D-2487 and as 

tested by ASTM-C-136 or other equivalent test methods approved by EPA, ARB, 

and the APCD.

C.34 STABILIZED SURFACE: Any disturbed surface area 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 this 

Section and as determined by the test methods specified in Appendix B, Section 

A, B and D-G tests of this rule:

C.34.a A visible crust; or

C.34.b A threshold friction velocity (TFV) for disturbed surface areas corrected 

for non-erodible elements of 100 centimeters per second or greater; or
Imperial County Air Pollution Control District Rule 800

800-6

C.34.c A flat vegetative cover of at least 50 percent that is attached or rooted 

vegetation; or unattached vegetative debris lying on the surface with a 

predominant horizontal orientation that is not subject to movement by 

wind; or

C.34.d A standing vegetative cover of at least 30 percent that is attached or rooted 

vegetation with a predominant vertical orientation; or

C.34.e A standing vegetative cover that is attached or rooted vegetative with a 

predominant vertical orientation that is at least 10 percent and where the 

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

elements; or

C.34.f A surface that is greater than or equal to 10 percent of non-erodible 

elements such as rocks, stones, or hard-packed clumps of soil.

C.35 STABILIZED UNPAVED ROAD: Any Unpaved Road or unpaved

vehicle/equipment traffic area surface which meets the definition of Stabilized 

Surface as determined by the test method in Appendix B, Section C of this rule, 

and where VDE is limited to 20% opacity.

C.36 TACTICAL TRAINING: Training conducted by the U.S. Department of Defense, 

the U.S. military services, or its allies for combat, combat support, combat service 

support, tactical or relief operations. Examples include but are not limited to 

munitions training.

C.37 TEMPORARY UNPAVED ROAD: Any Unpaved Road surface which is created 

to support a temporary or periodic activity and the use of such road surface is 

limited to vehicle access for a period of not more than six months during any 

consecutive three-year period. 

C.38 THRESHOLD FRICTION VELOCITY (TFV): The corrected velocity necessary 

to initiate soil erosion as determined by the test method specified in Appendix B, 

Section D, of this rule. The lower TFV, the greater the propensity for fine 

particles to be lifted at relatively low wind speeds.

C.39 TRACK-OUT/CARRY-OUT: Any and all Bulk Materials that adhere to and 

agglomerate on the exterior surfaces of motor vehicles and/or equipment

(including tires) that may then fall onto the pavement.

C.40 TRACK-OUT PREVENTION DEVICE: A Gravel pad, grizzly, wheel wash

system, or a paved area, located at the point of intersection of an unpaved area 

and a Paved Road that prevents or controls Track-Out.

C.41 UNPAVED ROADS:Streets, alley ways, or roadways that are not covered by one 

of the following: concrete, asphaltic concrete, asphalt, or other similar materials 
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specified by the U.S.EPA, CARB and/or the APCO. 

C.42 UNPAVED TRAFFIC AREA: Any nonresidential area that is:

C.42.a Not covered by asphalt, recycled asphalt, asphaltic concrete, concrete, or 

concrete pavement, and

C.42.b Used for fueling and servicing; shipping, receiving and transfer; or

parking or storing equipment, haul trucks, vehicles, and any conveyances.

C.43 URBAN AREA: An area within an incorporated city boundary or within

unincorporated areas completely surrounded by an incorporated city. 

C.44 VDE: Visible dust emissions. Dust emissions that are visible to an observer.

C.45 VMT: Vehicle miles traveled. 

C.46 WIND GUST: Is the maximum instantaneous wind speed as measured by an 

anemometer.

D. Compliance Schedule

D.1 Existing sources subject to this Regulation shall comply with its requirements no 

later than 90 days after its adoption date.

D.2 New sources subject to this Regulation shall comply with its requirements prior to 

initiation of activity.

D.3 The BLM and BP shall each comply with the following compliance schedule:

D.3.a Submit a draft dust control plan addressing all applicable portions of this 

Regulation including section F.5 within three (3) months of the adoption 

date of this rule, to which the APCO shall respond within 60 days;

D.3.b Submit a final dust control plan addressing all APCO comments within 

two (2) months after receiving APCO’s comments, which the APCO shall 

transmit to CARB and U.S. EPA for 45-day review and comment; 

D.3.c Implement all final dust control plan elements within six (6) months of 

submittal; and

D.3.d Submit an updated dust control plan every two calendar years by the 

procedures described in D.3.a to D.3.c. The updated plans shall be 

transmitted to the District no later than 90 days after the end of the 

calendar year and, in addition to information required of the initial plan, 
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shall include a summary of actions taken to prevent or mitigate PM10 

emissions during the previous two years.

E. Exemptions 

The following activities are exempt from provisions of this Regulation:

E.1 Actions required by the Federal or State Endangered Species Act or any order 

issued by a court or governmental agency.

E.2 Off-Field Agricultural Sources necessary to minimize or respond to adverse

effects on agricultural crops caused during freezing temperatures as declared by 

the National Weather Service.

E.3 Emergency maintenance of flood control channels and water spreading basins.

E.4 Any emergency operation activities performed to ensure public health and safety. 

Emergency activities lasting more than 30 days shall be subject to this Regulation, 

except where compliance would limit the effectiveness of the emergency activity 

performed to ensure public health and safety.

E.5 Blasting operations permitted by the California Division of Industrial Safety. 

Other activities performed in conjunction with blasting are not exempt from

complying with the provisions of this rule.

E.6 The Recreational Use of public lands covered by the most recent BLM dust 

control plan that complies with Rule 800, including but not limited to Off-Road 

Vehicles, all-terrain vehicles, trucks, cars, motorcycles, motorbikes or

motorbuggies.

E.7 The following military training activities conducted by the Department of

Defense: (1) military Tactical Training, (2) maintenance, repair, and removal of 

targets and munitions associated with military Tactical Training, (3) open areas on 

active military ranges, including but not limited to designated impact areas,

landing zones, and bivouac areas. Other activities performed in conjunction with 

military Tactical Training are not exempt from complying with the provisions of 

this rule.

F. General Requirements

F.1 Materials used for Chemical 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. Materials accepted by the 

California Air Resources Board (ARB) and the United States Environmental 

Protection Agency (EPA), and which meet State water quality standards, shall be 

considered acceptable to the ICAPCD.
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F.2 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.

F.3 Use of hygroscopic materials may be prohibited by the APCD 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.

F.4 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.

F.5 Bureau of Land Management (BLM) Requirements

The BLM shall prepare a dust control plan to minimize PM10 emissions for 

sources under the control of BLM. The dust control plan shall include at a 

minimum the following:

F.5.a A stipulation that all new authorizations for point and area stationary 

emission sources obtain all necessary permits and satisfy all applicable 

SIP provisions, including Regulation VIII specific control measures;

F.5.b A summary of: the total miles of BLM roads that are paved, paved with 

unpaved shoulders, and unpaved roads with 50 or more average 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 PM-10 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; the plans for control of PM-10 

emissions from these areas;

F.5.c 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.

F.5.d Where compliance with any control measure in Rules 804 and 805 is 

prohibited pursuant to F.5.c, the dust control plan must discuss and 

commit to implement other possible control measures, such as vehicle 

speed limits.
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F.5.e 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 Recreation Area Management Plan (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.c;

F.5.f Use BLM-standard road design and drainage specifications when

maintaining existing roads or authorizing road maintenance and new road 

construction; and

F.5.g Include public educational information on reducing PM-10 emissions with 

BLM open area literature (e.g. identification of restricted areas and/or 

applicable speed limits) and on related information signs in heavily used 

areas.

F.6. Border Patrol (BP) Requirements

The BP shall prepare a dust control plan designed to minimize PM10 emissions 

from sources under the control of the BP. The dust control plan shall include 

those dust control measures found in Rules 804 and 805. The dust control plan 

shall include the following fugitive dust control measures:

F.6.a A stipulation that all new authorizations for point and area stationary 

emission sources obtain all necessary permits and satisfy all applicable 

SIP provisions, including Regulation VIII specific control measures;

F.6.b Implement alternatives to tire-dragging that result in fewer PM10

emissions, unless BP demonstrates such alternatives to be inconsistent

with the monitoring of immigration across the U.S.-Mexico border; and

F.6.c Control dust emissions from certain Unpaved Roads and routes owned or 

operated by the BP as identified through general BP planning consistent 

with Rule 805 unless those dust control measures are demonstrated to be 

inconsistent with BP authority and/or mission.

G. Administrative Requirements

G.1 Test Methods

G.1.a Determination of VDE Opacity

Opacity observations to determine compliance with VDE standards shall 

be conducted in accordance with the test procedures for “Visual

Determination of Opacity” as described in Appendix A of this rule. 
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Opacity observations for sources other than unpaved traffic areas (e.g., 

roads, parking areas) shall be conducted per Section B of Appendix A and 

shall require 12 readings at 15-second intervals.

G.1.b Determination of Stabilized Surface

Observations to determine compliance with the conditions specified for a 

stabilized surface, in any inactive disturbed surface area, whether at a

work site that is under construction, at a work site that is temporarily or 

permanently inactive, or on an open area and vacant lot, shall be

conducted in accordance with the test methods described in Appendix B of 

this rule. If a disturbed surface area passes any of the applicable Appendix 

B-Section A, B and D-G tests, then the surface shall be considered

stabilized.

G.1.c Determination of Soil Moisture Content

Soil moisture content shall be determined by using ASTM Method D2216-

98 (Standard Test Method for Laboratory Determination of Water

[Moisture] Content of Soil and Rock by Mass), or other equivalent test 

methods approved by the EPA, ARB, and the APCO.

G.1.d Determination of Silt Content for Bulk Materials

Silt content of a Bulk Material shall be determined by ASTM Method 

C136a (Standard Test Method for Sieve Analysis of Fine and Coarse 

Aggregates), or other equivalent test methods approved by EPA, ARB, 

and the APCD.

G.1.e Determination of Silt Content for Unpaved Roads and Unpaved

Vehicle/Equipment Traffic Areas

Silt Content for Unpaved Roads and Unpaved Traffic Areas shall be 

determined by using Section C of Appendix B of this Rule or other 

equivalent test methods approved by EPA, ARB, and the APCO.

G.1.f Determination of Threshold Friction Velocity (TFV)

TFV shall be determined by using Section D of Appendix B of this Rule 

or other equivalent test methods approved by EPA, ARB, and the APCO.

H. Record of Control Implementation

Any Person subject to the requirements of this rule shall compile and retain records that 

provide evidence of control measure application and compliance with this rule (i.e., 

receipts and/or purchase records). Such Person shall describe, in the records, the type of 
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treatment or control measure, extent of coverage, and date applied. For control measures 

which require multiple daily applications, recording the frequency of application will 

fulfill the recordkeeping requirements of this rule (i.e., water being applied three times a 

day and the date) Records shall be maintained and be readily accessible for two years 

after the date of each entry and shall be provided to the APCD upon request.

I. Violations

Failure to comply with any provisions of this rule shall constitute a violation of

Regulation VIII. Failure to comply with the provisions of an APCO approved dust 

control plan shall also constitute a violation of this Regulation. Regardless of whether an 

APCO approved dust control plan is being implemented or not, or whether a Person 

responsible for an Active Operation(s) is complying with an approved dust control plan, 

the Person is still subject to the requirements of Regulation VIII at all times.
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APPENDIX A

Visual Determination of Opacity

SECTION A Test Method For Unpaved Roads and Unpaved Traffic Areas

SECTION B Test Method For Time-Averaged Regulations

SECTION A TEST METHOD FOR UNPAVED ROADS AND UNPAVED TRAFFIC 

AREAS

A. Opacity Test Method. The purpose of this test method is to estimate the percent opacity of 

Fugitive Dust plumes caused by vehicle movement on Unpaved Roads and Unpaved 

Traffic Areas. This method can only be conducted by an individual who has current

certification as a qualified observer.

A.1 Step 1: Stand at least 16.5 feet from the fugitive dust source in order to provide a 

clear view of the emissions with the sun oriented in the 140° sector to the back. 

Following the above requirements, make opacity observations so that the line of 

vision is approximately perpendicular to the dust plume and wind direction. If 

multiple plumes are involved, do not include more than one plume in the line of 

sight at one time.

A.2 Step 2: Record the Fugitive Dust source location, source type, method of control 

used, if any, observer’s name, certification data and affiliation, and a sketch of the 

observer’s position relative to the Fugitive Dust source. Also, record the time, 

estimated distance to the Fugitive Dust source location, approximate wind direction, 

estimated wind speed, description of the sky condition (presence and color of

clouds), observer’s position to the Fugitive Dust source, and color of the plume and 

type of background on the visible emission observation form both when opacity 

readings are initiated and completed.

A.3 Step 3: Make opacity observations, to the extent possible, using a contrasting

background that is perpendicular to the line of vision. Make opacity observations 

approximately 1 meter above the surface from which the plume is generated. Note 

that the observation is to be made at only one visual point upon generation of a 

plume, as opposed to visually tracking the entire length of a dust plume as it is 

created along a surface. Make two observations per vehicle, beginning with the 

first reading at zero seconds and the second reading at five seconds. The zerosecond observation should begin immediately after a plume has been created above 

the surface involved. Do not look continuously at the plume but, instead, observe 

the plume briefly at zero seconds and then again at five seconds.

A.4 Step 4: Record the opacity observations to the nearest 5% on an observational 

record sheet. Each momentary observation recorded represents the average opacity 

of emissions for a 5-second period. While it is not required by the test method, 

EPA recommends that the observer estimate the size of the vehicles which generate 

dust plumes for which readings are taken (e.g. mid-size passenger car or heavy-duty 
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truck.) and take the approximate speeds the vehicles are traveling when the readings 

are being taken.

A.5 Step 5: Repeat Step 3 (Section A.3. of this appendix) and Step 4 (Section A.4. of 

this appendix) until you have recorded a total of 12 consecutive opacity readings. 

This will occur once six vehicles have driven on the source in your line of

observation for which you are able to take proper readings. The 12 consecutive 

readings must be taken within the same period of observation but must not exceed 1 

hour. Observations immediately preceding and following interrupted observations 

can be considered consecutive.

A.6 Step 6: Average the 12 opacity readings together. If the average opacity reading 

equals 20% or lower, the source is in compliance with the opacity standard

described in the applicable rule.

SECTION B TEST METHOD FOR VISUAL DETERMINATION OF OPACITY OF

EMISSIONS FROM SOURCES FOR TIME-AVERAGED REGULATIONS

B. Applicability. This method is applicable for the determination of the opacity of emissions 

from sources of visible emissions for time-averaged regulations. A time-averaged 

regulation is any regulation that requires averaging visible emission data to determine the 

opacity of visible emissions over a specific time period.

B.1 Principle. The opacity of emissions from sources of visible emissions is determined 

visually by a qualified observer who has received certification.

B.2 Procedures. A qualified observer who has been certified shall use the following 

procedures for visually determining the opacity of emissions.

B.2.a Position. Stand at a position at least 5 meters from the Fugitive Dust 

source n order to provide a clear view of the emissions with the sun

oriented in the 140° sector to the back. Consistent as much as possible 

with maintaining the above requirements, make opacity observations from 

a position such that the line of sight is approximately perpendicular to the 

plume and wind direction. The observer may follow the Fugitive Dust 

plume generated by mobile earthmoving equipment, as long as the sun 

remains oriented in the 140° sector to the back. As much as possible, if 

multiple plumes are involved, do not include more than one plume in the 

line of sight at one time.

B.2.b Field Records. Record the name of the site, Fugitive Dust source type 

(i.e., pile, material handling (i.e., transfer, loading, sorting)), method of 

control used, if any, observer’s name, certification data and affiliation, 

and a sketch of the observer’s position relative to the Fugitive Dust source. 

Also, record the time, estimated distance to the Fugitive Dust source 

location, approximate wind direction, estimated wind speed, description of 
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the sky condition (presence and color of clouds,) observer’s position

relative to the fugitive dust source, and color of the plume and type of the 

background on the visible emission observation form when opacity

readings are initiated and completed.

B.2.c Observations. Make opacity observations, to the extent possible, using a 

contrasting background that is perpendicular to the line of sight. For

storage piles, make opacity observations approximately 1 meter above the 

surface from which the plume is generated. For extraction operations and 

the loading of haul trucks in open-pit mines, make opacity observations 

approximately one meter above the rim of the pit. The initial observation 

should begin immediately after a plume has been created above the

surface involved. Do not look continuously at the plume, but instead 

observe the plume momentarily at 15-second intervals. For Fugitive Dust 

from Earthmoving equipment, make opacity observations approximately 1 

meter above the mechanical equipment generating the plume.

B.2.d Recording Observations. Record the opacity observations to the nearest 

5% every 15 seconds on an observational record sheet. Each momentary 

observation recorded represents the average opacity of emissions for a 15-

second period. If a multiple plume exists at the time of an observation, do 

not record an opacity reading. Mark an “x” for that reading. If the 

equipment generating the plume travels outside of the field of observation, 

resulting in the inability to maintain the orientation of the sun within the 

140° sector or if the equipment ceases operating, mark an “x” for the 15 –

second interval reading. Readings identified as “x” shall be considered 

interrupted readings.

B.2.e Data Reduction For Time-Averaged Regulations. For each set of 12 or 24 

consecutive readings, calculate the appropriate average opacity. Sets must 

consist of consecutive observations, however, readings immediately

preceding and following interrupted readings shall be deemed consecutive 

and in no case shall two sets overlap, resulting in multiple violations.
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APPENDIX B

Determination of Stabilization

SECTION A Test Methods for Determining Stabilization

SECTION B Visible Crust Determination

SECTION C Determination of Silt Content for Unpaved Roads and Unpaved

Vehicle/Equipment Traffic Areas

SECTION D Determination of Threshold Friction Velocity

SECTION E Determination of Flat Vegetative Cover

SECTION F Determination of Standing Vegetative Cover

SECTION G Rock Test Method

SECTION A TEST METHODS FOR DETERMINING STABLIZATION

The test methods described in Section B through Section G of this appendix shall be used 

to determine whether an area has a Stabilized Surface. Should a disturbed area contain 

more than one type of disturbance, soil, vegetation, or other characteristics, which are 

visibly distinguishable, test each representative surface separately for stability, in an area 

that represents a random portion of the overall disturbed conditions of the site, according 

to the appropriate test methods in Section B through Section G of this appendix, and 

include or eliminate it from the total size assessment of disturbed surface area(s)

depending upon test method results.

SECTION B VISIBLE CRUST DETERMINATION

B.1 Where a visible crust exists, drop a steel ball with a diameter of 15.9 millimeters (0.625 

inches) and a mass ranging from 16-17 grams from a distance of 30 centimeters (one 

foot) directly above (at a 90° angle perpendicular to ) the soil surface. If blowsand is 

present, clear the blowsand from the surfaces on which the visible crust test method is 

conducted. Blowsand is defined as thin deposits of loose uncombined grains covering 

less than 50% of a site which have not originated from the representative site surface 

being tested. If material covers a visible crust, which is not blowsand, apply the test 

method in Section D of this appendix to the loose material to determine whether the 

surface is stabilized.

B.2 A sufficient crust is defined under the following conditions: once a ball has been dropped 

according to section B.1 of this appendix, the ball does not sink into the surface, so that it 

is partially or fully surrounded by loose grains and, upon removing the ball, the surface 

upon which it fell has not been pulverized, so that loose grains are visible.

B.3 Drop the ball three times within a survey area that measures 1 foot by 1 foot and that 

represents a random portion of the overall disturbed conditions of the site. The survey 

area shall be considered to have passed the Visible Crust Determination Test if the results 

of at least two out of the three times that the ball was dropped, met the criteria in section 

B.2 of this appendix. Select at least two other survey areas that represent a random 
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portion of the overall disturbed conditions of the site, and repeat this procedure. If the 

results meet the criteria of section B.2 of this appendix for all of the survey areas tested, 

then the site shall be considered to have passed the Visible Crust Determination Test and 

shall be considered sufficiently crusted.

B.4 At any given site, the existence of a sufficient crust covering one portion of the site may 

not represent the existence or protectiveness of a crust on another portion of the site. 

Repeat the visible crust test as often as necessary on each random portion of the overall 

conditions of the site for an accurate assessment.

SECTION C DETERMINATION OF SILT CONTENT FOR UNPAVED ROADS AND

UNPAVED VEHICLE/EQUIPMENT TRAFFIC AREAS

The purpose of this test method is to estimate the silt content of the trafficked parts of 

Unpaved Roads and Unpaved vehicle/equipment Traffic Areas. The higher the Silt 

content, the more fine dust particles that are released when vehicles travel on Unpaved 

Roads and Unpaved vehicle/equipment Traffic Areas.

C.1 Equipment:

C.1.a. A set of sieves with the following openings: 4 millimeters (mm), 2mm, 1mm, 

0.5mm and 0.25 mm, a lid, and collector pan.

C.1.b A small whisk broom or paintbrush with stiff bristles and dustpan 1 ft. in width 

(the broom/brush should preferably have one, thin row of bristles no longer than 

1.5 inches in length.)

C.1.c A spatula without holes.

C.1.d A small scale with half-ounce increments (e.g., postal/package scale.)

C.1.e A shallow, lightweight container (e.g., plastic storage container.)

C.1.f A sturdy cardboard box or other rigid object with a level surface.

C.1.g A basic calculator.

C.1.h Cloth gloves (optional for handling metal sieves on hot, sunny days.)

C.1.i Sealable plastic bags (if sending samples to a laboratory.)

C.1.j A pencil/pen and paper.

C.2 Step 1: Look for a routinely traveled surface, as evidenced by tire tracks. Only collect 

samples from surfaces that are not damp due to precipitation or dew. This statement is 

not meant to be a standard in itself for dampness where watering is being used as a 

control measure. It is only intended to ensure that surface testing is done in a

representative manner. Use caution when taking samples to ensure personal safety with

respect to passing vehicles. Gently press the edge of a dustpan (1 foot in width) into the 

surface four times to mark an area that is 1 square foot. Collect a sample of loose surface 

material into the dustpan, minimizing escape of dust particles. Use a spatula to lift 

heavier elements such as gravel. Only collect dirt/Gravel to an approximate depth of 3/8 

inch or 1 cm in the 1 square foot area. If you reach a hard, underlying subsurface that is 

<3/8 inch in depth, do not continue collecting the sample by digging into the hard 

surface. In other words, you are only collecting a surface sample of loose material down 
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to 1 cm. In order to confirm that samples are collected to a 1cm depth, a wooden dowel 

or other similar narrow object at least one-foot in length can be laid horizontally across 

the survey area while a metric ruler is held perpendicular to the dowel. (Optional: At this 

point, you can choose to place the sample collected into a plastic bag or container and 

take it to an independent laboratory for silt content analysis. A reference to the procedure 

the laboratory is required to follow is at the end of this section.)

C.3 Step 2: Place a scale on a level surface. Place a lightweight container on the scale. Zero 

the scale with the weight of the empty container on it. Transfer the entire sample 

collected in the dustpan to the container, minimizing escape of dust particles. Weigh the 

sample and record its weight.

C.4 Step 3: Stack a set of sieves in order according to the size openings specified above, 

beginning with the largest size opening (4mm) at the top. Place a collector pan

underneath the bottom (0.25mm) sieve.

C.5 Step 4: Carefully pour the sample into the sieve stack, minimizing escape of dust 

particles by slowly brushing material into the stack with a whiskbroom or brush. On 

windy days, use the trunk or door of a vehicle as a wind barrier. Cover the stack with a 

lid. Lift up the sieve stack and shake it vigorously up and down and sideways for at least 

1 minute.

C.6 Step 5: Remove the lid from the stack and disassemble each sieve separately, beginning 

with the top sieve. As you remove each sieve, examine it to make sure that all of the 

material has been sifted to the finest sieve through which it can pass (e.g., material in 

each sieve (besides the top sieve that captures a range of larger elements) should look the 

same size.) If this is not the case, re-stack the sieves and collector pan, cover the stack 

with the lid, and shake it again for at least 1 minute. You only need to reassemble the 

sieve(s) that contain material, which require further sifting.

C.7 Step 6: After disassembling the sieves and collector pan, slowly sweep the material from 

the collector pan into the empty container originally used to collect and weigh the entire 

sample. Take care not to minimize escape of dust particles. You do not need to do 

anything with material captured in the sieves – only the collector pan. Weigh the 

container with the materials from the collector pan and record its weight.

C.8 Step 7: If the source is an unpaved road, multiply the resulting weight by 0.38. If the 

source is an Unpaved vehicle/equipment Traffic Area, multiply the resulting weight by 

0.55. The resulting number is the estimated silt loading. Then, divide the total weight of 

the sample you recorded earlier in Step 2 (Section C.4) and multiply by 100 to estimate 

the percent Silt content.

C.9 Step 8: Select another two routinely traveled portions of the Unpaved Road or Unpaved 

vehicle/equipment Traffic Area and repeat this test method. Once you have calculated 

the silt loading and percent silt content of the 3 samples collected, average your results 

together.
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C.10 Step 9: Examine Results. If the average silt loading is less than 0.33 oz/ft2, the surface is 

STABLE. If the average silt loading is greater than or equal to 0.33 oz/ft2, then proceed 

to examine the average percent Silt content. If the source is an Unpaved Road and the 

average percent Silt content is 6% or less, the surface is STABLE. If the source is an 

unpaved parking lot and the average percent Silt content is 8% or less, the surface is 

STABLE. If your field test results are within 2% of the standard (for example, 4%-8% 

Silt content on an Unpaved Road) it is recommended that you collect 3 additional

samples from the source according to Step 1 (section C.2) and take them to an

independent laboratory for Silt content analysis.

C.11 Independent Laboratory Analysis: You may choose to collect samples from the source, 

according to Step 1 (section C.2) and send them to an independent laboratory for Silt 

content analysis rather than conduct the sieve field procedure. If so, the test method the 

laboratory is required to use is: “Procedures For Laboratory Analysis for Surface/Bulk 

Dust Loading Samples,” (Fifth Edition, Volume 1, Appendix C.2.3 “Silt Analysis,”

1995,) AP-42, Office of Air Quality Planning & Standards, U.S. Environmental

Protection Agency, Research Triangle Park, North Carolina.

SECTION D DETERMINATION OF THRESHOLD FRICTION VELOCITY (TFV)

For disturbed surface areas that are not crusted or vegetated, determine threshold friction 

velocity (TFV) according to the following sieving field procedure (based on a 1952 

laboratory procedure published by W.S. Chepil).

D.1 Obtain and stack a set of sieves with the following openings: 4 millimeters (mm), 2 mm, 

1 mm, 0.5 mm, and 0.25 mm or obtain and stack a set of standard/commonly available 

sieves. Place the sieves in order according to size openings, beginning with the largest 

size opening at the top. Place a collector pan underneath the bottom (0.25 mm) sieve. 

Collect a sample of loose surface material from an area at least 30 cm by 30 cm in size to 

a depth of approximately 1 cm using a brush and dustpan or other similar device. Only 

collect soil samples from dry surfaces (i.e. when the surface is not damp to the touch). 

Remove any rocks larger than 1 cm in diameter from the sample. Pour the sample into 

the top sieve (4 mm opening) and cover the sieve/collector pan unit with a lid. Minimize 

escape of particles into the air when transferring surface soil into the sieve/collector pan 

unit. Move the covered sieve/collector pan unit by hand using a broad, circular arm 

motion in the horizontal plane. Complete twenty circular arm movements, ten clockwise 

and ten counterclockwise, at a speed just necessary to achieve some relative horizontal 

motion between the sieves and the particles. Remove the lid from the sieve/collector pan 

unit and disassemble each sieve separately beginning with the largest sieve. As each 

sieve is removed, examine it for loose particles. If loose particles have not been sifted to 

the finest sieve through which they can pass, reassemble and cover the sieve/collector pan 

unit and gently rotate it an additional ten times. After disassembling the sieve/collector 

pan unit, slightly tilt and gently tap each sieve and the collector pan so that material 

aligns along one side. In doing so, minimize escape of particles into the air. Line up the 

sieves and collector pan in a row and visibly inspect the relative quantities of catch in 
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order to determine which sieve (or whether the collector pan) contains the greatest 

volume of material. If a visual determination of relative volumes of catch among sieves 

is difficult, use a graduated cylinder to measure the volume. Estimate TFV for the sieve 

catch with the greatest volume using Table 1 of this appendix, which provides a

correlation between sieve opening size and TFV.

Table 1. Determination of Threshold Friction Velocity (TFV)

Tyler Sieve No. ASTM 11

Sieve No.

Opening

(mm)

TFV

(cm/s)

5 5 4 135

9 10 2 100

16 18 1 76

32 35 0.5 58

60 60 0.25 43

Collector Pan --- --- 30

D.2 Collect at least three soil samples which represent random portions of the overall

conditions of the site, repeat the above TFV test method for each sample and average the 

resulting TFVs together to determine the TFV uncorrected for non erodible elements. 

Non-erodible elements are distinct elements, in the random portion of the overall

conditions of the site, that are larger than 1 cm in diameter, remain firmly in place during 

a wind episode, and inhibit soil loss by consuming Section of the shear stress of the wind. 

Non-erodible elements include stones and bulk surface material but do not include flat or 

standing vegetation. For surfaces with non-erodible elements, determine corrections to 

the TFV by identifying the fraction of the survey area, as viewed from directly overhead, 

that is occupied by non-erodible elements using the following procedure. Select a survey 

area of 1 meter by 1 meter that represents a random portion of the overall conditions of 

the site. Where many non-erodible elements lie within the survey area, separate the nonerodible elements into groups according to size. For each group, calculate the overhead 

area for the non-erodible elements according to the following equations: 

Average Dimensions =

(Average Length) x ( Average Width) Eq. 1

Overhead Area =

(Average Dimensions) x (Number of Elements) Eq. 2

Total Overhead Area =

Overhead Area Of Group 1 + Overhead Area of Group 2 (etc)

Eq. 3
Imperial County Air Pollution Control District Rule 800

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Total Frontal Area =

Total Overhead Area/2 Eq. 4

Percent Cover of Non-Erodible Elements =

(Total Frontal Area/Survey Area) x 100 Eq. 5

Note: Ensure consistent units of measurements (e.g., square meters or square inches when 

calculating percent cover).

Repeat this procedure on an additional two distinct survey areas that represent a random 

portion of the overall conditions of the site and average the results. Use Table 2 of this 

appendix to identify the correction factor for the percent cover of non-erodible elements. 

Multiply the TFV by the corresponding correction factor to calculate the TFV corrected 

for non-erodible elements.

Table 2. Correction Factors for Threshold Friction Velocity

Percent Cover of Non-Erodible Elements Correction Factor

Greater than or equal to 10% 5

Greater than or equal to 5% and less than 10% 3

Less than 5% and greater than or equal to 1% 2

Less than 1% None

SECTION E DETERMINATION OF FLAT VEGETATIVE COVER

Flat vegetation includes attached (rooted) vegetation or unattached vegetative debris 

lying on the surface with a predominant horizontal orientation that is not subject to 

movement by wind. Flat vegetation, which is dead but firmly attached, shall be

considered equally protective as live vegetation. Stones or other aggregate larger than 1 

centimeter in diameter shall be considered protective cover in the course of conduction 

the line transect test method. Where flat vegetation exists conduct the following line

transect test method.

E.1 Line Transect Test Method. Stretch a 100 foot measuring tape across a survey area that 

represents a random portion of the overall conditions of the site. Firmly anchor both ends 

of the measuring tape into the surface using a tool such as a screwdriver, with the tape 

stretched taut and close to the soil surface. If vegetation exists in regular rows, place the 

tape diagonally (at approximately a 45° angle) away from a parallel or perpendicular 

position to the vegetated rows. Pinpoint an area the size of a 3/32 inch diameter brazing 

rod or wooden dowel centered above each 1 foot interval mark along one edge of the 

tape. Count the number of times that flat vegetation lies directly underneath the

pinpointed area at 1 foot intervals. Consistently observe the underlying surface from a 

90° angle directly above each pinpoint on one side of the tape. Do not count the 
Imperial County Air Pollution Control District Rule 800

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underlying surface as vegetated if any portion of the pinpoint extends beyond the edge of 

the vegetation underneath in any direction. If clumps of vegetation or vegetative debris 

lie underneath the pinpointed area, count the surface as vegetated, unless bare soil is 

visible directly below the pinpointed area. When 100 observations have been made, add 

together the number of times a surface was counted as vegetated. This total represents 

the percent of flat vegetations cover (e.g., if 35 positive counts were made, then

vegetation cover is 35%.) If the survey area that represents a random portion of the 

overall conditions of the site is too small for 100 observations, make as many

observations as possible. Then multiply the count of vegetated surface areas by the 

appropriate conversion factor to obtain percent cover. For example, if vegetation was 

counted 20 times within a total of 50 observations, divide 20 by 50 and multiply by 100 

to obtain a flat vegetation cover of 40%.

E.2 Conduct the line transect test method, as described in section E.1 of this appendix, an 

additional two times on areas that represent a random portion of the overall conditions of 

the site and average results. 

SECTION F DETERMINATION OF STANDING VEGETATIVE COVER.

Standing vegetation includes vegetation that is attached (rooted) with a predominant 

vertical orientation. Standing vegetation, which is dead but firmly rooted, shall be 

considered equally protective as live vegetation. Conduct the following standing

vegetation test method to determine if 30% cover or more exists. If the resulting percent 

cover is less than 30% but equal to or greater than 10%, then conduct the test in Section 

D; “Determination Of Threshold Friction Velocity (TFV,) of this appendix in order to 

determine if the site is stabilized, such that the standing vegetation cover is equal to or 

greater than 10%, where threshold friction velocity, corrected for non-erodible elements, 

is equal to or greater than 43cm/second.

F.1 For standing vegetation that consists of large, separate vegetative structures (e.g., shrubs 

and sagebrush,) select a survey area that represents a random portion of the overall 

conditions of the site that is the shape of a square with sides equal to at least 10 times the 

average height of the vegetative structures. For smaller standing vegetation, select a 

survey area of three feet by three feet.

F.2 Count the number of standing vegetative structures within the survey area. Count 

vegetation, which grows in clumps as a single unit. Where different types of vegetation 

exist and/or vegetation of different height and width exists, separate the vegetative 

structures with similar dimensions into groups. Count the number of vegetative

structures in each group within the survey area. Select an individual structure within 

each group that represents the average height and width of the vegetation in the group. If 

the structure is dense (e.g., when looking at it vertically from base to top there is little or 

zero open air space within its perimeter,) calculate and record its frontal silhouette area, 

according to Equation 6 of this appendix. Also, use Equation 6 of this appendix to 

estimate the average height and width of the vegetation if the survey area is larger than 

nine square feet. Otherwise, use the procedure in section F.3 of this appendix to calculate 
Imperial County Air Pollution Control District Rule 800

800-23

the frontal silhouette area. Then calculate the percent cover of standing vegetation

according to Equations 7, 8, and 9 of this appendix.

Note: Ensure consistent units of measurement (e.g., square meters or square inches when 

calculating percent cover.)

F.3. Vegetative Density Factor. Cut a single, representative piece of vegetation (or

consolidated vegetative structure) to within 1cm of surface soil. Using a white paper grid 

or transparent grid over white paper, lay the vegetation flat on top of the grid (but do not 

apply pressure to flatten the structure.) Grid boxes of 1 inch or 1⁄2 inch squares are 

sufficient for most vegetation when conducting this procedure. Using a marker or pencil, 

outline the shape of the vegetation along its outer perimeter, according to Figure B, C, or 

D of this appendix, as appropriate. (Note: Figure C differs from Figure D primarily in 

that the width of vegetation in Figure C is narrow at its base and gradually broadens to its 

tallest height. In Figure D, the width of the vegetation generally becomes narrower from 

its midpoint to its tallest height.) Remove the vegetation, count and record the total 

number of gridline intersections within the outlined area, but do not count gridline 

Frontal Silhouette Area =

(Average Height) x (Average Width) Eq. 6

Frontal Silhouette Area Of Group=

(Frontal Silhouette Area Of Individual Vegetative Structure) x 

(Number Of Vegetation Structures Per Group)

Eq. 7

Total Frontal Silhouette Area =

Frontal Silhouette Area Of Group 1 + Frontal Silhouette Area Of 

Group 2 (etc.)

Eq. 8

Percent Cover Of Standing Vegetation =

(Total Frontal Silhouette Area/Survey Area) x 100 Eq. 9

Percent Open Space =

[(Number Of Circled Gridlines Within The Outlined Area 

Counted That Are Not Covered By Vegetation/Total Number Of 

Gridline Intersections Within The Outlined Area) x 100]

Eq.10

Percent Vegetative Density =

100 – Percent Open Space Eq. 11

Vegetative Density =

Percent Vegetative Density/100 Eq. 12

Frontal Silhouette Area =

[Max. Height x Max. Width] x [Vegetative Density/.04]o.5 Eq. 13
Imperial County Air Pollution Control District Rule 800

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intersections that connect with the outlined shape. There must be at least 10 gridline 

intersections within the outlined area and preferably more than 20, otherwise, use smaller 

grid boxes. Draw small circles (no greater than a 3/32 inch diameter) at each gridline 

intersection counted within the outlined area. Replace the vegetation on the grid within 

its outlined shape. From a distance of approximately 2 feet directly above the grid, 

observe each circled gridline intersection. Count and record the number of circled 

gridline intersections that are not covered by any piece of the vegetation. To calculate 

percent vegetative density, use Equations 10 and 11 of this appendix. If percent

vegetative density is equal to or greater than 30, use an equation (one of the equationsEquations 16, 17, or 18 of this appendix) that matches the outline used to trace the 

vegetation (Figure B, C, or D) to calculate its frontal silhouette area. If percent

vegetative density is less than 30, use Equations 12 and 13 of this appendix to calculate 

the frontal silhouette area.

Figure B. Cylinder

Frontal Silhouette Area = Maximum Height x Maximum Width Eq.16

Figure C. Inverted Cone

Frontal Silhouette Area = Maximum Height x 1⁄2 Maximum Width Eq. 17
Imperial County Air Pollution Control District Rule 800

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Figure D. Upper Sphere

Frontal Silhouette Area = (3.14 x Maximum Height x 1⁄2 Maximum Width)/2 Eq.18

SECTION G ROCK TEST METHOD

The Rock Test Method, which is similar to Section D, Test Methods For StabilizationDetermination Of Threshold Friction Velocity (TFV) of this appendix, examines the 

wind-resistance effects of rocks and other non-erodible elements on disturbed surfaces. 

Non-erodible elements are objects larger than 1 centimeter (cm) in diameter that remain 

firmly in place even on windy days. Typically, non-erodible elements include rocks, 

stones, glass fragments, and hardpacked clumps of soil lying on or embedded in the 

surface. Vegetation does not count as a non-erodible element in this method. The 

purpose of this test method is to estimate the percent cover of non-erodible elements on a 

given surface to see whether such elements take up enough space to offer protection 

against windblown dust. For simplification, the following test method refers to all nonerodible elements as ‘rocks.”

G.1 Select a 1 meter by 1 meter survey area that represents the general rock distribution on 

the surface. A 1 meter by 1 meter area is slightly greater than a 3 foot by 3 foot area. 

Mark-off the survey area by tracing a straight, visible line in the dirt along the edge of a 

measuring tape or by placing short ropes, yard sticks, or other straight objects in a square 

around the survey area.

G.2 Without moving any of the rocks or other elements, examine the survey area. Since 

rocks >3/8 inch (1cm) in diameter are of interest, measure the diameter of some of the 

smaller rocks to get a sense of which rocks need to be considered.

G.3 Mentally group the rocks >3/8 inch (1cm) diameter lying in the survey area into small, 

medium, and large size categories. Or, if the rocks are all approximately the same size, 

simply select a rock of average size and typical shape. Without removing any of the 

rocks from the ground, count the number of rocks in the survey area in each group and 

write down the resulting number.

G.4 Without removing rocks, select one or two average-size rocks in each group and measure 

the length and width. Use either metric units or standard units. Using a calculator, 

multiply the length times the width of the rocks to get the average dimensions of the 
Imperial County Air Pollution Control District Rule 800

800-26

rocks in each group. Write down the results for each rock group.

G.5 For each rock group, multiply the average dimensions (length times width) by the number 

of rocks counted in the group. Add the results from each rock group to get the total rock 

area within the survey area.

G.6 Divide the total rock area, calculated in section G.5 of this appendix, by two (to get 

frontal area.) Divide the resulting number by the size of the survey area (make sure the 

units of measurement match,) and multiply by 100 for percent rock cover. For example, 

the total rock area is 1,400 square centimeters divide 1,400 by 2 to get 700. Divide 700 

by 10,000 (the survey area is 1 meter by 1 meter, which is 100 centimeters by 100 

centimeters or 10,000 centimeters) and multiply by 100. The result is 7% rock cover. If 

rock measurements are made in inches, convert the survey area from meters to inches (1 

inch = 2.54 centimeters.)

G.7 Select and mark-off two additional survey areas and repeat the procedures described in 

section G.1 through section G.6 of this appendix. Make sure the additional survey areas 

also represent the general rock distribution on the site. Average the percent cover results 

from all three survey areas to estimate the average percent of rock cover.

G.8 If the average rock cover is greater than or equal to 10%, the surface is stable. If the 

average rock cover is less than 10%, follow the procedures in section G.9 of this 

appendix.

G.9 If the average rock cover is less than 10%, the surface may or may not be stable. Follow 

the procedures in Section D.3 Determination Of Threshold Friction Velocity (TFV) of 

this rule and use the results from the rock test method as a correction (i.e., multiplication) 

factor. If the rock cover is at least 1%, such rock cover helps to limit windblown dust. 

However, depending on the soil’s ability to release fine dust particles into the air, the 

percent rock cover may or may not be sufficient enough to stabilize the surface. It is also 

possible that the soil itself has a high enough TFV to be stable without even accounting 

for rock cover.

G.10 After completing the procedures described in Section G.9 of this appendix, use Table 2 of 

this appendix to identify the appropriate correction factor to the TFV, depending on the 

percent rock cover.
rule in.txt

Subject: Regulation VIII SIP Submittal

Date: Thu, 30 Mar 2006 17:15:15 -0800

From: Monica Soucier <monicasoucier@imperialcounty.net>

To: David Brown <dabrown@arb.ca.gov>

Dave,

I tried earlier to e-mail the whole regulation VIII zipped and I got an

undeliverable notification. So, I am sending it piecemeal. Here is a copy

of the original e-mail.... Expect seven e-mails

Dave,

Good day! Attached please find the zipped file for Regulation VIII broken

down into the seven individual rule packages. Rule 800, Rule 801, Rule 802,

Rule 803, Rule 804, Rule 805 and Rule 806. Should you have any concerns

please let me know. Thank you

Monica N. Soucier

APCD Specialist

150 S 9th Street

El Centro, CA 92243

(760) 482-2074 or (760) 482-4606

 Name: Rule 800 SIP Submittal.zip

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