[Federal Register Volume 64, Number 244 (Tuesday, December 21, 1999)]
[Rules and Regulations]
[Pages 71304-71317]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-32760]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[AZ 012-FIP; FRL-6511-3]
RIN 2060-AI54


Revision to Promulgation of Federal Implementation Plan for 
Arizona--Maricopa Nonattainment Area; PM-10

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: Under the authority of section 110(c)(1) of the Clean Air Act 
(CAA or ``the Act''), EPA is finalizing proposed amendments to the 
moderate area federal implementation plan (FIP) for the Phoenix PM-10 
nonattainment area. These amendments modify the fugitive dust rule to 
add or replace certain test methods and allow alternative control 
measures (ACMs) to be implemented without prior EPA approval. For the 
convenience of readers, the entire FIP rule is reprinted in this 
publication.

DATES: This action is effective on January 20, 2000.

ADDRESSES: A copy of docket No. A-98-42 containing material relevant to 
this final action, including EPA's responses to comments received on 
the proposed amendments, is available for review at: EPA Region 9, Air 
Division, 75 Hawthorne Street, San Francisco, CA 94105. Interested 
persons may make an appointment with Eleanor Kaplan (415) 744-1159 to 
inspect the docket at EPA's San Francisco office on weekdays between 9 
a.m. and 4 p.m.
    A copy of the docket No. A-98-42 is also available to review at the 
Arizona Department of Environmental Quality, Library, 3033 N. Central 
Avenue, Phoenix, Arizona 85012. (602) 207-2217.
    Electronic Availability: This document is also available as an 
electronic file on EPA's Region 9 Air Web Page at http://www.epa.gov/
region09/air.

FOR FURTHER INFORMATION CONTACT: Karen Irwin (415) 744-1903.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Background
II. Summary of Final Action on Proposed Revisions
    A. Test Methods
    1. Silt Content Test Method
    2. Visible Crust Test Method
    3. Standing Vegetation Test Method Density Procedure
    B. Alternative Control Measures
III. Unpaved Roads
IV. Agency Responses to Comments
V. Text Corrections to the Final Rule
VI. Administrative Requirements
    A. Executive Order 12866
    B. Executive Order 13045
    C. Executive Order 13084
    D. Executive Order 13132
    E. Regulatory Flexibility Analysis
    F. Unfunded Mandates Reform Act (UMRA)
    G. Paperwork Reduction Act
    H. National Technology Transfer and Advancement Act (NTTAA)
    I. Submission to Congress and the General Accounting Office
    J. Petitions for Judicial Review

I. Background

    On August 3, 1998 (63 FR 41326), EPA finalized a FIP for the 
Phoenix PM-10 nonattainment area (the ``final FIP''). Readers should 
refer to 63 FR 41326 for details of the history and contents of the 
final FIP.
    The final FIP includes a fugitive dust rule to control PM-10 
emissions from vacant lots, unpaved parking lots and unpaved roads 
codified at 40 CFR 52.128 (63 FR 41326, 41350), hereafter referred to 
as ``the final FIP rule''.1 EPA subsequently proposed 
specific revisions related to the test methods, ACMs, and unpaved road 
requirements of the final FIP rule (64 FR 3263, January 21, 1999). EPA 
accepted comments on the proposed amendments through March 8, 1999. EPA 
is now finalizing action on all but one of the proposed amendments and 
re-publishing the final FIP fugitive dust rule in its entirety.
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    \1\ EPA promulgated the final FIP rule as part of its court-
ordered obligation to provide for the implementation of Reasonably 
Available Control Measures (RACM) (required by section 189(a)(1)(C) 
of the Clean Air Act) in the Phoenix PM-10 nonattainment area.
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    A detailed discussion of the FIP rule revisions proposed by EPA can 
be found in 64 FR 3263, January 1999. EPA proposed to add a silt 
content test method for unpaved roads and unpaved parking lots, add a 
new visible crust test method or replace the visible crust test method 
for vacant lots, add a procedure for measuring the density of standing 
vegetation to the standing vegetation test method, include coverage of 
privately owned unpaved roads that are privately maintained or not 
maintained,2 and allow ACMs to be implemented without prior 
EPA approval.
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    \2\ Note: the FIP rule as finalized in August 1998 includes 
coverage of privately owned unpaved roads that are publicly 
maintained; EPA's proposal in January 1999 to include privately 
owned roads that are privately maintained or not maintained has no 
bearing on existing FIP rule coverage of privately owned, publicly 
maintained unpaved roads.

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[[Page 71305]]

II. Summary of Final Action on Proposed Revisions

A. Test Methods

1. Silt Content Test Method
    The final FIP rule contains an opacity standard of twenty (20) 
percent, or Ringlemann 1, for unpaved roads and unpaved parking lots. 
Compliance with this standard is to be tested using visible emissions 
test methods included in the final Phoenix FIP rule.3 EPA 
proposed an additional, new test method for measuring silt 
content.4
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    \3\ Reference Method 9 (40 CFR part 60, appendix A) and Methods 
203A and 203C. Appendix A.I. to Sec. 52.128 (63 FR 41326, 41353-
41355).
    \4\ 64 FR 3263, 3267-3268.
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    EPA solicited comments on this additional test method and whether 
or not to retain the existing opacity test method in the final FIP 
rule. EPA received no comments suggesting that the existing opacity 
test method be eliminated from the FIP rule. In this final action, EPA 
has added the silt content test method into the FIP rule and retained 
the opacity test method. Therefore, sources subject to the FIP rule 
will need to comply with both a silt content standard and an opacity 
standard.
    Also, EPA received public comments suggesting that silt loading be 
taken into account. In this final action, EPA has included a silt 
loading value in the silt content test method, below which a source may 
be deemed in compliance with the FIP rule. Text changes to accommodate 
this addition occur in paragraph (b)(16) and in Appendix A, I.B of the 
final amendments.
    Furthermore, EPA has clarified the following items from the 
proposed test method text:
     Samples should be collected to a depth of approximately 1 
centimeter or until a hard subsurface is reached, whichever occurs 
first.
     If sieving is simplified by combining three samples, each 
sample should weigh within one ounce of the other two samples. (EPA's 
contractor clarified that samples must be of approximately the same 
weight in order to ensure technical accuracy if they are combined.) 
5

    \5\ Chatten Cowherd, MRI Research Institute in Kansas City, 
Missouri, January 1999.
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EPA has corrected the following two items from the proposed test method 
text:
     An incorrect reference to collector pan material as silt 
fraction has been eliminated.
     A printing error in the AP-42 silt content test method 
with respect to the method's equation to calculate percent silt 
content.
2. Visible Crust Test Method
    The final FIP rule's test method for measuring visible crust 
thickness on vacant lots involved breaking off a piece of crust, 
checking whether the crust crumbles easily and measuring its thickness 
with a ruler.6 EPA proposed an alternative method to 
determine the sufficiency of a visible crust.7 The 
alternative test method involves dropping a small steel ball from a 
height of one foot in select one square foot areas and checking to see 
whether the ball penetrates the surface or causes loose grains to 
appear. Public comments received support the alternative method. In 
this final action, EPA has replaced the earlier visible crust thickness 
test method with the alternative visible crust test method. This 
required renumbering of the proposed text 8 for consistency 
with the numbering of other vacant lot test methods. Also, EPA has 
modified the text to allow the weight of the ball used in the test 
method to range from 16 to 17 grams, as opposed to an exact weight of 
16.33 grams.
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    \6\ 63 FR 41324, 41355.
    \7\ 64 FR 3263, 3268-3269.
    \8\ 63 FR 3263, 3268.
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3. Standing Vegetation Test Method Density Procedure
    The final FIP rule contains a test method for standing 
vegetation.9 EPA proposed to add a vegetation density 
procedure involving the use of a grid with one inch or half-inch 
squares to help ensure that various vegetative structures can be 
assessed accurately and consistently.10 Public comments 
received support the inclusion of the vegetation density procedure in 
the standing vegetation test method. In this final action, EPA has 
added the density procedure into the final FIP rule. EPA also made two 
minor text corrections to the proposed test method which are enumerated 
in the Technical Support Document associated with this action, which 
can be found in Docket No. A-98-42.
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    \9\ 63 FR 41326, 41356.
    \10\ 64 FR 3263, 3269-3271. The procedure was provided to EPA by 
Larry Hagen, Agricultural Engineer, United States Department of 
Agriculture, Wind Erosion Research Unit, 2004 Throckmortion Hall, 
Kansas State University, Manhatten, Kansas 66506.
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B. Alternative Control Measures

    In the final FIP rule (August 1998), ACMs are allowed provided that 
they are submitted to EPA and receive EPA approval.11 ACMs 
are any RACM not specifically listed in the rule that can meet the 
rule's stabilization standards for each source category.12 
EPA proposed to amend the final FIP rule such that ACMs would not 
require prior EPA approval.13 In today's action, EPA has 
accordingly eliminated the final FIP rule requirement that ACMs receive 
prior EPA approval.
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    \11\ 63 FR 41326, 41352.
    \12\  The ACM provisions of the rule do not otherwise authorize 
any modification of the FIP rule's requirements.
    \13\ 64 FR 3263, 3267.
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III. Unpaved Roads

    The final FIP rule contains requirements to control fugitive dust 
from unpaved roads that are publicly owned and/or operated (i.e., 
maintained). This includes privately owned roads that are publicly 
maintained. EPA proposed to include in the FIP rule unpaved privately 
owned roads that are privately maintained or not maintained. EPA is not 
taking final action at this time on the proposed amendments to the 
unpaved road requirements of the final FIP rule. The Maricopa 
Association of Governments (MAG) recently announced its intent to pave 
or otherwise control all unpaved roads located in the PM-10 
nonattainment area with traffic levels that meet or exceed 130 average 
daily trips.14 EPA believes that the County's action may 
supersede the need for EPA to control additional unpaved roads as 
specified in the proposed FIP revision, and thus is not taking action 
on the proposed revision at this time.
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    \14\ Memorandum from Lindy Bauer, MAG, to Members of the MAG Air 
Quality Planning Team, November 30, 1999, summarizing the MAG 
Transportation Review Committee's funding recommendations presented 
on November 23, 1999.
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IV. Agency Responses to Comments

    A 45-day public comment period was provided in 64 FR 3263. EPA 
received several comments on the proposed FIP rule revisions and 
responds to the most significant below. EPA has responded to all 
comments associated with this final action in the Technical Support 
Document, which can be found in Docket No. A-98-42.
    Comment: Maricopa County Environmental Services Division (MCESD) 
comments that by itself, the silt content of the surface material on an 
unpaved road is a unidimensional parameter and does not indicate 
whether or not the road is stabilized. It is the silt loading value 
which provides an indicator of stabilization as it estimates the amount 
of fine particulate per surface area which may become airborne. The 
proposed test method should be modified to derive silt loading in place 
of silt content.

[[Page 71306]]

    Response: EPA has modified the test method to include a silt 
loading parameter, such that surfaces with less than 0.33 oz/ft.\3\ 
silt loading will be considered stable under the FIP rule. However, EPA 
has retained the silt content standards of 6 percent for unpaved roads 
and 8 percent for unpaved parking lots when silt loading is greater 
than or equal to 0.33 oz/ft \2\
    Comment: MCESD, Maricopa County Department of Transportation 
(MCDOT) and Arizona Department of Environmental Quality (ADEQ) comment 
on the benefits associated with retaining the opacity test method in 
the FIP rule while adding a silt content test method. With respect to 
visible crust test methods, however, MCESD and ADEQ comment that EPA 
should replace (i.e., not retain) the visible crust test currently 
found in the FIP rule with the proposed ``drop ball'' visible crust 
test. Arizona Center for Law in the Public Interest (ACLPI) comments 
that they support the use of the most accurate test methods available, 
however, test methods should not be replaced where the superiority of 
the replacement tests has not been established; requiring both existing 
and proposed tests, at least for a certain time period, would not be 
unduly cumbersome or expensive to the regulated community, and this 
would also allow EPA to compare the relative value and accuracy of the 
two sets of tests.
    Response: EPA has retained the opacity standard in the FIP rule, 
while adding a new test method for measuring silt content. Retaining 
both the opacity and silt content standards and test methods in the 
final FIP rule will provide greater flexibility for qualified persons 
to conduct compliance testing of fugitive dust sources and will allow 
opportunities to compare the relative value and accuracy of the two 
tests.
    With respect to visible crust test methods, EPA has replaced the 
former visible crust test with the proposed ``drop ball'' visible crust 
test. EPA conducted field testing of both the visible crust test method 
in the final FIP rule and the proposed ``drop ball'' visible crust test 
method. Field testing showed that the proposed ``drop ball'' test 
method is easier to conduct, more accurately repeatable by various 
parties, and more indicative of whether a sufficiently stabilizing 
crust exists. To ensure the use of a superior method, EPA is replacing 
the test method in the final FIP rule with the ``drop ball'' test 
method. (Interested parties should note that the test method for 
threshold friction velocity promulgated in the final FIP rule can also 
be used to determine source compliance where some visible crusting is 
present.)
    Comment: ADEQ comments that adding the vegetative density procedure 
to the current test method would clarify the method and produce more 
accurate results when performed by different individuals.
    Response: EPA has added the vegetative density procedure to the 
standing vegetation test method.
    Comment: ADEQ comments that they support eliminating the 
requirement to submit ACMs to EPA because implementation costs will 
decrease since parties will not need to commit time and resources to 
submit ACMs to EPA and wait for approval before utilizing them. ACLIPI, 
however, comments that they strongly object to the implementation of 
ACMs without EPA approval because without such approval, ACMs will 
inevitably become ``least effective control measures''.
    Response: EPA has eliminated the requirement to submit ACMs to EPA 
for approval. Since the FIP rule contains standards and test methods 
which indicate whether a surface is stabilized, owners/operators can be 
allowed flexibility as to the type of control measure applied as long 
as the control measure results in a stabilized surface. The elimination 
of the requirement to submit ACMs for prior EPA approval does not 
lessen the owners'/operators' responsibility to implement control 
measures effectively on the sources subject to the rule. In fact, by 
emphasizing the intended result, as opposed to the type of control, EPA 
hopes to increase owners'/operators' understanding that their 
responsibility under the FIP rule will remain until a source is 
controlled, even if the owner/operator inadequately implements a 
control measure or implements an ineffective control measure. If 
applied, ACMs must meet the minimum standards established by the FIP 
rule, therefore, requiring that ACMs be submitted to EPA for approval 
would result in unnecessary administrative burden.

V. Text Corrections to the Final Rule

    In addition to finalizing the proposed rule amendments, EPA is 
incorporating a few minor corrections to final FIP rule text at 40 CFR 
52.128. These are enumerated in the Technical Support Document 
associated with this action, which can be found in Docket No. A-98-42.

VI. Administrative Requirements

A. Executive Order 12866

    Under Executive Order 12866, 58 FR 51735 (October 4, 1993), the 
Agency must determine whether the regulatory action is ``significant'' 
and therefore subject to Office of Management and Budget (OMB) review 
and the requirements of the Executive Order. The Order defines 
``significant regulatory action'' as one that is likely to result in a 
rule that may:

    (1) have an annual effect on the economy of $100 million or more 
or adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local or tribal governments or 
communities;
    (2) create a serious inconsistency or otherwise interfere with 
an action taken or planned by another agency;
    (3) materially alter the budgetary impact of entitlements, 
grants, user fees, or loan programs or the rights and obligations of 
recipients thereof; or
    (4) raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.

    Due to potential novel policy issues this action is considered a 
significant regulatory action and therefore must be reviewed by OMB. 
Changes made in response to OMB suggestions or recommendations will be 
documented in the public record.

B. Executive Order 13045

    Protection of Children from Environmental Health Risks and Safety 
Risks (62 FR 19885, April 23, 1997), applies to any rule that: (1) Is 
determined to be ``economically significant'' as defined under 
Executive Order 12866, and (2) concerns an environmental health or 
safety risk that EPA has reason to believe may have a disproportionate 
effect on children. If the regulatory action meets both criteria, the 
Agency must evaluate the environmental health or safety effects of the 
planned rule on children, and explain why the planned regulation is 
preferable to other potentially effective and reasonably feasible 
alternatives considered by the Agency.
    This rule is not subject to Executive Order 13045 because it does 
not involve decisions intended to mitigate environmental health or 
safety risks.

C. Executive Order 13084

    Under Executive Order 13084, EPA may not issue a regulation that is 
not required by statute, that significantly affects or uniquely affects 
the communities of Indian tribal governments, and that imposes 
substantial direct compliance costs on those communities, unless the 
Federal government provides the funds necessary to pay the direct 
compliance costs incurred by the tribal

[[Page 71307]]

governments. If EPA complies by consulting, Executive Order 13084 
requires EPA to provide to the Office of Management and Budget, in a 
separately identified section of the preamble to the rule, a 
description of the extent of EPA's prior consultation with 
representatives of affected tribal governments, a summary of the nature 
of their concerns, and a statement supporting the need to issue the 
regulation. In addition, Executive Order 13084 requires EPA to develop 
an effective process permitting elected and other representatives of 
Indian tribal governments ``to provide meaningful and timely input in 
the development of regulatory policies on matters that significantly or 
uniquely affect their communities.''
    Today's rule does not significantly or uniquely affect the 
communities of Indian tribal governments. This action does not involve 
or impose any requirements that affect Indian Tribes. Accordingly, the 
requirements of section 3(b) of Executive Order 13084 do not apply to 
this rule.

D. Executive Order 13132

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' is defined in the 
Executive Order to include regulations that have ``substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government.'' Under 
Executive Order 13132, EPA may not issue a regulation that has 
federalism implications, that imposes substantial direct compliance 
costs, and that is not required by statute, unless the Federal 
government provides the funds necessary to pay the direct compliance 
costs incurred by State and local governments, or EPA consults with 
State and local officials early in the process of developing the 
proposed regulation. EPA also may not issue a regulation that has 
federalism implications and that preempts State law unless the Agency 
consults with State and local officials early in the process of 
developing the proposed regulation.
    If EPA complies by consulting, Executive Order 13132 requires EPA 
to provide to the Office of Management and Budget (OMB), in a 
separately identified section of the preamble to the rule, a federalism 
summary impact statement (FSIS). The FSIS must include a description of 
the extent of EPA's prior consultation with State and local officials, 
a summary of the nature of their concerns and the agency's position 
supporting the need to issue the regulation, and a statement of the 
extent to which the concerns of State and local officials have been 
met. Also, when EPA transmits a draft final rule with federalism 
implications to OMB for review pursuant to Executive Order 12866, EPA 
must include a certification from the agency's Federalism Official 
stating that EPA has met the requirements of Executive Order 13132 in a 
meaningful and timely manner.
    This final rule will not have substantial direct effects on the 
States, on the relationship between the national government and the 
States, or on the distribution of power and responsibilities among the 
various levels of government, as specified in Executive Order 13132. 
The revisions finalized in this rulemaking concern test methods and 
flexibility for alternative compliance. Thus, the requirements of 
section 6 of the Executive Order do not apply to this rule.

E. Regulatory Flexibility Analysis

1. Regulatory Flexibility Act Requirements
    Under the Regulatory Flexibility Act (RFA), 5 U.S.C. 600 et seq., 
EPA must prepare a regulatory flexibility analysis assessing the impact 
of any proposed or final rule on small entities. Alternatively, EPA may 
certify that the rule will not have a significant impact on a 
substantial number of small entities. Small entities include small 
businesses, small not-for-profit enterprises, and government entities 
with jurisdiction over populations of less than 50,000.
    For the purposes of this inquiry, as it applies to the proposed 
amendments to the federal fugitive dust rule (40 CFR Sec. 52.128), EPA 
is assuming that the affected or potentially affected sources 
constitute ``small entities'' as defined by the RFA.
    A detailed discussion of the RFA analysis for the final FIP is 
found in section V.B. at 63 FR 41326. In general, the finalized 
amendments to the final FIP fugitive dust rule are intended to provide 
more flexibility in complying with the FIP rule and to improve the test 
methods as they currently exist in the rule. Thus, EPA believes that 
the amendments will not change the final FIP RFA analysis, except 
possibly to have a lesser impact on small entities.
2. RFA Analysis

a. Finalized Amendments to Federal Rule for Unpaved Roads, Unpaved 
Parking Lots and Vacant Lots

    EPA believes that the finalized test method amendments will provide 
either more flexibility or an improved procedure for determining 
compliance with the FIP fugitive dust rule. The silt content test 
method will allow persons who are not certified in visible emissions 
training to test the stability of an unpaved road or unpaved parking 
lot by using an alternative method to the opacity test method. EPA 
plans to ensure that the necessary sieve units are available for loan 
by local entities to regulated sources. Also, the newly added visible 
crust test method accomplishes the same objective as the previous 
visible crust test method yet is more practical and can be accurately 
repeated by various parties. The additional procedure to assist parties 
in measuring frontal silhouette area of various vegetative structures 
is merely intended to address circumstances that may arise in the field 
which are not addressed in the final FIP rule. Finally, eliminating the 
requirement for EPA approval of ACMs increases the rule's flexibility 
for source owners/operators and reduces the paperwork burden of the 
rule.

b. Certification

    For reasons discussed above, EPA has determined that it is not 
necessary to prepare a regulatory flexibility analysis in connection 
with the final rule amendments. After consideration of the economic 
impacts of today's final rule amendments on small entities, I hereby 
certify that the final rule will not have a significant economic impact 
on a substantial number of small entities.

F. Unfunded Mandates Reform Act (UMRA)

    Under Section 202 of the Unfunded Mandates Reform Act of 1995 
(``Unfunded Mandates Act''), signed into law on March 22, 1995, EPA 
must prepare a budgetary impact statement to accompany any proposed or 
final rule that includes a Federal mandate that may result in estimated 
costs to State, local, or tribal governments in the aggregate; or to 
private sector, of $100 million or more. Under Section 205, EPA must 
select the most cost-effective and least burdensome alternative that 
achieves the objectives of the rule and is consistent with statutory 
requirements. Section 203 requires EPA to establish a plan for 
informing and advising any small governments that

[[Page 71308]]

may be significantly or uniquely impacted by the rule.
    A detailed discussion of the UMRA requirements and how they are 
addressed can be found in section V.C. of the final FIP rulemaking (63 
FR 41326). As explained above, today's finalized amendments to the 
final FIP fugitive dust rule are intended to provide more flexibility 
in complying with the FIP rule and to improve the test methods 
currently in the rule. Thus, EPA believes that the amendments will not 
change the final FIP UMRA analysis, except possibly to have a lesser 
impact on most regulated entities.

G. Paperwork Reduction Act

    The finalized test method and ACM amendments do not impact the 
information collection request analysis for the final FIP (EPA ICR 
1855.02). The final FIP (63 FR 41326) provides more information on the 
information collection request requirements.

H. National Technology Transfer and Advancement Act (NTTAA)

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law No. 104-113, Sec. 12(d) (15 U.S.C. 
272 note) directs EPA to use voluntary consensus standards in its 
regulatory activities unless to do so would be inconsistent with 
applicable law or otherwise impractical. Voluntary consensus standards 
are technical standards (e.g., materials specifications, test methods, 
sampling procedures, and business practices) that are developed or 
adopted by voluntary consensus standards bodies. The NTTAA directs EPA 
to provide Congress, through OMB, explanations when the Agency decides 
not to use available and applicable voluntary consensus standards.
    In this action, EPA has incorporated voluntary consensus standards 
where feasible [See language for Appendix A to Sec. 52.128, I.B(iv)]. 
However, in most cases there are no applicable technical standards or 
field procedures specifically designed for the source categories at 
hand. OMB has reviewed and concurred on the applicable technical 
standards finalized in this revision.

I. Submission to Congress and the General Accounting Office

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this rule and other 
required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. This rule is not a 
``major'' rule as defined by 5 U.S.C. 804(2).

J. Petitions for Judicial Review

    Under section 307(b)(1) of the Clean Air Act, petitions for 
judicial review of this action must be filed in the United States Court 
of Appeals for the appropriate circuit by February 22, 2000. Filing a 
petition for reconsideration by the Administrator of this final rule 
does not affect the finality of this rule for the purposes of judicial 
review nor does it extend the time within which a petition for judicial 
review may be filed, and shall not postpone the effectiveness of such 
rule or action. This action may not be challenged later in proceedings 
to enforce its requirements. (See section 307(b)(2).)

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Intergovernmental 
relations, Particulate matter.

    Dated: December 13, 1999.
Carol M. Browner,
Administrator.
    For the reasons set forth in the preamble, part 52, chapter I, 
title 40 of the Code of Federal Regulations is amended as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

    1. The authority citation for part 52 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

Subpart D--Arizona

    2. Section 52.128 is revised as follows:


Sec. 52.128  Rule for unpaved parking lots, unpaved roads and vacant 
lots.

    (a) General. (1) Purpose. The purpose of this section is to limit 
the emissions of particulate matter into the ambient air from human 
activity on unpaved parking lots, unpaved roads and vacant lots.
    (2) Applicability. The provisions of this section shall apply to 
owners/operators of unpaved roads, unpaved parking lots and vacant lots 
and responsible parties for weed abatement on vacant lots in the 
Phoenix PM-10 nonattainment area. This section does not apply to 
unpaved roads, unpaved parking lots or vacant lots located on an 
industrial facility, construction, or earth-moving site that has an 
approved permit issued by Maricopa County Environmental Services 
Division under Rule 200, Section 305, Rule 210 or Rule 220 containing a 
Dust Control Plan approved under Rule 310 covering all unpaved parking 
lots, unpaved roads and vacant lots. This section does not apply to the 
two Indian Reservations (the Salt River Pima-Maricopa Indian Community 
and the Fort McDowell Mojave-Apache Indian Community) and a portion of 
a third reservation (the Gila River Indian Community) in the Phoenix 
PM-10 nonattainment area. Nothing in this definition shall preclude 
applicability of this section to vacant lots with disturbed surface 
areas due to construction, earth-moving, weed abatement or other dust 
generating operations which have been terminated for over eight months.
    (3) The test methods described in Appendix A of this section shall 
be used when testing is necessary to determine whether a surface has 
been stabilized as defined in paragraph (b)(16) of this section.
    (b) Definitions. (1) Average daily trips (ADT)--The average number 
of vehicles that cross a given surface during a specified 24-hour time 
period as determined by the Institute of Transportation Engineers Trip 
Generation Report (6th edition, 1997) or tube counts.
    (2) Chemical/organic stabilizer--Any non-toxic chemical or organic 
dust suppressant other than water which meets any specifications, 
criteria, or tests required by any federal, state, or local water 
agency and is not prohibited for use by any applicable law, rule or 
regulation.
    (3) Disturbed surface area--Any portion of the earth's surface, or 
materials placed thereon, which has been physically moved, uncovered, 
destabilized, or otherwise modified from its undisturbed natural 
condition, thereby increasing the potential for emission of fugitive 
dust.
    (4) Dust suppressants--Water, hygroscopic materials, solution of 
water and chemical surfactant, foam, or non-toxic chemical/organic 
stabilizers not prohibited for use by any applicable law, rule or 
regulation, as a treatment material to reduce fugitive dust emissions.
    (5) EPA--United States Environmental Protection Agency, Region IX, 
75 Hawthorne Street, San Francisco, California 94105.

[[Page 71309]]

    (6) 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 from the 
exhaust of motor vehicles and other internal combustion engines, from 
portable brazing, soldering, or welding equipment, and from 
piledrivers.
    (7) Lot--A parcel of land identified on a final or parcel map 
recorded in the office of the Maricopa County recorder with a separate 
and distinct number or letter.
    (8) Low use unpaved parking lot--A lot on which vehicles are parked 
no more than thirty-five (35) days a year, excluding days where the 
exemption in paragraph (c)(2) of this section applies.
    (9) Motor vehicle--A self-propelled vehicle for use on the public 
roads and highways of the State of Arizona and required to be 
registered under the Arizona State Uniform Motor Vehicle Act, including 
any non-motorized attachments, such as, but not limited to, trailers or 
other conveyances which are connected to or propelled by the actual 
motorized portion of the vehicle.
    (10) Off-road motor vehicle--any wheeled vehicle which is used off 
paved roadways and includes but is not limited to the following:
    (i) Any motor cycle or motor-driven cycle;
    (ii) Any motor vehicle commonly referred to as a sand buggy, dune 
buggy, or all terrain vehicle.
    (11) Owner/operator--any person who owns, leases, operates, 
controls, maintains or supervises a fugitive dust source subject to the 
requirements of this section.
    (12) Paving--Applying asphalt, recycled asphalt, concrete, or 
asphaltic concrete to a roadway surface.
    (13) Phoenix PM-10 nonattainment area--such area as defined in 40 
CFR 81.303, excluding Apache Junction.
    (14) PM-10--Particulate matter with an aerodynamic diameter less 
than or equal to a nominal 10 micrometers as measured by reference or 
equivalent methods that meet the requirements specified for PM-10 in 40 
CFR part 50, Appendix J.
    (15) Reasonably available control measures (RACM)--Techniques used 
to prevent the emission and/or airborne transport of fugitive dust and 
dirt.
    (16) Stabilized surface--(i) Any unpaved road or unpaved parking 
lot surface where:
    (A) Any fugitive dust plume emanating from vehicular movement does 
not exceed 20 percent opacity as determined in section I.A of Appendix 
A of this section; and
    (B) Silt loading (weight of silt per unit area) is less than 0.33 
ounces per square foot as determined by the test method in section I.B 
of Appendix A of this section OR where silt loading is greater than or 
equal to 0.33 ounces per square foot and silt content does not exceed 
six (6) percent for unpaved road surfaces or eight (8) percent for 
unpaved parking lot surfaces as determined by the test method in 
section I.B of Appendix A of this section.
    (ii) Any vacant lot surface with:
    (A) A visible crust which is sufficient as determined in section 
II.1 of Appendix A of this section;
    (B) A threshold friction velocity (TFV), corrected for non-erodible 
elements, of 100 cm/second or higher as determined in section II.2 of 
Appendix A of this section;
    (C) Flat vegetation cover equal to at least 50 percent as 
determined in section II.3 of Appendix A of this section;
    (D) Standing vegetation cover equal to or greater than 30 percent 
as determined in section II.4 of Appendix A of this section; or
    (E) Standing vegetation cover equal to or greater than 10 percent 
as determined in section II.4 of Appendix A of this section where 
threshold friction velocity, corrected for non-erodible elements, as 
determined in section II.2 of Appendix A of this section is equal to or 
greater than 43 cm/second.
    (17) Unpaved parking lot--A privately or publicly owned or operated 
area utilized for parking vehicles that is not paved and is not a Low 
use unpaved parking lot.
    (18) Unpaved road--Any road, equipment path or driveway used by 
motor vehicles or off-road motor vehicles that is not paved which is 
open to public access and owned/operated by any federal, state, county, 
municipal or other governmental or quasi-governmental agencies.
    (19) Urban or suburban open area--An unsubdivided or undeveloped 
tract of land adjoining a residential, industrial or commercial area, 
located on public or private property.
    (20) Vacant lot--A subdivided residential, industrial, 
institutional, governmental or commercial lot which contains no 
approved or permitted buildings or structures of a temporary or 
permanent nature.
    (c) Exemptions. The following requirements in paragraph (d) of this 
section do not apply:
    (1) In paragraphs (d)(1), (d)(2) and (d)(4)(iii) of this section: 
Any unpaved parking lot or vacant lot 5,000 square feet or less.
    (2) In paragraphs (d)(1) and (d)(2) of this section: Any unpaved 
parking lot on any day in which ten (10) or fewer vehicles enter.
    (3) In paragraphs (d)(4)(i) and (d)(4)(ii) of this section: Any 
vacant lot with less than 0.50 acre (21,780 square feet) of disturbed 
surface area(s).
    (4) In paragraph (d) of this section: Non-routine or emergency 
maintenance of flood control channels and water retention basins.
    (5) In paragraph (d) of this section: Vehicle test and development 
facilities and operations when dust is required to test and validate 
design integrity, product quality and/or commercial acceptance. Such 
facilities and operations shall be exempted from the provisions of this 
section only if such testing is not feasible within enclosed 
facilities.
    (6) In paragraph (d)(4)(i) of this section: Weed abatement 
operations performed on any vacant lot or property under the order of a 
governing agency for the control of a potential fire hazard or 
otherwise unhealthy condition provided that mowing, cutting, or another 
similar process is used to maintain weed stubble at least three (3) 
inches above the soil surface. This includes the application of 
herbicides provided that the clean-up of any debris does not disturb 
the soil surface.
    (7) In paragraph (d)(4)(i) of this section: Weed abatement 
operations that receive an approved Earth Moving permit under Maricopa 
County Rule 200, Section 305 (adopted 11/15/93).
    (d) Requirements. (1) Unpaved parking lots. Any owners/operators of 
an unpaved parking lot shall implement one of the following RACM on any 
surface area(s) of the lot on which vehicles enter and park.
    (i) Pave; or
    (ii) Apply chemical/organic stabilizers in sufficient concentration 
and frequency to maintain a stabilized surface; or
    (iii) Apply and maintain surface gravel uniformly such that the 
surface is stabilized; or
    (iv) Apply and maintain an alternative control measure such that 
the surface is stabilized, provided that the alternative measure is not 
prohibited under paragraph (b)(2) or (b)(4) of this section.
    (2) Any owners/operators of a low use unpaved parking lot as 
defined in paragraph (b)(8) of this section shall implement one of the 
RACM under paragraph (d)(1) of this section on any day(s) in which over 
100 vehicles enter the lot, such that the surface area(s) on which 
vehicles enter and park is/are

[[Page 71310]]

stabilized throughout the duration of time that vehicles are parked.
    (3) Unpaved roads. Any owners/operators of existing unpaved roads 
with ADT volumes of 250 vehicles or greater shall implement one of the 
following RACM along the entire surface of the road or road segment 
that is located within the Phoenix non-attainment area by June 10, 
2000:
    (i) Pave; or
    (ii) Apply chemical/organic stabilizers in sufficient concentration 
and frequency to maintain a stabilized surface; or
    (iii) Apply and maintain surface gravel uniformly such that the 
surface is stabilized; or
    (iv) Apply and maintain an alternative control measure such that 
the surface is stabilized, provided that the alternative measure is not 
prohibited under paragraph (b)(2) or (b)(4) of this section.
    (4) Vacant lots. The following provisions shall be implemented as 
applicable.
    (i) Weed abatement. No person shall remove vegetation from any 
vacant lot by blading, disking, plowing under or any other means 
without implementing all of the following RACM to prevent or minimize 
fugitive dust.
    (A) Apply a dust suppressant(s) to the total surface area subject 
to disturbance immediately prior to or during the weed abatement.
    (B) Prevent or eliminate material track-out onto paved surfaces and 
access points adjoining paved surfaces.
    (C) Apply a dust suppressant(s), gravel, compaction or alternative 
control measure immediately following weed abatement to the entire 
disturbed surface area such that the surface is stabilized.
    (ii) Disturbed surfaces. Any owners/operators of an urban or 
suburban open area or vacant lot of which any portion has a disturbed 
surface area(s) that remain(s) unoccupied, unused, vacant or 
undeveloped for more than fifteen (15) calendar days shall implement 
one of the following RACM within sixty (60) calendar days following the 
disturbance.
    (A) Establish ground cover vegetation on all disturbed surface 
areas in sufficient quantity to maintain a stabilized surface; or
    (B) Apply a dust suppressant(s) to all disturbed surface areas in 
sufficient quantity and frequency to maintain a stabilized surface; or
    (C) Restore to a natural state, i.e. as existing in or produced by 
nature without cultivation or artificial influence, such that all 
disturbed surface areas are stabilized; or
    (D) Apply and maintain surface gravel uniformly such that all 
disturbed surface areas are stabilized; or
    (E) Apply and maintain an alternative control measure such that the 
surface is stabilized, provided that the alternative measure is not 
prohibited under paragraph (b)(2) or (b)(4) of this section.
    (iii) Motor vehicle disturbances. Any owners/operators of an urban 
or suburban open area or vacant lot of which any portion has a 
disturbed surface area due to motor vehicle or off-road motor vehicle 
use or parking, notwithstanding weed abatement operations or use or 
parking by the owner(s), shall implement one of the following RACM 
within 60 calendar days following the initial determination of 
disturbance.
    (A) Prevent motor vehicle and off-road motor vehicle trespass/ 
parking by applying fencing, shrubs, trees, barriers or other effective 
measures; or
    (B) Apply and maintain surface gravel or chemical/organic 
stabilizer uniformly such that all disturbed surface areas are 
stabilized.
    (5) Implementation date of RACM. All of the requirements in 
paragraph (d) of this section shall be effective eight (8) months from 
September 2, 1998. For requirements in paragraph (d)(4)(ii) and 
(d)(4)(iii) of this section, RACM shall be implemented within eight (8) 
months from September 2, 1998, or within 60 calendar days following the 
disturbance, whichever is later.
    (e) Monitoring and records. (1) Any owners/operators that are 
subject to the provisions of this section shall compile and retain 
records that provide evidence of control measure application, 
indicating the type of treatment or measure, extent of coverage and 
date applied. For control measures involving chemical/organic 
stabilization, records shall also indicate the type of product applied, 
vendor name, label instructions for approved usage, and the method, 
frequency, concentration and quantity of application.
    (2) Copies of control measure records and dust control plans along 
with supporting documentation shall be retained for at least three 
years.
    (3) Agency surveys. (i) EPA or other appropriate entity shall 
conduct a survey of the number and size (or length) of unpaved roads, 
unpaved parking lots, and vacant lots subject to the provisions of this 
section located within the Phoenix PM-10 nonattainment area beginning 
no later than 365 days from September 2, 1998.
    (ii) EPA or other appropriate entity shall conduct a survey at 
least every three years within the Phoenix PM-10 nonattainment area 
beginning no later than 365 days from September 2, 1998, which 
includes:
    (A) An estimate of the percentage of unpaved roads, unpaved parking 
lots, and vacant lots subject to this section to which RACM as required 
in this section have been applied; and
    (B) A description of the most frequently applied RACM and estimates 
of their control effectiveness.

Appendix A to Sec. 52.128--Test Methods To Determine Whether A Surface 
Is Stabilized

I. Unpaved Roads and Unpaved Parking Lots

A. Opacity Observations

    Conduct opacity observations in accordance with Reference Method 
9 (40 CFR Part 60, appendix A) and Methods 203A and 203C of this 
appendix, with opacity readings taken at five second observation 
intervals and two consecutive readings per plume beginning with the 
first reading at zero seconds, in accordance with Method 203C, 
sections 2.3.2. and 2.4.2 of this appendix. Conduct visible opacity 
tests only on dry unpaved surfaces (i.e. when the surface is not 
damp to the touch) and on days when average wind speeds do not 
exceed 15 miles per hour (mph).

(i) Method 203A--Visual Determination of Opacity of Emissions From 
Stationary Sources for Time-Arranged Regulations

    Method 203A is virtually identical to EPA's Method 9 (40 CFR 
Part 60 Appendix A) except for the data-reduction procedures, which 
provide for averaging times other than 6 minutes. That is, using 
Method 203A with a 6-minute averaging time would be the same as 
following EPA Method 9 (40 CFR Part 60, Appendix A). Additionally, 
Method 203A provides procedures for fugitive dust applications. The 
certification procedures provided in section 3 are virtually 
identical to Method 9 (40 CFR Part 60, Appendix A) and are provided 
here, in full, for clarity and convenience.

1. Applicability and Principle

    1.1 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.
    1.2 Principle. The opacity of emissions from sources of visible 
emissions is determined visually by an observer qualified according 
to the procedures of section 3.

2. Procedures

    An observer qualified in accordance with section 3 of this 
method shall use the following procedures for visually determining 
the opacity of emissions.
    2.1 Procedures for Emissions from Stationary Sources. These 
procedures are not applicable to this section.
    2.2 Procedures for Fugitive Process Dust Emissions. These 
procedures are applicable for the determination of the opacity of 
fugitive emissions by a qualified observer. The qualified field 
observer should do the following:

[[Page 71311]]

    2.2.1 Position. Stand at a position at least 5 meters from the 
fugitive dust source in order to provide a clear view of the 
emissions with the sun oriented in the 140-degree 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 vision is approximately perpendicular to the plume and 
wind direction. As much as possible, if multiple plumes are 
involved, do not include more than one plume in the line of sight at 
one time.
    2.2.2 Field Records. Record the name of the plant or site, 
fugitive source location, source type [pile, stack industrial 
process unit, incinerator, open burning operation activity, material 
handling (transfer, loading, sorting, etc.)], 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 
source. Also, record the time, estimated distance to the fugitive 
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 source, and color of 
the plume and type of background on the visible emission observation 
form when opacity readings are initiated and completed.
    2.2.3 Observations. Make opacity observations, to the extent 
possible, using a contrasting background that is perpendicular to 
the line of vision. For roads, storage piles, and parking lots, make 
opacity observations approximately 1 meter above the surface from 
which the plume is generated. For other fugitive sources, make 
opacity observations at the point of greatest opacity in that 
portion of the plume where condensed water vapor is not present. For 
intermittent sources, 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.
    2.3 Recording Observations. Record the opacity observations to 
the nearest 5 percent every 15 seconds on an observational record 
sheet. Each momentary observation recorded represents the average 
opacity of emissions for a 15-second period.
    2.4 Data Reduction for Time-Averaged Regulations. A set of 
observations is composed of an appropriate number of consecutive 
observations determined by the averaging time specified. Divide the 
recorded observations into sets of appropriate time lengths for the 
specified averaging time. Sets must consist of consecutive 
observations; however, observations immediately preceding and 
following interrupted observations shall be deemed consecutive. Sets 
need not be consecutive in time and in no case shall two sets 
overlap, resulting in multiple violations. For each set of 
observations, calculate the appropriate average opacity.

3. Qualification and Testing

    3.1 Certification Requirements. To receive certification as a 
qualified observer, a candidate must be tested and demonstrate the 
ability to assign opacity readings in 5 percent increments to 25 
different black plumes and 25 different white plumes, with an error 
not to exceed 15 percent opacity on any one reading and an average 
error not to exceed 7.5 percent opacity in each category. Candidates 
shall be tested according to the procedures described in paragraph 
3.2. Any smoke generator used pursuant to paragraph 3.2 shall be 
equipped with a smoke meter which meets the requirements of 
paragraph 3.3. Certification tests that do not meet the requirements 
of paragraphs 3.2 and 3.3 are not valid.
    The certification shall be valid for a period of 6 months, and 
after each 6-month period, the qualification procedures must be 
repeated by an observer in order to retain certification.
    3.2 Certification Procedure. The certification test consists of 
showing the candidate a complete run of 50 plumes, 25 black plumes 
and 25 white plumes, generated by a smoke generator. Plumes shall be 
presented in random order within each set of 25 black and 25 white 
plumes. The candidate assigns an opacity value to each plume and 
records the observation on a suitable form. At the completion of 
each run of 50 readings, the score of the candidate is determined. 
If a candidate fails to qualify, the complete run of 50 readings 
must be repeated in any retest. The smoke test may be administered 
as part of a smoke school or training program, and may be preceded 
by training or familiarization runs of the smoke generator during 
which candidates are shown black and white plumes of known opacity.
    3.3 Smoke Generator Specifications. Any smoke generator used for 
the purpose of paragraph 3.2 shall be equipped with a smoke meter 
installed to measure opacity across the diameter of the smoke 
generator stack. The smoke meter output shall display in-stack 
opacity, based upon a path length equal to the stack exit diameter 
on a full 0 to 100 percent chart recorder scale. The smoke meter 
optical design and performance shall meet the specifications shown 
in Table A. The smoke meter shall be calibrated as prescribed in 
paragraph 3.3.1 prior to conducting each smoke reading test. At the 
completion of each test, the zero and span drift, shall be checked, 
and if the drift exceeds 1 percent opacity, the 
condition shall be corrected prior to conducting any subsequent test 
runs. The smoke meter shall be demonstrated at the time of 
installation to meet the specifications listed in Table A. This 
demonstration shall be repeated following any subsequent repair or 
replacement of the photocell or associated electronic circuitry 
including the chart recorder or output meter, or every 6 months, 
whichever occurs first.
    3.3.1 Calibration. The smoke meter is calibrated after allowing 
a minimum of 30 minutes warm-up by alternately producing simulated 
opacity of 0 percent and 100 percent. When stable response at 0 
percent or 100 percent is noted, the smoke meter is adjusted to 
produce an output of 0 percent or 100 percent, as appropriate. This 
calibration shall be repeated until stable 0 percent and 100 percent 
readings are produced without adjustment. Simulated 0 percent and 
100 percent opacity values may be produced by alternately switching 
the power to the light source on and off while the smoke generator 
is not producing smoke.
    3.3.2 Smoke Meter Evaluation. The smoke meter design and 
performance are to be evaluated as follows:
    3.3.2.1 Light Source. Verify from manufacturer's data and from 
voltage measurements made at the lamp, as installed, that the lamp 
is operated within 5 percent of the nominal rated 
voltage.
    3.3.2.2 Spectral Response of Photocell. Verify from 
manufacturer's data that the photocell has a photopic response; 
i.e., the spectral sensitivity of the cell shall closely approximate 
the standard spectral-luminosity curve for photopic vision which is 
referenced in (b) of Table A.
    3.3.2.3 Angle of View. Check construction geometry to ensure 
that the total angle of view of the smoke plume, as seen by the 
photocell, does not exceed 15 degrees. Calculate the total angle of 
view as follows:

v = 2 tan-1 d/2L

Where:

v = total angle of view;
d = the photocell diameter + the diameter of the limiting aperture; 
and
L = distance from the photocell to the limiting aperture.

    The limiting aperture is the point in the path between the 
photocell and the smoke plume where the angle of view is most 
restricted. In smoke generator smoke meters, this is normally an 
orifice plate.
    3.3.2.4 Angle of Projection. Check construction geometry to 
ensure that the total angle of projection of the lamp on the smoke 
plume does not exceed 15 degrees. Calculate the total angle of 
projection as follows:

p = 2 tan-1 d/2L

Where:

p = total angle of projection;
d = the sum of the length of the lamp filament + the diameter of the 
limiting aperture; and
L = the distance from the lamp to the limiting aperture.

    3.3.2.5 Calibration Error. Using neutral-density filters of 
known opacity, check the error between the actual response and the 
theoretical linear response of the smoke meter. This check is 
accomplished by first calibrating the smoke meter according to 3.3.1 
and then inserting a series of three neutral-density filters of 
nominal opacity of 20, 50, and 75 percent in the smoke meter path 
length. Use filters calibrated within 2 percent. Care 
should be taken when inserting the filters to prevent stray light 
from affecting the meter. Make a total of five nonconsecutive 
readings for each filter. The maximum opacity error on any one 
reading shall be 3 percent.
    3.3.2.6 Zero and Span Drift. Determine the zero and span drift 
by calibrating and operating the smoke generator in a normal manner 
over a 1-hour period. The drift is measured by checking the zero and 
span at the end of this period.
    3.3.2.7 Response Time. Determine the response time by producing 
the series of five simulated 0 percent and 100 percent opacity 
values and observing the time required to reach stable response. 
Opacity values of 0 percent and 100 percent may be simulated by 
alternately switching the power to the light

[[Page 71312]]

source off and on while the smoke generator is not operating.

4. References

    1. U.S. Environmental Protection Agency. Standards of 
Performance for New Stationary Sources; appendix A; Method 9 for 
Visual Determination of the Opacity of Emissions from Stationary 
Sources. Final Rule. 39 FR 219. Washington, DC. U.S. Government 
Printing Office. November 12, 1974.
    2. Office of Air and Radiation. ``Quality Assurance Guideline 
for Visible Emission Training Programs.'' EPA-600/S4-83-011. Quality 
Assurance Division. Research Triangle Park, N.C. May 1982.
    3. ``Method 9--Visible Determination of the Opacity of Emissions 
from Stationary Sources.'' February 1984. Quality Assurance Handbook 
for Air Pollution Measurement Systems. Volume III, section 3.1.2. 
Stationary Source Specific Methods. EPA-600-4-77-027b. August 1977. 
Office of Research and Development Publications, 26 West Clair 
Street, Cincinnati, OH.
    4. Office of Air Quality Planning and Standards. ``Opacity Error 
for Averaging and Nonaveraging Data Reduction and Reporting 
Techniques.'' Final Report-SR-1-6-85. Emission Measurement Branch, 
Research Triangle Park, N.C. June 1985.
    5. The U.S. Environmental Protection Agency. Preparation, 
Adoption, and Submittal of State Implementation Plans. Methods for 
Measurement of PM10 Emissions from Stationary Sources. 
Final Rule. Federal Register. Washington, DC. U.S. Government 
Printing Office. Volumes 55. No. 74. pps. 14246-14279. April 17, 
1990.

(ii) Method 203C--Visual Determination of Opacity of Emissions From 
Stationary Sources for Instantaneous Limitation Regulations

    Method 203C is virtually identical to EPA's Method 9 (40 CFR 
Part 60, Appendix A), except for the data-reduction procedures which 
have been modified for application to instantaneous limitation 
regulations. Additionally, Method 203C provides procedures for 
fugitive dust applications which were unavailable when Method 9 was 
promulgated. The certification procedures in section 3 are identical 
to Method 9. These certification procedures are provided in Method 
203A as well, and, therefore, have not been repeated in this method.

1. Applicability and Principle

    1.1 Applicability. This method is applicable for the 
determination of the opacity of emissions from sources of visible 
emissions for instantaneous limitations. An instantaneous limitation 
regulation is an opacity limit which is never to be exceeded.
    1.2 Principle. The opacity of emissions from sources of visible 
emissions is determined visually by a qualified observer.

2. Procedures

    The observer qualified in accordance with section 3 of this 
method shall use the following procedures for visually determining 
the opacity of emissions.
    2.1 Procedures for Emissions From Stationary Sources. Same as 
2.1, Method 203A.
    2.1.1 Position. Same as 2.1.1, Method 203A.
    2.1.2 Field Records. Same as 2.1.2, Method 203A.
    2.1.3 Observations. Make opacity observations at the point of 
greatest opacity in that portion of the plume where condensed water 
vapor is not present.
    Do not look continuously at the plume. Instead, observe the 
plume momentarily at the interval specified in the subject 
regulation. Unless otherwise specified, a 15-second observation 
interval is assumed.
    2.1.3.1 Attached Steam Plumes. Same as 2.1.3.1, Method 203A.
    2.1.3.2 Detached Steam Plumes. Same as 2.1.3.2, Method 203A.
    2.2 Procedures for Fugitive Process Dust Emissions.
    2.2.1 Position. Same as section 2.2.1, Method 203A.
    2.2.2 Field Records. Same as section 2.2.2, Method 203A.
    2.2.3 Observations.
    2.2.3.1 Observations for a 15-second Observation Interval 
Regulations. Same as section 2.2.3, Method 203A.
    2.2.3.2 Observations for a 5-second Observation Interval 
Regulations. Same as section 2.2.3, Method 203A, except, observe the 
plume momentarily at 5-second intervals.
    2.3 Recording Observations. Record opacity observations to the 
nearest 5 percent at the prescribed interval on an observational 
record sheet. Each momentary observation recorded represents the 
average of emissions for the prescribed period. If a 5-second 
observation period is not specified in the applicable regulation, a 
15-second interval is assumed. The overall time for which recordings 
are made shall be of a length appropriate to the regulation for 
which opacity is being measured.
    2.3.1 Recording Observations for 15-second Observation Interval 
Regulations. Record opacity observations to the nearest 5 percent at 
15-second intervals on an observational record sheet. Each momentary 
observation recorded represents the average of emissions for a 15-
second period.
    2.3.2 Recording Observations for 5-second Observation Interval 
Regulations. Record opacity observations to the nearest 5 percent at 
5-second intervals on an observational record sheet. Each momentary 
observation recorded represents the average of emissions for 5-
second period.
    2.4 Data Reduction for Instantaneous Limitation Regulations. For 
an instantaneous limitation regulation, a 1-minute averaging time 
will be used. Divide the observations recorded on the record sheet 
into sets of consecutive observations. A set is composed of the 
consecutive observations made in 1 minute. Sets need not be 
consecutive in time, and in no case shall two sets overlap. Reduce 
opacity observations by dividing the sum of all observations 
recorded in a set by the number of observations recorded in each 
set.
    2.4.1 Data Reduction for 15-second Observation Intervals. Reduce 
opacity observations by averaging four consecutive observations 
recorded at 15-second intervals. Divide the observations recorded on 
the record sheet into sets of four consecutive observations. For 
each set of four observations, calculate the average by summing the 
opacity of the four observations and dividing this sum by four.
    2.4.2 Data Reduction for 5-second Observation Intervals. Reduce 
opacity observations by averaging 12 consecutive observations 
recorded at 5-second intervals. Divide the observations recorded on 
the record sheet into sets of 12 consecutive observations. For each 
set of 12 observations, calculate the average by summing the opacity 
of the 12 observations and dividing this sum by 12.

3. Qualification and Test

    Same as section 3, Method 203A.

                           TABLE A.--Smoke Meter Design and Performance Specifications
----------------------------------------------------------------------------------------------------------------
               Parameter                                              Specification
----------------------------------------------------------------------------------------------------------------
a. Light Source........................  Incandescent lamp operated at nominal rated voltage.
b. Spectral response of photocell......  Photopic (daylight spectral response of the human eye--Reference 4.1 of
                                          section 4.)
c. Angle of view.......................  15 degrees maximum total angle
d. Angle of projection.................  15 degrees maximum total angle.
e. Calibration error...................  3 percent opacity, maximum.
f. Zero and span drift.................  1 percent opacity, 30 minutes.
g. Response time.......................  5 seconds.
----------------------------------------------------------------------------------------------------------------

B. Silt Content

    Conduct the following test method to determine the silt loading 
and silt content of unpaved road and unpaved parking lot surfaces.
    (i) Collect a sample of loose surface material from an area 30 
cm by 30 cm (1 foot by 1 foot) in size to a depth of approximately 1 
cm or until a hard subsurface is reached, whichever occurs first. 
Use a brush and dustpan or other similar device. Collect the sample 
from a routinely-traveled portion of the surface which receives a 
preponderance of vehicle traffic, i.e. as commonly evidenced by tire 
tracks. Conduct sweeping slowly so

[[Page 71313]]

that fine surface material is not released into the air. Only 
collect samples from surfaces that are not wet or damp due to 
precipitation or dew.
    (ii) Obtain a shallow, lightweight container and a scale with 
readings in half ounce increments or less. Place the scale on a 
level surface and zero it with the weight of the empty container. 
Transfer the entire sample collected to the container, minimizing 
escape of particles into the air. Weigh the sample and record its 
weight.
    (iii) Obtain and stack a set of sieves with the following 
openings: 4 mm, 2 mm, 1 mm, 0.5 mm, and 0.25 mm. 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. Pour the entire sample into the top sieve, 
minimizing escape of particles into the air by positioning the 
sieve/collector pan unit in an enclosed or wind barricaded area. 
Cover the sieve/collector pan unit with a lid. Shake the covered 
sieve/collector pan unit vigorously for a period of at least one (1) 
minute in both the horizontal and vertical planes. 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 a complete separation of material in order 
to ensure that all material has been sifted to the finest sieve 
through which it can pass. If not, reassemble and cover the sieve/
collector pan unit and shake it for period of at least one (1) 
minute. After disassembling the sieve/collector pan unit, transfer 
the material which is captured in the collector pan into the 
lightweight container originally used to collect and weigh the 
sample. Minimize escape of particles into the air when transferring 
the material into the container. Weigh the container with the 
material from the collector pan and record its weight. Multiply the 
resulting weight by 0.38 if the source is an unpaved road or by 0.55 
if the source is an unpaved parking lot to estimate silt loading. 
Divide by the total sample weight and multiply by 100 to arrive at 
the percent silt content.
    (iv) As an alternative to conducting the procedure described 
above in section I.B.(ii) and section I.B.(iii) of this appendix, 
the sample (collected according to section I.B.(i) of this appendix) 
may be taken to an independent testing laboratory or engineering 
facility for silt loading (e.g. net weight < 200 mesh) and silt 
content analysis according to the following test method from 
``Procedures For Laboratory Analysis Of Surface/Bulk Dust Loading 
Samples'', (Fifth Edition, Volume I, 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.
    1. Objective--Several open dust emission factors have been found 
to be correlated with the silt content(< 200 mesh) of the material 
being disturbed. The basic procedure for silt content determination 
is mechanical, dry sieving. For sources other than paved roads, the 
same sample which was oven-dried to determine moisture content is 
then mechanically sieved.
    2.1 Procedure--Select the appropriate 20-cm (8-in.) diameter, 5-
cm (2-in.) deep sieve sizes.
    Recommended U. S. Standard Series sizes are 3/8 in., No. 4, No. 
40, No. 100, No. 140, No. 200, and a pan. Comparable Tyler Series 
sizes can also be used. The No. 20 and the No. 200 are mandatory. 
The others can be varied if the recommended sieves are not 
available, or if buildup on 1 particulate sieve during sieving 
indicates that an intermediate sieve should be inserted.
    2.2 Obtain a mechanical sieving device, such as a vibratory 
shaker or a Roto-Tap  1 without the tapping 
function.
---------------------------------------------------------------------------

    \1\ CFR part 60, App. A, Meth. 5, 2.1.2, footnote 2.
---------------------------------------------------------------------------

    2.3 Clean the sieves with compressed air and/or a soft brush. 
Any material lodged in the sieve openings or adhering to the sides 
of the sieve should be removed, without handling the screen roughly, 
if possible.
    2.4 Obtain a scale (capacity of at least 1600 grams [g] or 3.5 
lb) and record make, capacity, smallest division, date of last 
calibration, and accuracy. (See Figure A)
    2.5 Weigh the sieves and pan to determine tare weights. Check 
the zero before every weighing. Record the weights.
    2.6 After nesting the sieves in decreasing order of size, and 
with pan at the bottom, dump dried laboratory sample (preferably 
immediately after moisture analysis) into the top sieve. The sample 
should weigh between  400 and 1600 g ( 0.9 
and 3.5 lb). This amount will vary for finely textured materials, 
and 100 to 300 g may be sufficient when 90% of the sample passes a 
No. 8 (2.36 mm) sieve. Brush any fine material adhering to the sides 
of the container into the top sieve and cover the top sieve with a 
special lid normally purchased with the pan.
    2.7 Place nested sieves into the mechanical sieving device and 
sieve for 10 minutes (min). Remove pan containing minus No. 200 and 
weigh. Repeat the sieving at 10-min intervals until the difference 
between 2 successive pan sample weighings (with the pan tare weight 
subtracted) is less than 3.0%. Do not sieve longer than 40 min.
    2.8 Weigh each sieve and its contents and record the weight. 
Check the zero before every weighing.
    2.9 Collect the laboratory sample. Place the sample in a 
separate container if further analysis is expected.
    2.10 Calculate the percent of mass less than the 200 mesh screen 
(75 micrometers [m]). This is the silt content.
    Figure A. Example silt analysis form.

Silt Analysis

Dated: __________
By: ________________________
Sample No: ________ Sample Weight (after drying)
Material: ________
    Pan + Sample: ____________
    Pan: ____________
    Split Sample Balance: ____________
    Dry Sample: ______________
Make ____________ Capacity: ____________
Smallest Division ________
Final Weight ____________
% Silt = [Net Weight <200 Mesh]  [Total Net Weight  x  100] 
=____%

                                 Sieving
------------------------------------------------------------------------
               Time: Start:                       Weight (Pan Only)
------------------------------------------------------------------------
Initial (Tare):
10 min:
20 min:
30 min:
40 min:
------------------------------------------------------------------------


----------------------------------------------------------------------------------------------------------------
                                                         Final weight (screen +
             Screen               Tare weight (screen)           sample)           Net weight (sample)      %
----------------------------------------------------------------------------------------------------------------
\3/8\ in.......................
4 mesh.........................
10 mesh........................
20 mesh........................
40 mesh........................
100 mesh.......................
140 mesh.......................
200 mesh.......................
Pan............................
----------------------------------------------------------------------------------------------------------------

    (v) The silt loading and percent silt content for any given 
unpaved road surface or unpaved parking lot surface shall be based 
on the average of at least three (3) samples that are representative 
of routinely-traveled portions of the road or parking lot surface. 
In order to simplify the sieve test procedures in section I.B.(ii) 
and section I.B.(iii) of this appendix, the three samples may be 
combined as long as all material is sifted to the finest sieve 
through which it can pass, each sample weighs within 1 ounce of the 
other two samples, and the combined weight of the samples and unit 
area from which they were collected is calculated and recorded 
accurately.

[[Page 71314]]

II. Vacant Lots

    The following test methods shall be used for determining whether 
a vacant lot, or portion thereof, has a stabilized surface.
    Should a disturbed vacant lot contain more than one type of 
disturbance, soil, vegetation or other characteristics which are 
visibly distinguishable, test each representative surface for 
stability separately in random areas according to the test methods 
in section II. of this appendix and include or eliminate it from the 
total size assessment of disturbed surface area(s) depending upon 
test method results. A vacant lot surface shall be considered 
stabilized if any of the test methods in section II. of this 
appendix indicate that the surface is stabilized such that the 
conditions defined in paragraph (b)(16)(ii) of this section are met:

1. Visible Crust Determination

    (i) 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 to 17 grams from a distance of 30 centimeters (one foot) directly 
above (at a 90 degree 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 
percent of a vacant lot which have not originated from the 
representative vacant lot surface being tested. If material covers a 
visible crust which is not blowsand, apply the test method in 
section II.2 of this appendix to the loose material to determine 
whether the surface is stabilized.
    (ii) A sufficient crust is defined under the following 
conditions: once a ball has been dropped according to section 
II.1.(i) 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.
    (iii) Conduct three tests, dropping the ball once per test, 
within a survey area the size of one foot by one foot. The survey 
area shall be considered sufficiently crusted if at least two out of 
three tests meet the definition in section II.1.(ii) of this 
appendix. Select at least two other survey areas that represent the 
disturbed surface area and repeat this procedure. Whether a 
sufficient crust covers the disturbed surface area shall be based on 
a determination that all of the survey areas tested are sufficiently 
crusted.
    (iv) At any given site, the existence of a sufficient crust 
covering one portion of a disturbed surface may not represent the 
existence or protectiveness of a crust on another disturbed 
surface(s). Repeat the visible crust test as often as necessary on 
each representative disturbed surface area for an accurate 
assessment of all disturbed surfaces at a given site.

2. 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).
    (i) 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. 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 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, 
which provides a correlation between sieve opening size and TFV.

  Table 1 (Metric Units).--Determination of Threshold Friction Velocity
                                  (TFV)
------------------------------------------------------------------------
                                                      Opening   TFV (cm/
                  Tyler Sieve No.                       (mm)       s)
------------------------------------------------------------------------
5..................................................       4         >100
10.................................................       2          100
18.................................................       1           76
35.................................................       0.5         58
60.................................................       0.25        43
Collector Pan......................................  .........        30
------------------------------------------------------------------------

    Collect at least three (3) soil samples which are representative 
of the disturbed surface area, repeat the above TFV test method for 
each sample and average the resulting TFVs together to determine the 
TFV uncorrected for non-erodible elements.
    (ii) Non-erodible elements are distinct elements on the 
disturbed surface area that are larger than one (1) cm in diameter, 
remain firmly in place during a wind episode and inhibit soil loss 
by consuming part 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 one (1) meter by 1 meter. Where many non-
erodible elements lie on the disturbed surface area, separate them 
into groups according to size. For each group, calculate the 
overhead area for the non-erodible elements according to the 
following equations:

(Average length)  x  (Average width) = Average Dimensions    Eq. 1 
(Average Dimensions)  x  (Number of Elements) = Overhead Area    Eq. 
2 
Overhead Area of Group 1 + Overhead Area of Group 2 (etc.) = Total 
Overhead Area    Eq. 3 
Total Overhead Area/2 = Total Frontal Area    Eq. 4 
(Total Frontal Area/Survey Area)  x  100 = Percent Cover of Non-
erodible Elements    Eq. 5 
(Ensure consistent units of measurement, e.g. square meters or 
square inches when calculating percent cover.)

    Repeat this procedure on an additional two (2) distinct survey 
areas representing a disturbed surface and average the results. Use 
Table 2 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
------------------------------------------------------------------------
10%.............................  5
5% and < 10%....................  3
< 5% and  1%....................  2
< 1%.......................................  None.
------------------------------------------------------------------------

3. Determination of Flat Vegetation 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 one centimeter in diameter shall be considered 
protective cover in the course of conducting the line transect 
method. Where flat vegetation exists, conduct the following line 
transect method.
    (i) Stretch a one-hundred (100) foot measuring tape across a 
disturbed surface area. 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 degree angle) away from a parallel or perpendicular position to 
the vegetated rows. Pinpoint an area the size of a \3/32\ inch 
diameter brazing

[[Page 71315]]

rod or wooden dowel centered above each one-foot interval mark along 
one edge of the tape. Count the number of times that flat vegetation 
lies directly underneath the pinpointed area at one-foot intervals. 
Consistently observe the underlying surface from a 90 degree 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 vegetation cover (e.g. if 35 positive counts were made, then 
vegetation cover is 35 percent). If the disturbed surface area 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 percent.
    (ii) Conduct the above line transect test method an additional 
two (2) times on areas representative of the disturbed surface and 
average results.

4. Determination of Standing Vegetation 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 percent cover or 
more exists. If the resulting percent cover is less than 30 percent 
but equal to or greater than 10 percent, then conduct the Threshold 
Friction Velocity test in section II.2 of this appendix in order to 
determine whether the disturbed surface area is stabilized according 
to paragraph (b)(16)(ii)(E) of this section.
    (i) For standing vegetation that consists of large, separate 
vegetative structures (for example, shrubs and sagebrush), select a 
survey area representing the disturbed surface that is the shape of 
a square with sides equal to at least ten (10) times the average 
height of the vegetative structures. For smaller standing 
vegetation, select a survey area of three (3) feet by 3 feet.
    (ii) 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 exists 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 (i.e. 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 if the survey area 
is larger than nine square feet, estimating the average height and 
width of the vegetation. Otherwise, use the procedure in section 
II.4.(iii) 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. (Ensure 
consistent units of measurement, e.g. square feet or square inches 
when calculating percent cover.)
    (iii) Vegetative Density Factor. Cut a single, representative 
piece of vegetation (or consolidated vegetative structure) to within 
1 cm 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 one inch 
or one half 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 and 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 two 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 the equation (Eq. 14, 15 or 16) 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.
    (iv) Within a disturbed surface area that contains multiple 
types of vegetation with each vegetation type uniformly distributed, 
results of the percent cover associated with the individual 
vegetation types may be added together.
    (v) Repeat this procedure on an additional two (2) distinct 
survey areas representing the disturbed surface and average the 
results.

Height  x  Width = Frontal Silhouette Area    Eq. 6 
(Frontal Silhouette Area of Individual Vegetative Structure)  x  
Number of Vegetation Structures Per Group = Group Frontal Silhouette 
Area of Group    Eq. 7 
Frontal Silhouette Area of Group 1 + Frontal Silhouette Area of 
Group 2 (etc.) = Total Frontal Silhouette Area    Eq. 8 
(Total Frontal Silhouette Area/Survey Area)  x  100 = Percent Cover 
of Standing Vegetation    Eq. 9 
[(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] = Percent Open 
Space    Eq. 10 
100 = Percent Open Space = Percent Vegetative Density    Eq. 11 
Percent Vegetative Density/100 = Vegetative Density    Eq. 12 
BILLING CODE 6560-50-P
[GRAPHIC] [TIFF OMITTED] TR21DE99.000

      

[[Page 71316]]

[GRAPHIC] [TIFF OMITTED] TR21DE99.001



[[Page 71317]]

BILLING CODE 6560-50-C

III. Alternative Test Methods

    Alternative test methods may be used upon obtaining the written 
approval of the EPA.

[FR Doc. 99-32760 Filed 12-20-99; 8:45 am]
BILLING CODE 6560-50-P