UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX AIR DIVISION

Technical Support Document

For

EPA’s Notice of Proposed Rulemaking

For the

California State Implementation Plan

Great Basin Unified Air Pollution Control District

Rule 433 – Control of Particulate Emissions at Owens Lake

Christine Vineyard

August 2016
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RULE IDENTIFICATION 

Agency Great Basin Unified Air Pollution Control District (GBUAPCD)

SIP-approved 

Rule

None

Subject of this 

TSD

Rule 433 – Control of Particulate Emissions at Owens Lake

Adopted – April 13, 2016

Submitted – June 9, 2016

Completeness 

Finding

July 6, 2016 

BACKGROUND

The GBUAPCD describes the geographic area controlled by Rule 433 as follows: “The 

Owens Valley Planning Area (OVPA) is located in Inyo County in eastern-central 

California. It is situated at the south end of the deep, long, narrow Owens Valley with 

the Sierra Nevada mountain range to the west (max. elevation 14,505 feet), the WhiteInyo Mountains to the east (max. elevation 14,246 feet), and the Coso Range to the 

south (max. elevation 8,160 feet). A major feature in the OVPA is the predominantly dry, 

alkaline Owens Lake bed located approximately eight miles south of the community of 

Lone Pine on U.S. Highway 395, 60 miles north of the city of Ridgecrest, and 35 miles 

west of Death Valley. The communities of Olancha and Keeler are located on the 

southwestern and eastern shores of the lake bed, respectively. The bed of Owens Lake 

is defined as the area below 3,600 feet above mean sea level. It extends about 

seventeen miles north and south and ten miles east and west and covers an area of 

approximately 110 square miles (70,000 acres). The majority of the lake bed (over 

89%) is state land under the jurisdiction of the California State Lands Commission 

(CSLC). The remaining portions of the lake bed are owned by the City of Los Angeles, 

the U.S. Bureau of Land Management (BLM), and other public and private entities.” 1

The OVPA is a serious nonattainment area for the National Ambient Air Quality 

Standard (NAAQS) for particulate matter less than 10 microns in diameter (PM10). 40 

CFR 81.305. The alkaline Owens Lake bed described above is the predominate source 

of PM10 emissions causing the OVPA to be classified as a serious nonattainment area.

Air quality monitoring by the GBUAPCD has shown that the bed of Owens Lake is the 

major source of PM10 emissions contributing to air quality violations in the OVPA. The 

GBUAPCD has also determined that: “The Owens Lake bed is considered an 

 1 2016 OVPA State Implementation Plan, Appendix V-1 - BACM Assessment, April 2016, p.1.
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anthropogenic (human caused) source of PM10 because the City of Los Angeles’ 

Aqueduct diverts water sources that historically supplied the lake.”2

Rule 433 requires the City of Los Angeles, through the Los Angeles Department of 

Water and Power (collectively “City”), to implement the control measures on the Owens 

Lake bed to mitigate the PM10 nonattainment resulting from the historic diversion of 

water sources, as discussed in more detail below. The OVPA PM10 nonattainment 

problem is unique and the development of Rule 433 is based on a long history of 

interaction and cooperation between GBUAPCD and the City. 

The control measures established in Rule 433 represent a significant step toward 

bringing the area into attainment. GBUAPCD has also adopted and submitted to EPA a 

comprehensive State Implementation Plan (SIP) revision to bring the OVPA into 

attainment in 2017 and demonstration that Rule 433 is the Best Available Control 

Measure (BACM). Although Rule 433 plays a central role in the 2016 PM10 attainment 

SIP, we are evaluating the SIP separately from this action on Rule 433 and will 

complete our assessment of whether Rule 433 is BACM in that separate rulemaking.

RULE SUMMARY

As noted above, GBUAPCD Rule 433 establishes requirements at Owens Lake to 

significantly reduce emissions of PM10 from a substantial portion of the dry Owens Lake 

bed. GBUAPCD describes the purpose of Rule 433 as intended to provide “a regulatory

mechanism under the federal Clean Air Act to attain the National Ambient Air Quality 

Standards (NAAQS) and to implement the Stipulated Judgment between GBUAPCD 

and the City of Los Angeles (City) dated December 30, 2014.”3 Rule 433 defines a list of 

“BACM PM10 Control Measures”, such as shallow flooding, gravel blankets and 

managed vegetation, and establishes the temporal and geographic requirements for 

implementing these control measures at Owens Lake. The goal of Rule 433 is to reduce

PM10 emissions from the dry lake bed to attain the 24-hour PM10 NAAQS in 2017.

Specific rule requirements are summarized below.

A. Definitions

Definitions are included of critical terms.

B. Requirements

 2 2016 OVPA SIP, Appendix V-1 - BACM Assessment, April 2016, p.1.

3 2016 OVPA SIP, April 2016 p. 89, Exhibit 10-1. The Stipulated Judgment was entered by the Superior 

Court of the State of California, County of Sacramento (City of Los Angeles, et al. v California Air 

Resources Board, Sacramento County Superior Court, Case No. 34-2013-80001451-CU-WM-GDS), 

December 30, 2014.
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1. For the geographic area defined as the 2003 Dust Control Area (DCA), the City 

must operate any mix of the measures defined as BACM to control PM10

emissions by at least a 99% control efficiency (CE). 

2. For the 2006 DCA, except for defined exceptions for Eligible Cultural Resource 

Areas, the City must operate BACM to meet specified PM10 CE targets and 

BACM managed vegetation requirements must be met by December 31, 2017.

3. For the geographic area defined as the Phase 8 Area, the City must implement 

the Gravel Blanket BACM.

4. With limited specified exceptions for Eligible Cultural Resource Areas within the 

Phase 9/10 Project Area, the City must implement any mix of the measures 

defined as BACM by December 31, 2017.

5. As an alternative to BACM shallow flooding, the City may implement any of the 

following control measures, which are described below under “Attachment A –

Performance Requirements for BACM”:

a. Tillage with BACM backup;

b. Brine shallow flooding; or

c. Dynamic water management.

C. Contingency Measures

1. At least once each year, the District shall determine whether additional areas of 

the lake bed require BACM to attain/maintain the PM10 NAAQS.

2. If attainment or reasonable further progress (RFP) milestones are not 

demonstrated by December 31, 2017, GBUAPCD shall order the City to apply 

additional BACM.

3. If monitoring and/or modeling demonstrate control measures are needed in an 

Eligible Cultural Resource Area to attain or maintain the NAAQS, GBUAPCD 

shall order the City to apply additional BACM.

4. Control measures defined as BACM are required on 48.62 square miles of the 

lake bed. GBUAPCD may order the City to implement up to 53.4 square miles of 

BACM on the lake bed below the shoreline and above the high water level.

5. The City generally must implement measures with 99% CE within three years 

after any such order. 

Attachment A – Performance Requirements for BACM

The control measures defined in Rule 433 as “BACM” are summarized below. 

1. BACM Shallow Flooding requires the application of water to the surface of the 

lake bed in amounts and by means sufficient to achieve specified performance 

standards. E.g., for Shallow Flooding areas, except those within the 2006 DCA, 

at least 75% of each square mile must continuously be covered by standing 

water or surface-saturated soil evenly distributed between October 16 each year

and May 15 the next year. In order to conserve water, specific areas that have a 

history of low emissivity may be allowed to delay the start date and have an 

earlier end date (Dynamic Water Management or “DWM) for the flooding period. 
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If a DWM area becomes susceptible to wind erosion outside the modified dust 

control period, flooding will be required. 

2. BACM Managed Vegetation requires planting surfaces with vegetation to meet 

99% CE by maintaining 37% overall vegetation cover.

3. BACM Gravel Blanket requires that the entire area implementing this BACM must 

be covered with either: (a) a layer of gravel at least four inches thick; or (b) a 

layer of gravel at least two inches thick underlain with a permanent permeable 

geotextile fabric, sufficient to achieve 100 percent CE. The gravel must be 

screened to a size greater than one half inch diameter.

4. Tillage with BACM (Shallow Flood) Backup (TWB) requires roughening of the soil

surface and installing necessary shallow flood infrastructure so the area can be 

flooded if the defined erosion threshold is exceeded.

5. Brine BACM requires the application of brine and the creation of wet and/or nonemissive surfaces sufficient to achieve 99 percent CE. If the area exceeds the 

defined erosion threshold, BACM Shallow Flooding must be implemented.

6. Minimum Dust Control Efficiency (MCDE) BACM applies in certain defined areas

within the 2006 DCA and is designed to achieve specified dust CE that can be 

less than 99 percent, but is designed to prevent exceedances of the NAAQS.

The required CE for these areas is based on air quality modeling. MDCE BACM 

includes shallow flooding, vegetation cover, and sand fences.

Emission Reductions: The OVPA’s SIP forecasts PM10 emissions from the dry lake 

bed will be 355 tons per year upon implementation of the controls required under Rule 

433. Taken together, the lakebed controls implemented since 2003, which continue to 

be enforceable through Rule 433, will have reduced PM10 emissions by over 69,000 

tons per year as compared to peak emissions in 2005, when the lake bed emitted 

69,778 tons.4

EPA RULE EVALUATION

1. Enforceability - The Bluebook (Issues Relating to VOC Regulation Cutpoints, 

Deficiencies, and Deviations, EPA, May 25, 1988) and the Little Bluebook 

(Guidance Document for Correcting Common VOC & Other Rule Deficiencies,

EPA Region 9, August 21, 2001) were used to help evaluate compliance with the 

CAA §110(a)(2)(A) requirement for enforceability. The rule contains definitions, 

control requirements, work practice standards, monitoring, test methods and 

other provisions that are sufficiently clear and enforceable. 

2. SIP Relaxation - CAA §110(l) prohibits EPA from approving any SIP revision that 

would interfere with any applicable requirement concerning attainment and RFP

or any other applicable requirement of the CAA. In addition, CAA §193 prohibits 

the modification of any SIP-approved control requirement in effect before 

November 15, 1990, in a nonattainment area. New Rule 433 does not interfere 

with the on-going process for ensuring that requirements for RFP and attainment 

of the NAAQS are met. Section 193 of the CAA does not apply to our proposed 

 4 2016 OVPA SIP, Table 4-3.
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action because this is a new rule to the SIP and does not modify any SIPapproved control requirement in effect before November 15, 1990, in a 

nonattainment area.

3. Rule Stringency – EPA designated the OVPA as “serious” nonattainment for the 

24-hour average PM10 NAAQS.5 The CAA directs such areas to implement all 

PM10 BACM. In our guidance for serious PM10 SIPs, EPA defined BACM to be, 

among other things, the maximum degree of emission reduction achievable from 

a source or source category which is determined on a case-by-case basis, 

considering energy, economics and environmental impacts.6 EPA intends to 

evaluate BACM for Rule 433 in the near future in context of action on the overall 

2016 PM10 SIP submitted with the rule. 

Although we are deferring a determination at this time regarding whether Rule 

433 satisfies all of the requirements for BACM, we note that GBUAPCD searched 

for requirements for analogous lake bed and dune sources in other PM10

nonattainment areas including Imperial County, San Joaquin, Maricopa, South 

Coast and Clark County. However, they were unable to identify any analogous 

active controls for these kinds of sources in other areas. The primary source of 

windblown dust in the OVPA is from the dry lake bed and the area immediately 

surrounding the bed of Owens Lake. The OVPA contains the largest source of 

dust pollution in the United States due to the winds and dust storms that occur 

throughout the year. Since the OVPA is the only PM10 nonattainment area of its 

kind in the United States, the controls currently implemented on the lake bed are 

unique and satisfy stringency requirements for purposes of proposing approval 

into the SIP.7

EPA ACTION

The submitted GBUAPCD Rule 433 strengthens the SIP by requiring the City to 

implement dust control measures at Owens Lake. The rule is consistent with relevant 

CAA requirements regarding enforceability and SIP revisions. Therefore, the EPA is 

proposing full approval of Rule 433.

 5 OVPA nonattainment serious status (40 CFR §81.305).

6 State Implementation Plans for Serious PM10 Nonattainment Areas and Attainment Waivers for PM10

Nonattainment Areas Generally; Addendum to the General Preamble for the Implementation of Title I of 

the Clean Air Act Amendments of 1990, 59 FR 41998, August 16, 1994.

7 2016 OVPA SIP, Appendix V-1 - BACM Assessment, April 2016, p.14.