Staff Report 

ARB Review of 

PM10 State Implementation Plan

for Owens Valley

Release Date: April 29, 2016

Hearing Date: May 19, 2016
Electronic copies of this report are online at

http://www.arb.ca.gov/planning/sip/planarea/gbasin/gbasin.htm. Alternatively, paper 

copies may be obtained from the Visitors and Environmental Services Center of the Air 

Resources Board, located at 1001 I Street, Sacramento, California 95814, or by 

contacting ARB’s Office of Communications at (916) 322-2990.

For individuals with sensory disabilities, this document is available in Braille, large print, 

audiocassette, or compact disc. Please contact ARB’s Disability Coordinator at (916) 

323-4916 by voice or through the California Relay Services at 711 to place your request 

for disability services. If you are a person with limited English and would like to request 

interpreter services, please contact ARB’s Bilingual Manager at (916) 323-7053.

This document has been prepared by the staff of the Air Resources Board. Publication 

does not signify that the contents reflect the views and policies of the Air Resources 

Board, nor do trade names or commercial products constitute endorsement or 

recommendation for use.

For questions, contact:

Webster Tasat, Manager

Central Valley Air Quality Planning Section 

Air Resources Board

P.O. Box 2815

Sacramento, CA 95812

Phone: (916) 323-4950

Email: wtasat@arb.ca.gov

Or 

Earl Withycombe

Air Resources Engineer

Central Valley Air Quality Planning Section

Phone: (916) 322-8487

Email: ewithyco@arb.ca.gov
TABLE OF CONTENTS

I. OVERVIEW.............................................................................................................. 2

A. Owens Valley Planning Area ....................................................................................... 3

B. Regulatory History ....................................................................................................... 3

C. Nature of PM10 Air Quality in the Owens Valley.......................................................... 4

II. ATTAINMENT DEMONSTRATION ......................................................................... 5

A. Modeling Methodology................................................................................................. 5

B. Baseline and Attainment Emission Levels ................................................................. 6

C. Results .......................................................................................................................... 6

III. CONTROL STRATEGY........................................................................................... 7

IV. CLEAN AIR ACT REQUIREMENTS ....................................................................... 8

A. Demonstration of Compliance with Prior SIP Commitments .................................... 8

B. Significant Source Categories..................................................................................... 9

C. Best Available Control Measures and Most Stringent Measures.............................. 9

D. Emissions Inventory ...................................................................................................10

E. Reasonable Further Progress and Quantitative Milestones.....................................10

F. Contingency Measures ...............................................................................................11

G. Transportation Conformity .........................................................................................11

V. ENVIRONMENTAL IMPACT ................................................................................. 11

VI. SUMMARY AND RECOMMENDATION................................................................ 11
EXECUTIVE SUMMARY

This report provides Air Resources Board (ARB) staff’s assessment of the Great Basin 

Unified Air Pollution Control District’s (District) PM10 State Implementation Plan for Owens 

Valley (2016 Plan). The 2016 Plan was developed to supersede previous state 

implementation plans (SIP), and comply with the terms of a court-approved 2014 

Stipulated Judgment (2014 Judgment) resolving litigation between the District and the Los 

Angeles Department of Water and Power (City) over the extent and timing of dust control 

implementation on the Owens Lake dry lakebed. The 2016 Plan forecasts attainment of 

the PM10 national ambient air quality standard (standard) by the end of 2017, a major 

accomplishment to abate PM10 values recorded 30 years ago in excess of 12,000 μg/m3

downwind of Owens Lake.

The history of windblown dust at Owens Lake dates back over 100 years to the 

diversion of the Owens River into the Los Angeles Aqueduct, an engineering marvel of 

its time. Upon desiccation of the terminal lake that had been fed by the Owens River, 

Owens Lake was transformed into a brine pool and over 70 square miles of salt-crusted 

dry lakebed. The lakebed has been a source of windblown PM10 since then with 

emissions rising over time to earn the Lake recognition as once being the largest dust 

source in North America.

A continuous program of air quality monitoring, lakebed emissivity research, control 

measure testing, and control application over broad expanses of lakebed surface 

conducted under H&SC 42316 has greatly reduced windblown PM10 emissions and 

ambient PM10 concentrations at Owens Lake, earning the District national recognition. 

In complying with attainment requirements of the Clean Air Act (Act), the District has 

adopted a series of SIPs certifying progress, expanding the portion of lakebed found to 

be emissive and designated for control, and refining and adding approved control 

measures for use by the City in meeting emission reduction targets.

The 2016 Plan supersedes a number of these previously submitted SIPs and 

incorporates for implementation many of the requirements of the 2014 Judgment. The 

2016 Plan forecasts attainment of the PM10 standard by December 31, 2017, the 

maximum extension allowed by the Act. The 2016 Plan addresses the planning

requirements specified under Subpart 4 of the Act that allows for two 5-year extensions 

of the serious PM10 area attainment date to 2017. In complying with these provisions, 

the 2016 Plan includes a demonstration that most stringent measures are in place and 

that all commitments included in the 1998 SIP have been fulfilled. Additional Act 

requirements addressed in the 2016 Plan include reasonable further progress with a 

corresponding milestone, transportation conformity and contingency measures.

ARB staff has evaluated the 2016 Plan and concluded that it fully satisfies applicable 

requirements of the Act. ARB staff furthermore has concluded that the requirements of 

the California Environmental Quality Act (CEQA) are satisfied by actions taken by the 

District Board in adopting the 2016 Plan. As a result, ARB staff therefore recommends 

that the Board approve the 2016 Plan as a revision to the California SIP. 

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I. OVERVIEW

Exposure to particulate matter less than 10 microns in aerodynamic diameter (PM10) is 

associated with a variety of health problems. Breathing PM10 can increase the

incidence and severity of asthma and bronchitis attacks, cause breathing difficulties in 

people with heart or lung disease, and increase the risk for, or complicate, existing 

respiratory infections. Children, the elderly and people with existing heart and lung 

problems are especially sensitive to elevated levels of PM10. Even healthy people can 

be adversely affected by dust at extremely high concentrations. 

The Act requires the U.S. Environmental Protection Agency (U.S. EPA) to establish

standards to protect public health on a long term basis, and to regularly update these 

standards to reflect new health information. U.S. EPA first established PM10 standards

in 1987 - a 24-hour PM10 standard of 150 micrograms per cubic meter (μg/m3) and an 

annual standard of 50 μg/m3. Based on an extensive assessment and scientific review 

of the health impacts of PM10 pollution, U.S. EPA rescinded the annual standard and 

retained the 24-hour standard of 150 μg/m3 in 1997. Meeting this standard provides 

critical public health protection, especially in the Owens Lake area which historically has 

experienced the highest PM10 levels in the nation.

The history of windblown dust control at Owens Lake begins in 1983 with intervention 

by the California Legislature to balance resource protection with air quality 

improvement. Senate Bill 70 (1983) enacted Health & Safety Code Section 42316 

which protects the City’s Owens River water right activities from District regulation while 

simultaneously vesting the District with authority to require the City to mitigate the air 

quality impacts related to water export and to fund District mitigation measure 

development costs. Subsequent court decisions upheld this statute and deemed the 

City responsible for mitigation of PM10 emissions from the dried lakebed.

Windblown dust from the Owens Lake dry lakebed and affected areas is the single 

source of PM10 emissions responsible for causing the federal PM10 standard to be 

exceeded in the Owens Valley Planning Area (Owens Valley). Controlling windblown 

dust emissions on the lakebed has proven to be a very complex undertaking, requiring a 

multi-decade research effort with respect to the characteristics of emission generation 

and the effectiveness of candidate control approaches. At each significant juncture in 

this research effort, the District revised the SIP for the Owens Valley to incorporate new

scientific findings and implement new controls when demonstrated to be effective. The

PM10 State Implementation Plan for Owens Valley (2016 Plan) 1 represents one of these 

significant junctures – in this case, an expansion of the list of control measures deemed 

to qualify as Best Available Control Measures (BACM) to include approvable waterless

controls, the addition of a process for approving “water neutral” controls, and the 

addition of a cap on the total expanse of dry lakebed required to be controlled by the

Los Angeles Department of Water and Power (City). 

1

2016 Owens Valley Planning Area PM10 State Implementation Plan, Great Basin Unified Air Pollution 

Control District, April 13, 2016. Available at http://www.gbuapcd.org/ovpm10sip.htm 

2

 
The new elements of the 2016 Plan are being added to satisfy the requirements of the 

2014 Judgment that settled several judicial and administrative appeals by the City of 

past District control orders. For the City, the 2014 Judgment allows for reductions in the 

quantity of Owens River water being diverted for dust control during the current 

statewide drought and establishes a limit on the lakebed area to which the City may be 

required to apply BACM. For the District, the 2014 Judgment streamlines the process 

for having the City implement BACM after the District issues orders for bringing new 

areas under control, and assures District use of City property and electricity for 

monitoring station operation.

A. Owens Valley Planning Area

The Owens Valley is located in Inyo County in eastern-central California. The Valley is 

approximately 68 miles long and 20 miles wide, with the long axis extending along a 

NNW-SSE azimuth. Owens Lake lies in the southern half of the Owens Valley, 

approximately 8 miles south of the town of Lone Pine and 60 miles north of the city of 

Ridgecrest.

The Owens Lake dry lakebed is almost entirely owned by the State and the City. The 

State’s portion of the lakebed, constituting about 65,000 acres or 89 percent, is 

managed by the California State Lands Commission (CLSC). The remainder of the 

lakebed, consisting of about 8,000 acres or 11 percent, is managed by the City’s 

Department of Water and Power.

B. Regulatory History

On August 7, 1987, U.S. EPA identified the Owens Valley as one of the areas in the 

nation that violated the standards and required the State of California to prepare a State 

Implementation Plan (SIP) revision that demonstrated how PM10 emissions would be 

reduced to comply with the standards.

Subsequent to this date, the District adopted a series of SIPs as understandings of 

lakebed emissivity and control evolved. In summary, these SIPs:

• (November 1991) Updated technical data and work performed since 1988;

• (June 1994) Identified potential control alternatives and committed to the testing 

and selection of measures satisfying emission reduction targets;

• (July 1997) Approved three BACM and required the City to control 35 square 

miles of lakebed surface by 2002;

• (November 1998) Revised control requirements to 16 square miles by 2004 and 

2 square miles per each year afterward until attainment was reached, committed 

to the development of a better emission and air quality models, and required 

revision of the SIP in 2003 to incorporate the new models;

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• (November 2003) Approved the Dust ID model for emissions and air quality 

forecasting, required the City to control an additional 13.3 square miles by 2007, 

and approved the Supplemental Control Requirement Determination (SCRD) 

process for the annual identification and control of additional emissive lakebed 

areas;

• (January 2008) Required the City to control an additional 12.7 square miles by 

2010, and suspended annual SCRD evaluations until 2011;

• (September 2013) Approved two additional BACM, and relieved the City of 

responsibility for dust control on off-lake sand dunes in exchange for payment by 

the City of $10 million to the District for dust control on Keeler Dunes; and

• (April 2016) Approved one additional BACM, authorized the City to convert 

controlled area to waterless BACM on an accelerated basis, and capped the total 

lakebed area to which the City could be required to control to 53.4 square miles.

C. Nature of PM10 Air Quality in the Owens Valley

Owens Lake has historically been referred to as the dustiest location in North America. 

This distinction results from a combination of topographic features and the historic 

diversion of the Owens River into the Los Angeles Aqueduct. The Aqueduct 

commenced operation in 1913, eliminating the primary inflow to Owens Lake. By 1927, 

the 110 square mile lake surface had shrunk to a 35 square mile brine pool, leaving 

more than 70 square miles of dry lakebed composed of fine grained sediment, salt and 

sand.

The dry lakebed is exposed to high wind events several times each year that historically 

scoured the surface and entrained fine particulate matter from the lakebed into the air. 

Wind speeds at Owens Lake are enhanced by the eastern walls of the Sierra Nevada, 

reaching elevations of nearly 11,000 feet above the lakebed surface. The steepness 

and height of the Sierra Nevada slope to the west, in combination with the Inyo 

Mountains in close proximity and immediately to the east of Owens Lake, produce 

strong descending eddies as prevailing winds pass eastward over the Sierra Nevada. 

The juxtaposition of the two mountain ranges creates the long, narrow Owens Valley, 

which channelizes and increases the velocities of wind flows moving north and south 

along the valley floor. The strength of these winds and the fine granularity of lakebed 

surface soils generated thick clouds of fine particles that, in the past, contained PM10

concentrations of up to 40,000 μg/m3 – almost 300 times the federal 24-hour PM10

standard of 150 μg/m3.

Research conducted in the late 1980s and early 1990s found two mechanisms were 

responsible for the bulk of windblown dust emissions: the formation of efflorescent salts 

on the lakebed surface after precipitation episodes and the movement of sand particles 

across the lakebed surface during high wind events. The understandings gained 

through the extensive source characterization research conducted at Owens Lake 

framed the initial goals of dust control measures: to maintain surface moisture during 

the wet season to prevent efflorescent salt formation or shield these formations from 

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wind shear, and to stabilize sand particles on the lakebed surface to eliminate saltation 

during high wind events.

II. ATTAINMENT DEMONSTRATION

District staff has prepared an attainment demonstration that provides for expeditious 

attainment of the standards accounting for primary emissions from the lakebed and 

secondary emissions resulting from re-entrainment of deposited lakebed dust on nearby 

downwind areas. The attainment demonstration uses the Dust ID model that the District 

has relied upon since 2003 to identify emissive lakebed areas and to quantify 

windblown emissions and shoreline impacts. The controls that have been constructed 

and maintained on lakebed areas identified through use of the Dust ID model have 

reduced annual lakebed PM10 emissions by 97 percent between 2001 and 2015, 

supporting the adequacy and effectiveness of the Dust ID model’s use.

A. Modeling Methodology

The Dust ID model is used to both estimate emissions from discrete lakebed areas and 

forecast the air quality impacts of these emissions at the lakebed shoreline and beyond. 

The emission estimation component uses sand movement data collected by a network 

of monitors scattered across the lakebed surface to calculate zone-specific PM10

emission rates using seasonally-adjusted conversion factors. The input file is used by a 

CALPUFF model, a U.S. EPA-approved dispersion model designed to handle complex 

wind fields and highly variable emission sources, to forecast PM10 concentrations at 

each of the seven shoreline PM10 monitors and at closely spaced shoreline points in 

between.

The baseline period used for emission tracking in the 2016 Plan’s attainment 

demonstration extended from June 2009 through June 2014, the most recent five years of 

Dust ID model input and output analyzed by the District. During this baseline period, the 

number of exceedances of the 24-hour PM10 standard recorded at each of ten monitors

operated near the lakebed ranged from 1 (Lone Pine) to 42 (Lizard Tail), with maximum 

24-hour PM10 concentrations at each monitor ranging from 169 to 4,571 μg/m3. Design 

day concentrations calculated for each station ranged from 180 to 1,654 μg/m3. The 

attainment demonstration focused on these design days, but modeled the entire 5 years 

of baseline meteorological data for weight-of-evidence purposes.

Analysis of PM10 concentrations measured at shoreline monitors when winds blow to 

the lakebed from off-shore areas show declining trends as lakebed emissions decline. 

This result suggests that dust entrained from these off-shore lands most likely was 

transported from the lakebed during high wind events and settled out of the air within 

two kilometers downwind of the shoreline. Although a small number of 24-hour PM10

exceedances are presently caused by emissions from these non-lakebed lands (2-km 

buffer), this frequency is forecast to decline to attainment levels by the current deadline

as less and less dust is transported from the lakebed to these off-shore lands.

5
 

B. Baseline and Attainment Emission Levels

Table 1 lists the emissions levels used in the attainment demonstration. Baseline 

emission levels – represented by 2008 emissions - reflect the benefits of lakebed 

controls in place as of the start of the 2009 to 2014 baseline period. Attainment 

emission levels are represented by 2017 emissions forecasts and incorporate the 

benefits of scheduled controls.

Table 1. Annual Baseline and Attainment Year PM10 Emissions (tons per year)

Emission Inventory Annual PM10 Emissions (tpy)

2008 2017 

Lakebed Windblown Emissions 22,754 355

Off-Lake Windblown Emissions

Keeler Dunes 2,130 41

Olancha Dunes 4,487 1,093

2-km Buffer 2,736 1,180

Remaining Nonattainment Area, 20,033 20,033

Non-Windblown Emissions 854 747

TOTAL 53,994 23,450

C. Results

The attainment demonstration results are shown in Table 2. This table presents two 

sets of comparisons: the measured baseline design day PM10 concentration at each 

monitor in conjunction with the concentration forecast by the Dust ID model, and the 

attainment year design day PM10 concentration. The baseline period extends from July 

2009 through June 2014. By the results of attainment demonstration modeling, all 

former and current monitoring sites near the lakebed are forecast to attain the 24-hour 

PM10 standard of 150 μg/m3

. These results range from 39 to 142 μg/m3.

Table 2. PM10 Design Day Concentration Predictions (24-hour average micrograms per 

cubic meters)

Monitoring Site

Design Day 24-Hour Average PM10 (μg/m3)

Observed Modeled Concentration Predictions

7/2009 – 6/2014 7/2009 – 6/2014 2017

Dirty Socks 998 1,235 93

Flat Rock 233 228 94

Keeler 524 592 67

Lizard Tail 1,654 1,993 142

Mill Site 712 642 125

North Beach 385 448 67

Olancha 310 294 41

Shell Cut 395 586 105

Stanley 180 115 39

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III. CONTROL STRATEGY

The control strategy proposed in the 2016 Plan is an extension of those adopted in the 

1998, 2003, 2008, and 2013 Plans that has proved to be effective when applied to 

emissive lakebed areas. The District protocols for identifying emissive areas, 

constructing and maintaining BACM controls, and enforcing the long term effectiveness 

of these controls, are based on an comprehensive research and testing program that 

underpin a windblown dust control program that is recognized nationally for its success.

The BACM controls adopted in the 1998 Plan – shallow flooding, managed vegetation, 

and gravel blanket – have been applied to 76 percent of the lakebed surface to which 

windblown dust controls are currently being applied. Newer, less water-dependent 

BACM controls approved by the District since 2013 are in place on the remaining 24 

percent of currently controlled areas. Table 3 shows the cumulative areas at present 

and by the attainment deadline of December 31, 2017, per BACM type.

Table 3. BACM Area Totals (square miles of lakebed surface)

BACM Type Controlled Area (square miles)

Present 2017

Shallow Flooding 27.9 28.4

Managed Vegetation 3.5 3.8

Gravel Blanket 3.2 6.0

Hybrid BACM 4.7 4.7

Tillage with BACM Backup 4.5 4.5

Experimental 0.9 0.9

Brine Test 0.8 0.8

TOTAL 45.4 49.0

The 2016 Plan authorizes the City to convert areas currently controlled by Shallow 

Flooding to less water-dependent BACM, such as Tillage with BACM Backup, provided 

that the construction activities occur only during those months of the year when water 

applications are not required by Shallow Flooding BACM. As a result, the control area 

totals by BACM type shown in Table 3 for the attainment deadline (2017 Year-End) may 

well be redistributed after attainment as the City converts from Shallow Flooding to 

other BACM to reduce overall water consumption by the dust control program.

The current implementation schedule requires completion of construction of controls on 

all areas designated for control by December 31, 2017. The attainment year emission 

forecast is based on this assumption for lakebed areas, and an extrapolation of the 

declining emissions estimates is used to forecast emissions from the off-shore areas. 

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IV. CLEAN AIR ACT REQUIREMENTS

In addition to the elements related to the attainment demonstration, the Act also 

requires SIPs for serious PM10 nonattainment areas requesting an attainment date 

extension to address the following requirements:

• Demonstration that the State complied with all requirements and commitments 

pertaining to the area in the SIP;

• Provisions to assure that the best available control measures/best available 

control technology (BACM/BACT) for the control of PM10 and PM10 precursors be 

implemented no later than four years after area reclassification to serious;

• Inclusion of the most stringent measures (MSM) that are included in the 

implementation plan of any state or are achieved in practice in any state, and can 

feasibly be implemented in the area; 

• Inclusion of base year emission inventories and future year forecasts for 

manmade sources of PM10 and PM10 precursors;

• Annual reductions of emissions equal to or in excess of five percent of baseline 

levels until attainment is reached;

• Plan provisions that require reasonable further progress (RFP) and quantitative 

milestones;

• Provisions for sufficient contingency measures for RFP and attainment; and

• Transportation conformity emission budgets to ensure transportation plans and 

projects are consistent with the SIP.

A. Demonstration of Compliance with Prior SIP Commitments

The 1998 Plan contained an implementation program designed to dynamically adjust 

BACM design and lakebed coverage requirements, and attain the PM10 standards by 

December 31, 2006. The commitments made in the 1998 Plan to achieve these goals 

were:

• Completion of the first increment of BACM implementation on 16.5 square miles 

of lakebed surface by December 31, 2003, unless the District found that 

attainment would be achieved by controlling a smaller area;

• Completion of the second increment of BACM implementation, if required, on 

sufficient lakebed surface to reach attainment by December 31, 2006;

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• Revision of the 1998 Plan by December 31, 2003, to incorporate new information 

on emissions and controls, and require implementation of appropriate BACM to 

reach attainment by December 31, 2006 if standards were not attained by 

December 31, 2003; and

• Assure RFP by completing BACM implementation on 10 square miles by 

December 31, 2001; an additional 3.5 square miles by December 31, 2002; an 

additional 3.0 square miles by December 31, 2003; and an additional 2.0 square 

miles in each succeeding year until December 31, 2006, unless attainment was 

achieved earlier.

The 2016 Plan documents that all prior commitments have been met.

B. Significant Source Categories

The Act requires areas designated as serious nonattainment for PM10 to implement 

BACM and BACT for all significant sources of PM10 or PM10 precursors, such as oxides 

of nitrogen, reactive organic gases, and ammonia. The District concludes in the 2016 

Plan, and the research studies in Plan appendices confirm, that PM10 precursors do not 

contribute significantly to PM10 concentrations measured during high wind events, the 

sole meteorological condition under which the PM10 standard is exceeded in the Owens 

Valley. The emission inventory in the 2016 Plan also confirms that only windblown 

PM10 sources are significant in the nonattainment area and subject to BACM controls.

The methodology used to determine the emission threshold for source significance in 

the 2016 Plan is the application of an air quality scaling factor to the emission inventory

for the Owens Lake Subarea. The Owens Lake Subarea is designated in the Plan as 

the lakebed surface area plus the area within the 2-km buffer zone surrounding the 

lakebed. From District analysis, this is the area from which windblown PM10 emissions 

cause exceedances of the PM10 standard at near-lakebed monitors. PM10 monitors 

outside this area did not report violations of the standard in the baseline period of 2012 

through 2014.

Following U.S. EPA guidance setting an air quality impact of 5 μg/m3 as a significant 

contribution in relation to the 24-hour standard of 150 μg/m3

, the District divided this 

5 μg/m3 benchmark by the level of the standard to create an air quality scaling factor for 

calculating an emission level of significance. When the scaling factor was applied to the 

emission inventory of a design day that minimally exceeded the 24-hour standard, only 

two source categories were found to exceed the resulting significance threshold: 

windblown dust from lakebed surfaces, and windblown dust from near-lakebed sand 

dunes. On this basis, the 2016 Plan focused the analysis of BACM exclusively on these 

two sources.

C. Best Available Control Measures and Most Stringent Measures

Since 1989, the District has pursued a comprehensive research and testing program to 

develop windblown PM10 control measures that are effective in the unusual Owens Lake 

9
playa and sand dune environment. The three original BACM measures contained in the 

1998 Plan - that are carried forward with little change into the 2016 Plan - were 

approved by U.S. EPA on September 3, 1999. The 2016 Plan also includes two BACM 

controls approved in the 2013 Plan and includes two being approved as BACM for the 

first time in an Owens Valley plan. An analysis contained in the 2016 Plan 

demonstrates that no other PM10 SIP or PM10 control regulation adopted by another 

California district or other state is more stringent with respect to control efficiency than 

the BACM controls approved in the 2016 Plan. 

Serious PM10 nonattainment areas that cannot achieve the standard by the serious area 

attainment date are allowed to request a five-year attainment date extension if BACM 

has been implemented on all significant sources and the plan is amended to 

demonstrate the identification and implementation of MSM for significant sources. The 

Act specifies that MSM is the maximum degree of emission reduction that has been 

required or achieved from a source or source category in other SIPs or in practice in 

other states and is feasible for implementation on significant sources in the subject 

nonattainment area. An analysis contained in the 2016 Plan demonstrates that the 

BACM controls approved in the Plan provide the maximum degree of emission 

reduction of any control included in a state PM10 SIP or achieved in practice on the areal 

scale of Owens Lake emission lakebed surfaces.

D. Emissions Inventory

SIPs must contain base-year inventories for PM10 and significant PM10 precursor

emissions as well as future year forecasts for these emissions. An emission inventory 

consists of a systematic listing of the sources of air pollutants with estimates of the 

quantities of pollutant emissions from each source or source category over specified 

time periods. 

District staff and contractors jointly prepared annual PM10 emission inventories and 

design day 24-hour inventories to demonstrate RFP and attainment in the 2016 Plan. 

These inventories include a category-by-category review and update using the most 

recent information available on emissions-generating activities in the nonattainment 

area.

E. Reasonable Further Progress and Quantitative Milestones

The Act requires SIPs to commit to the steady reduction of emissions between the base 

year required of the plan and the forecast attainment year. This requirement is referred 

to in the Act as RFP. As part of this requirement, a SIP must include quantitative 

milestones to be achieved every three years until the area is redesignated to attainment

and which demonstrates RFP. The 2016 Plan identifies the attainment year of 2017 as 

the only milestone year for SIP RFP planning purposes and quantitative milestone 

requirements. The District commits in the 2016 Plan to submit to U.S. EPA within 90 

days after this milestone date a demonstration that the forecast emissions reductions 

have been achieved.

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F. Contingency Measures

SIPs are required by the Act to contain contingency measures that provide additional 

emission reductions in the event a nonattainment area fails to achieve RFP targets or 

attain the PM10 standard by the attainment date. These contingency measures are to 

take effect without further ARB or District action and consist of reductions that are not 

required as part of the attainment demonstration. The 2016 Plan includes by reference 

the SCRD program that was adopted as the contingency measure in the 2008 Plan. 

The SCRD program requires the District APCO to annually evaluate PM10 monitoring 

data and area-specific emissions estimates provided by the Dust ID model and to 

determine whether any controlled or uncontrolled lakebed area generated sufficient 

windblown dust emissions to cause an exceedance of the PM10 24-hour standard at a 

shoreline location. On the basis of SCRD analysis, the District APCO can unilaterally 

order the implementation of BACM controls on uncontrolled lakebed areas to assure 

maintenance of the standard.

G. Transportation Conformity

Under section 176(c) of the Act, transportation activities that receive federal funding or 

approval must be fully consistent with the SIP. U.S. EPA’s transportation conformity 

rule exempts nonattainment areas from the requirement to provide a regional emissions 

analysis if the SIP demonstrates that regional motor vehicle emissions are an 

insignificant contributor to the air quality problem addressed in the SIP. The 2016 Plan, 

through analysis of emission inventory source categories, concludes that motor vehicle 

emissions are an insignificant portion of the design day emission inventories for the 

nonattainment area.

V. ENVIRONMENTAL IMPACT

The 2014 Judgment upon which the control strategy of the 2016 Plan is based requires 

the City to prepare all environmental documentation for actions required by the 

Judgment. In 2015, the City approved the Final Environmental Impact Report for the 

Owens Lake Dust Mitigation Program – Phase 9/10 Project (Phase 9/10 EIR) which 

analyzes the environmental impacts of BACM implementation on lakebed areas 

designated for control by December 31, 2017 by the 2014 Judgment. These areas and 

the BACM considered are the same as those contained in the 2016 Plan. The District 

Board, prior to approving the 2016 Plan, approved the Phase 9/10 EIR as the document 

satisfying CEQA requirements for the 2016 Plan.

VI. SUMMARY AND RECOMMENDATION

The 2016 Plan builds upon the foundation of a continuous program of monitoring, 

research, testing, and implementation of windblown dust controls covering more than 30 

11
years at Owens Lake. The progress achieved in emissions reductions and air quality 

improvement serves as a testament to the success of this program. After evaluation of 

the 2016 Plan, ARB staff has determined that the 2016 Plan satisfies the requirements

of the Act and therefore recommends that the Board approve the 2016 Plan as a 

revision to the California SIP. 

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