RULE 433. CONTROL OF PARTICULATE EMISSIONS AT OWENS LAKE Adopt ed : 04/13/2016

The purpose of this regulation is to effectuate 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 the Great Basin Unified Air Pollution Con trol District (“District”) and the City of Los Angeles (“City”) dated December 30, 2014 and entered by the Superior Court of the State of California, County of Sacramento. This regulation does not alter or supersede any provision in the Stipulated Judgment, nor does it relieve any party from full compliance with the requirements of the Stipulated Judgment. This regulation sets the basic requirements for the Best Available Control Measures (“BACM”) and defines the areal extent of these controls at Owens Lake
, California required in order to meet the NAAQS. This regulation does not preclude the City or the District from implementing more stringent or additional mitigation pursuant to the Stipulated Judgment.

A. DEFINITION S

1. “BACM PM 10 Control Areas” are areas on the dried bed of Owens Lake at or below the R egulatory Shoreline elevation of 3,600 feet and at or above Owens Lake’s ordinary high
water elevation of 3,553.55 feet on which BACM PM 10 Control Measures shall be implemented
, and

BACM PM 10 Control Areas are:

a. Areas
, as shown on the map in Exhibit 1 – Dust Control Area Map , including:

i. 29.8 square miles of the Owens Lake Bed with approved BACM PM 10 Control Measures (“2003 Dust Control Area”);

ii

. 13.2 square miles of the Owen s Lake Bed with approved BACM PM 10 Control Measures
, except for Eligible Cultural Resource Areas where PM 10 BACM selection and implementation dates will be deferred as set forth in Paragraph C.3. (“2006 Dust Control Area” and “Channel Area” );

i ii

. 2.0 square miles of the Owens Lake Bed with approved BACM PM 10 Control Measures (“Phase 8 Area”);

i v. 3.62 square miles of the Owens Lake Bed with approved BACM PM 10 Control M easures to be installed by December 31, 2017, except for Eligible Cultural Resource Areas, where PM 10 BACM selection and implementation dates will be deferred as set forth in Paragraph C.3. (“Phase 9/10 Area”); and

b. Additional areas as designated pursuant to Section C., “CONTINGENCY MEASURES” of this rule.

2. “BACM PM 10 Control Measures” are best available control measures designed to reduce PM 10 emissions to Control Efficiency (“CE”) levels specified below through compliance

Rule 433with performance standards specified in Attachment A or in specific control measure definitions below. The following BACM PM 10 Control Measures are approved to be used

.

a. “BACM Shallow Flooding” means the application of water to the surface of the lake bed in accordance with the performance standards for shallow flooding in Attachment A, Section I - Perfo rmance Requirements for BACM Shallow Flooding. Water shall be applied in amounts and by means sufficient to meet a CE level of 99% or CE targets for Minimum Dust Control Efficiency Areas.

b. “Tillage w ith BACM (Shallow Flood) Backup or TW B2 ” means the roughening of a soil surface using mechanical methods in accordance with the specifications in Attachment A, Section IV – Performance Requirements for Tillage with BACM Back -up, and to utilize BACM shallow flooding as a back -up control method in order
to prevent NAAQS violations. BACM Shallow Flooding must be implemented in TWB 2 areas if the erosion threshold as defined in Paragraph A.2.h is exceeded. Water shall be applied in amounts and by means sufficient to meet the CE level of 99% or CE targets for M inimum Dust Control Efficiency areas.

c. “Brine BACM” means the application of brine and the creation of wet and/or nonemissive salt deposits sufficient to meet the CE level of 99% as described in Attachment A, Section V – Performance Requirements for Brine BACM. BACM Shallow Flooding must be implemented in Brine BACM areas if the erosion threshold

as defined in Paragraph A.2.h is exceeded.

d. “ BACM Managed Vegetation ” means planting surfaces of the BACM PM 10 Control Areas with protective vegetation to meet the CE level of 99% by maintaining overall
average vegetation cover of at least 37% for each contiguous Managed Vegetation

area and an areal distribution based on vegetation cover thresholds and grid size

.

e. “BACM Gravel Blanket” means the application of a layer of gravel sufficient to meet the CE level of 100% by covering the control area with

• a layer of gravel at least four inches thick with gravel screened to a size greater than 1⁄2 inch in diameter , or

• a layer of gravel at least two inches thick with gravel screened to 1⁄2 inch in diameter underlain with a permanent permeable geotextile fabric

. f. “Dynamic Water Management or DWM” is a BACM Shallow Flooding operational modification that allows delayed start dates and/or earlier end dates required for shallow flooding in specific areas that have historically had low PM 10 e missi ons within the modified time periods. The truncated dust control periods allows for water savings while achieving the required CE level. Areas eligible for the DWM program and their modified start and/or end dates for shallow flooding are identified in

Rule 433Attachment A, Section VI – Performance Re quirements for Dynamic Water Management

. If any DWM area becomes susceptible to wind erosion outside of the modified dust control period the area will be required to be flooded to meet the required CE for that area. BACM Shallow Flooding must be implement ed in DWM

areas if the erosion threshold as defined in Paragraph A.2.h is exceeded.

g. “Minimum Dust Control Efficiency or MDCE” BACM is a dust control measure for which the control efficiency target is adjusted to match the required control level based on air quality modeling for the 2006 dust control areas as shown on the map in Exhibit 2 – Dust Control Efficiency Requirements

. The control efficiency targets
may be less than 99%, but the level of control in all areas is intended to prevent exceedances of the NAAQS. MDCE BACM includes:

i. Shallow flood areas where the wetness cover is adjusted following the curve in Exhibit 3 - Shallow Flood Control Efficiency and Wetness Cover Curve,

ii. Channel Area - a state

- regulated wetland area as shown in Exhibits 1 and 2 where vegetation cover is enhanced by irrigation and seeding with native plants in a

manner sufficient to prevent windblown dust from causing exceedances of the NAAQS
, and

iii. S and F en ce A rea – an area as shown in Exhibits 1 and 2 located in area T1A -1 where sand fences, vegetation and natural water runoff combine to provide sufficient protection to prevent windblown dust from causing exceedances of the NAAQS.

h. “Erosion Threshold” is applicable to TWB 2

, DWM
, and Brine BACM to trigger BACM Shallow Flooding which must be implemented to comply with the shallow flood CE target for that area

. The erosion threshold is determined from sand flux
measurements or the Induced Particulate Erosion Test (IPET) test method as described in Attachment A, Par agraphs IV.C.2 and IV.C.4. BACM Shallow Flooding must be implemented in TWB 2

, DWM or Brine BACM areas if any of the following thresholds are exceeded as determined using the methods described in Attachment A:

i. Sand flux measured at 15 cm above the surfac e exceeds 5.0 g rams per square centimeter per day on DWM or Brine BACM areas or 1.0 g ram per square centimeter per day on TWB 2 areas, or
ii. Induced Particulate Erosion Test method shows visible dust emissions when operated at the reference test height.

i. “Approved BACM” includes the control measures specified above and other

measures approved by the APCO and the US Environmental Protection Agency as equivalent to these methods.

Rule 4333. “Eligible Cultural Resource Area or ECR Area” is an area or areas where dust control

measures will be implemented on a deferred schedule due to the presence of significant cultural resources that make the areas eligible for listing under the California Register of Historic Resources

.

B. REQUIREMENTS

1. For the 2003 Dust Control Area the City shall continuously operate and maintain any mix of approved BACM PM 10 Control Measures as defined above in Section A to meet the 99% efficient CE level

. Selection of the type and location of BACM PM 10 Control Measures within the area is solel y the responsibility of the City.

2. For the 2006 Dust Control Area the City shall continuously operate and maintain approved BACM PM 10 Control Measures defined above in Section A to meet the CE target specified in Exhibit 2, except for ECR Areas where BACM PM 10 Control Measure selection and implementation dates will be deferred as set forth in Paragraph C.3., and
any areas of BACM Managed Vegetation, for which the City shall comply with the minimum 37% average vegetation cover target and areal distribution r equirements by December 31, 2017.

3. For t he Phase 8 Area consisting of 2.0 square miles the City shall continue to operate and maintain BACM Gravel Blanket

. 4. For the Phase 9/10 Project Area consisting of 3.62 square miles the City shall select and install BAC M PM 10 Control Measures by December 31, 2017, except for ECR Areas, where PM 10 BACM selection and implementation dates will be deferred as set forth in Paragraph C.3.

5. In areas containing infrastructure capable of achieving and maintaining compliant BACM Shallow Flooding the City may implement TWB 2

, Brine Shallow Flooding or Dynamic Water Management as alternatives to BACM Shallow Flooding or MDCE BACM shallow flooding.

C. CONTINGENCY MEASURES

1. At least once each calendar year, the District shall determine whether additional areas of the lake bed require BACM PM 10 Control Measures in order to attain or maintain the PM 10 NAAQS

. 2. If the District has not demonstrated attainment with the PM 10 NAAQS on or before December 31, 2017, or has not met reasonable further progress milestones, the District shall order the City to apply one or more BACM PM 10 Co ntrol M easures as set forth in

Rule 433Paragraph s A.2 and C.4 on those areas of the Owens Lake bed that cause or contribute to exceedances of the PM 10 NAAQS.

3. If monitoring and/or modeling demonstrates BACM PM 10 Control Measures are needed in an ECR Area(s) to attain or maintain the PM 10 NAAQS after BACM PM 10 Control Measures are implemented in adjacent areas, the District shall order the City to select and implement B ACM PM 10 Control M easures s et forth in Paragraph A.2.

4. The District may order the City to implement, operate and maintain a total of up to 53.4
square miles of waterless or water

- neutral BACM PM 10 Control M easures on the Owens Lake bed below the Regulatory Shoreline (elev. 3,600 feet) and above the ordinary high
water level of Owens Lake (elev. 3,553.55 feet).

5. As expeditiously as practicable and not more than three years after any such order for additional BACM PM 10 Control M easures, the City shall install, operat e and maintain BACM PM 10 Control M easures that achieve a control efficiency of 99%. If BACM Managed Vegetation is chosen up to two additional years for vegetation growth is allowed to achieve the 37% vegetation cover requirement.

EX HIBIT 1 – Dust Control Area Map

EXHIBIT 2 – Dust Control Efficiency Requirements

EXHIBIT 3 – Shallow Flood Control Efficiency and Wetness Cover Curve

ATTACHMENT A – Performance Requirements for BACM

Rule 433Great Basin Unified Air Pollution Control District 

# Exhibit 1 - PM10 Dust Control AreasT2-1Addition T1A-2 T10-1 T10-2 T17-2 T18-0 T21T1A-1 T1A-4T12-1

T3NE

T3SE T3SW T4-3 T28N

T27N T28S

T27S T26

T24 T25N

T25S
T23E
T23W T35-1

T35-2

T36-1

T36-2 T36-3 T29-4

T18N

T18S

T13-3 T11 T13-2

T9

T1-1 T2-5

T2-4

T2-3 T2-2
T5-1

T2-1 T29-1 T30-3 T29-2

T29-3 T30-1 T30-2

T5-3 T8W

T4-5

T4-4 T16T23-5 T25-3

T8 T7

T6 T5

C2 C1 T10-3 T17-1 Area AT32-1

T37-2

T1A-3T37-1

T10-3-L1 T21-L1 T21-L2 T32-1-L1

T21-L3

T13-1

T5-1 Add T5-3 Add T36-3 Add

T18N AddCorridor 1

T27 Add T24 Add

T5-2

T3SE Add T4-3 Add T5-4 T13-1 Add Area B

C2-L1 DuckPond-L1 T10-L1 T17-2-L1T35-2-L1 T37-1-L1

T37-2-L1

T37-2-L4 T37-2-L2

T37-2-L3

T21-L4

DuckPond-L2 T9 Keeler Dunes

Owens Lake ordinary high water elevation: 3553.55' 410000

410000 415000

415000 420000

420000 425000

425000 430000

430000402000040200004025000402500040300004030000403500040350004040000404000040450004045000

3/9/2016 1:08:16 PM SIP Revision 2016 Exhibit 1 Dust Control Map 20160309 rule 433.mxd Regulatory Shoreline: 3600' Ordinary High Water Elevation
Keeler Dunes Control Area
Dust Controls
2003 Dust Control Area: 29.8 sq mi
2006 Dust Control Area: 12.7 sq mi
Channel Area: 0.5 sq mi
Phase 8 Area: 2.0 sq mi
Phase 9/10 Area: 3.62 sq mi 

### Owens Lake

Arizona California Idaho Montana

Nevada Oregon

Utah Washington Location Map:

0 1 2 Miles 

# É UTM:UTM:Great Basin Unified Air Pollution Control District 

# Exhibit 2 - Dust Control Efficiency Map

98 0

0 0 53

63

63 63

66 72

79

81 84 85

91 92

95 95

97

98 98 T1A-2_b

T1A-1 T23-5 T25-3

Channel 2 Channel 1 Keeler Dunes Dust Control Area



### Owens

Lake

Legend:
DCAs with Minimum Dust Control Efficiency
3600' Shoreline Control Efficiency

MDCE / Keeler Dunes
85% - Keeler Dunes 99% - SF, Man Veg, TWB2, Brine, Hybrid
100% - Gravel 0 1 2 Miles 

# É

2/2/2016 3:40:27 PM SIP Revision 2016 Exhibit 2 Control Efficiency 201602202.mxd

# Exhibit 3 - Shallow Flood control efficiency curve

Percent Water Cover 0 10 20 30 40 50 60 70 80 90 100Percent Efficiency

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100Rule 433 – Attachment A Ru le 433 – At tachment A Pe rfo rm an ce Requ ir ements for BA CM

I. BAC M Sha llow Flooding

A. The “ BACM Sha llow Flooding” PM 10 contr ol m ea su re wi ll apply water to the su rf ac e of
those ar eas of the lake bed wh ere sha llow flooding is used as a PM 10 control m ea su re

. Water sh al l be applie d in amounts and by mea ns su ff icie nt to achie ve the performance

st and ar ds s e t forth in P ar ag ra phs I. B and I. C of th is a tt ac hment. The dates by whi ch
BACM Shallow Flooding a rea s ar e to c omp ly with th e se p erf or mance st andards may be modified by the Dynamic Wat er Management provisions se t forth in Rule 433.A.2.f and Paragraph VI.B.

B. For a ll BACM Sha llow Flooding area s ex ce pt those within the 2006 DC A:
1. At l ea st 75 p er cent of each squ ar e mile designated a s BAC M Sha llow Flooding ar eas sh a ll continuously c onsi st of st anding water or s ur fac e-sa tu rated soil, substa nti ally evenly distributed for the p er iod c omm encing on O ctober 16 of eac h y ea r, and ending on May 15 of the next year. For th ese BACM Sha llow Flood dust control area s, 75

p er ce nt of e ac h entir e c onti guous a re a sha ll con sist of substa nti ally evenly distr ibut ed

st anding water or su rf ac e- sa tu ra ted soil.
2. Beginning May 16 and through May 31 of every y ear , sha llow flooding ar ea l

we tn e ss cover may be re du ce d to a minimum of 70 p erce nt.
3. Beginning June 1 and through June 15 of every ye ar , sha llow flooding area l

we tn e ss cover may be re du ce d to a minimum of 65 p erce nt.
4. Beginning June 16 and through June 30 of every y ear , s ha llow flooding ar ea l

we tn e ss cover may be re du ce d to a minimum of 60 p erce nt.
C. For BACM Sha llow Flooding ar ea s within the 12.7 square- mile 2006 DC A:
1. The per ce ntage of e ac h a re a th a t must h ave substantially evenly distr ibut ed

st anding water or su rf a ce -sa tu ra ted soil sh a ll be based on the Sha llow Flood
Control E ff iciency Curve (Exhibit 3) to ac hieve the contr ol eff iciency leve ls in the Minimum Dust Control Efficiency ( MDCE) M ap ( Ex hibit 2 ).
2. For only those BACM Sha llow Flooding ar ea s with contro l eff iciencie s of 99 pe rc ent

or mo re :

a. Beginning May 16 and through May 31 of every y ear , sha llow flooding

ar ea l w e tn e ss cover may be redu ce d to a minimum of 70 p erce nt.Rule 433 – Attachment A b. Beginning June 1 and through June 15 of every ye ar , sha llow flooding area l

we tn e ss cover may be re du ce d to a minimum of 65 p erce nt.

c. Beginning June 16 and through June 30 of every y ear , sha llow flooding

ar ea l w e tn e ss cover may be redu ce d to a minimum of 60 p erce nt.

II. BAC M Managed Vegetation
The “ BACM Managed Vegetation ” PM 10 control measure requires planting surfaces of the
BACM PM 10 control areas with protective vegetation to meet the control efficiency level of 99% by maintaining an overall average vegetation cover of 37% for each contiguous managed v egetation area.

III. BACM Gravel Blanket
The BACM Gravel Blanket” PM 10 control measure requires the application of a layer of gravel sufficient to meet the control efficiency level of 100% by one of the following

means:

• covering 100% of the control area with a layer of gravel at least four inches thick with gravel screened to a size greater than 1⁄2 inch in diameter, or

• covering 100% of the control area with a layer of gravel at least two inches thick with gravel screened to 1⁄2 inch in diameter underlain with a permanent permeable geotextile fabric.

IV. Till age with BACM ( Sha llow Flood) B ac kup (or TWB 2 )
A. The City of Los Angeles (“ City”) may impl ement or t ra nsition BAC M Sha llow Flood

ar ea s to “ Till age with BACM ( Sha llow Flood ) B ac k-up (TWB 2 ),” whi ch sha ll con sist of (1) soil tilling within all or portions of BACM Shallow Flood PM 10 control areas (TWB 2 Areas), and (2) the installation of all necessary shallow flood infrastructure so th a t the

TWB 2 A rea s c an be sh a llow -flooded if the er osion th re shold is ex cee de d or the

p erf ormance cr it er ia ar e not me t.
B. Construction of TWB 2 A rea s 1. Till age sha ll cr ea te r ows and fu rr o ws in roughly ea st to w e st di rec tions in o rder to

cr ea te m ax imum su rfac e roughne ss for winds from the nor th a nd south. Addition a l roughne ss to p rot ec t su rf ace s fr om w e st winds sh a ll be crea ted in till ed area sRule 433 – Attachment A su ff icie nt to p re vent e missions from ea st and west winds.
2. The till ed su rfa ce s will also be ar mo re d with soil clods of 1/2 inch diameter or large r cov er ing 60 pe rce nt or more of the till e d su rf ace

. 3. TWB 2 ar ea s sh a ll be con st ructe d with ridge heigh ts (R H) averaged on 40-a cr e blocks

at or above 1.25 f ee t (fu rr o w d epth to ridge top di ff e re nce a t l ea st 2.5 f ee t) and r ow
sp ac ing ( RS ) su ff icient to provide a ra tio of the r ow sp acing to ridge height ( RS /R H) below 10, e.g. distance betw ee n rows is 12.5 fee t with average ridge height gr ea ter
than 1.25 fee t.
C. Monitoring and Maintenance
1. Su rfac e Roughne ss

a. L id ar, aeria l photog ra phy or other field measurement method s with equivalent

acc ur ac ies will be used by the City to m ea su re RS/RH ratio and ridge height. Roughne ss m ea su re ment s will be made in the no rth- to -south di rec tion

-- - the
di rec tion of the pr im ary dust produc ing winds. Roughne ss m ea su re me nts m ay also be ma de in other di rec tions. Roughne ss measu re me nts will be re ported to the
A PC O within 30 day s of m ea su rement.
b. The RS/RH ratio a nd r id ge height m ea su reme nts will be ma de at 6 month, or

mo r e fre quent, int er va ls. Inver se roughne ss and ridge height for a TwB 2 A re a

w ill be t rac ked and plotted a s a function of tim e. Wh er e f ea sible, field

m ea su re me nts m ay also be taken to confirm Lidar or other remot ely sensed

re sults. The Ci ty will conduc t roughne ss m ea su re ments at least once every 6 months and repor t the m ea su re ments within 30 days to the A PC O. The Dist ric t

re serve s the rig ht to conduct its own roughne ss m ea su rements a t any tim e.

c. Assuming th a t d egradation of the till ed ridge s m ay occur over tim e , till age maintenance will be p er formed by the City if the av er age RS/RH roughness ratio
is b e tw een 10.1 and 12.0 or if the av er age ridge heig ht is le ss th an 1.1 fee t in a
till ed ar ea

. d. The City sh a ll re-flood a TWB 2 ar ea to c omp ly with the re qui re d BACM S ha llow
Flood control efficiency for the ar ea if the RS /R H ra tio is greater th an 12.0 (12 /1) or the ridge height fal ls b elow 1.0 f eet for any d ef in ed 40- ac re av er aging area.

e. The City sh a ll m ea su re clod cov er age using the point- intercept method (U.S. Bureau of Land Management, Sampling Vegetation Attributes, Method G,Rule 433 – Attachment A Technical Reference BLM/RS/ST -96/002+1730) or other field measurement
methods with equivalent accuracy . Clod cover will be measured concurrently with surface roughness at least once every 6 months and re po rte d to the A PC O within 30 days of measu re ment.
2. Sand Flux

a. The City sh a ll monitoreach TWB 2 area with a t l ea st four Se nsits and C ox s and

ca tcher s ( CSC s) with in le ts s e t at 15 c m above un till ed su rface s (ci rc ular pads
with 3 m ra dius) in the gene ra l nor th er n, south er n, ea st ern a nd w e st er n portions
of a till age. In TWB 2 a rea s greater than 320 acre s the City sh a ll inst all one
Se nsit and CSC p a ir per 80 ac re s. b. The City will p a ir CSC s with Se nsits, ra dio equipment and datalogg er s
progra mm ed to rec ord 5-minute sand motion data. All Se nsit d a ta will be

re ported daily to the Dist rict. Sand motion da ta from the CSC s and Se nsits will be pro ce ss ed to t rac k sa nd flux a t ea ch sit e.

c. All s and flux monitoring equipme nt will be inst a ll ed prior to the st ar t of
till age ac tiviti e s. d. Hi gh sand flux va lu e s re corded during maintenance ac tiviti e s or from non- till age sand flux sou rce s sh a ll be excluded from the sa nd flux data . M aintenance

ac tiviti e s and non- till age sand flux sou rce s m ay in c lu de, but ar e not limit ed to,

ra in

- spl att er s, bug s, adj ace nt grading and road c onst ruction ac tiviti es, a s w e ll a s vehicle t ra ffic. Sensits should be pl ace d so a s to minim ize imp ac ts fr om nontill age sand flux sou rce s.

e. When (other th an durin g m aintenance ac tiviti e s t aking place in the “ till a ge a rea” which is defined as the tilled portion of the TWB 2 area ) th e s a nd flux ex cee ds 0.50 g/cm 2 /d ay, the City will p e rf or m m aintenance in the till ag e area , whi ch may
in clude su rfa ce we tti ng, re-e st abl ishm ent of the su rfa ce roughness, or full or

p ar ti a l r ef lood ing of a TWB 2

.

3. P M 10 Monito ring

a. E ac h TWB 2 a re a will be a ssi gned upwind and downwind PM 10 monitor s (not

n ece ss arily a t the TwB 2 A re a boundary) to monitor PM 10 em issions fr om the
till ag e area . For a g iv e n wind d i rec tion, the downwind monitor s sh a ll be withinRule 433 – Attachment A 22 deg ree s (±11.5°) of the upwind monitors. Upwind/downwind monitor

a ssi gnments will be re que st ed by the City and approved by the A PC O. E x is ting monitors op era ted by th e Dist ric t m ay be used a s u pwind/downwind monit ors. Additiona l E PA reference and equivalent method PM 10 monito r s (40 CFR Part
53 ) sh a ll be op era ted by the City, unle ss mutu ally ag ree d oth er wis e. b. If a monitor is op era ted by the City, its ope ra tion a nd m aintenance must foll ow Dist ric t p ro ce dure s and da ta c oll ec tion must be in corpo ra te d into the Dist ric t
communi ca tions ne two rk. The Dist ric t re serve s t he rig ht to audit monitors and monitoring da ta c oll ected by the City. The Dist rict also re s er ves the rig ht to
insta ll and operate or require the City to install and operate additional PM 10

mo ni to rs to adequately monitor the PM 10 emi ssions coming fr om till ed area s.

c. All PM 10 monitoring equipment will be in place as soon as practicable as shallow flood areas dry, but no later than the start of tillage activities.
d. I mp ac ts ca used by maintenance ac tiviti e s and non- till age sour ce s sh a ll be

exclud ed fr om the PM 10 data. Maintenance ac tiv i ti e s and non- till age PM 10

sou rce s m ay in clude, but ar e not limit ed to, adjacent g ra ding and road

construc tion ac tiviti es, a s we ll a s v ehic le tr aff ic. PM 10 monitors should be pl ace d so a s to minimi ze i mp ac ts fr om non- till a ge source s.

e. Whe n the daily downwind to upwind PM 10 con ce nt ra tion di ffe rence for any dust event (other than during maintenance ac tiviti e s in the till age area) ex cee ds 50 μg/m 3 and th er e is no evidence t o show th a t the additional downwind PM 10 did

not c ome fr om the TWB 2 Ar ea , maintenance will be p erf ormed in the till age

area. 4. Indu ce d P ar ti cula te Erosion Te st

a. The Induce d P ar ti c ul a te Erosion Te st (IP ET) method will be used to deter mine if
till ed are a su r fa ce s are st ar ting to bec ome e missi ve. The IP ET m ethod uses a

sm a ll ra dio-contr oll ed he li copt er -ty pe cr af t (Ra dio -Contr oll e d Wind Induction
Device or RCW InD) to cr ea te wind on the su rfa ce. Each RC WI nD c raf t sh a ll be

p re -te st e d to det er mine the te st h eig ht above the su rface (H t ) at whi c h the cr af t

cr ea tes a t ar g et max imum ho rizonta l wi nd sp ee d (T WS ) m ea su red at 1 ce ntim eter (U 0. 01 ) above a fl at su rfa ce equal to 11.3 met er s p er s ec ond ( m/s ). If the pay lo ad

on a cr af t is changed, e.g. a diff ere nt camera is used, then H t must be re

-Rule 433 – Attachment A det er min ed for the ne w paylo ad sin ce it will affec t the amount of th rust n ee ded to
k ee p the RC WInD a lo f t.
b. Te sting to deter mine H t and TWS will be done on a smooth fla t su rfa ce, e.g.

con cre te or aspha lt p avement or plywood test platfor m with ca lm a mbi ent winds (< 2 m/s ). H t is measured from the bottom of the rotor blade to the surface. The

max im um wind sp ee d for any flig ht h ei ght is t aken a t a height one ce ntim eter
above the su r fac e a t a point th a t is one rotor bla de length away from the point
ben ea th the center of the fa st e st r otor blade taken on a line extending outw ar d
from the rotor ar m. The wind sp ee d m ea su reme nt is t aken with a pitot tube pointing tow ar d the ce nt er of the rotor blade. The RC WI nD mu st be flown in a

st a tion ary position to ge t a sust a in ed wind sp ee d m ea su reme nt.

c. When the craf t is flown over a ridged su rf ace H t is m ea su re d fr om the bottom of
the craft’s rotor blades to the highest surface projection anywhere directly
below the craft.
d. Th re e er osion al er t l eve ls ar e set using the IP ET method: 1) an early w ar ni ng of possible c lod and su rf ace st a bili ty det er io ra tion, 2) a w ar ning leve l to al er t t he
Ci ty of a potentia l b rea kd own of the su rfa ce st a bili ty and to advise voluntary

ma in tenanc e eff orts, and 3) a mitig a tion ac tion leve l to re qui re re- tilling and/or
re-f looding of a ll or p ar t of a TWB 2 , D WM or Brine BAC M A r ea.

e. The IPE T m e thod will be used to det er mine erosion al er t l eve ls as follows:

• Level 1 – An erosion ear ly w ar ning is indi ca ted when any visible dust is
obs er ve d to be e mitt ed from a su rf ac e or p ar ti cles ar e dislo dged wh en the

RC WIn D is flown a t a height be low one ha lf of H t . Voluntary miti ga tion m ay be appropriate to prevent further surface degradation.

• Level 2 – An erosion warning is indi ca ted when any visible dust is obs er ved

to be e mitt ed from a su rf ac e whe n the RC WI nD is f lo wn a t a height be low H t and above one ha lf of H t . Vo luntary mit iga tion is advised to p re vent fur th e r

su rfa ce degradation.

• Level 3 – Miti ga tion action is re qui re d if visible dust is obs er ved to be

e mitt ed fr om a su rf ac e wh en the RCW I nD is f lown a t a height of H t or high er

. D. The City sh a ll re-flood TwB 2 ar ea s to c omp ly with the BACM S ha llow Flood controlRule 433 – Attachment A eff iciency targ et f or th a t ar ea , if e ith er of the following er osion thresholds ar e ex cee ded

a s det er min ed using the sand f lu x and IP ET m ea su re ments descr ib e d in Pa rag ra phs
IV.C. 2 and IV.C. 4.
1. Sand flux m ea su re d a t 15 c m above the su r fa ce ex cee ds 1.0 g ram per square centimeter per day, or
2. Indu ce d P ar ti cula te Erosion Te st m ethod shows visible dust e missions wh en

op era ted a t the re f ere nce te st h eight, H t.

V. Brine BACM
A. Stable su rfa ce s for Br ine BAC M sh a ll be def in ed a s consisting of st anding wat er , evapor ite s a lt d eposit, a nd ca pill ary brine sa lt crust a s f ollo w s: 1. Wat er : Standing water or hydr olo gi ca lly sa tu ra ted su rfa ce a s d ef in ed by BACM
Sha llow Flooding, regardless of salinity level

. 2. Ev apor ite Sa lt D e posit: A cry st a lline deposit of sa lt min era ls p rec ipit ated on the

su rfa ce of the lakebed fro m evapo ra tion of Owe ns Lake br in e. The evaporite sa lt deposit does not inc lude the deve lopm ent of sa lt crust by upw ard ca pill ary

mov ement of sa line f luids th rough t he soil column. The evapor ite sa lt d eposit
must h ave an av er age thi ckne ss of 1.5 ce nt im et er s or g rea ter and may be ei th er we t or dry.
3. Ca pill ary Brine Sa lt Cru st: A crust enriched in sa lt min era ls formed a t the soil

su rfac e by up w ar d ca pill ary mo vement of water th rough the soil. The ca pill ary brine

cr ust typi ca lly consists of a mix of sa lt min era ls and soil p ar ti cles in v ar ious proportions, and must m ee t the following th re e conditions:

a. The ca pill ary brine sa lt crust w ithin a Brine BAC M are a must h ave an
averag e thi ckne ss of 10 ce ntim eter s orgreater a nd may be e ith er wet or dry,
b. a ca pill ary brine sa lt cr ust must be acc omp anied by e ith er water and/or a n
evapor ite s a lt d eposit, a nd

c. the proportion of qua li fying ca pill ary brine cr ust w ithin a Br ine BAC M area

ca nnot ex cee d one-thir d of the requi re d tota l compliant cover within a Br ine
BAC M area.
B. E ac h Brine BAC M area sha ll be op era ted suc h th at the tota l area l exte nt of the su rf ace

cov er of the qua li fying su rf a ce s ar e mainta in ed such that th ey meet or ex cee d those a sRule 433 – Attachment A d ef ined by the Sha llow Flooding Control E ff iciency Curve in Exhibit 3. The c ombin ed

mos a ic of st able Brine BAC M su rfa ce s sh a ll cover the entire dust contr ol area

. C. Brine BAC M can be used by the City of Los Angele s (City) th roug hout t he Ow ens Lake
be d wh er e b ac kup BACM Sha llow Flood in fra st ruc tu re ex ists and ca n be impl emented,

a s s et f orth in this pr oto col, to ensure th a t Brine BAC M area s do not ca use or contr ibute

to exceedance of the NAAQS for PM 10

. D. The bound ar ies for e ac h Brine BAC M area will be p re -d ef in ed by the City prior to impleme nt ation. E ac h Brine BAC M area will be monito re d sep ara tely to
det er mine c ompli ance with re qui re d su rfa ce c ov er conditions.

E. The City will monitor e ac h Brine BAC M area with a t l ea st one sand flux monitor (SF M) site inst rumented with p ai re d Cox Sand Catch er s ( CSC s) and Se nsits with
inle ts position ed 15 c m above the su rf a ce , radio equipment, and datalogger s
prog ramm ed to rec ord 5-minute sand motion data. SF M sit e s will p r im ar ily be
lo ca te d in portions of Brine BAC M ar ea s covere d with a ca pill ary cr ust. All Se nsit
da ta will be re ported daily to the Dist rict. Sand motion da ta from the CSC s and
Se nsits will be pro ce ss ed to t rac k sa nd flux a t ea ch sit e.
F. Brine BAC M ar ea s will be monito re d using the IP ET m ethod following the pro ce du re s used for Till age w ith BAC M B ac k-up ar ea s in Paragraph IV.C.4

. G. The City sh a ll re-flood Brine BAC M ar ea s to comply with the BACM S ha llow Flood
control eff iciency targe t for th at area , if e ith er of the follo wing erosion th re sholds ar e exceeded as det er min ed using the sand flux and IP ET m ea su rements des cr ib ed in Paragraphs IV.C.2 and IV.C.4.
1. Sand flux m ea su re d a t 15 c m above the su r fa ce ex cee ds 5.0 g ram s per square centimeter per day, or
2. Indu ce d P ar ti cula te Erosion Te st m ethod shows visible dust e missions wh en

op era ted a t the re f ere nce te st h eight, H t.

VI. Dyna mic Wat er Management
A. A rea s th at ar e e li g ible for Dyna mic Water Management (DW M) must m ee t the following sand flux histo ry cr it er ia:
1. 5 ye ar s or mo re of sand flux da ta fr om b ef ore dust c ont r ol impl ementation,
andRule 433 – Attachment A 2. The fre quency of si gnificant sand f lux (>5 g/cm 2 /d ay) taking place outside of the
modified sha llow flood dust contr ol p er iod did not o cc ur in mo re than one calendar year over any continuous six y ea r period.

B. The modified dust s ea sons for DW M h ave th ree di ffere nt star t d ate s in the beginning of
the s ea son th a t refl ec t the delayed st ar t of so u rc e ar ea ac tivi ty a cr oss the lakebed. The
modified st ar t d ate s are appli ca ble to cer tain dust control area s b ased on the sand flux
histo ry a s eva lu ate d in Parag ra ph VI. A and the method of sh a llow flooding using
conventiona l flooding or sp r inkl e r i rr ig ation.
1. For a rea s s ha llow flooded by methods other than sp rinkler i rr igation, the stand ar d and modified dust control periods are : Sta nd ard Du st Season October 16 to June 30 (w ith ra mping of 99% contr ol area s af ter May 15)
Modifi ed Du st Seasons for Dy nam ic Wat er Manag eme nt October 16 – Apr il 30

D ece mber 1 – Ap r il 30 January 16 – Apr il 30
2. For elig ible a rea s th at ar e shall ow flooded wi th sp rinkler i rr igation, the modified

DW M s ea sons sh a ll be adjusted to provide water two weeks ear li er in the beginning
of the dust s ea son to simula te ra mp up a s applie d in conventi on a l BACM S ha llow
Flood ar eas and one month later a t the end of the dust s ea son due to the l ac k of

we tn e ss du ring the dry down p er iod with conve ntion al BACM S ha llow Flood ar ea s. The adjustme nts to the DW M s ea sons for sprinkler i rr igated sha ll o w flooding ar ea s
are pro vid e d be low.
Modified Du st Seasons Adjus te d f or Sp rinkl er I rr iga ted Sh allow Flooding A re as October 16 – May 31

Nov e mb er 16 – May 31 January 1 – May 31
3. In ar ea s approved for DWM, the City of Los Angele s (City) sha ll m ee t the sh a llow
flood control eff iciency and we tn e ss t ar ge ts indi ca ted in Ex hib its 2 and 3 by or before the appli ca ble st ar t d ates in P ar agraph VI. B and water may be shut o ff with no

sp ring ramping a t the end of the modi fied s ea son. C. E ac h DW M ar ea will be instrumented by the Ci ty with s and flux monitoring (SF M) sit e sRule 433 – Attachment A using paire d Se nsits and Cox Sand Catch er s ( CSC s) during the modifie d st ar t and e nd

p er iods. The lo ca tions of SF M sit e s sh a ll be deter min ed by the City in coordina tion with
the Dist ric t.
1. The numb er of SF M sit e s a t the modified st ar t of the dust s ea son will be propor tion a l
to the ar ea l extent of the DW M area . All D W M ar ea s will re quire a t l ea st o ne SF M
site howev er ; the A PC O m ay re quire propor tion ally more SF M sit e s for DWM area s
g rea t er th a n 320 ac re s su ch tha t th er e is approx im ately one SF M site per 160 ac res of

DW M area. 2. Du ring the modified e nd p er iod of the dust s ea son, the LADWP sh a ll inst a ll SF M
sit e s in cre mentally in st age s a s a DW M are a drie s. T he number of SF M sit e s is provided i n T able 1 be low.

Tab le 1 . Number of SF M sit e s re qui re d per DW M are a during the modified end of the dust s ea son.

D r yi n g S t age E x p os e d L a k e b e d N u m be r of S F M si tes

1 L e ss th a n 50 a c res 0 2 50

– 160 acres 1 3 > 160 ac r es 1 p e r e v e r y 160 a cre s

3. The City will p a ir CSC s with Se nsits with inl e ts p osition ed a t 15 c m above the

su rfa ce, ra dio equipment and datalogg er s prog ramm ed to r ec ord 5-minute sand

mo tion data . All Se nsit d a ta will be re ported daily to the Dist rict. Sand motion da ta
from the CSC s and Se nsits will be pro ce ss ed to t rac k sand flux a t ea c h sit e. 4. Du ring the modified st ar t of the dust s ea son a ll s and flux mon i to ring equipme nt will be pl ace d by the City no later th an Oc to ber 16. D uring the modified end of the dust

s ea son a ll SF M sit e s will be pl ace d by the City within 7 ca le nd ar days of re ac hing

ea ch drying st age. The City sha ll in for m the Dist rict of a ll SF M site inst a ll ations
within 7 day s of insta ll ation.
5. SF M sit e s inst a ll ed for monitoring in the modified beginning dust s ea son may b e

re mov ed fr om a DW M area once the modified dus t s ea son ha s st ar ted for e ac h

DW M are a or once the site lo ca tion is endanger of ge tting f lood ed. The City sha ll
in for m the Dist rict of a ll SF M site re mov a ls within 7 ca lendar days of th e ir remov a lRule 433 – Attachment A date. SF M sit e s inst a ll e d for monitoring of the modi fied end of the dust s ea son may be re mov ed from a DW M ar ea af ter June 30.

D. DWM area s will be monito re d using the IP ET method following the pro ce du re s used
fo r Till age with BAC M Back-up ar eas in Paragraph IV.C.4.

E. The City sh a ll re-flood a DW M are a or su b-area as indi ca ted by the availab le
in formation to c omp ly with the BACM S ha llow Flood control eff iciency targe t for tha t

ar ea , if e it her of the following erosion th re sh olds ar e ex cee ded a s d eter min ed using the
sand flux a nd IP ET m ea su re ments des cr ib ed in Pa rag ra phs IV.C. 2 and IV.C.4.
1. Sand flux m ea su re d a t 15 c m above the su r fa ce ex cee ds 5.0 g rams per square centimeter per day, or
2. Indu ce d P ar ti cula te Erosion Te st m ethod shows visible dust e missions wh en

op era ted a t the re f ere nce te st h eight, H t. F. If any DW M area exceed s e ith er er osion th re sho ld in P ara g ra ph VI. E in mo re th an one calenda r y ea r over any continuous six-year period, tha t area will re v er t to the st andard
BACM S ha llow Flood dust s ea son as shown in P ar agraph VI. B.1 since the ar ea will no longer m ee t the D W M cr it er ia in P ar agraph VI.A.