Owens Lake Background

Vicinity Map | 1998 Memorandum of Agreement | Description of Control Measures

Looking East towards Owens Lake from Wonoga Peak. Photo: Phill Kiddoo

Owens Lake is one of the largest sources of PM10 in the United States

Water was first diverted from the Owens River to the City of Los Angeles in 1913, and by 1926 Owens Lake was dry. Today, the Owens lakebed produces enormous amounts of windblown dust in exceedence of federal air pollution standards for particulate matter. Particulate pollution is generally associated with dust, smoke and haze and is measured as PM-10 , which is an acronym for particulate matter less than 10 microns in diameter. Breathing PM-10 can cause a variety of health problems. The National Ambient Air Quality Standard for PM10 is set at 150 µg/m³ for a 24-hour average. Studies of dust transport from Owens Lake show that the standard can be exceeded more than 50 miles away and expose many more people to violations of the PM-10 standard than just the residents near Owens Lake. The dust from Owens Lake affects about 40,000 permanent residents between Ridgecrest and Bishop.

1998 MEMORANDUM OF AGREEMENT BETWEEN
THE CITY OF LOS ANGELES AND
THE GREAT BASIN UNIFIED AIR POLLUTION CONTROL DISTRICT

1. The City of Los Angeles ("City") commits to its responsibility to reduce particulate emissions from the Owens Lake bed so that the Owens Valley Planning Area ("OVPA") will attain and maintain the federal Clean Air Act ambient air quality standards for particulate matter (PM-10, hereafter referred to as "the Standards") by the statutory deadline. In 2006, the District will make a determination whether the OVPA attains the Standards. In making that determination, the District will apply EPA’s Natural Events Policy.

2. The City and Great Basin Unified Air Pollution Control District ("Great Basin APCD") commit to take the described actions with respect to the pending proceedings identified in Exhibit A. These actions will be taken in the context of settlement of existing disputes between the parties and in no way prejudices future actions on similar issues.

3. Great Basin APCD agrees upon execution of this Agreement to revise its proposed 1997 State Implementation Plan (1997 SIP) and associated control measure Order (District Order 070297-04) to substantially conform to the provisions set forth below and consider for adoption such revised 1997 SIP and associated control measure Order by November 30, 1998. The City agrees not to legally challenge or appeal a revised 1997 SIP and associated control measure Order, provided they substantially conform to the provisions set forth below.

(a) City will implement control measures on 10 square miles of the Owens Lake bed by December 31, 2001.

(b) City will implement control measures on an additional 3.5 square miles of the Owens Lake bed by December 31, 2002, unless the District determines on or before December 31, 2001, that the OVPA will attain the Standards by the statutory deadline without implementation of further control measures.

(c) City will implement control measures on an additional 3 square miles of the Owens Lake bed by December 31, 2003, unless the District determines on or before December 31, 2002, that the OVPA will attain the Standards by the statutory deadline without implementation of further control measures.

(d) City will implement control measures on an additional 2 square miles of the Owens Lake bed in each calendar year after 2003, unless the District determines on or before December 31 of the previous year, that the OVPA will attain the Standards by the statutory deadline without implementation of further control measures.

(e) Control measures implemented pursuant to items (a), (b), (c) and (d), above, shall be located within the area identified in Exhibit C. The Great Basin APCD and the City may jointly agree to modify the locations identified in Exhibit C.

(f) Control measures implemented pursuant to items (a), (b), (c) and (d), above shall conform to the following. The City shall implement the control measures identified by Great Basin APCD as described in Exhibit B. The Great Basin APCD and the City may jointly agree to modify, or add one or more control measures to those identified in Exhibit B. On the 3.5 square miles of the "Dirty Socks" area identified as Areas F and G in Exhibit C, the City has the authority to try one or more control measures of its choosing not identified in Exhibit B.

(g) Great Basin APCD will revise the SIP in 2003 to incorporate the knowledge gained by early implementation of control measures (the "2003 SIP"). The 2003 SIP will provide for attainment in the OVPA of the Standards by the statutory deadline.
 

4. In the event of a 2003 SIP legal challenge by the City, the City agrees to implement control measures on an additional 2 square miles of the Owens Lake bed annually, as provided in Section 3(d) above. Upon State approval of the 2003 SIP pursuant to Health & Safety Code Section 41650, the City shall be required to make-up any control shortfall caused by the City SIP challenge, if any, or shall be provided credit for control measure installation beyond the State approved SIP, if any. Any required control measure shortfall will be made up within one year of the approval of the SIP by the State. 

5. The City agrees to fully participate in the SIP revision public review process.

6. The determination of when the OVPA has attained the Standards is the authority and responsibility of the Great Basin APCD. The City does not waive any legal right or remedy available to it with respect to any such determination.

7. The City and Great Basin APCD staff shall meet at least annually for the purpose of evaluating the progress of control measures and will consider the advice of scientific experts that each party may invite to the meeting.

8. This Memorandum of Agreement is effective upon adoption by the governing bodies of the parties.

9. Either if CARB does not approve the revised 1997 SIP before February 28, 1999, or if EPA does not approve the revised 1997 SIP before August 20, 1999, this Memorandum of Agreement shall terminate.

10. The City may establish a Joint Powers Authority or other appropriate entity as a mechanism to provide the water necessary to implement this Memorandum of Agreement.

11. Wherever in this Memorandum of Agreement actions are authorized by joint agreement of the parties, neither party shall be obligated to agree.

12. In this Agreement, the terms "Great Basin APCD" and "District" shall mean the Governing Board of the Great Basin Unified Air Pollution Control District.

Description of Best Available Control Measures

Shallow Flooding

The shallow flooding control measure will apply water to the surface of the areas of the lake bed designated for control by shallow flooding, in amounts and by means sufficient to achieve the following performance standard commencing on September 15 of each year, and ending on June 15 of the next year: 75% percent of each square mile of the designated areas shall continuously consist of standing water or surface saturated soil. Coverage shall be confirmed by aerial photography or other methods satisfactory to the District.

Between June 16 and July 31 of each calendar year, the City will supply, within the boundaries of the designated areas, water in amounts and locations adequate to maintain sources of food and water suitable for sustaining nesting and fledgling shorebirds, including western snowy plovers, nesting within the boundaries of those control areas or within ½ mile of their boundaries. If the control measure as implemented creates vegetation of the type and density used as wildlife habitat, the City shall supply water in amounts sufficient to maintain that vegetation in a state suitable for wildlife habitat during the period between June 15 and July 31 of each calendar year.

The City shall construct a berm keyed into the lake bed sediments along the lower boundary of each of the designated areas to minimize the transmission of excess water from the control areas toward the Owens Lake brine pool. The design and implementation of this berm will incorporate snowy plover crossings located at each 500 feet along the length of the berm, adequate in design to freely allow traverse of the berm by both snowy plover adults and chicks. Surface waters that reach the lower boundary of those control areas will be collected and recirculated for reapplication to the control areas. The control measure areas will have lateral boundary edge berms as necessary to contain waters in the control areas and to isolate the control measure areas from each other and from areas not controlled.

The City shall remove any exotic pest plants, including salt cedar ( Tamarix ramosissima), that invade any of the designated areas. As necessary to protect human health, the City shall avoid or abate mosquito breeding and swarming in the control areas by effective means that minimize adverse effects upon adjacent wildlife.

Managed Vegetation

In areas designated for control by the Managed Vegetation control measure, the City shall achieve coverage of at least 50% on each acre in substantially evenly distributed live or dead vegetation, as measured by the point-frame method. The vegetation shall consist only of locally-adapted native species or species approved by both the District and the State Lands Commission.

The following portions of the designated areas are exempted from the requirement of 50% vegetative coverage: (1) portions consistently inundated with water, such as reservoirs and canals, (2) roadways necessary to access, operate and maintain the control measure which are otherwise controlled to render them substantially non-emissive, (3) portions used as floodwater diversion channels or desiltation/retention basins, (4) portions set aside as Transmontane Alkaline Meadow (TAM) habitat restoration zone as may be required to mitigate environmental impacts associated with the loss of existing TAM.

The City shall remove any exotic pest plants, including salt cedar ( Tamarix ramosissima), that invade the control area. To the extent necessary to protect human health, the City shall avoid or abate mosquito breeding and swarming in those control areas by means which minimize adverse effects upon adjacent wildlife.

To protect the control measure from natural flooding, the City shall incorporate drains and channels in the control measure area adequate to divert the flood waters away from the vegetated areas and to outlet the flood waters into the Owens Lake brine pool (or reservoir(s), if any). The drains and channels shall be designed to incorporate features (such as desiltation/ retention basins) adequate to capture the alluvial material carried by the flood waters and to avoid greater than normal deposition of this material into the Owens Lake brine pool.

The City shall construct a berm keyed into the lake bed sediments along the lower boundary of the designated areas to minimize the transmission of excess water from the control area toward the Owens Lake brine pool. The design and implementation of this berm will incorporate snowy plover crossings located at each 500 feet along the length of the berm, adequate in design to freely allow traverse of the berm by both snowy plover adults and chicks. Surface waters that reach the lower boundary of the control area will be collected and recirculated for reapplication to the control area or other discharge. The control measure areas will have lateral boundary edge berms as necessary to contain waters in the control areas and to isolate the control measure areas from each other and from areas not controlled.

Gravel

Areas designated for control with gravel shall be covered with a layer of gravel at least four inches thick. All gravel material placed must be screened to a size greater than 3/8-inch in diameter. Where necessary to support the gravel blanket, it shall be placed over a permanent permeable geotextile fabric. The gravel shall have resistance to leaching and erosion. It shall be no more toxic than the gravel analyzed by the District from the Keeler fan site. It shall also be comparable in coloration to the lake bed soils.

To protect the control measure from natural flooding, the City shall incorporate drains and channels in the control measure areas adequate to divert the flood waters away from the graveled areas and to outlet the flood waters into the Owens Lake brine pool. The drains and channels shall be designed to incorporate features (such as desiltation/retention basins) adequate to capture the alluvial material carried by the flood waters and to avoid greater than normal deposition of this material into the Owens Lake brine pool. The gravel placement design and implementation shall adequately protect the graveled areas from the deposition of wind- and water-borne soil. The City will apply best available control measures (BACM) and New Source Performance Standard (NSPS) emission limits to its gravel mining and transportation activities occurring in the District’s geographic boundaries as required by the District in the City’s District-issued Permit to Construct and Permit to Operate.



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