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Pacific Southwest, Region 9

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Air Actions, California

NOTE: This content is no longer being updated. The most up to date information can be found in Federal Register Notices and Approved Air Quality Implementation Plans in Region 9.

Owens Valley, CA Particulate Matter Plan: History

Particulate Matter (PM-10) Planning Efforts


Under California law, the Great Basin Unified Air Pollution Control District has the authority to order the City of Los Angeles to undertake reasonable measures to mitigate the air quality impacts of water-gathering if the District shows, by substantial evidence, that the City’s water-gathering activities have caused or contributed to violations of state or federal air quality standards. In addition, the measures shall not affect the right of the City to produce, divert, store or convey water.

In 1987, the USEPA designated the Owens Valley Planning Area as non-attainment for the Federal PM-10 standards. In 1988, 1991, and 1994 the District submitted to EPA committal SIP’s describing how the District would develop and order the City to implement PM-10 control measures on Owens Lake, which was identified as the source of the standard violation. Each of those SIP’s projected that the measures would be developed at least by 1997 and the standard met by 2001. In accordance with section 189(b)(2) of the Clean Air Act, EPA established February 8, 1997 as the applicable deadline for submittal of a State Implementation Plan (SIP) for Owens Valley demonstrating reasonable further progress and expeditious attainment of the PM-10 standard.

Recent Events:

  • On February 8, 1997, the deadline to submit a serious PM-10 plan for the Owens Valley, the California Air Resources Board failed to submit a SIP.
  • On June 25,1997 EPA received a 60-day notice of intent to sue alleging that EPA had failed to perform its non-discretionary duty under the Clean Air Act to make a finding of failure to submit a SIP by the February 8, 1997 deadline. The notice was filed on behalf of two residents of Inyo County.
  • On August 20, 1997, a Finding of Failure To Submit a SIP was signed by EPA Regional Administrator, Felicia Marcus.
  • On December 10, 1998, EPA received the Owens Valley SIP from the State of California.
  • On February 2, 1999, EPA sent to the State of California a completeness review of the Owens Valley PM-10 SIP. The SIP submitted satisfied the completeness requirements of the Clean Air Act. This letter ‘shut-off’ the off-set sanctions clock that were to go into effect on February 20 as well as the highway funds sanctions that was scheduled for August 20, 1999. The FIP clock can only be ‘shut-off’ when EPA approves the SIP.

Number of People Affected by Owens Lake:

The District estimates that about 40,000 permanent residents live in the area affected by Owens Lake particulate emissions. Federal air quality standards (24-hour average of 50 ug/m3) are exceeded from Big Pine to Ridgecrest. The District has measured an Owens Lake dust storm that caused a 24-hour average PM-10 reading of 235 ug/m3 in Ridgecrest. The Navy has photographs showing 11 Owens Lake events during one year (April 96 through April 97) in the Ridgecrest area.

The Inyo National Forest Supervisor stated in an April 24, 1997 letter to the District that "The health of Forest visitors and employees as well as the numerous sensitive air quality related resources of the Inyo National Forest will benefit by the control of the Owens Lake dust and the attainment of the PM-10 standard." The Navy has been concerned about Owens Lake dust events since 1975, because the dust affects their ability to conduct tests at the China Lake Naval Air Weapons Station.

Control Measures:

The plan includes three control measures, each of which is designed to reduce emissions from the Owens Lake bed. They are shallow flooding, managed vegetation, and gravel cover. The following is a short summary of each of the measures.

1) Shallow Flooding

    • This control measure consists of releasing water along the upper edge of the Owens Lake bed and allowing it to spread and flow down-gradient toward the center of the lake. To attain the required PM-10 control efficiency, the District concludes that at least 75 percent of each square mile of the control area must be wetted to produce standing water or surface saturated soil, between September 15 and June 15 of each year. The District estimates that a maximum of 4 acre-feet of water is required annually to control PM-10 emissions from an acre of lake bed.
    • To maximize project water use efficiency, flows to the control area will be precisely regulated so that only the exact amount of water is released to keep the soil wet. Although the quantity of excess water will be minimized through system operation, any water that does reach the lower end of the control area will be collected along collection berms keyed into lake bed sediments and pumped back to the outlets to be reused.

2) Managed Vegetation

    • This control measure consists of creating a farm-like environment containing a mosaic of small (approximately 4- to 20-acre) confined fields constructed of saltgrass that are irrigated with shallow pulses of water. Saltgrass will be the only plant species introduced to the fields. It is tolerant of relatively high soil salinity, spreads rapidly via rhizomes, and provides good protective cover year-round even when dead or dormant. Saltgrass stands can subsist with minimal amounts of applied water during the summer and dust control effectiveness remains undiminished, provided that adequate irrigation has stimulated plant growth and has provided stored water in the rooting zone during the spring months. Biological, mechanical, and chemical control methods will be used to remove pest plants and noxious grasses.

3) Gravel Cover

    • A 4-inch layer of coarse gravel laid on the surface of the Owens Lake playa will prevent PM-10 emissions by:
    • Preventing the formation of efflorescent evaporite salt crusts, because the large spaces between the gravel particles interfere with the capillary forces that transport the saline water to the surface where it evaporates and deposits salts; and
    • Raising the threshold wind velocity required to lift the large gravel particles so that transport of the particles is not possible by wind speeds typical of the Owens Lake area. To prevent the loss of any protective gravel material into lake bed soils, a permeable geotextile fabric may be placed between the soil and the gravel where necessary.
    • Gravel areas must be protected from water, and wind-borne soil and dust. The gravel blanket will be the last control measure to be implemented in order to eliminate wind-borne depositions. Gravel areas will be protected from flood deposits with flood control berms, drainage channels and desiltation and retention basins, which will ensure that the gravel blanket will remain an effective PM-10 control measure for many years.

Additional Measures:

In addition to these three control measures, the City of Los Angeles is authorized to implement one or more control measures of its choosing on 3.5 square miles of the lake bed in the "Dirty Socks" area. The controls placed in this area may be one of the three identified measures, modified versions of these measures, or other unidentified measures. The control measures placed in this area do not need to be approved by the District. However, the City is responsible for assuring that the PM-10 emissions from the Dirty Socks area are reduced sufficiently such that the controls implemented in this area can be integrated into an entire control strategy that meets the PM-10 NAAQS by December 31, 2006. The Demonstration of Attainment adopted by the Great Basin Board on July 2, requires the City to implement a combination of shallow flooding (51,000 acre feet of water per year), managed vegetation (salt grasses), and gravel (1,000,000 cubic yards) on 35 square miles of Owens Lake that has been identified by the District as the most frequent source of PM-10 emissions.

Public Process:

The District has participated in a long and public process to identify Owens Lake as the major source of particulates in Owens Valley, to study and identify possible control measures, and to choose the measures presented in the SIP. The City has been an active participant in this process since 1979.

Owens Lake was first identified as a source of large dust storms in 1975 by scientists at the China Lake Naval Weapons Center. In 1979, after receiving a large number of complaints from the public, the Inyo County Board of Supervisors passed Resolution 79-43 requesting the District to "take whatever steps are necessary to abate said hazard". On September 5, 1979 the Southeast Desert Basin wide Air Pollution Control Council identified Owens Lake as a local and regional air pollution problem and recommended that the State Lands Commission (SLC), the owner of the lake, and the District work on "developing and instituting sufficient measures to control this regional air quality problem."

The Owens Dry Lake Task Force was formed on August 23, 1979 to begin addressing the problem. The membership included the District, Inyo County, the City of Los Angeles Department of Water and Power (LADWP), the China Lake Naval Air Weapons Station (NAWS), Mono County, Kern County, SLC, Bureau of Land Management, U. S. Soil Conservation Service, the Inland Counties Health Systems Agency, Lake Minerals Corporation, and several public members. State Senator Stiern and Assemblyman Wyman introduced Senate Bill 1591 to fund the first tests on the lake bed. This $250,000 appropriation resulted in the Phase I report. State Lands Commission was project manager for that project. The Management Committee of the Task Force consisted of SLC, LADWP, NAWS and the District.

In 1983, the City of Los Angeles began funding tests under Health and Safety Code Section 42316. Every annual assessment has been negotiated with City representatives, and each year items suggested by the District have been eliminated from the budget after objections were voiced by the City. In the 12 years during which the current District staff has been involved in developing these budgets, the City has never asked for tests to be added. Each assessment has been the subject of a noticed public hearing before the California Air Resources Board.

In 1984 Assemblyman Wyman introduced AB3762 which appropriated $150,000 from the Environmental License Plate Fund for continued research on Owens Lake under the control of the Task Force. The City of Los Angeles and the Naval Weapons Center also each contributed $75,000, and the City was project manager for the Phase II Sand Fence Study which was concluded in 1988, with the Final Report delivered to the City in December 1991. An LADWP staff member was Task Force Chairman.

On December 14, 1988 the District held a public hearing on the first Owens Valley State Implementation Plan. Thirteen dust control measures were presented: shallow flooding, sprinkling, leaching, vegetation, lowering the water table, gravel, tires, chemical modification, chemical treatments, sand fences, tree rows, compaction, and algae mats. The 1988 SIP committed to further study. The City was not required to implement any controls.

In 1990 the State of California contributed $1.5 million over 3 years to fund additional testing. The City of Los Angeles voluntarily contributed $500,000 as matching funds. The District was project manager for Phase III. The City was closely involved in the decision that sprinklers were not a reliable control measure on the sandy soils , that the Davis sand fence study did not follow the agreed-upon protocol, and that sufficient pre-construction monitoring data had been collected on the North Flood Irrigation Project.

In 1991, the Owens Dry Lake Task Force became the Owens Lake Advisory Group, with membership offered to all interested parties. The Owens Lake Advisory Group now consists of over 100 individuals and about 170 public agencies and private companies, and generally has met twice a year. At the Fall meeting, the District reports on test results over the summer season and project proponents present their proposals to the Group for comment. At the Spring meeting, the District reports on what projects it has proposed to be funded for the next summer season, and takes comments from the members. Also in the same year, the District held a public hearing on the second Owens Valley SIP, and again outlined further studies. The City was not required to implement any controls.

In 1994, the District held a public hearing on the third Owens Valley SIP, and identified BACM as shallow flooding, vegetation, and sand fences. The SIP committed to further study. Again the City was not required to implement any controls.

In 1996, in order to assist the District Board in choosing reasonable control measures to propose in the Draft SIP and EIR, the District developed the Owens Valley PM-10 Planning Area Demonstration of Attainment State Implementation Plan Project Alternatives Analysis (PAA). This document described the effectiveness, technical feasibility, and environmental impacts of eight potential control measures (shallow flooding, vegetation, managed vegetation, tilling, salt flats, refilling the lake, gravel and sand fences), and the reasons for not considering seven other potential control measures (compaction, salt composition modification, chemical stabilizers, sprinklers, lowering the groundwater table, tires and other waste materials, and riparian corridors). Three public meetings and a public hearing were held to solicit public input on the choice of the measures to be considered in the Draft SIP and EIR. The City attended and actively participated in all four opportunities for public comment.

Based on the above analysis of cost-effectiveness, dust-control effectiveness, technical feasibility, water availability, and environmental impacts, District staff has concluded that shallow flooding, managed vegetation, and gravel (as required by the Attainment Demonstration SIP) are reasonable control measures for the dust-producing areas on Owens Lake. On July 2, 1997, Great Basin Unified Air Pollution Control District after notice and a public comment period, passed their proposed SIP. This was challenged at the State level by the City of Los Angeles. On June 25,1997 EPA received a 60-day notice of intent to sue alleging that EPA had failed to perform its non-discretionary duty under the Clean Air Act to make a finding of failure to submit a SIP by the February 8, 1997 deadline.

On August 20, 1997, a Finding of Failure To Submit a SIP was signed by EPA Regional Administrator, Felicia Marcus.

Starting in September, 1997 and concluding in June, 1998, the District along with the City of Los Angeles and LADWP, CARB, State Lands Commission and EPA (as an observer only) held meetings to resolve LA's objection to the District's July 2, 1997 SIP. In July 1998, an agreement was reached. Though not very different for the original July 2, 1997 SIP, the new agreement provided flexibility for the City of Los Angeles to apply control measures on the Owens Lake bed and monitor the results. The City believes that an area smaller that the 35 mile control area called for in both the old and new SIP will in fact meet the PM-10 NAAQS. For this flexibility, the District commits to revise the SIP in 2003 to implement additional controls if necessary to attain the NAAQS by 2006 if the City of LA's plan to control only 22.5 square miles fails. Should the District determine that the area will not attain the PM-10 NAAQS by 2006, it will order the City to implement the necessary additional control measures (additional square miles).

On November 16, 1998, the Governing Board of the Great Basin Unified Air Pollution Control District unanimously adopted the 1998 Revision to the Owens Valley PM-10 SIP, and on December 10, 1998, it was adopted by CARB for submittal to EPA.

For more information:

Please contact Larry Biland of the Air Planning Office at (415) 947-4132 or biland.larry@epa.gov.

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