Dust Control at Owens Dry Lake

Presented to __________ by Ted Schade

_________, 2005

Great Great Basin Basin Unified Unified Air Air Pollution Pollution Control Control District District

What is the Main Source of PM-10 in the Southern Owens Valley?

In the late 1800s, Owens Lake, at about 110 square miles, was one of the largest natural lakes in California. It was a saline terminal lake with a salinity about 1½ that of seawater.

This photo, taken in 1891, from the eastern shore of Owens Lake near Keeler, shows the crest of the Sierra in the background.

(Collection of the Henry E. Huntington Library)

In 1913, the City of Los Angeles’ Department of Water and Power (LADWP) completed construction of the Los Angeles Aqueduct. The Aqueduct diverted Owens River water destined for Owens Lake 223 miles south to Los Angeles.

With the lake’s main source of water diverted, by the mid1920s, Owens Lake had shrunk to a small hypersaline remnant brine pool of about 40 square miles, but only a few feet deep.

The newly exposed bed of Owens Lake, with its unstable saline soils, began to emit large amounts of fugitive dust and has become the largest single source of particulate matter air pollution in the U.S. Currently, approx. 25 to 40 sq. mi. (16,000 to 26,000 acres) along the eastern shore of the lake bed emits dust on a regular basis.

The exposed Owens Lake bed showing wind eroded salt crust

The up-wind edge of a dust storm

Leading Edge of an Owens Lake Dust Plume 10

Dust storms originating from the dried bed of Owens Lake make it the largest single source of PM-10 air pollution in the United States. Great Basin estimates that the lake bed emits over 76,000 tons of PM-10 annually (almost 7,000 tons on a peak day.)

Two views of the Owens Valley from the same aerial vantage point – the top photo was taken on a calm day, the bottom photo on a windy day.

Why is the Dust a Problem?

Owens Lake Dust Descending on Inyokern, California (1977)

1. Because the PM-10 Values are Very High • The Federal 24-hr standard for particulate matter is 150 µg/m³. • The “significant harm to health” level is 600 µg/m³. • 24-hr levels of 3,900 µg/m³ (26 times Std.) have been measured in Keeler and 12,000 µg/m³ (80 times Std.) at Dirty Socks.

µg/m³

14,000 12,000 10,000 8,000 6,000 4,000 2,000 µg/m³ 0

24-hr

Sig. Keeler Dirty Harm Socks

2. Because Severe Exceedances are Frequent 1. Owens (3/1)

7915

2. Owens (5/19)

6505

3. Owens (4/17)

5166

4. Owens (4/14)

3089

5. Owens (6/9)

2962

6. Owens (11/25)

2638 2525

7. Owens (2/28) 8. Owens (4/15)

2295

9. Owens (11/26)

1785

10. Owens (11/7)

1745

11. to 25. Owens

777 to 1627

26. El Paso TX

590

27. Owens (1/29)

589

28. El Paso TX

534

0

2000

4000 µg/m³

6000

8000

The US EPA AIRS Data for 2002 show that of the highest 30 PM-10 days reported nationally, 28 occurred at Owens Lake. Owens Lake’s highest day of 7,915 was over 13 times higher than the highest non-Owens day (590 in El Paso, Texas).

How Will the Dust be Controlled?

1998 SIP In 1998, the District adopted a SIP that required the LADWP to control dust emissions from Owens Lake by the end of 2006. The 1998 SIP required that, within a 35 square mile envelope, 16.5 square miles of the lake bed had to be controlled by the end of 2003. It also required the District to continue to collect data on those areas of the lake bed that needed dust controls and revise the SIP in 2003 to incorporate the latest information.

Approved Dust Control Measures Great Basin’s research has resulted in three approved methods of controlling dust that are feasible on a large scale: native vegetation, flooding with shallow sheets of water and a gravel blanket.

Managed Vegetation Great Basin’s research indicates that if 50% of a dust producing area consists of live or dead vegetative cover, dust emissions will be reduced by 99%. Our research also determined that it takes approximately 7 acre-feet of water per acre to reclaim the saline soils and establish vegetation the first year. In subsequent years it takes about 2.5 acre-feet of water per year per acre to maintain the 50% vegetative cover necessary to control PM-10.

Saltgrass (Distichlis spicata) Saltgrass is attractive for use at Owens Lake because: • It is a locally adapted native species. • It is very salt-tolerant. • It spreads via underground runners and thus new growth is protected from wind damage. • It creates a surfaceprotecting mat. However, it is not particularly drought tolerant.

Great Basin’s early research developed techniques to reclaim saline soils and establish 50% vegetative cover with flood irrigation. This technique works on both sand and clay soils.

We also used micro-sprinklers to successfully establish saltgrass on sandy soils.

In order to reduce the total water demand, we are now exploring the use of drip irrigation to reclaim the soil and establish the plants.

This results in a pattern of nodes, instead of a meadow.

Native Vegetation Vegetation controls dust emissions by 99 percent when at least 50 percent of the surface is covered by plants. Saltgrass is the plant being used on the lake bed.

One of District’s Native Vegetation Test Plots

Shallow Flooding Shallow flooding controls dust emissions by releasing water from outlets spaced along the lake bed. When 75 percent of the emissive area consists of standing water and saturated soil, dust emissions are reduced by 99 percent.

Aerial photo of 12 sq. mi. shallow flood area completed by Los Angeles in December 2001. The flooded area is about 6 miles long by 2 miles wide.

Wildlife Attracted to Shallow Flood

What has the LADWP been up to since the 1998 SIP was adopted?

Phase 1 By the end of 2001, the LADWP had constructed about 14 square miles of shallow flooding on the northern portion of the lake bed and had begun flooding 10 mi² near Keeler.

Phase 2 By the end of 2002, the LADWP had constructed about 19.5 square miles of controls (15¾ mi² of shallow flooding and 3¾ mi² of managed vegetation) and was controlling dust from 13.5 mi² of lake bed. By the end of 2003, the LADWP is required to have dust control measures implemented on at least 16½ square miles of the lake bed.

Recent photo taken from the Space Shuttle showing the LADWP’s Owens Lake projects.

The LADWP has constructed two connections to the Los Angeles Aqueduct to provide water to the lake bed…

… and buried well over 200 miles of pipeline and drainline to distribute and collect water on the lake bed.

They have moved over 9 million cubic yards of earth to construct roads and berms…

… and constructed over 30 pumping and water treatment stations.

They have installed over 7,300 shallow flood bubblers…

…and 3,500 miles of drip irrigation tubing.

And finally, they collected seed, raised juvenile plants in greenhouses, planted and are encouraging over 27 million plants…

… to spread out on the formerly barren Owens Lake bed to control dust.

What has Great Basin been doing since the 1998 SIP was adopted?

Control Measure Research We have continued our research to make…

…the approved dust control measures more cost and water efficient.

Shown here are a Cox Sand Catcher, a Sensit and a solar-powered data logger.

The Dust ID Program uses on-lake equipment to determine where and when lake bed surfaces are active. Between January 2000 and June 2002, the Dust ID Program collected over 3 million data points.

In addition to collecting sand motion data, Great Basin staff also collects meteorological data, air quality data, we visually map dust plumes during dust storms (map shown here) and we map the boundary of disturbed lake bed areas after storms with GPS units. This data was used to refine the shapes of the lake bed areas that will require controls in order to meet the PM-10 Standard.

2003 SIP Revision Based on the results of the District’s research, we have determined that a total of 29.8 square miles of lake bed needs dust controls in order to meet the National PM-10 Standard. As 19.5 square miles have been constructed to date, the City will need to construct and have fully operational an additional 10.3 square miles before the end of 2006.

Provisions for Changes The District will continue to monitor air quality and lake bed dust activity. If new sources of dust threaten exceedance of the PM10 Standard, the SIP automatically requires the LADWP to install additional controls. In addition, after the Standard is met the LADWP may adjust the final configuration of measures in order to optimize water use.

By the end of 2006, the District expects that all identified dust control areas will have dust controls installed and functional and…

… the Owens Valley will be meeting the National PM-10 Standard.