Stabilization and Restoration of Owens Dry Lake California

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1 Stabilization and Restoration of Owens Dry Lake California Jim Jordahl, Ph.D. USEPA International Phytotechnologies Conference Atlanta, Georgia April 22, 2005

2 Acknowledgements John Dickey, Maurice Hall, Mark Madison, Jason Smesrud, Quitterie Cotten, Mica Heilman, Greg Roland, Richard Coles, Kevin Burton (CH2M HILL) Margot Griswold (Earthworks) Richard Harasick, Thayne DeVorss, and Ray Prittie (Los Angeles Department of Water and Power)

3 Outline Project location and history Agronomic and engineering challenges Dust control measure description and implementation

4 Project Location Introduction Photo/map that shows location and size of project CH and LADWP logos

5 Owens Lake, c. 1900

6 Owens Lake History 1850 s to 1908: Owens Valley water developed for irrigated agriculture reducing inflow to the lake 1913: Los Angeles Aqueduct begins export of Owens River flow to Los Angeles nearly eliminating inflow 1930: Much of 110 sq. mi. (28,490 ha) lakebed area exposed 1972: Clean Air Act 1980: Owens Dust problem linked to LA water exports 1997: MOA between LA and GBUAPCD establishes time frame for dust control 2001: First 10 sq. mi. (2,590 ha) of dust mitigation operated Today: 19 sq. mi. (4,920 ha) constructed, 10 sq. mi. (2,590 ha) more by 2006

7 Owens Lake, CA

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9 Owens Lake - An Environmental Problem of Epic Proportion 110 square miles of dusty, saline, desert lakebed Single largest source of PM 10 in the U.S. A very aggressive timeline for a solution

10 Salt crust covers the Playa from years of saline shallow groundwater evaporation

11 Spring salt bloom on lakebed Reduced, cracking, clay subsoil

12 Environmental Challenges High desert ET o = 62.1 precipitation = 5.4 (inches/year) Hot summers, frozen winters Shallow groundwater (4X seawater) Soils (avg. 160 ds/m) Winds and mobile sand Sensitive shorebird spp. Large stormwater flows

13 Challenges of working on a dry lakebed Railroad ties after years on the playa Extreme weathering and intensively corrosive environment

14 Los Angeles Aqueduct

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16 MV control mechanism: Stabilizes and protects land surface Slows surface wind velocity Ties up mobile sand MV specifications: Saltgrass (Distichlis spicata) stands 50% of each acre covered in vegetation (live or dead) MV pluses: 1 to 2.5 feet of water/year Stable once established Less ancillary habitat than SF MV challenges: Extreme environment requires cutting edge farming, increases risk Soils and Groundwater Extreme chemistry Waterlogging, cementation Requires saltwater recycling Planting material not readily available Higher capital costs Drainage and recycling Saltgrass propagation Construction in difficult areas

17 Subsurface drip irrigation network Why subsurface? More efficient water use Minimizes drainage loads Less prone to damage and displacement from thermal expansion, roaming cattle, vertebrate pests, sunshine, wind, and stormwater Stable temperature reduces scaling and associated plugging risk Mobile sand on the Playa will result in portions becoming buried anyway Mechanized transplanting is feasible.

18 Subsurface Drip Irrigated Saltgrass (Distichlis spicata)

19 Tillage and planting profile Pre-plant roto-tillage Transplant Drip tubing Reclaimed zone Bed surface Depth of tillage Fertilizer placement 5 feet

20 Aqueduct Mix Irrigation (ETc + leaching) Drainwater and Tailwater recycling Irrigation (ET) MV SF* Ponds Irrigation Storage and recovery Saltwater Drains Inflow Percolation Shallow groundwater Seepage * Habitat SF areas can be served with fresher water also.

21 Drainwater Reuse Drivers Economic: LAA water value is at a premium (approximately $7M to $24M per year in water cost) Soil Management: LAA water is not saline enough to prevent soil dispersion and structural collapse of the highly sodic lakebed soils Regulatory: The project is permitted with zero-discharge requirements

22 Drainwater Collection and Reuse System Subsurface drainwater collected from managed vegetation fields is pumped into a dedicated drainwater conveyance system Freshwater and saline drainwater are blended to an EC of 9 ds/m at irrigation turnouts Excess saline drainwater is directed to shallow flooding dust control areas

23 Blended Drip Irrigation Water Quality Objectives Sand media filtration / secondary screen Adjust water chemistry to avoid emitter plugging by biological growth, mineral precipitation, or root intrusion Phosphonate scaling inhibitor Trifluralin NaOCl NaBr Fertilization (fertigation)

24 Water Treatment and Fertigation

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27 Saltgrass After Establishment

28 Vegetated Playa Surface

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30 Vegetation in row exceeds 50% cover quickly

31 Conclusions Reuse of very saline water in an extreme environment is possible with the appropriate consideration of: soil and crop upper and lower salinity limits irrigation water quality management in the conveyance system corrosion control of irrigation and drainage equipment

32 Conclusions Shallow flooding areas nearly 100% compliant, covering about 15.7 square miles 1,173 acres (49%) of the saltgrass area was compliant (50% cover) after 2 growing seasons Compliance calculations originally ignored strips of compliant vegetation in rows, taking an area average 2,240 acre site (saltgrass) contributed little dust to storms in that region of the lakebed