Stabilization and Restoration of Owens Dry Lake California

Stabilization and Restoration of Owens Dry Lake California

Jim Jordahl, Ph.D.USEPA International Phytotechnologies Conference

Atlanta, GeorgiaApril 22, 2005

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)

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

implementation

Project LocationIntroduction

• Photo/map that shows location andsize of project

• CH and LADWP logos

Owens Lake, c. 1900

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

Owens Lake, CA

Owens Lake - An Environmental Problem of Epic Proportion

•110 square miles of dusty, saline, desert lakebed•Single largest source of PM10 in the U.S.•A very aggressive timeline for a solution

Salt crust covers the Playa from 50-100 years of saline shallow groundwater evaporation

Reduced, cracking, clay subsoil

Spring salt bloom on lakebed

Environmental Challenges

• High desert– ETo = 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

Railroad ties Railroad ties after years after years

on the playaon the playa

Challenges of working on Challenges of working on a a ““drydry”” lakebedlakebed

Extreme weathering and Extreme weathering and intensively corrosive intensively corrosive

environmentenvironment

Los Angeles Aqueduct

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 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

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

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.

Subsurface Drip Irrigated Saltgrass (Distichlis spicata)

Tillage and planting profile

Drip tubing

Transplant

Bed surfaceReclaimed zone

Depth of tillage

Fertilizer placement

Pre-plant roto-tillage

5 feet

Aqueduct

Saltwater

Shallow groundwater

MV SF* Ponds

Drains

Mix

* Habitat SF areas can be served with fresher water also.

Drainwaterand Tailwater

recyclingIrrigation (ETc +

leaching)

Irrigation Storage and

recovery

PercolationSeepage

Inflow

Irrigation (ET)

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

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

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)

Water Treatment and Fertigation

Saltgrass After Establishment

Vegetated Playa Surface

Vegetation in row exceeds 50% cover quickly

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

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