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Grand Prize - Environmental Sustainability

Los Angeles Aqueduct - Owens Lake Environmental Protection and Dust Mitigation

Entrant: Los Angeles Department of Water and Power
Engineer in Charge: James G. Yannotta, P.E.
Location: Los Angeles, California
Media Contact: James G. Yannotta, P.E.

Entrant Profile

The Los Angeles Department of Water and Power (LADWP), the largest municipal water and power utility in the nation, serves water and electricity to nearly 4 million residents and businesses in the City of Los Angeles (City). Historically, the City's water supply comes from several sources: local groundwater and imported water from the Los Angeles Aqueduct, State Water Project, and the Colorado River Aqueduct. These supplies have been significantly impacted by environmental factors, climate change, and increasingly frequent droughts.

LADWP is proactively addressing these challenges by pursuing the goals of Los Angeles' Sustainable City pLAn (pLAn). LADWP is aggressively expanding water conservation, stormwater, and recycled water supplies. The development of these drought-resilient, local supplies will help achieve the pLAn's ambitious water supply goals of:

Reducing imported water purchases by 50 percent by 2025;
Expanding local water sources to 50 percent of total supply by 2035; and
Reducing per capita water use by 20 percent by 2017, 22.5 percent by 2025, and 25 percent by 2035.

The Owens Lake Program represents an extraordinary commitment and effort to address environmental challenges that are the legacy of historical water gathering. By meeting these challenges, LADWP balances the continued beneficial use of critical surface water supplies while maintaining a sustainable environment for people and habitat. Preserving this supply in a sustainable manner is critical to ensuring a reliable water supply for the residents and business of Los Angeles.

Project Background

The Los Angeles Department of Water and Power (LADWP) is implementing the largest dust mitigation effort in the United States, the Owens Lake Program, to mitigate wind-borne particulate matter of 10 microns in diameter (PM10 or "dust") from the exposed bed of Owens Lake, improve air quality in the Owens Valley, and protect the health and safety of surrounding communities and habitat. Since 2000, LADWP has invested more than $2 billion to successfully mitigate 99% of the dust from a 48.6 square-mile area of exposed lakebed.

The Los Angeles Aqueduct (LAA) remains an engineering marvel that provides water to millions of people. For over 100 years, the LAA has helped create the second largest city in the United States and preserved Owens Valley in a natural state. However, diverting water from the Owens River, first by farmers in the Owens Valley and then by the City of Los Angeles (City), contributed to the lake shrinking and the lakebed becoming exposed.

The Owens Lake Program represents extraordinary commitment and effort to address environmental challenges that are the legacy of historical water gathering. These challenges are addressed to balance the continued beneficial use of critical surface water supplies and a sustainable environment for people and habitat. As climate change impacts become apparent, agencies like LADWP are working to diversify their water-supply portfolios to promote a more sustainable, reliable water supply by developing local supplies, such as groundwater, recycled water, captured stormwater, and conserved water. Figure 1 depicts the City's planned water supply portfolio in 2040 and reflects reduced reliance on purchased imported water from the State Water Project and Colorado River. These supplies are increasingly unreliable due to aging infrastructure, prolonged drought, climate change, and increased demand.

Integrated Approach

The Owens Lake Program uses a balanced approach and adaptable framework to meet multiple goals, including dust mitigation to achieve air quality and reduce public health risk; habitat value protection and maintenance; public trust value enhancement; cultural resource protection; and water use reduction through efficient dust mitigation measures.

For example, Phase 7a included the installation of 3.4 square miles of water-efficient dust mitigation. A Habitat Suitability Model (HSM) was developed for six different groups of focal species to quantify the amount and quality of existing habitat value in the Owens Lake area. The HSM provides information regarding necessary conditions to maintain habitat baselines and can be used for future projects to balance habitat value with dust mitigation and water conservation.

Utilizing the HSM, LADWP found that preferred habitat conditions require less water than is currently used. As such, LADWP is able to implement dust mitigation while decreasing water use and meeting all environmental goals.

Quality

To achieve Program goals, LADWP coordinated and consulted with technical experts from various environmental fields and design disciplines. LADWP also maintains quality through the use of inspectors of various disciplines to inspect all work, performance of environmental monitoring, and adherence to protocols for environmental protection, including for nesting birds and cultural resources. LADWP's extensive monitoring, analysis, and review aims to successfully mitigate dust and meet goals for air quality within regulatory deadlines, while balancing environmental resource protection and water savings goals.

Originality and Innovation

For the Program, LADWP implemented not only conventional, approved dust-control measures, such as shallow flooding and managed vegetation, but, where possible, also innovative methods that addressed the goal of utilizing water-efficient control measures.

In November 2014, LADWP and the Great Basin Unified Air Pollution Control District reached a historic agreement regarding remaining dust mitigation measures and methods that enabled the replacement of shallow flooding with alternative dust mitigation techniques.

As a result, LADWP was able to apply the alternative of Tillage with Best Available Control Measure Back-up (TwB2) to 3.2 square miles. TwB2 requires no water and costs less than traditional methods. The resulting water savings was 8,600 AFY, which is approximately 1.5% of the City's annual water demand. The 2017 cost of buying a comparable volume of untreated water from MWD at Tier 1 rates would have been about $6.1 million.

LADWP continues to work towards optimal, integrated solutions as it moves forward with the Program. Future improvements will rely on important experiences and innovations developed during Program implementation to transition to waterless and water-wise solutions at Owens Lake.

Complexity

The large scope of dust mitigation at Owens Lake is a continuing challenge. For the Program, LADWP installed one of the world's largest shallow-flooding systems, consisting of a network of automated shallow-flooding infrastructure across more than 30 square miles of lakebed. The overall dust mitigation system includes over 60 miles of pipelines and 2,000 miles of buried drip irrigation lines.

Program development and implementation has been challenging due to the complexity, intricacy, and magnitude of the Owens Valley region. Geography-related challenges include adverse and extreme weather, and soft and corrosive soils. Protecting cultural resources and managing conflicting stakeholder interests has also provided challenges.

Social and Economic Advancement

Through the implementation of water-efficient dust mitigation measures, the Program assists LADWP in diversifying its water supply portfolio and reducing reliance on purchased imported water from the State Water Project and Colorado River, which benefits the state and the region.

The Program also includes the Owens Lake Trails Project, which now provides facilities for public access, recreation, and education, including information kiosks, trails, and a Plaza overlook of the highest-value habitat. During peak migration, over 75,000 birds have been observed utilizing Owens Lake in a single day. By creating viewing areas, the Program provides a unique recreational experience and promotes local tourism.

Click images to enlarge in separate window.


Historic photo of Los Angeles Aqueduct construction.	Water flowing from the Los Angeles Aqueduct.

Dust storm on Owens Lake before dust mitigation implemented.	Owens Lake exposed lake bed shown as the dark red spot.

Dust mitigation measure: shallow flooding.	Dust mitigation measure: Gravel.

Dust mitigation measure: Managed native vegetation.	Dust mitigation measure: Tillage with Best Available Control Measure Back-up (TwB2). TwB2 is a waterless dust mitigation method.

Construction of dust mitigation and habitat features.	After construction of dust mitigation and habitat features.

Waterfowl and shorebirds in Owens Lake shallow flooding pond.	Western Sandpiper foraging in Owens Lake shallow flooding pond.

Owens Lake Trails (Phase 7a): Grand Opening at the Plover Wing Plaza.	Owens Lake Trails: Plover Wing Plaza shade structure and interpretive panel.

Owens Lake Trails: Visitor information kiosk at entrance to Owens Lake dust control.	Owens Lake Trails: Interpretive panel at the main parking area and trailhead.

Owens Lake Trails: Recently constructed habitat island for shorebirds.	Owens Lake Trails: Plover wing plaza and adjacent habitat with wave features.