5

Addressing Current and Future Management Challenges with a Systems Approach

Chapters 2 and 3 present the complex context of air quality, water resources, and cultural and environmental factors that affect decisions at Owens Lake. Chapter 4 describes many current and potential dust control measures (DCMs), but no single measure meets dust control requirements while substantially reducing water use (compared to the shallow flooding Best Available Control Measure [BACM]) and consistently providing moderate- or high-value habitat on the lakebed. Meeting the broad goals for Owens Lake will instead require an integrated systems approach to dust control. This chapter outlines a systems approach to address current and future challenges.

MANAGEMENT FOR MULTIPLE GOALS

Management goals at Owens Lake have shifted substantially over time, with the evolution of regulations and societal values. In the early 1900s, the water of Owens Valley and Owens Lake was viewed by many as a resource to support the growing city of Los Angeles. The desiccation resulted in the region around the lake having the highest concentrations of particulate matter 10 micrometers or less in diameter (PM₁₀) in the United States. Decades after Owens Lake was drained, the U.S. Environmental Protection Agency (EPA) and California air quality standards mandated dust control efforts. The Los Angeles Department of Water and Power (LADWP) and the Great Basin Unified Air Pollution Control District (the District) developed dust control approaches, which LADWP implemented in phases, each with strict compliance time frames. These dust control efforts have greatly reduced PM₁₀ emissions at Owens Lake, although additional progress is needed to meet both federal and state air quality standards (see Chapter 2).

The current dust control approaches are largely engineered approaches, and most require ongoing inputs of energy and resources, such as water or labor rather than the creation of a

system that is self-sustaining over the long term. Even the managed vegetation BACM was designed as an engineered system—a monoculture that requires perpetual groundwater drainage and irrigation. Now that PM₁₀ emissions have been reduced over large portions of the lakebed, LADWP management strategies are evolving toward those that conserve resources, particularly water. Owens Valley water is projected to become an increasingly important portion of LADWP’s future water supplies (see Chapter 3).

Shallow flooding, a water-intensive DCM, is used on nearly 30 square miles of Owens Lake, representing 62 percent of the lakebed area that is currently controlled (see Figure 1-4). As discussed in Chapter 3, shallow flooding created extensive habitat for water birds. Owens Lake, is now one of the most important breeding sites in California for the Snowy Plover (Oring et al., 2000) and provides critical habitat for diverse bird species along the Pacific Flyway, hosting more than 100,000 birds during the spring and fall. This development has regional to global conservation implications, because migrant shorebirds rely almost exclusively on saline lakes in the Western United States, which are overexploited for their water. Those bird populations in the Great Basin have decreased by 70 percent since 1973, and population declines are likely to continue because of increasing human water use and climate change. By 2050, it is projected that most Great Basin waterbirds will have lost more than one-half of their habitat to climate change, and their remaining habitat will be less conducive to successful breeding because of shorter inundation seasons and higher-salinity water (Haig et al., 2019). On Owens Lake, the California Department of Fish and Wildlife requires no net loss of aquatic habitat functions, values, and acreage, based on the 2008 dust control areas, and that 1,500 acres (2.3 square miles) be specifically managed to protect shorebirds and the Snowy Plover (LADWP, 2010), underscoring the importance of considering how efforts to reduce water use might affect habitat functions and values.

Other objectives affect lakebed management decisions, such as consistency with public trust values, as determined by the California State Lands Commission, the main landowner. For example, the commission opposed moat and row as a DCM for its unnatural aesthetics that compromised the viewshed.¹ For currently uncontrolled areas, many of the dust control efforts require extensive land disturbance, which could destroy artifacts and landscape features that are important cultural resources for Native American tribes.

Managing for multiple goals is challenging. Even when solely focused on conservation goals, there can be direct tradeoffs in managing different ecosystem services (Raudsepp-Hearre et al., 2010) or in managing species diversity and certain ecosystem services (Chan et al., 2006). Balancing management for multiple goals can be particularly challenging when optimization of one goal (e.g., diversion of water to Los Angeles) occurs at the

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¹ The moat and row DCM does not require the addition of supplemental water to reduce dust emissions from the lakebed. Moat and row consists of an array of earthen berms (rows) about 5 feet high above the lakebed surface with sloping sides, flanked on either side by slope-sided ditches (moats) about 4 feet deep. Sand fences up to 5 feet high are placed on the row tops to increase the effective height of the rows (GBUAPCD, 2008).

expense of another (e.g., shorebird habitat). Management at Owens Lake over the past few decades has been primarily focused on the goal of dust control, which may have inadvertently increased these tradeoffs and limited the ability of the current patchwork of management approaches to address multiple goals. Multiple goals are more effectively achieved when there is deliberate co-management across the goals from the outset (Chan et al., 2006; Fremier et al., 2013; Raudsepp-Hearre et al., 2010). No single dust control approach addresses all management goals and community priorities, but collectively, the goals can best be met lake-wide by coordinating across parcels. This coordination requires project-wide planning that determines where progress toward each goal can be maximized without compromising the progress at adjacent control areas (Chan et al., 2006; Fremier et al., 2013).

By necessity, dust control implementation at Owens Lake occurred in phased projects on strict timelines, rather than through integrated lakebed-wide planning. This lack of lake-wide planning can limit the effectiveness and efficiency of specific DCMs. For example, gravel areas can become emissive following the deposition of dust emitted from adjacent areas (e.g., managed vegetation that is not fully established). As another example, shallow flooding areas can raise levels of saline groundwater in neighboring managed vegetation areas, leading to plant mortality, if not carefully controlled.

Lake-wide planning approaches will become critical with climate changes, as temperature and evaporation rates increase and precipitation becomes more variable, with increased floods and droughts. For example, climate change will make Owens Lake even more important for conservation of shorebirds, but decreased water use for dust control to conserve water resources will necessarily decrease the size of habitat. Lake-wide planning efforts can explicitly identify high-priority locations for water use for habitat management, while targeting the remaining areas as priorities for dust management with decreased water use.

Although large investments have been made in DCMs on Owens Lake to date, an important opportunity for long-term lake-wide planning now exists for several reasons. LADWP’s stated objective of decreased water use will necessitate broad-scale changes and integrated planning across multiple goals. In addition, infrastructure is aging and may soon require replacement. Now that many previously emissive areas are meeting dust control requirements, the opportunity exists to conduct lake-wide planning that could reduce water use and improve long-term outcomes. An integrated landscape-based planning approach can take into consideration and take advantage of the recognized spatial variability of the soil textures, depth to shallow groundwater, and salinity, among other factors, to enhance dust control operations. This integrative landscape approach would also reduce maintenance requirements and costs by siting DCMs where they are most appropriate on the lakebed, taking advantage of the most suitable hydrology, soil, groundwater depth, and salinity for specific dust control strategies.

WHAT IS A SYSTEMS APPROACH?

Ecosystem and landscape ecology provide key principles for ecosystem management that are relevant to the development of a long-term systems approach for dust control at Owens Lake, particularly when balancing the multiple objectives of dust control, habitat creation and conservation, and reduced water use. The key components include the following (Biggs et al., 2012; CBD, 2004; Chapin et al., 2009; Christensen et al., 1996; Clark and Jupiter, 2010; Dale et al., 2000; Seastedt et al., 2008):

• Management of multiple goals, with explicit recognition of tradeoffs and synergies across multiple goals;
• Understanding of the key factors that contribute to each goal, with long-term planning and management focused on developing self-maintenance of these factors, where feasible;
• Adoption of suitable goals and practices based on local conditions;
• Management at the scale/size of the processes that control management goals, and consideration of the landscape configuration of patch types;
• Consideration of temporal scale and variations; and
• Management for resilience.

In the sections below, each of the principles is discussed, including how each can be addressed at Owens Lake as part of a lake-wide, integrated dust management approach.

Management of Multiple Goals

Balancing multiple goals at Owens Lake (e.g., goals related to dust emissions, habitat provisioning, water use, and protection of cultural resources and the viewshed), particularly under a changing climate and decreased water availability, warrants an integrative systems approach to minimize tradeoffs. At the level of an individual dust control area, decreases in water use will necessarily compromise the specific habitat provided by that water. However, the broad ecological effects can be minimized, if water use on the lakebed is prioritized toward sustaining the most valuable, regionally rare habitat, allowing reductions in water use for dust control on other areas of the lakebed.

Development of an integrative, long-term strategy for dust control that meets multiple goals while reducing tradeoffs necessitates an assessment of various dust control configurations as a lake-wide system. Evaluations of alternative configurations should be informed by spatially and temporally explicit priorities, developed through multiple agency and stakeholder collaboration. This process includes identifying priorities that are specific enough to manage. For example, current habitat modeling focuses on habitat for specific bird guilds, without a priority for habitats that are unique along avian flyway corridors or regionally rare.

Roberts et al. (2016) recommends prioritization of management of shorebirds, because their regional conservation is most dependent on the regionally rare habitats provided by Owens Lake.

Systems analysis across multiple goals needs to be supported by a better understanding of the interactions among air quality, wind dynamics, landscape conditions, protection of cultural resources, hydrology, salinity, and the ecology of the system, including the regional significance of habitat types and other ecosystem services in the Owens Valley. Research is also needed on the spatial and temporal factors that affect performance, the effects of adjacent DCMs, and the resilience of various DCMs under a range of conditions (see Chapter 4).

Once a long-term, integrative strategy is developed, it will need to be implemented in phases as DCM infrastructure needs replacement or as opportunities emerge to implement water-conserving measures. Transition of dust control management approaches is currently limited to 3 square miles at any time, which will limit the rate at which more integrated lake-wide dust management can be implemented.

Understanding and Planning for the Key Factors That Affect Attainment of Multiple Goals

A principle of managing for resilient ecosystems is identification of conditions that will fundamentally alter the system and its ability to persist (Biggs et al., 2012; Seastedt et al., 2008). This same principle applies to long-term dust management at Owens Lake, which will benefit from strategies that have the capacity to self-maintain, where possible. As discussed in Chapter 4, long-term salinity accumulations need to be avoided to ensure the continuing performance of managed vegetation sites, and the food webs in the shallow flooding areas that support large bird populations. The effect of climate change on managed vegetation, precision surface wetting, and shallow flooding operations needs to be understood (see Chapter 4), including the effects of higher evaporation rates on water demand and the availability of water supplies to meet that demand under future projected conditions. In a desert landscape where all ecosystems are critically dependent on water, future planning will also necessitate an understanding of the effects of changing water application on Owens Lake habitats and implications within the larger Great Basin ecosystem and beyond. Two examples of understanding thresholds for DCMs are discussed in the following sections.

Shallow Flooding and Its Effects on Avian Habitat

The California Department of Fish and Wildlife requires no net loss of riparian or aquatic habitat functions, values, and acreage, based on the 2008 dust control areas. LADWP must also manage at least 523 acres (0.82 square miles) at Owens Lake for Snowy Plovers and 1,000 acres (1.56 square miles) for shorebirds, in general, because of the importance of saline lake habitat to the conservation of these species throughout the western United States (Haig et al. 2019; LADWP, 2010). A habitat suitability model is used at Owens Lake to

assess which specific control areas meet guild-level habitat needs, thus facilitating planning decisions on the depth and areas of flooding and the allowable water salinity of those ponds. The model assesses the suitability of habitat for the different guilds based on salinity, water depth, seasonality/stability of water availability, vegetation, size of dust control area, and microtopography. LADWP is studying habitat suitability, rather than species populations, because bird populations and migrations are affected by many factors that extend far beyond the geographic scope of Owens Lake.

However, assessments of habitat quality based on habitat suitability models are often poorly linked to population health or performance because they fail to consider spatial variation and temporal changes in communities and environmental factors and how individual species react to multiple interacting factors (Seoane et al., 2005; Stauffer, 2002; Tirpak et al., 2009). Shorebirds are diverse, with species differing in salinity tolerance and preferred foraging habitats that range from dry surfaces to deeper ponds, and a guild-wide approach does not necessarily provide habitat for any given species (Roberts et al., 2016). If water use is constrained through natural variability or policy choices, management practices explicitly matched to the conservation needs of priority species are more likely to be successful compared to generic habitat characteristics that do not necessarily support any given species. Expert reviews on the bird Habitat Suitability Model suggested a suite of guidelines for improvement (see Box 5-1). Key recommendations that could provide additional flexibility in Owens Lake dust management decisions include weighting species by their conservation priority (rather than giving each bird guild equal weight), improving assessments of habitat (by including more direct measures of habitat features in both monitoring and modeling), and clarifying the relationship between dust control area size and habitat area.

Self-Sustaining Vegetated Habitat for Dust Control

The majority of Owens Lake is being managed by dust control approaches that are highly engineered. Although they may be effective at dust control, many BACMs require substantial ongoing maintenance, periodic infrastructure replacement, and significant inputs of water (Robinson, 2018). Increased use of self-sustaining systems for dust control would decrease long-term costs associated with energy, water, labor, and materials. DCMs, such as natural artificial roughness and shrubs, could provide habitat with little maintenance or water requirements. Persistence of managed vegetation across the range of lake conditions and in a variable and changing climate necessitates genetic and species diversity. Current efforts at Owens Lake recognize the importance of this approach, because the use of shrubs are being explored and more species and community types have been added to the managed vegetation BACM (see Chapter 4). Consideration of the core needs of managed vegetation includes carefully taking into account the location of managed vegetation, as discussed in the next section.

Development of more self-sustaining systems at Owens Lake would likely benefit from more flexibility in regulations. Recently, managed vegetation BACMs that were establishing, but did not meet the targeted percent cover in year 3, were converted to shallow flooding. If these BACMs were sited in areas that were not suitable to their long-term success, conversion to another BACM is the proper decision. However, the short time frame for establishing performance criteria is likely decreasing opportunities to create self-sustaining dust control systems.

Suitable Goals and Practices Based on Local Conditions

A key to successful long-term sustainable management of ecosystems or dust control systems is the setting of goals and approaches that are compatible with the natural conditions of the landscape, considering variability and potential limitations. Managers at Owens Lake have developed a site-specific understanding of which types of management are successful at which types of sites. For example, tillage is more effective in clay soils, which produce clods that are more resistant to erosion. Spatial designs that “let the lake be what it wants to be,” with brine pools toward the center and vegetation concentrated along the higher elevation areas, would require lower amounts of water and less intensive drainage and pumping system. Further incorporation of the existing spatial variability and spatial structure of the lakebed conditions, (e.g., depth to groundwater, topography, soils) into dust control design will lead to improvements in dust control efficiencies and reduced costs. Such strategies are essential for the development of long-term self-sustaining systems.

One example of a promising approach is the restoration of native vegetation on the less saline areas of the playa, dunes, and shoreline areas. Although these areas may need initial management to decrease soil salinity, they have low likelihood of continued salt accumulation where groundwater is deep. In these areas, a self-sustaining DCM could be developed by establishing desert shrubs, which are tolerant to low water supply and salinity, and after initial establishment, have relatively low irrigation needs. Other areas may be appropriate for a hybrid of precision surface wetting and vegetation to meet dust control requirements, with much less water use than existing managed vegetation plots.

Selecting practices and goals for a dust control area that are most suitable for local conditions can be achieved by spatially explicit mapping of the key variables that shape a system. The 2010 Habitat Management Plan (LADWP, 2010) provides a clear delineation of seven distinct zones in the lakebed that differ in surface soil, groundwater depth, groundwater salinity, sediment type, surface morphology, and location. It is not clear to what extent the spatial layout of dust management approaches has been guided by these zones, combined with more fine-scale site characteristics and manager knowledge of sites.

A key local condition to consider in any future expansion of dust control is the location of environmentally sensitive areas, particularly areas of cultural significance and those that are

likely to contain important artifacts. In a xeric climate, human activity is most likely to be centered upon water sources, although a broad margin of the lakebed will encompass fluctuations in historic lake edges that could contain significant cultural resources. To the extent possible, predictive mapping of likely “hotspots” of currently unidentified areas of cultural significance outside of the current ordered dust control areas could help inform future planning.

Management at the Scale of the Processes That Control Management Goals, Considering Adjacency

The previous section discusses the importance of managing a specific dust control area in a way that best suits local conditions. However, landscape-scale processes (e.g., hydrology, salt accumulation, vegetation spread, decreases in wind speed) are substantially influenced by the size, shape, and configuration of multiple dust control areas across the landscape (Dale et al., 2000). Integrated planning across the extent of Owens Lake will improve the potential to achieve all goals by considering the impacts of adjacent DCMs and the size of the dust control area needed to effectively manage for fundamental processes that control the system, such as groundwater depth, salinity, and wind speed.

More effective and efficient dust control can be achieved by shifting away from the current practice of small-scale patchiness of different types of management across the lakebed (see Figure 1-4) to larger areas of a given management type that are suitable to the location in the lakebed. A small-scale patchwork of dust control approaches that are not coordinated to address issues related to surface water, groundwater, and salinity collectively, will likely lead to DCMs at each patch failing to be as synergistic as possible, because the approaches do not manage those issues on a sufficiently broad scale. For example, long-term sustainability of managed vegetation requires prevention of saline groundwater encroaching into the rooting zone. Sustaining managed vegetation may be more effectively achieved at large scales, compared to having managed vegetation interspersed amid other DCMs that could increase groundwater salinity (e.g., brine pool) or groundwater levels (e.g., shallow flooding) (Scheidlinger, 2008b). Water movement designed to flush salts toward the brine pool over time supports sustainability of the system.

Similarly, DCMs that rely on decreasing surface wind speed, such as managed vegetation and artificial roughness, can result in substantial dust emissions from the windward edges of the dust control area, which receive the brunt of the wind scour. Roughness-based DCMs are more effective when they are large in size and surrounded by other DCMs that decrease wind speed (e.g., managed vegetation, artificial roughness, sand fences, tillage).

The size and nature of neighboring DCMs can also reduce emissions from currently uncontrolled areas. Currently, 1.2 square miles of the total ordered dust control area on the lakebed are uncontrolled, in part due to the presence of cultural resources (see Table 1-1). If the Owens Valley Planning Area continues to be in nonattainment of the National Ambient

Air Quality Standards (NAAQS) for PM₁₀, DCMs may need to be applied in these areas and could adversely affect artifacts, culturally important sites, and habitat features. Careful selection of dust control approaches on upwind adjacent patches—for example, the use of shrubs or other roughness elements—could decrease wind speeds at the boundary of these uncontrolled areas.

It is also important to consider how management of Owens Lake interacts with the surrounding landscape. In the past, there has been a long-term movement of sand from the lake to off-lake dunes and other areas (Lancaster and McCarley-Holder, 2013; Pavlik, 2008), essentially creating new emissive areas. Although LADWP’s mandated dust control efforts are within the regulatory boundaries of the historic lake shoreline, the dust, wind patterns, hydrology, and salt movement are influenced by broader scale processes, and management of emissive sources beyond the lake boundaries are an important consideration for most effective long-term control.

A key challenge to effective management is that the environmental variables and processes that affect progress toward management goals often occur at different scales. Therefore, it is important to match the scale of management and monitoring with the scale of the processes.

Consideration of Temporal Scale and Variability

Critical to the establishment of processes and systems that are designed to be self-sustaining is a realistic time frame. However, that time frame may not match regulatory time frames. The managed vegetation BACM can be risky to implement because vegetation establishment may take longer than the regulatory time frame, especially in dry years. It may take 5 years for mature shrubs to establish (see Chapter 4). Additional temporary DCMs may be needed to manage dust in areas to promote the establishment of plant communities that may be self-sustaining in the long term.

In addition, management approaches that work in the short term may fail in the long term, and awareness of long-term change is necessary. For example, minimizing water use can lead to surface salinity issues over the long term, as salts that inevitably accumulate in a saline basin are not leached over the long term.

Management for Resilience

A resilient ecosystem can maintain itself in response to disturbances, variability, and directional change (e.g., climate change). Particularly in heavily managed novel ecosystems (Biggs et al., 2012; Seastedt et al., 2008), this flexibility can be achieved by many of the core principles discussed in this chapter. As discussed in Chapter 4, however, many information gaps remain about the capacity of current BACMs and potential DCMs to withstand future change.

TOWARD A LONG-TERM, INTEGRATED STRATEGY

In addition to the principles discussed in this chapter, other approaches support the development of a long-term systems approach (Biggs et al., 2012), including the following:

• Establishing monitoring, adaptive management, and learning in the management decision-making process;
• Encouraging experimentation, flexibility, and innovation in management; and
• Broadening participation of multiple community partners in all stages of the planning, implementation, monitoring, and adaptive management processes.

Addressing multiple goals in a systems context amid a changing climate warrants a flexible adaptive management approach (Olsson et al., 2004; Roberts et al., 2016). Especially with the objective of decreasing water use in dust control, innovative experiments are needed at Owens Lake (Roberts et al., 2016), including a focus on hybrid dust management approaches.

Providing advice on the implementation of a long-term, integrated strategy for Owens Lake is beyond the scope of this report but could be a topic in future reports by the Owens Lake Scientific Advisory Panel. As indicated in the 2014 Stipulated Judgment,² this report represents the first in an expected series of reports to be prepared by the panel assembled by the National Academies of Sciences, Engineering, and Medicine. Through continued engagement, the panel will provide ongoing assessments and scientific advice on the challenges to developing sustainable approaches to reduce dust in the Owens Valley. Through its upcoming activities, the panel may provide valuable advice on implementing the recommendations in this report, especially regarding the application of landscape-based, systems approaches for assessing dust control configurations at Owens Lake and the use of PM₁₀ concentration measurements to quantify emissions from control areas (see Chapter 2).

CONCLUSIONS AND RECOMMENDATION

This section presents the panel’s key conclusions and a recommendation concerning a systems approach to address current and future challenges at Owens Lake.

Conclusion: Further improvements in dust control to reduce PM₁₀ concentrations with lower water use, while protecting environmental resources, ultimately will result in tradeoff challenges that are not fully understood today. Such tradeoffs will need

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² Stipulated Judgment in the matter of the City of Los Angeles v. the California Air Resources Board et al. Superior Court of the State of California, County of Sacramento. Case No. 34-2013-80001451-CU-WM-GDS. Approved by the court on December 30, 2014.

to be evaluated in a systematic way to identify the best selection and application of DCMs and to understand how alteration of one DCM can affect overall lake-wide performance.

Conclusion: The complex challenge that Owens Lake PM₁₀ management faces in meeting multiple goals, including dust control, protection of environmental and cultural resources, and water savings, can be addressed in an effective manner through a landscape-based, systems approach that is flexible and adaptive. Such an approach also has the potential to decrease energy use and long-term maintenance costs. In addition to managing multiple goals and recognizing tradeoffs, a systems approach at Owens Lake would consider and plan for key factors that affect attainment of the goals both at individual sites and collectively. Such factors include local conditions, spatial and temporal variability, and the potential for self-maintenance, sustainability, and resilience.

Recommendation: To support the development of a landscape-based, systems approach with multiple goals, dust control configurations should be assessed within a lake-wide system, considering long-term management of air quality, surface water and groundwater, and salinity; protection of cultural resources; and the regional significance of habitat types and other ecosystems services in the Owens Valley.