Chapters from the Salton Sea Report
The below chapter excerpts are taken from Crisis at the Salton Sea - The Vital Role of Science.
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Chapter One - Water Policy
A key science need is to determine the optimal lake water level to reduce lakebed dust, maintain wildlife habitat and improve livelihoods in the region.
The problems facing the Salton Sea are multi- faceted and complex, spanning from ecological and medical concerns to health disparities and eco- nomic opportunities. Continued shrinking of the sea exposes dry lakebed that exacerbates windblown dust as aquatic ecosystems crash or disappear. Managing lake levels is challenging in large part because urban water districts in San Diego and Los Angeles compete
with agricultural irrigation and natural ecosystems for the same inflows from the Colorado River, which are projected to decline. As the construction of wetland restoration and dust mitigation projects ramps up on the northern and southern shores of the lake in the coming years, it will become increasingly imperative that scientific research and monitoring guides these activities.
Chapter Two - Watershed Hydrology
A comprehensive assessment of lake-groundwater interactions is needed to explain the underlying causes of significant reductions in Salton Sea volume since 1995.
The Salton Sea watershed is one of the most produc- tive agricultural regions in the United States. With an area of 8,417.4 square miles, this watershed’s hydrology is coupled tightly to water imported from the Colora- do River, which provided about 1.1 million acre feet per year of water to the lake via irrigated agricultural runoff and subsurface drainage from 1980 to 2018. Despite no substantial decrease in agricultural inflows, lake levels declined significantly from -227.06 feet in 1995 to -236.4 feet in 2018. One possible explanation for this unexpect- ed drop is poorly understood connections among the lake, local groundwater aquifers and subsurface water flows, which have never been evaluated adequately.
The water volume of the Salton Sea is a straightforward difference between inflows and outflows. The Sea’s only surface outflow is via well-understood rates of evaporation; inflow is estimated from measured flow rates near the mouths of various rivers. The unknown factor is the dynamics of subsurface water. The mod- el that the Salton Sea Management Program has used to predict lake levels for current management plans assumes constant net groundwater flows into the lake, but it does not consider the possibility that the lake may discharge to groundwater. Accurate predictions of future lake levels require new research to properly quantify all lake-groundwater interactions.
Chapter Three - Water Quality
Shrinking of the Salton Sea will exacerbate water quality issues as dead zone episodes last longer and the receding shoreline exposes mud that is more highly concentrated in toxic metals and pesticides.
Changing water chemistry at the Salton Sea is already causing serious perturbations to fish stocks and waterfowl feeding habits. It also makes windblown dust
from the dry lakebed increasingly toxic as the Sea recedes. Each summer the deeper waters lose oxygen and accumu- late hydrogen sulfide through the activities of algae and bacteria. These dead zone waters mix with the surface layers on windy days, resulting in fish kills and airborne accumulation of foul-smelling hydrogen sulfide. It is likely that these conditions will become longer-lived and more frequent as lake volume decreases. Concentrated in the
central portions of the basin, these waters also tend to enrich the underlying sediment in metals far beyond concentrations observed on the lake margin. Molybde- num and selenium, for example, are beneficial at low lev- els but become health hazards when elevated. Along with pesticides, these metals will likely remobilize to surface waters as the sea recedes and be transported into ambi- ent air as dust from the dried lakebed. It is imperative to monitor the dynamic biogeochemistry of the lake water for patterns of oxygen loss and toxic metal remobiliza- tion under different water management strategies.
Chapter Four - Air Quality
Airborne dust fluxes at sites close to the Salton Sea are already in the high range of values observed at Owens Lake, California, before mitigation began; dust control there has already cost more than $2 billion.
Despite uncertainties in quantifying the impact of the shrinking Salton Sea on local air pollution, measurement and modeling studies suggest that ongoing declines in lake volume will contribute to lower air quality for residents throughout the basin and be- yond. A large fraction of the coarse particulate mat- ter captured at sites closest to the shore of the Salton Sea is associated with emissions from the lakebed and sea spray. Pungent and reactive gases are regularly produced in the Sea and emitted to the atmosphere, contributing to noxious odors and formation of fine particulate matter. As the shoreline recedes, harmful algal blooms will likely become more frequent, producing microbial toxins that may become airborne, and new- ly exposed fumaroles will emit greenhouse gases and ammonia directly to the atmosphere. Worsening air qual- ity will further burden local residents already dealing with disproportionately high levels of ambient particu- late matter and related respiratory issues. More research is necessary to fully understand the transport, compo- sition, and health impacts of air pollutants originating from the Salton Sea and its exposed lakebed, and to inform and guide mitigation efforts aimed at improving the health and well-being of local communities.
Chapter Five - Ecology
Without significant freshwater introduction to the Salton Sea, the lake ecosystem faces collapse due to excessive nutrients, rising salinity, and declining water levels.
The dynamic and unstable Salton Sea region histori- cally has supported abundant wildlife, ranging from a diverse array of microorganisms to endangered species of fish and birds. Terrestrial desert ecosystems give way to agricultural fields, riparian zones, natural and man- aged wetlands, and the aquatic ecosystems of the lake itself, which are supported by water and nutrients de- rived largely from agricultural run-off. Excessive nutrientflows into the Sea result in harmful algal blooms and dead zones, threatening wildlife and humans. Declining lake levels disrupt migration patterns for fish-eating
birds and isolate populations of endangered desert pupfish inhabiting the Sea’s margins, putting them at increased risk of extinction. The salinity of the Sea— already at 74 parts per thousand, more than double that of the Pacific Ocean—will continue to rise as the Sea shrinks, leading to a catastrophic collapse of the aquatic food web if the current trend is not halted. Planned construction of wetland habitats may ben- efit certain species of non-fish-eating birds; howev- er, there are currently no official plans to maintain or restore a fully functioning lake ecosystem.
Chapter Six - Human Health
Respiratory illness and other consequences of the environmental hazards in and around the Salton Sea will likely amplify the region’s significant social and economic disparities.
The ongoing crisis at the Salton Sea presents multi- ple consequences for the region’s human residents. In communities already subject to disparities in social and economic status, the environmental hazards of life in the region—particularly increases in windblown dust that are expected as the shrinking sea exposes more dry lakebed—are evident from the epidemiology of diseas- es, especially pulmonary diseases such as asthma. Co- morbid factors including the high incidence of obesity,
poverty, poor access to health care, and chemical expo- sures from agriculture work further degrade the quality of life, driving additional impacts on mental health in the community. Continued environmental degradation at the Salton Sea accompanied by increased production of dust and other air pollutants has already impaired the eco- nomic and social fabric of the region. Health disparities and costs to the community will likely increase unless steps are taken to address the issues raised here.
Chapter Seven - Geothermal Resources
Economic opportunities for developing non-traditional mineral and energy resources at the Salton Sea could help offset expected environmental and human health costs.
The existing renewable electrical generation industry at the Salton Sea Geothermal Field has tremendous potential to become a world-class producer of lithium and other critical metals, which can be extracted from geothermal brines. The industry could also generate nontraditional geothermal energy via production of electricity from pumped storage and by producing hydrogen via electrolysis, thereby boosting California’s ability to meet legal mandates to produce more renewable energy while lowering greenhouse gas emissions.
Development of these nontraditional resources together could make expanded geothermal power production at the Salton Sea more competitive with solar and wind power. These efforts would lead to substantial local job creation and increased tax revenues. Multiple benefits would be maximized by coordinating the expansion of geothermal resources with reclamation plans for the Sea, as the receding shoreline opens up new land suitable for construction of both artificial wetlands and new geothermal infrastructure.
