Terminal lakes occur in semi-arid regions of continental interiors where precipitation is sufficient to allow the formation of surface waters, but not sufficient to create waterways which flow to the sea, leading to the formation of an ecosystem where wetlands are maintained by the balance between precipitation and evaporation. The largest such lake in North America is Great Salt Lake in Utah, a major driver of biodiversity and economic activity in the western United States. Great Salt Lake is estimated to generate about US$2.5 billion in economic activity each year, and to support about 9000 jobs, in fields such as mineral extraction, recreation, and Brine Shrimp harvesting. Evaporation from the lake is estimated to contribute 5-10% of the snowfall onto nearby mountains, generating a further US$1.8 billion in economic activity, and supporting a further 20 000 jobs.
Great Salt Lake provides a vital link in the 'Pacific Flyway' Bird migration route, creating a food-rich habitat used by about 10 million migratory Birds each year. About 350 species of Birds are thought to depend on Great Salt Lake and its associated wetlands, including Eared Grebes, Tundra Swans, Snowy Plovers, American Avocets, and multiple species of Ducks, Phalaropes, Owls, and Blackbirds. The widespread loss of wetlands across the western United States is has made this environment an even more vital resource for wildlife.
Great Salt Lake also provides a range of ecosystem services of direct importance to Humans, including the protection of air quality, removing water pollutants, and moderating the local climate. It is also of significant cultural importance to the people of Utah, and has inspired numerous countless scientists, pioneers, artists, writers, photographers, and recreationists. As such good stewardship of the lake is important not only because of its ecological, environmental, and economic importance, but also because of its central place in the culture of the state.
However, in recent years, the extraction of water by Humans has driven the lake far beyond the natural fluctuations that it has endured over the past millennia, pushing the lake-associated ecosystems into structural decline. Since 2020 Great Salt Lake has lost over 1.2 billion cubic metres of water per year, a trend which could see the lake disappear completely by 2028. The lake is currently 3.5 m lower and 7.4 billion cubic metres short of its minimum healthy level, and has reached this minimum on only a single occasion since 2002.
In a report published by Plant and Wildlife Services at Bingham Young University on 4 January 2024, a team of scientists headed by Benjamin Abbott of Bigham Young University, lay out the current threats faced by Great Salt Lake, and discuss the measures that could be taken to address them.
The nature of saline lakes is highly dependent on the relationship between precipitation and evaporation. If there is to little rainfall or two much evaporation, then the lake becomes to saline to support the micro-organisms at the base of its food chain. Conversely, if there is to much rainfall, or to little evaporation, then the lake becomes less saline, altering the community which can live there. Water extracted from the lake or its watershed for use in agriculture can alter this balance, harming the lake's delicate ecology. Water extraction for agriculture is known to have been affecting Great Salt Lake since the mid-1800s, becoming the dominant controlling force in the watershed in the twentieth century. During this period, numerous federal and state projects, including dams, canals, and pipelines, took water from the watershed for use in agriculture, industry, and municipal purposes. This high extraction caused water levels in Great Salt Lake to fall precipitously from the 1960s, although a 'pluvial' period of high rainfall in the 1980s enabled it to recover somewhat.
During the past three years Great Salt Lake has received less than a third of its natural water-input, due to excessive water extraction for Human purposes. In 2022 the lake surface dropped to its lowest ever recorded elevation, 4188 foot (1276 m) above sealevel. These figures do not include groundwater extraction or levels, making it likely that the situation in the Great Salt Lake Basin is even more severe; the loss from the lake represents about 32 billion cubic metres, but it is likely that twice as much has been loss from the basin's aquifers, which will slow the lake's recovery even if the waterflow is restored.
The watershed for Great Salt Lake spreads across four states, and includes the Bear, Jordan, and Weber basins. Six percent of this watershed is covered by agricultural land, drawing its irrigation from the lake's water supply; 63% of this agricultural land lies in Utah, with 31% in Idaho, 5% in Wyoming, and 1% in Nevada. Another 3% of the watershed is covered by urban development, 93% of which lies in Utah.
Agriculture is the single largest consumer of water from the Great Salt Lake watershed, with about 75% of the water extracted going to irrigate Alfalfa and other crops, while 5-10% is lost during transport within irrigation systems. About 9% of the extracted water is consumed during mineral extraction from the lake, while another 9% is used for domestic and urban purposes, with 90% of that estimated to be spent on outdoor water use, such as watering lawns and ornamental Plants; the amount used for internal domestic purposes is negligible, as most of this is returned to the lake via wastewater treatment plants. The remaining extracted water is used in thermoelectric power generation, industry, and mining.
Climate change is also affecting Great Salt Lake, with average temperatures in Utah having risen by 2°C since 1900, which is exacerbating draughts across the southwestern United States. This climate change is thought to be responsible for about 9% of the decline in water within Great Salt Lake. This trend is likely to continue for the foreseeable future, requiring Utah's Human population to plan for a drier future.
Saline lake ecosystems are being destroyed by excess water extraction for agriculture on every continent except Antarctica. This excess water extraction has been shown to trigger a sequence of ecological and economic consequences, which are almost impossible to reverse. The circumstances of this vary from site to site, but generally involve pollution of both the water and air supply, collapse of agriculture and industry, economic depression, and a breakdown of the lake and wetland ecosystems.
Even without complete loss of the lake, exposure of large areas of the former lake bed can cause problems, as this exposes sediments often laden with large amounts of pollutants, harmful minerals, and toxins. The sediments at Great Salt Lake have been shown to contain : arsenic, cadmium, mercury, nickel, chromium, lead, copper, selenium, organic contaminants, and cyanotoxins. When exposed these substances are easily picked up and distributed by the wind, as the average particle size is about 10μm. Exposure to these substances in air pollution has been linked to a number pf medical conditions, including reproductive disfunction, developmental defects, cognitive impairment, cardiovascular damage, and cancer. At a time when awareness of the problems of air pollution have risen globally, and almost all urban communities have taken steps to improve air quality, exposed lake beds can rapidly undermine improvements that took decades to achieve. Such dusts can also damage agricultural land, damaging crops and undermining soil fertility, as well as building up on top of snow packs, where their dark colour enables them to absorb thermal energy which would normally be reflected by the white snow, leading to premature melting.
The damage to the local ecology from the loss of a saline lake is also typically severe. Changes in the water coverage and depth affect local Plant and Animal communities, and tend, in the case of salt lakes, to be accompanied by changes in the water chemistry, which can have profound impacts across wide areas. The loss of evaporative water coming from the former lake can aridify the local climate, leading to desertification, wider swings in temperature, and lower rainfall within the catchment area, leading to further aridification. This in turn profoundly affects Human populations dependent on the lake, causing industries to collapse, loss of property values, and eventually mass migration away from the area, which in turn can lead to social conflicts and a loss of social identity.
Great Salt Lake is already showing signs of developing many of these problems, and is likely to proceed further along this path without urgent action. The salinity of the lake has already begun to rise, and ,currently sits at about 19%. At this level the micro-organisms upon which the Brine Shrimps (a vital food-source for migratory Birds) depend are becoming much less productive, and the Brine Shrimps themselves are beginning to suffer metabolic problems. The lake suffered a catastrophic crash in its Brine Fly population in 2022, and the same is currently predicted to happen to the Brine Shrimp this year (2023). Several Bird species using the lake, including Wilson’s Phalaropes and Eared Grebes, are protected by federal regulations, which might lead to the enforced stopping of some economic activities on the lake if they become threatened. Even if this does not happen, the falling water levels are predicted to make mineral extraction from the lake non-viable in 2023 or 2024. At the moment the drying lake is forming salty evaporite crusts over newly exposed sediments, but if these remain exposed for long, they are likely to be a source of dust storms; dust from the lake is already reaching areas from southern Utah to Wyoming, with the majority of dust falling in the Wasatch Front area now derived from the lake. Salt-laden dust storms can lead to severe pollution levels, and are damaging to agricultural land.
The worst problems facing Great Salt Lake can be seen in the lake's North Arm, which was cut off by a railway causeway in 1959, and now receives almost no water input. This has led to salt in the water here reaching evaporation point, which in turn has killed off all the Algae in this part of the lake and causing the food web here to collapse. In addition, water circulation in the North Arm of the lake has broken down, causing pollutants to build up, giving this part of the lake the highest methylmercury levels recorded anywhere in the United States.
Recent changes to legislation in Utah have favoured conservation of water within natural waterways as as something to be valued in itself, allowing farmers to leave water in streams without losing water rights. In addition, the state government has significantly raised the funding available for conservation projects in 2022, and plans to do the same again in 2023. Similar changes to federal legislation has secured extra funding for the conservation of Great Salt Lake. Furthermore, many cities, towns, and districts within the Great Salt Lake basin have introduced their own water conservation projects, and many businesses and community groups are now also seeking to play an active role in the conservation of Great Salt Lake.
All of these changes are likely to have a positive impact on the lake's survival over the next few decades - as long as the lake can survive the immediate crisis, though they are probably not sufficient to avert that crisis. All of the water conservation efforts combined in 2022 is only estimated to have increased water-flow into Great Salt Lake by 123 million square metres.
Abbott et al. call for an emergency rescue plan to be put into plan for Great Salt Lake, which should be taking steps within the first half of 2023 in order to protect the lake from catastrophic changes. The lake is currently more than three metres below its minimum healthy level, a shortfall of over 7.5 billion cubic metres of water. It will require a dramatic increase in the amount of water flowing into the lake in 2023 and 2024 in order to give the lake any hope of recovery.
Abbott et al. calculate that the minimum acceptable amount of water flowing into the lake should be three billion cubic metres per year. Analysis of the past behaviour of the lake suggests that this is the point at which the water level in the lake begins to rise rather than falling. It is also roughly 1.25 billion cubic metres per year more than is currently flowing into the lake. How much water will need to be conserved each year in order to achieve this is somewhat dependent on the weather, but Abbot et al. estimate it to be between 865 million and 1.48 billion cubic metres of water per year, which would require water use within the watershed to be cut by between 30 and 50%.
The first instinct of planners, when faced with water scarcity, has often been to increase the supply using 'hard' engineering solutions, such as dams or pipelines. However, over the past century numerous studies have shown that this is generally the worst answer to such problems. Abbott et al. suggest that the correct way to address water shortages is to study the natural system of the water basin in question, conserve as much water as possible, and only augment the water flow with engineered solutions as a last resort.
The reasons for doing this are not purely ecological; large scale infrastructure projects such as dams are extremely expensive, and notoriously prone to both overrunning their predicted budgets and underachieving their aims, as well as often producing risks and problems which were not anticipated at the planning phase. Even when the construction phase of such projects is successful they are often unable to cope with natural changes in the hydrological cycle or variations in water demand, which can quickly make them obsolete, particularly if they are combined with overallocation of water, changes in landuse, or variations in the climate. Notably, moving water from one area to augment the supply in another can lead the area from which water is extracted facing shortfalls of its own.
The Great Salt Lake watershed is littered with such hard engineered water projects, including three huge pumping stations and a system of reservoirs which is calculated to lose as much water each year as the total domestic consumption within the watershed. An inter-basin transfer system also exists, which has been linked to the decline of the Colorado River water-system. However, many other proposed engineering solutions to the watershed's problems have been rejected, which Abbott et al. suggest indicates a degree of wisdom on the part of environmental managers.
Abbott et al. believe that decreasing water demand is always a better solution than trying to maintain water supplies through engineered solutions, both because it costs considerably less, and because it provides more resilience to changes in the water cycle. Careful pricing of water and caps on its usage can deliver reductions in water consumption quite quickly, and with relatively little expense. Estimates of the costs that would be associated with restoring the Great Salt Lake through water conservation alone vary between US$14 and US$96 million, or between US$5 and US$32 for every person living in the watershed, while the use of a water market system, which would give inhabitants the right to buy and sell water, could lower the cost to between US$6 and US$48 million, or between US$2 and US$14 per person living in the watershed.
More heavily modified water-systems tend to require more maintenance than more natural, less modified systems. This is currently the case with Great Salt Lake, where almost every aspect of the ecosystem, water-flow regime, and even lake chemistry is currently controlled by Humans, While all of these controls were put in place with good intent, collectively they are responsible for the majority of the problems facing the lake today.
Abbott et al. note that returning the lake to a 'pristine', pre-Human intervention state would be neither possible nor desirable, but do believe the natural state of the lake should be a major consideration when planning future changes. Such an approach should reduce the risk of harmful side-effects occurring when well-intentioned projects are put into place, increasing the likelihood of such projects are undertaken. Particular attention should be paid to maintaining the amount of water flowing into the lake, and also the seasonal nature of such water flow, as well as to the establishing a conservation buffer zone around the lake, where natural ecosystem-processes are allowed to take precedence over infrastructure projects. Efforts should be made to keep the lakes level above its natural lowest level (1282 m above sealevel). Abbott et al. believe that restoring a more natural hydrology to Great Salt Lake will have a knock-on effect, helping to restore more natural systems to upstream environments such as Utah Lake, Jordan River, Weber River, Logan River, and Farmington Bay.
Environmental concerns and the maintenance of natural water systems have traditionally been given a low legal priority in western cultures. This has failed to take into account that Humans often need these natural ecosystems in order to survive and flourish. Changing the allocation of water usage between different consumer groups can deal with short term problems, but fails to address the underlying problems of water supply. Abbot et al. believe that in order for Utah to establish a maintain a sound ecological foundation upon which its Human prosperity can be based, Great Salt Lake itself must be permanently allocated a large portion of the water flowing into its watershed. Current law in the state relies on the principle that users who can establish that they have been utilizing water for longer have precedence over other users, something which Abbott et al. believe should be extended to the lake itself as an entity. If the lake is accorded such status, then a the water required to maintain the natural system would be allocated ahead of that required by Human users, thereby insuring the continuance of the lake and associated water systems.
This would mean reducing the amount of water available for Human users, but would introduce a degree of security into the system, which would be of benefit to the Human occupants of the watershed. Once the lake's needs were met any excess water could then be distributed via a system of prior application (earliest Human users first), or divided equally among users. The later system has been deployed successfully in Nevada, while the former aligns more closely with standing law in Utah.
Abbott et al. also note that in strongly religious Utah, recognizing the Great Salt Lake as part of God's creation entrusted to Human stewardship, which therefore should have a right to continue to exist, is not at odds with the customs or beliefs of much of the population.
Abbott et al. recommend that the federal government makes more funds available for water conservation in the Great Salt Lake watershed, and takes an active role in coordinating water usage agreements across state lines. They further recommend that the federal government increases monitoring of the hydrology and climate of the basin, and that federal agencies work closely with state agencies on the monitoring and maintenance of the basin's ecosystems.
Abbot et al. further recommend that the state authorities in Utah release water held in reservoirs in order to increase the streamflow into Great Salt Lake during 2023 and 2024, if necessarily leasing, purchasing or using emergency mandate powers to obtain water from wholesalers (although they do stress that private organizations holding water should be compensated for such seizures). They further recommend that the state establish a long-term target lake-level, using the framework suggested in previous state reports, with a well-defined, and legally binding, timeline for reaching key goals in the restoration of the ecosystem. Furthermore, they recommend that the state develops a high-profile website dedicated to promoting the wellbeing of the lake, which highlights individuals and organizations doing the most to help conserve water, and also directly contacts all water users in the watershed, as well as community, church, and agricultural groups to ensure that they are kept up to date on the progress of the program, why it is being undertaken, and any changes to the legal structure through which water allocation is handled and how it will affect users.
Furthermore, Abbott et al. recommend that the state authorities should offer farmers in the watershed compensation for not growing crops this year, and provide aid to help them transition to less water-intensive crops. The state should also seek to extend develop water markets across the entire watershed, using models previously developed for the management of saline lake watersheds. The state should work with the Utah Water Task Force and other organizations to establish a 'law of the lake' framework within each of the major watershed basins, following the pattern used in the early 2000s to resolve water conflicts in the Bear River Basin. The state should be responsible for ensuring any water saved by state and federal programs is permanently assigned for the benefit of the lake, expand turf-removal programs to encourage less water-consumptive gardening practices in urban and country communities, hire more employees to work on all of these projects, and implement a system of tiered water pricing, as well as removing subsidies for water use.
Abbott et al. also recommend that local authorities within the Great Salt Lake watershed should coordinate with both state and federal programs to raise awareness of the problems facing the lake and its watershed, and to promote water conservation by cities, businesses, and individuals. In particular local authorities should convene homeowner and home-builder associations, who should be kept briefed on any changes to the rules regarding water management, and encouraged to take an active role in water conservation. Local authorities should also work with community groups to remove turf from public spaces, and promote less water-intensive forms of gardening, including the planting of vegetation native to the region, as well as introducing tiered charging for different water uses (in particular lower charges for indoor water use than outdoor).
Abbott et al. also make a number of recommendations for individuals and community groups within the Great Salt Lake watershed, including actively spreading information about the crisis facing the lake and the efforts being made to tackle it, sharing information about water conservation techniques, changing the vegetation in gardens and other outdoor spaces to types which need little or no irrigation, encouraging local, state, and federal authorities to adopt conservation measures, and maintaining or removing sprinkler systems.
As well as a list of recommendations for things that should be done, Abbot et al. strongly advise that a number of actions be avoided. The first of these is not attempting to prevent natural evaporation from the lake (something which is often done with reservoirs) as this will effect precipitation in areas downwind of the site, and impact the natural water/mineral balance of the lake. Secondly, Abbot et al. advice against cloud seeding to try to resolve water shortage problems, noting that this is (at best) an unreliable technology, and again has the potential to upset rainfall patterns in neighbouring areas. Thirdly, Abbot et al. recommend against the building of more infrastructure, observing that reservoirs and piping systems are major causes of the current problem, and that building more it unlikely to solve the situation. Fourthly, Abbott et al. strongly advise against simply waiting for rain, noting that, while this did work briefly in the 1980s when a short pluvial interval restored much of the water to an already drying lake system, that was regarded at the time as a once-in-a-thousand-years event, and that since then a warming global climate has shifted conditions in the Great Salt Lake watershed, making a repeat of the event even less likely. Finally, Abbott et al. advise strongly against simply abandoning the lake or any part thereof (something they refer to as the Aral Sea solution). Recent speculation has been made about the possibility of abandoning the North Arm of Great Salt Lake, which was cut off by the building of a railway causeway in 1959, and now naturally receives little natural irrigation, in order to conserve water for the rest of the lake. However, this course of action would mean allowing the Pelican colony on Gunnison Island to go extinct, sacrificing a valuable mineral extraction industry on this arm of the lake, and risking the creation of a major source of toxic dusts, including methyl mercury.
Finally, Abbott et al. suggest that what has ultimately been missing from the Great Salt Lake watershed has been not water but trust. Water conservation measures are present throughout the watershed, but the various users have not trusted each other enough to allow conserved water back into the lake. Abbott et al. concede that the proposed changes will have the most impact on farmers and rural communities within the Great Salt Lake watershed, but stress that the majority of the authors of the report come from such backgrounds, and that they are keen to see proper support, financial, legal, and technical, for farming communities during any change within the watershed.
The Great Salt Lake ecosystem is currently facing an unprecedented ecological collapse, and addressing this will require equally unprecedented changes in the way water conservation is managed within the Great Salt Lake watershed. However, Abbot et al. suggest that bold, collective action is not unprecedented in the history of Utah, and that they believe the people of the state are capable of rising to face the challenge before them.
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