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The future Aral Sea: hope and despair


Abstract and Figures

The Aral Sea in 1960 was a huge brackish water lake (4th in the world in surface area) lying amidst the deserts of Central Asia. The sea supported a major fishery and functioned as a key regional transportation route. Since 1960, the Aral has undergone rapid desiccation and salinization, overwhelmingly the result of unsustainable expansion of irrigation that dried up its two tributary rivers the Amu Darya and Syr Darya and severely damaged their deltas. The desiccation of the Aral Sea has had severe negative impacts, including, among others, the demise of commercial fishing, devastation of the floral and faunal biodiversity of the native ecosystems of the Syr and Amu deltas, and increased frequency and strength of salt/dust storms. However, efforts have been and are being made to partially restore the sea’s hydrology along with its biodiversity, and economic value. The northern part of the Aral has been separated from the southern part by a dike and dam, leading to a level rise and lower salinity. This allowed native fishes to return from the rivers and revitalized the fishing industry. Partial preservation of the Western Basin of the southern Aral Sea may be possible, but these plans need much further environmental and economic analysis. This paper, mainly utilizing hydrologic and other data as input to spreadsheet (Microsoft Excel)-based hydrologic and salinity models, examines the current efforts to restore the Aral and looks at several future scenarios of the Sea. It also delineates the most important lessons of the Aral Sea’s drying.
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Philip Micklin
Professor of Geography, Emeritus
Dept. of Geography
Western Michigan University
Kalamazoo, Michigan 49008
Phone: 01-269-345-6541
The Aral Sea in 1960 was a huge brackish water lake (4th in the world in surface area) lying
amidst the deserts of Central Asia. The sea supported a major fishery and functioned as a key
regional transportation route. Since 1960, the Aral has undergone rapid desiccation and
salinization, overwhelmingly the result of unsustainable expansion of irrigation that dried up its
two tributary rivers the Amu Darya and Syr Darya and severely damaged their deltas. The
desiccation of the Aral Sea has had severe negative impacts, including, among others, the demise
of commercial fishing, devastation of the floral and faunal biodiversity of the native ecosystems
of the Syr and Amu deltas, and increased frequency and strength of salt/dust storms. However,
efforts have been and are being made to partially restore the sea’s hydrology along with its
biodiversity, and economic value. The northern part of the Aral has been separated from the
southern part by a dike and dam, leading to a level rise and lower salinity. This allowed native
fishes to return from the rivers and revitalized the fishing industry. Partial preservation of the
Western Basin of the southern Aral Sea may be possible, but these plans need much further
environmental and economic analysis. This paper, mainly utilizing hydrologic and other data as
input to spreadsheet2 based hydrologic and salinity models, examines the current efforts to
restore the Aral and looks at several future scenarios of the Sea. It also delineates the most
important lessons of the Aral Sea’s drying.
Key words: Aral Sea, irrigation, water balance models, Amu, Syr, Small Aral Sea, Large Aral
The first volume of Environmental Earth Sciences Thematic Issue Sustainable Water
Resources Management in Central Asia dealt with Aral Sea related issues in several articles,
including the introductory editorial by Karthe, Chalov, and Borchardt (2015) and thematic
coverage by Abdullaev and Rakhmatullaev (2015), Groll (2013), Lioubimtseva (2015), and
Thevs (2015). The editorial briefly talked of the Aral Sea and its desiccation as a major water
issue in Central Asia. Abdullaev and Rakhmatullaev discussed many problems associated with
water resource development in the Aral Sea Basin that have led to its modern desiccation. Groll
examined the water management problems along the Zaravshan River located partially in the
Aral Sea Basin. Lioubimtseva discussed multiscale environmental changes and their
1 citation: Micklin, P. (2016). The Future Aral Sea: hope and despair. Environmental Earth Science, 75 (9): 1-15.
Electronic version available at
2 Microsoft Excel
ramifications for the natural environment and people of the Aral regions. Thevs et al focused on
water consumption and its influence on the Amu Darya, as the major influent to the Aral Sea.
This contribution to the second volume of Environmental Earth Sciences will not rehash
what has been covered on the Aral in volume 1. Here the emphasis will be on the Aral Sea
proper. The Introduction first briefly lays out the physical character of the sea prior to its
modern drying and its natural and economic value. A short recounting of what is known about
the history and pattern of advances (transgressions) and recessions of the sea follows. The next
section (Desiccation and its Consequences) provides a description of the rapid drying that
began in the early 1960s and the resulting major impacts from this. The following section
(Scenarios of the Future Aral) is the heart of the paper. This is the author’s attempt, based on
spreadsheet water balance and salinity models that he has developed and refined since the late
1980s, using available water resource and hydrologic data, satellite images and maps, to estimate
what the future(s) of the Aral may look like. The primary focus is on the Small (North) Aral for
which a partial restoration project has been completed and future efforts planned. However,
possible partial rehabilitation efforts for the originally much larger, but now severely desiccated
Southern (Large) Aral are also examined. Finally, in the last part of the paper (Lessons from the
Aral Sea) the author considers what we can learn from the Aral story about water resources and
environmental management.
The Aral Sea is a terminal, or closed basin (endorheic) lake, lying amidst the vast deserts of
Central Asia (Fig. 1). Its drainage basin encompasses more than two million km2 (Micklin
2014a). As a terminal lake, it has surface inflow but no outflow. Therefore, the balance between
inflows from its influent rivers, the Amu and Syr3 and net evaporation (evaporation from the lake
surface minus precipitation on it) fundamentally determine its level.
At 67,500 km2 in 1960, the Aral Sea was the world's fourth largest inland water body in
surface area (Micklin 2014b). The sea supported a major fishery and functioned as a key
regional transportation route (Micklin et al 2014a; Plotnikov et al 2014a). The extensive deltas
of the Syr and Amu rivers sustained a diversity of flora and fauna as well as irrigated agriculture,
animal husbandry, hunting and trapping, fishing, and harvesting of reeds. Since 1960, the Aral
has undergone rapid desiccation and salinization, overwhelming the result of unsustainable
expansion of irrigation that dried up the two tributary rivers (Table 1).
The last ten millennia have been considered the modern geologic epoch of the Aral Sea.
However, recent research based on extensive drilling on the dried sea bed and radio carbon
analyses of the sediment cores extracted by a team led by Dr. Sergey Krivonogov of the Institute
of Geology, Siberian Academy of Sciences in Novosibirsk, Russia, makes a convincing case the
sea’s age is more on the order of 20 to 24 thousand years (Krivonogov 2015; Krivinogov 2014).
This research also concluded that in contradiction to earlier accepted wisdom that the high
standings that have characterized the period from the 1600s to the early 1960s were more
common over the sea’s existence than low levels, the opposite is actually true.
During its modern geologic history the lake underwent a number of regressions and
transgressions (Micklin 2014c; Krivinogov 2014). Climate change in the Aral Sea drainage
basin and over the sea proper certainly contributed to both. Warm and dry periods reduced
3 References to the Amu and Syr often refer to them as the Amu Dar’ya River and Syr Dar,’a River. This is
redundant as dar’ya in the Turkic languages of Central Asia means river. However this is an accepted practice.
runoff and inflow while increasing evaporation from the sea surface promoting the former
whereas cold and wet times increased runoff and inflow while decreasing evaporation, promoting
the latter. However, the major regressions were related to the partial or full diversion of the Amu
westward away from the Aral and toward the Caspian Sea owing to natural forces. But ancient
civilizations also influenced Aral levels. Impacts included sizable irrigation withdrawals and
periodic diversions of the Amu Dar’ya westward. Irrigation along the Amu dates to 3000 years
B.P (before present). Irrigation during Classical Antiquity (4th Century B.C. to 4th Century A.D.)
was extensive with irrigation canals found over 5 to 10 million ha around the Aral. Diversions
both from natural causes and from human actions were by far the most important influence on
Figure 1. Location of Aral Sea Basin in Central Asia
Source: Modified from Micklin, P., Aladin N (2008): Reclaiming the Aral Sea. Scientific
American, 298, 4: 66.
The last major desiccation of the Aral prior to the modern drying, occurred from the 13th to
16th centuries when the level may have fallen below 29 meters above the zero level of the
Kronstadt gauge located near St. Petersburg, Russia, on the Gulf of Finland. Historical records
as well as archeological sites, preserved tree stumps and relict river channels on the dried bottom
of the Aral attest to this event (Fig. 2). The major cause of this recession was the anthropogenic
diversion of the Amu westward toward the Caspian Sea initially caused by the Mongol invasion
of Central Asia in the 13th Century. The Amu returned (or was returned) to the Aral and the sea
recovered by the mid 1600s. The lake was in a relatively stable generally “high” phase until the
modern regression began in the early 1960s. Level fluctuations were no more than 4-4.5 meters
and were chiefly related to climatic variation with, perhaps, some effects from irrigation.
Table 1. Hydrological and Salinity Characteristics of the Aral Sea, 1960–2015
Year and portion of sea
% 1960
% 1960
% 1960
1960 (all) 53.4 67,499 100 1,089 100 16.1 10 100
Large 53.4 61,381 100 1,007 100 16.4 10 100
Small 53.4 6,118 100 82 100 13.4 10 100
1971 (all) 51.1 60,200 89 925 85 15.4 12 120
1976 (all) 48.3 55,700 83 763 70 13.7 14 140
1989 (all) 39,734 59 364 33 9.2
Large 39.1 36,930 60 341 34 9.2 30 300
Small 40.2 2,804 46 23 28 8.2 30 300
Sept 22, 2009 (all) 7,146 10.6 83 7.7 10.8
W. Basin Large 27 3588 26.2
56 17.9
15.1 >100 >1000
E. Basin Large 27 516 0.64 0.7 >150? >1500
Tshche-bas Gulf 28 292 0.51 1.4 ~85 850
Small 42 3200 52 27 33 8.4 8 100-130
8/29 and 11/25, 2014 (all) 6,990 10.4 48.2 4.4 6.9
W. Basin Large 25.0 3,120 22.8
54 17.2
15.4 >150 >1000
E. Basin Large 25 0 0 0 0 0
Tshche-bas Gulf 28.5 372 0.72 1.4 89 890
Small 41.9 3197 52.3 27 33.2 8.5 6-8 0.6-0.8
Sources. (1) Values for 1960-1989 from Micklin, P. (2010): The past, present, and future Aral
Sea. Lakes & Reservoirs: Research and Management, 15, Table 1, p. 195. (2) Area data for
2009 and 2014 calculated from MODIS 250 meter resolution natural color images and Landsat 8
natural color images (30 meter resolution) using ImageJ software (freeware developed by U.S.
National Institutes of Health). (3) Volume data for 2009 and 2014 calculated from area changes.
(4) Salinity data for 2009 author estimates based on measurements taken with a YSI-85
electronic meter during an expedition to the Aral Sea in September 2007 and data provided by
Dr. N. Aladin of the Zoological Institute, Russian Academy of Sciences, St. Petersburg, Russia,
on salinity measurements taken in 2008. (5) Salinity data for 2013 based on measurements taken
with the YSI-85 meter and an optical refractometer during an expedition to the Aral Sea in
August and September 2011. (6) Salinity data for 2014 based on data provided by Dr. Aladin
from an expedition to the Aral in 2014 and via Dr. Aladin from Z. Ermukhanov, director of the
Aral’sk Affiliate of the Kazakhstan Fisheries Institute.
Desiccation and its Consequences
Over the past five decades, the sea has steadily shrunk and salinized (Table 1; Fig. 3).
Expanding irrigation that greatly diminished discharge from the two tributary rivers has been the
main cause (Micklin 2014d, 2000, pp. 24-42). As noted above, humans have practiced irrigation
in the Aral Sea Basin for at least three millennia. But until the 1960s this did not substantially
diminish inflow to the sea, owing to substantial return flows from irrigated fields to the Amu and
Syr and other compensatory factors such as reduced losses to transpiration from water loving
plants (phreatorphytes) along the lower courses of the rivers and in the deltas as well as lowered
evaporation from reduced spring flooding in the deltas of these rivers. However, growth from
around 5 million ha in 1960 to 8.2 million by 2010 pushed irrigation development beyond the
point of sustainability reducing or eliminating these compensatory effects and leading to a
marked reduction of river discharge to the Aral.
Figure 2. Kerdery 1 Masoleum with relict channel leading off former bed of Syr Darya in
the background)1
1Dr. Nikolay Aladin of the Zoological Institute, Russian Academy of Sciences, St. Petersburg,
Russia, is sitting by ceramic artifacts; photo by P. Micklin 2005.
The dramatic drop in river inflow for the period after 1960 is shown on Fig. 4 and the sea
level decline in Fig. 5 (Micklin 2014e). The difference between river inflow and net evaporation
increased substantially during the 1960s, 1970s and 1980s accompanied by growing water
balance deficits and rapidly dropping levels. More precipitation in the mountains and some
reduction in irrigation withdrawals increased river discharge during the 1990s and reduced the
water balance deficit, slowing the sea’s recession. There was a severe drought in 2000-2001 and
river inflow only averaged about 2 km3/yr. Higher inflows characterized the period 2002 through
2010 and water balance deficits were significantly lessened.
The Aral separated into two water bodies in 1987 - a “Small” Aral Sea in the north and a
“Large” Aral Sea in the south (Micklin 2014e). The Syr flows into the former, and the Amu into
the latter. A channel formed connecting the two lakes, allowing water to flow from the former to
the latter. Local authorities constructed an earthen dike in 1992 to block outflow in order to raise
the level of the Small Sea, lower salinity, and improve ecological and fishery conditions. This
makeshift construction breached and was repaired several times. In April 1999 after the level of
the Small Aral had risen well over 43 meters, the dike was overtopped, breached and completely
destroyed during a wind storm, with the death of two people.
Figure 3. The Changing Profile of the Aral Sea: 1960-2020
Subsequently, the World Bank and the Government of Kazakhstan funded construction of
an engineeringly sound 13-kilometer earthen dike with a concrete, gated outflow control
structure to regulate the flow from the Small to Large seas (Fig. 6) (Micklin 2014f; World Bank
2001). The structure was completed in August 2005 and raised and stabilized the level of the
Small Aral at around 42 meters above the Kronstadt gage by March of the next year. The total
cost of this project was 23.2 million USD, but other projects along the Syr Dar’ya to improve its
flow to the sea, provide more water to other important lakes in the delta, improve safety and
infrastructure at the large Chardar’ya Dam and Reservoir upstream, as well as reduce emergency
diversions to Lake Arnasay from it, thereby providing more water to the Syr downstream, and
other measures added another 62.6 million USD to project costs for a total of 85.8 million USD.
The bank provided a loan of 64.5 million USD and the Government of Kazakhstan funded the
remaining 21.3 million USD.
The desiccation of the Aral Sea has had severe negative impacts (Micklin 2010; Micklin
and Aladin 2008). The vibrant commercial fishing industries ended in the early 1980s as the
indigenous species that provided the basis for the fishery disappeared from rising salinity. The
more salinity tolerant Black Sea flounder (Platichthys flesus lulscus) was introduced to the Aral
in the 1970s. It flourished in the Small Aral and provided a sizable non-commercial catch, but
disappeared from the Large Aral as salinity rose.
Figure 4. Estimated Average Annual Inflow to the Aral Sea 1910-2010 (in km3)
Sources: Based on hydrologic data provided to the author by the Hydro Design Institute
(Gidroproyekt) and the Institute of Water Problems during academic exchanges in Moscow in
1984 and 1987; the Main Administration of Hydrometeorology of Uzbekistan (Uzglavgidromet)
during visits from 1994-2003; and a variety of other water management agencies in Kazakhstan
and Uzbekistan from 2004 - 2011.
The level stabilization project reinvigorated the fishery in the Small Aral by lowering
average salinity below the 10 g/l level of the early 1960s (Toman 2015; Plotnikov 2014a;
Ermukhanov 2012). This has allowed the return and flourishing of commercially valuable
indigenous species such as the sudak or pike-perch (Lucioperca lucioperca) and sazan (Cyprinus
carpio), a type of carp, as well as several others. Tens-of-thousands were thrown out of work
because of the loss of the fishery and associated activities and employment in these occupations
today is only a tiny fraction of what it was.
The rich ecosystems of the Amu Dar’ya and Syr Dar’ya deltas have suffered considerable
harm from reduced river flows, elimination of spring floods, and declining ground water levels
leading to spreading desertification (Micklin 2014b; 2000, pp. 13-23). Salts accumulating on the
surface have formed pans where practically nothing will grow. Expanses of unique tugay forests
along the main and secondary watercourses have drastically shrunk. Desiccation of the deltas
has significantly diminished the area of lakes, wetlands, and their associated reed communities.
These changes caused the number of species of mammals and birds to drop precipitously. Strong
winds blow sand, salt and dust from the dried bottom of the Aral Sea onto surrounding lands
causing harm to natural vegetation, crops, and wild and domestic animals (Indoitu 2015). As the
sea has dried and more of the bottom has been exposed, dust storms with entrained salts in
particulate and aerosol form have become more frequent and intense, covering at times more
than 100,000 km2 and extending downwind more than 500 kilometers.
Figure 5. Changing Level of the Aral Sea: 1950-2010
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010
meters above sea le vel (1)
Source: Micklin, P (2014e): Aral Sea Basin Water Resources and the Changing Aral Water
Balance. In Micklin, P, Aladin, N, Plotnikov, I (eds.), The Aral Sea: The Devastation and Partial
Rehabilitation of a Great lake. Springer, Heidelberg: Fig. 5.2, p. 122. (used by permission)
Owing to the sea’s shrinkage, climate has changed in a band up to 100 km wide along the
former shoreline in Kazakhstan and Uzbekistan (Micklin 2014b). Summers have warmed and
winters cooled, spring frosts are later and fall frosts earlier, humidity is lower, and the growing
season shorter.
The population living around the sea suffers acute health problems (Micklin 2014b, 2007).
Some of these are direct consequences of the sea’s recession (e.g. respiratory and digestive
afflictions, and cancer from inhalation and ingestion of blowing salt and dust and poorer diets
from the loss of Aral fish as a major food source). Other serious health problems owe to
environmental pollution associated with the heavy use of toxic chemicals in irrigated agriculture
mainly during the Soviet era. Nevertheless, the most serious health issues are directly related to
‘Third World’ medical, health, nutrition, hygienic and water supply conditions.
Perhaps the most ironic and dark consequence of the Aral’s modern shrinkage is the story
of Vozrozhdeniya (Resurrection) Island (Micklin 2014b; Micklin 2007). The Soviet military in
the early 1950s selected this, at the time, tiny, isolated island in the middle of the Aral Sea, as the
primary testing ground for its super-secret biological weapons program. This program stopped
with the collapse of the USSR in 1991. As the sea shrank, Vozrozhdeniya grew in size and in
2001 united with the mainland to the south as a peninsula. There was concern that weaponized
organisms survived decontamination measures by the departing Russian military and could
escape to the mainland via infected rodents or that terrorists might gain access to them. The U.S.
government worked with the Government of Uzbekistan to ensure the destruction of any
surviving weaponized pathogens in 2000.
Figure 6. Kok-Aral Dam and Dike from Lower Side (Sept. 2007)
(photo by P. Micklin)
By September 2009, the Aral had shrunk to a small remnant of its 1960 size and separated
into four parts (Table 1; Fig. 7). The dike and dam constructed to regulate flow from the Small
to Large Aral had raised and stabilized the level of the former leading to greatly improved
ecological conditions and a revitalized fishery. The Large Sea on the south was not so fortunate.
The deeper Western Basin had fallen 26 meters and had salinities in excess of 100 g/l, creating
conditions where no fishes could survive. The Eastern Basin endured a similar level decline and
became a shallow pond with salinity likely above 150 g/l. It appeared that it would dry up
completely during the summer of 2010. However, a heavy flow year on the Amu in 2010 refilled
and revitalized the basin, which since then has shrunk, at times (summer 2014) completely dried,
and expanded in a seasonal rhythm related to the annual hydrologic flow pattern combined with
longer term cycles of wet and dry years (Fig. 7).
Figure 7. Aral Sea on September 6, 2009 (top left), September 7, 2010 ( top right),
November 25, 2014 (bottom left), August 8, 2015 (bottom right)1
1MODIS 250 meter, true color images, bands 1-4-3 (
Scenarios of the Future Aral
What might the future hold for the Aral Sea and its immediate environs? The claim by
some that the lake will dry up completely in the 21st Century is false (Micklin 2014f, 2010).
Even if river inflow from the Amu and Syr were reduced to zero, a very improbable scenario,
there would still be residual input of irrigation drainage water, groundwater, and snow melt and
rain that would maintain at least two substantial lakes: the deeper western (Shevchenko Gulf)
and deeper parts of the central Small Aral Sea in the north, and the Western Basin of the Large
Sea in the south. These lakes would be hypersaline and of little ecological or economic value,
except, perhaps for the production of brine shrimp (Artemia) eggs.
Return of the sea to its 1960s state is possible but very unlikely in the foreseeable future
(Micklin 2014f). Based on a spreadsheet calculated fill-time model developed by the author, it
would necessitate restoring average annual river inflow to 56 km3 and take about 103 years.
Initial conditions of surface area, volume and level were established for the beginning of the
model run taken from actual conditions in September 2011. Then using average annual values
for inflow of 56 km3, net evaporation (evaporation from the sea’s surface minus precipitation on
it) of 869 mm, and net groundwater inflow of 2.5 km3 (these values are derived from data in
Bortnik and Chistyayeva, eds. 1990, pp.14, 34-43) and the water balance mathematical relations
between all these parameters, the growing surface area, volume and level were calculated year by
year until stability was reached at 53 meters above the zero on the Kronstadt sea level gage,
which is located near St. Petersburg, Russia.4 To provide a coefficient accounting for the
growing area as the sea rises, the area increase was divided by the level growth to give an
average figure in km2/m. Restoration would follow a logistic curve: rapid at first as inflow
greatly exceeded net evaporation, then slowing and approaching zero as net evaporation grew
and approached inflow. However, the sea would reach an area of 60,000 km2 (91% of stability
area) and level of 50 meters in just 45 years.
Average annual inflow to the entire sea from 2000 through 2011 is estimated by the author,
with corrections for losses below the last measuring point, at only 8.8 km3 (6.6 km3 from the Syr
and 2.2 km3 from the Amu-including irrigation drainage water input) – 16% of what would be
needed for realization of this scenario (Micklin 2014f). The only realistic means for substantially
increasing inflow to the Aral is reducing the use of river flow for irrigation. Irrigation accounts
for 92% of aggregate withdrawals (Micklin 2014d). It is true that more use could be made of
groundwater for irrigation. Total annual renewable groundwater resources in the Aral Sea
drainage basin may be as much as 44 km3. The portion with low enough salinity and sufficiently
near the surface to be useable has been estimated at around 16 km3 (Micklin 2000, pp. 7-8).
However, much of this is hydrologically connected with surface flow and the maximum net
contribution of such groundwater to irrigation may be much less than is apparent at first glance.
Irrigation efficiency could be substantially improved but at great cost and requiring a long
period for implementation. The area irrigated could also be significantly reduced, but would do
great economic harm as irrigation plays such an important role in the economies of the new
nations of Central Asia. Probably, the most feasible short-term approach to reducing water use in
irrigation is changing the crop mix. Switching hectarage on a large scale from high to low water
use crops (e.g. from cotton and rice to grains, vegetables, fruits, melons and soy beans) could
save considerable water ( Micklin 2014d; Micklin 2000, p. 41). Institutional modernization (e.g.
allowing private ownership of agricultural land) is also needed to incentivize farmer-irrigators to
4 Aral Sea levels are officially measured above this zero that is about 20 cm above ocean level.
use less water (Micklin 2000, pp. 54-67). Improvement of irrigation efficiency and other
measures to reduce water use in this activity are definitely worthwhile. They should be
diligently pursued and efforts are certainly being made in this regard (Dukhovnyy 2013). But
these are longer-term partial solutions to the region’s water shortage problems and not short-term
Of course, it is engineeringly possible to bring water to the Aral Sea from outside Central
Asia (Micklin 2014g). The Soviet government developed plans in the 1960s and 1970s to divert
up to 60 km3 from the Siberian rivers Irtysh and Ob’ to the Aral Sea Basin as the best means to
solve regional water problems for the long-term. The initial phase (27 km3) was on the verge of
implementation when stopped in 1986. Nationalist opposition in Russia to sending “precious”
Siberian water to Central Asia where it would be “wasted,” and concern about negative
environmental impacts on the Ob’ River, Ob’ Gulf, Kara Sea, and even the Arctic Ocean itself
into which the Ob flows played a role in the projects being put on hold. However, the primary
reason appears to have been deep concerns about cost (certainly in the tens-of-billions of USD
(U.S. dollars) and probably much higher. Central Asian water management, government officials
and large parts of the public were shocked by the project being put in limbo. They believed (and
many still do) that they had been “promised” Siberian water to meet what appeared to many in
Central Asia as actual and even worse impending water shortages
This grandiose scheme continues to be discussed and promoted in Central Asian water
management and governmental circles as well as among some in Russia. Nevertheless, it
appears to have little chance of implementation in the foreseeable future owing to high cost, long
construction time, strong opposition from powerful social, scientific and governmental forces in
Russia from which the water would be taken, lack of funding interest among international
donors, and the need for negotiating complex international agreements among the water donating
and water receiving nations. Even if implemented, much less than the 27 km3 diverted, probably
less than 15, would reach the Aral owing to substantial evaporation and filtration losses in the
transfer system, withdrawals along the transfer route for irrigation and other purposes, and usage
in Central Asia for irrigation expansion.
On the other hand, various partial rehabilitation scenarios for the Aral Sea and deltas of the
Amu Dar’ya and Syr Dar’ya hold considerable promise (Micklin 2014g). Calculations by the
author estimate 2.6 km3/yr, on average, is the inflow needed from the Syr to maintain the current
level of the Small Aral (~42 meters above the zero on the Kronstadt gage) with an area of ~3200
km2 )5. However, an additional 0.65 km3 is needed to provide sufficient outflow through the Berg
Strait (Kok-Aral) Dam to regulate salinity. Thus, the total average yearly inflow would need to
be maintained at a minimum of 3.24 km3. For 1992 –2011, the author estimates average annual
inflow at 5.9 km3 and the lowest yearly flow at 3.23 km3, indicating there is more than enough
water available to maintain the current stabilized hydrologic status of the Small Aral Sea.
Since the completion of the dike in 2005, excess water has been released southward
creating a large lake that extends westward and southward and in some years extends sufficiently
far south to aid in refilling the Eastern Basin of the Large Aral Sea. This lake also reaches what
was formerly Tshche-Bas Bay, lying southwest of the Small Aral, and supplements its water
balance. It also provides some water through the connecting channel to the Western Basin of the
Large Aral Sea. Fish from the Small Sea are carried into it by outflow from the Berg Strait Dam.
5 Water balance assumptions: surface precipitation (P)= 120mm/yr; surface evaporation (E) = 960; net groundwater
inflow (GW) = 0.1 km3 P and E are taken from Shivareva, Ponenkova , and Smerdov (1998) and GW is the
author’s .estimate.
Dr. Nikolay Aladin from the Zoological Institute in St. Petersburg and Zaulakhan
Ermukhanov, Director of the Aral’sk branch of the Kazakhstan Fisheries Institute, have named
this water body the Central Aral and consider that it could be developed into a productive fishery
(Personnel communications with Dr. Nikolay Aladin of the Zoological Institute, Russian
Academy of Sciences, fall 2015; Plotnikov I, Ermukhanov Z, Aladin V, Micklin P, 2015: Modern
state of the Small (Northern) Aral Sea fauna [unpublished paper – 7,735 words]).
However, the very shallow lake has a large surface area relative to its volume (the eastern
part is more wetland than true lake) and has extensive areas of reeds contributing to high rates of
evapo-transpiration and thus significant water loss. Also, the western part has salinity levels too
high (~70 g/l) for fish to survive. Finally, the area of the lake experiences great annual variation:
enlarging greatly during the winter/spring period of heavier inflow from the Syr Dar’va and
shrinking rapidly during the summer and fall (and some years entirely disappearing).
To ameliorate these problems, Dr. Aladin has proposed building a dike or dam to keep
water from the Central Aral from being lost to the Eastern Basin of the Large Aral Sea (Aladin V,
Micklin P, and Plotnikov I, 2015: The Partial Restoration of the Aral Sea and the Biological,
Socio-Economic and Health Conditions in the Region [unpublished paper – 7,948 words]). An
argument may be made that it would be wiser to substantially reduce the outflow from the Small
Sea and use the saved water to further raise the level of this water body (see discussion below).
This would of course significantly diminish the size of the Central Aral.
The Kazakhstan Government, with World Bank support, is planning a second phase of the
Small Aral restoration project (World Bank 2014). One of the two alternatives is to raise the
level of water only in the Gulf of Saryshaganak, which extends northeast off the eastern part of
the Small Sea, to 50 meters above the zero mark of the Kronstadt gage (Fig. 8). For this a new
dike and dam, with an outflow structure and navigation locks for ingress and egress, would be
necessary at the Gulf’s mouth. Part of the flow of the Syr Dar’ya would be diverted northward
via a 44 km canal into Saryshaganak to maintain its level. The gulf, now converted into a
reservoir with an area of 825 km2, volume of 6.3 km3, and average depth of 7.6 meters would be
brought back very near the town of Aral’sk the former main port at the northern end of the Aral
Sea. This would allow fishing vessels via a short canal direct access to the newly rebuilt fish
processing plant in that town. Cost of this project is estimated at 150 million USD (World Bank
A spread sheet based fill-time model incorporating mass balance salinity calculations
indicates the reservoir created would be a nearly fresh water body with salinity stabilizing at
around 1.7 g/l (Fig. 9). Such low salinity might not be optimal for indigenous commercial fishes
accustomed to more brackish conditions, although these fish seem to fare well and reproduce in
the lower course of the Syr and its associated lakes (e.g., Kamyshslybas and Karashalan) that
have similar salinities. This issue requires more research.
If one km3 were delivered into the reservoir on an average annual basis, the filling of it
would take 8-9 years (Fig. 9). Increasing this to 1.5 km3 would reduce the filling period to 5-6
years. Diversions from the lower Syr Dar’ya via a major canal would need to be higher to
compensate for conveyance losses to evaporation, transpiration and exfiltration. A reasonable
assumption for such losses (depending on whether and how the canal is lined) is a minimum 15%
of source withdrawals, meaning these would need to be 1.15 km3 for the one km3 scenario and
1.725 for the 1.5 km3 one. At the end of the filling phase, 0.59 km3 on an average annual basis
would need to be released to the main part of the Small Aral Sea (acronym SAM in Russian for
Severnoye Aral’skoye morye) for the former and 1.09 for the latter scenario. As indicated above,
only about 3.24 km3 is required to maintain the main part of the SAM’s level at 42 meters and
allow outflow through the Berg Strait (Kok Aral) dike and dam sufficient to maintain salinity at a
brackish level suitable for indigenous fishes (6-8 g/l). Thus, under either inflow scenario to the
Saryshaganak Reservoir and assuming the 1992-2011 average annual inflow pattern to the Small
Aral from the Syr, represents a reasonable indicator of what the future inflow may be, there
would appear to be enough water available to the main part of the SAM during filling and even
more afterward to maintain its level and allow sufficient flow over the Berg Straight Dam to
properly regulate its salinity. Under either Saryshaganak Reservoir plan enough water would
exit the Berg Strait Dam to maintain a sizable Central Aral water body.
Figure 8. Saryshaganak Gulf Reservoir Plan1
1 Base map is digitized version of 1:500,000 bathymetric map of the Aral Sea produced by the
Institute of Water Problems, Soviet Academy of Sciences in 1981.
The other alternative would rebuild (or replace with a new facility) the Kok Aral dike and
dam, raising the level of the entire lake to 48 meters above the Kronstadt gage (Fig. 10). At this
level, the area of the Small Aral would be 4927 km2, and the estimated inflow (assuming surface
precipitation of 120 mm, surface evaporation of 960 mm, and net groundwater inflow of 0.1
km3) to maintain such a level is 4.04 km3. With the additional outflow to maintain salinity at 6-7
g/l (about 0.8 km3), the total average annual flow needed is 4.85 km3. This alternative would
likely provide more economic and ecological benefits than the Saryshaganak Reservoir plan but
would also require more minimum inflow from the Syr Dar’ya.
Figure 9. Level and Salinity Changes for Saryshaganak Reservoir Under the 1 km3 Inflow
level ASL (meters)
outflow (km3) and salinity (g/l)
salinity (series 3)
level (series 1)
outflow (series 2)
1Figure 9 is based on an annualized fill time and salinity spreadsheet model. The
model’s parameters, other than inflow: precipitation on the gulf surface = 120 mm,
evaporation from the surface = 960 mm, initial gulf area = 150 km2, initial volume is
set at zero as gulf at 42 meters is very shallow and has little water, salinity of inflow
from the Syr = 1g/l, after reaching the target level of 50 meters, outflow is set to net
inflow (water balance surplus) to maintain that level. The change in area as the gulf
rises was determined from a digitized version of the 1:500,000 scale bathymetric map
of the Aral Sea produced by the Institute of Water Problems in 1981. That map was
based on an Aral Sea level of 53 meters above the zero of the Kronstadt gage and has
two (and for some shallow areas one) meter isobaths. Salinity values are calculated as
(salt weight entering the water body minus salt weight leaving the water body)
divided by water body volume.
Figure 10. Optimistic Scenario of the Future Aral Sea (after 2030).
Legend (figures are average annual values). Small Aral Sea: level = 48 m, surface area = 4927
km2, volume 54 km3, river inflow = 5.0 km3, net groundwater inflow = 0.1 km3, outflow = 1.0
km3, salinity = 6-7 g/l. Western Basin of Large Aral sea: level = 33 m, surface area = 6200 km2,
volume = 85 km3, river inflow = 6.4 km3, net groundwater influx 2.0 km3, avg. annual outflow to
Eastern Basin = 3.6 km3, salinity steadily decreasing reaching 42 g/l by 2055 and 15 g/l by 2110.
Eastern Basin of Large Aral Sea: level ~ 28.0 m, surface area ~3,800 km2, volume ~ 7.6 km3,
inflow from Western Basin Aral 3.6, inflow from Central Aral highly variable, avg. annual
salinity >200 g/l. Adzhibay Gulf Reservoir: level = 53 m, surface area = 1147 km2, volume =
6.43 km3, inflow = 8 km3, outflow to Western Basin of Aral Sea =6.6 km3, salinity = 2g/l. ASL,
above sea level, in this case is measured in relation to the Kronstadt gage near St. Petersburg,
Concerns have been raised that filling the entire Small Aral to 48 meters would take too
long. A spreadsheet based annualized fill model, which includes salinity calculations shows the
lake could be filled to 48 meters in 17 years with average annual inflow of 5.0 km3 (Fig. 11).
Filling would be rapid at first and then gradually slowing. After reaching design level, releases,
on average of about one km3/yr, would maintain a relatively stable level and salinity. This
scenario is for an average annual flow situation. Obviously actual annual flow varies from year
to year, sometimes significantly. But these variations should be manageable by careful control of
outflow (more in heavy inflow years, less, even zero, in low inflow years).
Figure 11. Fill Time and Salinity Changes for the Small Aral Sea under 48 meter level and
5 km3 inflow Scenario1
level ASL (meters)
outflow (km3) and salinity (g/l)
outflow (series 2)
salinity (series 3)
level (series 1)
salinity stabilizes at 6 g/l after many years
1Figure 11 is based on an annualized spreadsheet fill time and salinity model. The model’s
parameters, other than inflow: precipitation on the gulf surface = 120 mm, evaporation from the
surface = 960 mm, initial gulf area = 3200 km2, initial volume is 30 km3, salinity of inflow from
the Syr = 1g/l, after reaching the target level of 48 meters, outflow is set to net inflow (water
balance surplus) to maintain that level. The change in area as the gulf rises was determined from a
digitized version of the 1:500,000 scale bathymetric map of the Aral Sea produced by the Institute of
Water Problems in 1981. That map was based on an Aral Sea level of 53 meters above the zero of the
Kronstadt gage and has two (and for some shallow areas one) meter isobaths. Salinity values are
calculated as (salt weight entering the water body minus salt weight leaving the water body)
divided by water body volume.
If average annual inflow were 5.5 km3, fill time would be lowered to 12 to 13 years, after
which releases averaging around 1.50 km3/yr would maintain the 48-meter level and regulate
salinity. Given that estimated average annual discharge into the Small Aral from the Syr for
1992-2011 was 5.9 km3, it seems reasonable that the lower figure could be maintained. And even
the higher inflow is possible, particularly given the hydrological improvements along the middle
and lower course of the Syr Dar’ya to increase flow reaching the SAM that have been made and
those contemplated in the near future (World Bank 2001, 2014).
However, a cautionary note is in order. There is clear evidence from careful monitoring
that climate change in the form of anthropogenically caused global warming is contributing to
the shrinking of the glaciers and snowfields in the Tian-Shan mountains that are the chief water
source for the Syr Dar’ya (Choi 2015). (The same is true for the Amu Dar’ya primarily fed by
the glaciers and snowfields in the Pamirs.) For a period of time (several decades?), the
accelerated melting should increase river flow. But eventually the mass of ice and snow will
become so small that the flow from these will start to diminish. Hence, assumptions based on
the Syr Dar’ya flow record for 1992-2011 may turn out to be too optimistic. This is a subject
that deserves careful research, monitoring, and modeling.
Fig. 11 shows average salinity changes for the SAM during and after filling under the 5
km3 average annual inflow scenario. First year model salinity is 5.7 g/l and rises slowly to year
16 where it takes a slight jump to 6.1 g/l. This results from the initiation of releases of 1 km3 on
an average annual basis from the SAM via the Kok-Aral dam. From then on salinity is
maintained at 6-7 g/l by regulating releases as determined necessary from monitoring water
balance and salinity conditions of the Small Aral. Average salinity in this range would be ideal
for native fishes of the Small Aral and is a persuasive argument for this alternative vs. the
Saryshaganak variant. A somewhat longer channel would need to be constructed to link Aral’sk
to the Gulf of Saryshaganak, but this should not pose any serious problems. This plan would
greatly enhance the Small Aral fishery opportunities and mean that fishing boats from any part of
the sea would have easy access to the former port of Aral’sk as would other types of vessels.
The decision on which alternative to implement has been postponed indefinitely and the
Kazakhstan government with World Bank loan support is proceeding with a second phase of the
North Aral Project that entails only further improvements along the Syr Darya to increase flow to
the Small Aral Sea, reduce flooding along the river’s lower course, provide water to some deltaic
lakes, and expand irrigation. (World Bank 2014)
The future for the Large (Southern) Aral Sea is more problematic (Micklin 2014f). The
Eastern Basin, depending on inflow from the outflow over the Berg Strait Dam and inflow from
the Amu Dar’ya, is at times an extensive, very shallow lake or a dry playa basin contributing to
salt/dust storms arising from the dried Aral Sea bottom (Fig. 7). The lake when present has high
salinity and little ecological or economic value (aside from the potential for raising brine shrimp
and harvesting their eggs). The Western Basin depends largely on net groundwater inflow, direct
runoff from rain and snowmelt, and some input from the Central Aral (via the connecting
channel) when that water body is sufficiently filled by outflow from the Small Aral. On August
8, 2015, its level was between 24 and 25 meters above sea level measured above the Kronstadt
gage and its area was 2967 km2.6
6 The level was determined from comparison of MODIS 250 meter resolution satellite imagery and the Soviet
1:500,000 bathymetric map of the Aral Sea. The area was calculated by outlining the Western Basin on the image,
using Image J software (freeware available from the U.S. National Institutes of Health) to count the pixels enclosed
and then multiplying the number of pixels by 250 which is the pixel resolution in km2 of this MODIS imagery.
If present trends continue, the level of the Western Basin will continue to decrease for
some time, perhaps stabilizing around 21 meters above the Kronstadt gage (assuming
evaporation of 1100 mm, precipitation on the surface of 111 mm, net groundwater inflow of 2
km3/yr and surface inflow of 0.53 km3/yr). At that level its area would be 2560 km2 It would
continue on the path of hypersalinization, steadily moving toward conditions characteristic of the
Great Salt Lake in the United States, the Dead Sea in the Middle East, and Lake Urmia in Iran
(>300 g/l). Only brine shrimp (Artemia) and some bacteria could survive such harsh conditions.
But there are more optimistic scenarios for the Western Basin of the Large Aral. Figure 10
shows a concept developed by the author based on earlier work by two Soviet experts (L’vovich
& Tsigel’naya 1978). It would require an average annual inflow in the lowest reaches of the
Amu Dar’ya of around 12.5 km3. The author estimates average annual flow here for 1990
through 2011 at around 5.4 km3/yr. Hence, it would require a bit more than doubling this, which
could be accomplished via feasible improvements in irrigation efficiency in the Amu River
Basin. This alternative would likely cost more than the 85 million USD expended on the first
stage of the Small Aral restoration. The greatest obstacles to implementation of this plan are
political and economic related to the fact that the plan would complicate the ongoing exploration
for and exploitation of oil and gas deposits from parts of the now dried bottom of the southern
part of the Western Basin of the Aral Sea.
Rehabilitation and preservation of the lower Amu Dar’ya delta has been a priority since the
late 1980s (Micklin 2014f). This is being done through creation of artificial ponds and wetlands
and rehabilitation of former lakes and wetlands in the delta and on the dry bed of the Aral Sea.
Benefits are enhanced biodiversity, improved fisheries, greater forage production, treatment of
wastewater by aquatic vegetation, and some reduction in salt and dust transfer from the dried sea
bottom. A companion measure is the revegetation of parts of the dried bottom with salt tolerant
shrubs, grasses, and trees to stabilize them and lower their deflation potential. Efforts are also
underway to improve wetlands and lakes (e.g. Karashalan, Kamyslybas, and Tushchibas ) in the
lower Syr Dar’ya delta.
Lessons from the Aral Sea
The author finishes with what, based on his research, interactions with many scientists,
scholars, government officials and common people in the former Soviet Union and Post-Soviet
states of Central Asia, are the most important lessons to be drawn from the Aral experience
(Micklin 2014h).
1. The modern desiccation of the Aral Sea illustrates once again that the natural
environment can easily and quickly be wrecked by human actions but that repairing it, if
possible, is a long and arduous process. Hence, humankind needs to be very cautious
about large-scale interference in complex natural systems. And it is essential to carefully
evaluate the potential consequences of such proposed actions before hand rather than, as
so long has been the case, recklessly plunging ahead, hoping for the best as the Soviet
Union did with the Aral Sea.
2. Even though a particular human activity has not resulted in serious problems in the past
this is no guarantee that it will not cause problems in the future. Wide-spread irrigation
in the Aral Sea Basin did not seriously impact the sea prior to the 1960s because large
water withdrawals were off set by compensatory factors such as significant irrigation
return flows to the Syr and Amu rivers and reduced downstream flooding and associated
losses to evaporation and transpiration by phreatophytes growing along the rivers and in
the floodplain. However, these compensating factors were exhausted or overwhelmed as
irrigation expanded from the deltaic zones into the surrounding deserts, there were
increasing losses to exfiltration from lengthy, often unlined canals, and reduced return
flows to the rivers as water accumulated in drainage fed lakes and evaporated or went to
fill pore spaces in dry desert soils. The associated construction of extensive, shallow
reservoirs in the desert and semi-desert plains also contributed to large water losses to the
rivers owing to increased evaporation. Thus irrigation that had been practiced for
thousands of years in this region without placing major stresses on the natural
environment passed a tipping point in the early 1960s beyond which the expansion of this
activity could not be supported by the hydrologic and related natural systems without
incurring significant damage to them.
3. Beware of appealing but facile solutions for complex environmental and human
problems. The Aral situation has been unfolding for more than fifty five years and will
not be remediated over night. “Quick fixes” that have been proposed such as major cuts
in cotton growing to save water and help the Aral Sea may well cause problems worse
than they attempt to solve. Cotton growing is a key economic activity and source of
employment in the Aral Sea Basin. Major cuts in it, if implemented hurriedly and
carelessly, would not only cause damage to national economies, but also substantially
raise unemployment and contribute to social and political unrest. Long term, sustainable
solutions require not only major investments and technical innovations to improve
irrigation water use efficiency, but also fundamental political, social and economic
changes that take time.
4. But all is not gloom by any measure. The natural environment is amazingly resilient.
Hence, don’t abandon hope and efforts to save it, even when the task seems daunting.
Many wrote off the Aral Sea earlier as a lost cause, but it now has been unequivocally
demonstrated that sizable parts of it can be preserved and ecologically restored.
Furthermore, even though not realistic in the foreseeable future, over the long-term, it
may even be possible to reduce the use of water sufficiently to provide adequate
discharge to bring the sea back to what it was more than a half-century ago. As the
archeological and sedimentological record proves, the Aral has suffered desiccations as
great as the present one and recovered.
5. Preservation of biological refugia is key for saving endemic species. Even though a
species may disappear from one habitat owing to changing environmental conditions that
drive it to extinction, it may be preserved in another nearby location. If the alternative
site is preserved, then if and when habitat conditions in the original site become
favorable, endemic species are able to return on their own or can be reintroduced by
humans. This is exactly what happened in the Small Aral Sea. A number of endemic
species (fishes and invertebrates) could not withstand the dramatic increase in salinity.
But these species were preserved in the Syr Darya and in that river’s deltaic lakes. When
the Small Sea separated from the Large in the late 1980s and the first earthen dike was
constructed in 1992, salinity began to drop and some of these species began to return.
After the engineeringly sound Berg Strait (Kok-Aral) dike was completed in August 2005
and the level was raised and stabilized and salinity dropped to near the levels
characteristic of pre-desiccation conditions, many other endemic species repopulated the
6. Large-scale environmental restoration projects such as the Small Aral Sea project require
careful monitoring and follow-up. This is necessary not only to make sure they are
working as expected and to provide management feedback, but to learn new lessons that
may improve the success of similar actions elsewhere.
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... Optimal salinity range (120-160 g/L) face of greatly reduced inflows. However, in the case of the Aral Sea, the lakebed topography and available water have permitted consistent restoration of <10% of the natural surface area and 5% of the volume (Micklin, 2016). Lake Urmia, similar to GSL, has a mid-lake causeway with a central breach, although the available remaining river inflow after anthropogenic withdrawals would be insufficient to restore the endemic ecology on either side, even if the breach were sealed (Hamidi-Razi et al., 2019). ...
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Gilbert Bay, the largest embayment of the expansive Great Salt Lake (GSL) in the United States, is a productive aquatic system providing a suite of ecosystem services, both locally and across hemispheric flyways and global aquaculture networks. Gilbert Bay is currently at a record low stand and elevated salinity attributable to the coupled effects of drought and human water use in the basin. However, a recent management berm at the breach in the mid‐lake causeway provides a unique adaptive management tool to mitigate harmful salinity changes. The present study measured the fluctuating Gilbert Bay salinities and salt loads across a multi‐year period of changing causeway breach management. Opening of the breach in 2016 and a high spring runoff in 2017 exported a substantial portion of Gilbert Bay salt load into adjacent Gunnison Bay, lowering the salinity–elevation relationship in Gilbert. The salt load in the bay has since returned to nearly pre‐breach levels with salinities at the current low stand now exceeding the ecologically optimal range. The chronicled salt movement and salinity relationships were used to recommend short‐ and long‐term adaptive management strategies for the causeway berm in order to sustain the crucial Gilbert Bay aquatic ecosystem in the face of drought and future variability, as well as highlighting the structural advantages GSL has over other saline lakes experiencing anthropogenic water loss.
... Valley, CA, USA, and the Aral Sea) (Indoitu et al., 2015;Kittle, 2000;Micklin, 2016). ...
The Bonneville Salt Flats is a vast dynamic landscape that has been the focus of diverse activities ranging from land speed racing, recreation, potash mining, and an experimental salt crust restoration project. Over the past century, this site has been the focus of several studies, primarily on decadal changes in salt crust thickness and extent. Despite past research, much remained unknown about the origin of the Bonneville Salt Flats’ evaporite sediments, how the evaporite textures of these sediments have changed over time, and the unique hydrology of this system over daily to seasonal timescales. Furthermore, long-term studies demonstrated brine geochemical measurements were imprecise; therefore, an accurate and precise brine salinity measurement methodology was needed. To address these problems, this dissertation: makes paleoenvironmental interpretations of sediment cores; uses petrography of thick sections to determine how evaporite texture changed over time; analyzes several years of environmental measurements, including water level, evaporation, meteorological measurements, and surface time-lapse observations; and lastly, it demonstrates a methodology using brine density measurements at different temperatures to estimate salinity. Sediment deposits show the Bonneville Salt Flats is much younger than previously believed, first forming approximately ~8,300 years ago. Persistent halite accumulation first occurred ~5,400 years ago, not 13,000 years ago, with the desiccation of Lake Bonneville, as was commonly believed. Halite evaporite sediments at the Bonneville Salt Flats show a diversity of morphologies, demonstrating a complex record of post-depositional alteration. Environmental measurements reveal two groundwater states. During the sealed or flooded state, groundwater levels rise rapidly, bringing groundwater to the surface following precipitation. Groundwater level fluctuations are muted during this state. Under desiccated state conditions, groundwater levels primarily vary in response to seasonal and daily temperature changes. Finally, brine density measurements can be used for high-precision measurements of small changes in salinity and provide a valuable evaluation tool in saline systems.
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Environmental viruses have added a wealth of knowledge to ecological studies with the emergence of metagenomic technology and approaches. They are also becoming recognized as important genetic repositories that underpin the functioning of terrestrial ecosystems but have remain moslty unexplored. Using shotgun metagenome sequencing and bioinformatic tools, we found that the viral community structure was affected during natural revegetation in the dried-up Aral Sea area, a model habitat for investigating natural ecological restoration but still understudied. In this study, we highlight the importance of viruses, elements that are overlooked, for their potential contribution to terrestrial ecosystems, i.e., nutrient cycles, stress resilience, and host competitiveness, during natural revegetation.
Climate change has significantly affected global agricultural production, particularly in arid zones of Central Asia. Thus, we analyzed changes in the habitat suitability of cotton in Central Asia under various shared socioeconomic pathway (SSP) scenarios during 2021–2060. The results showed that the average minimum temperature in April, precipitation seasonality, and distance to rivers were the main environmental factors influencing the suitable distribution of cotton. Suitable habitats expanded toward the north and east, reaching a maximum net increase of 10.85 × 10⁴ km² under the SSP5–8.5 scenario during 2041–2060, while habitats in the southwestern area showed a contracting trend. The maximum decreased and increased habitats were concentrated at approximately 68°E and 87°E, respectively. In addition, their latitudinal distributions were concentrated at approximately 40°N and 44°N. The longitudinal and latitudinal dividing lines of increased and decreased habitats were 69°E and 41°N, respectively. Habitats at the same altitude showed an increasing trend, excluding the elevation range of 125–325 m. Habitat shifts could exacerbate spatial conflicts with forest/grassland and natural reserves. The maximum spatial overlap between them was observed under the SSP5–8.5 scenario during 2041–2060. These findings could provide scientific evidence for rational cotton cultivation planning in global arid zones.
This work is an attempt to trace changes in the fish fauna, their food supply and fish catches in the Small Aral Sea from the beginning of 1990s to the present. The purpose of our work is a comparative study of changes in the fishery value of the water reservoir at different stages of its development, including during the last anthropogenic regression. Both literature data and those obtained by the authors in the period 1991–2015 were used. Not only data related to the fauna and fish catches proper, but also data on their food supply, represented mainly by invertebrates, were taken into account. The stabilization of the level of the Small Aral Sea, which followed the construction of the Kokaral dam, greatly changed the situation. The gradual decrease in the salinity of the water reservoir allowed the fish living in the Syr Darya to return to the sea. There are currently 16 species of fish in the sea that can be found in commercial catches.
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The desertification of the Aral Sea basin in Uzbekistan and Kazakhstan represents one of the most serious anthropogenic environmental disasters of the last century. Since the 1960s, the world's fourth-largest inland body of water has been constantly shrinking, which has resulted in an extreme increase of salinity accompanied by accumulation of many hazardous and carcinogenic substances, as well as heavy metals, in the dried-out basin.
Through 2019, the Caspian Sea excluded, the majority (54–60%) of Earth’s irrigation-impacted endorheic lake and sea (ELS) areal extent has been lost in basins that contain as much as 20% of global irrigated agricultural land. Estimates of irrigated agriculture contribution to ELS desiccation based on a steady-state water balance equation for endorheic basins generally agree that this contribution is on the order of 70–90% at the global scale. However, large uncertainties or errors in attribution – as large as 100% – are observed with respect to particular ELS, suggesting that attributions based on a single irrigated agriculture dataset, should be treated cautiously. The observed areal contraction in ELS attributed to irrigated agriculture corresponds to an estimated one-third decrease in ELS volume, excluding the Caspian Sea. Such volumetric decrease is expected to at least double solute concentration in 40–47% of Earth’s ELS.
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The Aral sea used to be the fourth largest lake in the world. Its catchment area is huge, two main rivers (Amu Darya and Syr Darya) feed the lake. The balance of hydrological regime changed drastically after 1960 due to regulation of both main rivers and diversion of water for agricultural irrigation and intense cotton production. Salinity increased and most of invertebrate and fish species disappeared. A significant drop of water level has been recorded in the past 20 years and Aral Lake is presently divided into a small northern lake basin and a larger south basin. Kokaral dam construction resulted in increased water level and decreased salinity. Many invertebrate species reappeared in Small Aral and fish returned from Syr Darya river. Ecological situation in Large Aral is different, eastern part of this basin is completely dried out. The data on salinity levels, some chemical characteristics and above all the data about zooplankton, zoobenthos and fish in Small Aral have been recorded and presented in the article. Salinity ranges between 1 and 8 g/L, the lowest is near the river inlet. Five species of zooplankton (Keratella quadrata, Brachionus plicatilis, Evadne anonyx, Calanipeda aquaedulcis, Cyclops vicinus) and rotifers from the genus Synchaeta are very abundant, ten species are less numerous and seven summer species very rare. Different zoobenthos species are present, but only four abundant (Hediste diversicolor, Chironomus plumosus, Syndosmya segmentum and Cyprideis torosa). Zoobenthos mainly consist of Polychaeta, Mollusca, Crustacea and Diptera. The highest diversity was found near the Kokaral dam. Many fish species are commercially important: 14 of them are abundant, including endemic bream Abramis brama orientalis, Chalcalburnus chalcoides aralensis, carp Cyprinus carpio aralensis, and Aral roach Rutilus rutilus aralensis. White-eye bream Abramis sapa aralensis, silver carp Hypophtalmichthys molitrix, orfe Leuciscus idus oxianus, and snakehead Channa argus warpachowskii are less numerous. Aral barbel Barbus brachycephalus brachycephalus and Turke-stan barbel Barbus capito conocephalus remain very rare. It can be concluded that significant positive changes occurred after Kokaral dam construction. Particularly, biocenoses and the Aral lake environment have been improved and fisheries returned. Today Kazakhstan Government is discussing an idea to improve this dam and dike Izvleček: Aralsko jezero je bilo četrto največje jezero na svetu. Njegovo pri-spevno območje je zelo veliko, dve glavni reki sta pritekali v jezero, Amu Darja in Sir Darja. Hidrološko stanje jezera se je drastično spremenilo po letu 1960 po regulaciji in preusmeritvi obeh glavnih rek za namakanje bombažnih nasadov. Povečala se je slanost, številne vrste nevretenčarjev in rib so izginile. V 20 letih se je gladina vode v jezeru opazno znižala in jezero se je razdelilo na dva dela, manjši severni bazen in večji južni bazen. Po izgradnji jezu Kokaral se je gladina vode zvišala in slanost znižala. Mnoge nevretenčarske vrste so se vrnile v Mali Aral, iz Sir Darje so prišle tudi ribe. Ekološko stanje v Velikem Aralu je drugačno, vzhodni del tega bazena je popolnoma suh. V članku so zbrani podatki o slanosti, nekateri kemijski parametri in predvsem združbe zooplanktona, zoobentosa in rib v Malem Aralu. Slanost variira med 1 g/L in 8g/L, najnižja pri rečnem vtoku. Zelo pogostih je pet zooplanktonskih vrst (Keratella quadrata, Brachionus plicatilis, Evadne anonyx, Calanipeda aquaedulcis, Cyclops vicinus), ena nedoločena vrsta kotačnika Synchaeta. Deset vrst je manj pogostih, zelo redkih pa je šest vrst pomladnih zooplantontov. Prisotnih je tudi več različnih vrst zoobentosa, le štiri vrste pa so pogoste (Hediste diversicolor, Chironomus plumosus, Syndosmya segmentum, and Cyprideis torosa). Zoobentos sestavljajo Polychaeta, Mollusca, Crustacea in Diptera. Največja pestrost je bila ugotovljena ob jezu Kok-aral. Mnoge ribje vrste so gospodarsko pomembne, 14 od njih je pogostih, vključno z endemnimi taksoni Abramis brama orientalis, Chalcalburnus chalcoides aralensis, Cyprinus carpio aralensis, Rutilus rutilus aralensis. Manj številčne so Abramis sapa aralensis, Hypophtalmichthys molitrix, Leuciscus idus oxianus, Channa argus war-pachowskii. Zelo redki sta dve vrsti mrene Barbus brachycephalus brachycephalus in Barbus capito conocephalus. Ugotavljamo, da so se opazne in pozitivne spremembe zgodile po izgradnji jezu Kokaral. Zlasti se je izboljšala vrstna pestrost združb in je-zersko okolje nasploh, zato se je vrnilo ribištvo. Danes Kazahstanska vlada razmišlja o izboljšanju jezu in nasipa. To razmišljanje podpiramo in obenem svetujemo povišanje jezu, kar bi prineslo izboljšanje ekološkega stanja Malega Arala.
The book is structured into six core parts. The first part sets the scene and explains how the use of Aral basin water resources, primarily used for irrigation, have destroyed the Aral Sea. The team explains how spheres and events interact and the related problems. Part 2 examines the social consequences of the ecological catastrophe and the affect of the Aral Sea desiccation on cultural and economic conditions of near Aral region. Part 3 explores the scientific causes of the destruction using detailed analyses and data plus some of their own research spanning aquatic biology, terrestrial biology, hydrology, water management and biodiversity. They also share some of the latest archaeological discoveries and paleobotanical analysis to delineate past levels and characteristics of the Aral Sea. There is particular focus on modern remote sensing and GIS techniques and how they can monitor the Aral Sea and the environment. Part 4 discusses regional and international initiatives to mitigate human and ecological problems of the Aral Sea and the wider political and economic consequences. With thorough insight of the total environment cost, the final chapters of the book will provide lessons for the future. There are insightful case studies throughout. Multidisciplinary by nature, all titles in our new reference book series will explore significant changes within the Earth’s ecosystems and to some extent, and will tackle ways to think about our changing environment.
The first part of this final chapter summarizes the introductory chapter plus the chapters contained in Parts I, II, and III, exclusive of Chap. 18, to remind the reader of the key aspects of each. The second part lays out what in the author’s view are the key lessons to be learned from Aral Sea and its modern desiccation. The final part lists and briefly discusses what needs to be done in terms of research and monitoring of the Aral Sea.
The theme of this volume is continuities in sociological human ecology. The importance of assessing the degree of continuity of ideas and research findings within disciplines and substantive specialties has been recognized for a long time. Some of the work of Robert Merton and his colleagues at Columbia University, for instance, exemplifies this approach. Indeed it was an appreciation of the utility of their contributions to the accumulation of disciplinary knowledge that led to the title for this collection of original essays.
This chapter presents key background information on the Aral Sea and its region. The Aral Sea Basin’s geographical setting is discussed, including location, climate, topography, soils, water resources, constituent nations, and basic demographic parameters. Next, the physical characteristics of the Aral Sea (size, depth, hydrochemistry, circulation patterns, temperature characteristics, water balance, etc.) prior to the modern desiccation that began in the 1960s are summarized. This is followed by treatment of level fluctuations of the Aral and their causes prior to the modern drying. The final section is devoted to tracing the most important events in the history of research and exploration of the Aral up to 1960.
This chapter deals with two related water issues: the water resources of the Aral Sea Basin and the Aral Sea’s water balance. The Aral Sea’s size is dependent on the water resources in its basin and how much these are depleted by human usage. The chief water resources are the large basin rivers Amu Darya and Syr Darya and groundwater. The author discusses the size and character of these and their sufficiency for meeting human demand. Contrary to popular belief, the Aral Sea Basin is reasonably well endowed with water resources. But the high level of consumptive use, overwhelmingly for irrigated agriculture, has resulted in severe water shortage problems (see Chap 8). Since the Aral Sea is a terminal (closed basin) lake with no outflow lying amidst deserts, its water balance is basically composed of river inflow on the gain side and evaporation from its surface on the loss side. Precipitation on the sea’s surface contributes only about 10 % to the positive side of the balance. Net groundwater input is difficult to determine with any accuracy and likely had minimal influence until recent decades when, owing to major drops in river inflow, its impact on the water balance has grown. The Aral’s water balance was very stable from 1911 until 1960. However, since then it has been consistently negative (losses more than gains) owing to very substantial reductions in river inflow caused by large consumptive losses to irrigation. This was particularly pronounced for the decadal periods 1971–1980 and 1981–1990. More river flow reached the sea over the period 1991–2000 and its water balance, although remaining negative. However, the water balance situation deteriorated during the subsequent decade (2001–2010) owing to recurring droughts. The decidedly negative water balance has led to rapid and continuing shrinkage of the sea. (See also Chaps 9 and 11).
Fauna of the Aral Sea has very poor species composition. Its poverty is connected to the geological history of the sea. Originally in the Aral Sea there were at least 180 species (without Protozoa) of free-living invertebrates. Their fauna had heterogeneous origins. Prior to the modern recession/salinization, species originating from freshwater, brackish-water and saline continental water bodies predominated. The remaining were representatives of Ponto-Caspian and marine Mediterranean-Atlantic faunas. Parasitic fauna had poor species composition: 201 species were indigenous and 21 were introduced together with fishes. It had a freshwater character. Ichthyofauna consisted of 20 aboriginal and 14 introduced species. The aboriginal fish fauna consisted of species whose reproduction typically occurs in fresh water. There was no fishery on the Aral Sea and local people caught a few of fish only from the rivers until in the mid 1870s Russians came here. After 1905, a newly built railway stimulated further development of commercial fishing, and the Aral Sea became an important fishing water body. The majority of fishes were commercial. Bream, carp and roach provided approximately two-thirds of commercial catch tonnage. In the twentieth century, there was an increase in species diversity. It was a result of intentional and accidental introductions of initially absent species. Though biodiversity grew by 14 species of fishes and 4 species of free-living invertebrates, only a few of them became commercially viable or valuable as food for fishes. A large number of vertebrate species inhabited the Aral Sea, its shore and islands, the Syr Darya and Amu Darya, and the deltas and lakes of these rivers in their lower reaches. The Aral Sea and its shores provided nesting sites for a large number of various floating and near shore birds. Tugay forests along the banks of the rivers constituted a type of oasis where many animal species lived. By the 1960s the flora of the Aral Sea included 24 species of higher plants, 6 species of charophytes and about 40 other species of macroalgae.
Regression of the Aral Sea began in 1961. At first changes in the fauna were primarily the result of fish and invertebrates introductions. In the 1970s regression accelerated. The main factor influencing fauna is increasing water salinity. In 1970s–1980s invertebrate fauna went through two crises. Freshwater species and brackish water species of freshwater origin became extinct first. Then Ponto-Caspian species disappeared. Marine species and euryhaline species of marine origin survived, as well as species of inland saline waters fauna. By the end of the 1990s the Large Aral became a complex of hyperhaline lakes. Its fauna was passing through the third crisis period. Incapable of active osmoregulation, hydrobionts of marine origin, and the majority of osmoregulators disappeared. A number of species of hyperhaline fauna were naturally introduced into the Large Aral. Salinization of the Aral Sea has resulted in depletion of parasitic fauna. All freshwater and brackish-water ectoparasites and significant part of helminthes began to disappear. Together with the disappearance of hosts, the parasites associated with them in their life cycle had to disappear. Regulation of the Syr Darya and Amu Darya and decreasing of their flow altered living conditions of the Aral Sea fishes, especially their reproduction. In 1971 there were the first signs of negative effects of salinity on adult fishes. By the middle of the 1970s natural reproduction of fishes was completely destroyed. Commercial fish catches decreased. By 1981 the fishery was lost. In 1979–1987 flounder-gloss was introduced and in 1991–2000 it was the only commercial fish. After the flow of the Syr Darya again reached the Small Aral, aboriginal fishes began migrating back to the sea from lacustrine systems and the river. This allowed the achievement of commercial numbers of food fishes. Since the end of the 1990s the Large Aral Sea is a lake without fishes. Regression and salinization of the Aral Sea caused destruction and disappearance of the majority of vegetational biocenoses.
This chapter reviews the available data on the Aral Sea level changes and presents the current thinking on the sea’s recessions and transgressions prior to its modern desiccation. The geomorphologic, sedimentologic, paleoenvironmental, archaeologic and historiographic evidence is reconsidered and combined on the basis of calibrated 14C ages. The geomorphologic data appear contradictory and require re-examination. Lithology and paleoenvironmental proxies of the sediment cores provide much consolidated information, as they record lake level changes in sediment constitution by deep and shallow water facies and layers of gypsum and mirabilite, which are of special importance for determination of low levels. High levels are recorded in several on-shore outcrops. The new archaeological data from the now dry bottom of the Aral Sea and its surrounding zone in combination with the historiographic records provide a robust model for level changes during the last two millennia. Discovery of tree stumps in different parts of the bottom indicate low stands of the lake as well. During the last two millennia, there were two deep natural regressions of ca. 2.1–1.3 and 1.1–0.3 ka (1,000 years) BP (Before Present) followed by the modern anthropogenic one. The lake level dropped to ca. 29 m asl. Their separating transgressions were up to 52–54 m asl. The middle to early Holocene record of level changes is probably incomplete. Currently the middle Holocene regressions are documented for the periods of ca. 5.5–6.3, 4.5–5.0 and 3.3–4.3 ka BP. The early Holocene history of the Aral shows a long period of a shallow lake.
Irrigation is highly developed in the Aral Sea basin. In 2010, irrigation networks covered 8.1 million ha here and accounted for 84 % of all water withdrawals. Irrigation as a highly consumptive user of water is the primary cause of the desiccation of the Aral Sea as it has severely diminished the inflow to the Aral from the Amu Darya and Syr Darya. Irrigation has a long history in the Aral Sea Basin dating back at least 3,000 years. During the Soviet era, irrigation was greatly expanded and water withdrawals for it increased considerably, primarily to grow more cotton. In the post-Soviet period, the area irrigated only increased slightly while water withdrawals for it declined somewhat. The latter has been primarily due to shrinkage of the area planted to high water use crops such as rice and cotton and not to the introduction of more efficient irrigation techniques on a substantial scale. Irrigation systems in the Aral Sea Basin since collapse of the USSR have badly deteriorated owing to lack of proper maintenance of them and insufficient investment in them. And the problems of soil salinization and water logging continue to worsen. There is certainly much that could be done to improve irrigation and use less water for it. This in turn could allow much more water to be supplied to the Aral Sea. But significant improvement of irrigation will require much greater effort and investment along with institutional reforms.