scholarly journals Drying Lakes: A Review on the Applied Restoration Strategies and Health Conditions in Contiguous Areas

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 749 ◽  
Author(s):  
Kamshat Tussupova ◽  
Anchita Anchita ◽  
Peder Hjorth ◽  
Mojtaba Moravej

Decrease of saline lakes, which comprise 44% of all available lake water, is a major concern. It additionally accelerates the desertification process of the region. Thus, various countries have taken different actions in protecting their lake water levels. The aim of this paper is to assess different strategies directed to tackle the decreased lake water levels in Lake Urmia and the Aral Sea, which split into the North Aral Sea and South Aral Sea. These are among the world’s largest and fastest drying saline lakes observed in the past 50 years and have both reduced to 10% of their original size. The paper presents a thorough review of academic reports, official documents, and databases. Although the dry-up of a lake is a natural process, it has been sped up by human interventions in the hydrological cycle. Dust storms (strong winds) cause problems in the surroundings. In the case of the Aral Sea, they transmit the pollutants from the dry lake bed causing severe health issues. Various strategies were implemented to manage the socio-economic conditions caused due to the drying of lakes. The strategy implemented for the North Aral Sea was to restore the lake by reducing the water withdrawals from the Syr Darya river, which lead to increased water inflow to the sea. The suggested strategy for Lake Urmia was to restore the lake by water transfer activities from various water sources. These projects have not yet been realized. The strategy implemented for the South Aral Sea was to use a dry lake bed to diversify the economy by oil and mineral extraction along with developing a tourist industry based on the considerable interest to come and observe an ecological disaster of such monumental proportions. These findings show that there is no common best solution for this type of problem. The best fit depends on the local context and it is strongly path-dependent.

2020 ◽  
Author(s):  
Anchita Anchita ◽  
Kamshat Tussupova ◽  
Peder Hjorth

<p><strong>Abstract: </strong>Decrease of saline lakes, which comprises of 44% of all the available lake water, is a major concern. It additionally brings to desertification process to the region. Thus, various countries have taken different actions in protecting their lake’s water level. The aim of this paper is to assess different strategies directed to tackle the decreasing saline lake water levels. Lake Urmia and the Aral Sea which split into North Aral and South Aral were among the world's largest saline lakes and now have reduced to 10% of their original size. A thorough review of academic reports, official documents and databases were considered. Although the dry-up of the lake is a natural process, it has been sped up by human interventions in the hydrology cycle. Dust storms (strong winds) in the case of the Aral Sea, transmit the pollutants from dry lake surface which initially accumulated in the lakebed causing severe health issue. Various strategies were implemented to manage the socio-economic conditions caused due to the drying of lakes. The strategy implemented for the North Aral Sea was to restore the lake by reducing the water withdrawal from tributary rivers which leads to increased water level in the sea. The strategy implemented for Lake Urmia was to restore the lake by water transfer activities from neighbouring water sources which until now show no increase in water level. The strategy implemented for the South Aral Sea was to use a dry lakebed to diversify the economy by oil and mineral extraction which shows the adaptation to the environmental conditions with no restoration strategy. As a conclusion, it is found that there is no common best solution for this kind of problem. The best fit depends on the local context and it is strongly path dependent.<strong> </strong></p><p>Keywords: Drying saline lake; Dust storms; Aral sea; Health impacts; Lake Urmia; Restoration of saline lake; Strategies.</p>


2021 ◽  
Author(s):  
Jerker Jarsjö ◽  
Josefin Thorslund

<p>Water resources are deteriorating across the world, which is of particular concern in water-scarce arid and semi-arid regions. Saline lakes often lack outflow, and are vulnerable to environmental change. When they start to shrink, salinity levels increase, due to evapoconcentration of salts in the reduced water volumes. This may harm the aquatic environment and limit the usability for humans. The associated exposure of their dry lakebeds may also bring severe regional problems of wind-blown saline dust and soil degradation. Although some of the world’s major cases of lake drying have been well studied, like the case of the Aral Sea desiccation, there is a lack of coherent assessments made at the global scale. Such assessments are critical for identifying vulnerable regions and main drivers of change, which may contribute to the prevention of future catastrophes. We here synthesise information on and analyse the desiccation status of 28 major saline lakes, each one of them having a surface area of ≥ 100 km<sup>2</sup> and salinity of ≥ 10 g·L<sup>-1</sup>. They are geographically distributed over the world’s all continents, except Europe and Antarctica. In total, our results show that more than half of the world’s major saline lakes have dried up considerably in the last couple of decades. Out of these, 36 % are already, or are close to being completely desiccated. Preliminary analyses show correlations between original lake depth, lake bathymetry and resulting lakebed exposure from drying, suggesting that a lake’s general resilience to drying may be predictable. Our estimates further show that the world’s major saline lakes together contain 1177 billion tonnes of salt, of which 79 billion tonnes are currently in drying or already dried up lakes. If all of these lakes would desiccate, around 1 billion people are currently living within reach of saline dust storms that could spread from dry lakebeds.</p>


Author(s):  
Vera Rostovtseva ◽  
Vera Rostovtseva ◽  
Igor Goncharenko ◽  
Igor Goncharenko ◽  
Dmitrii Khlebnikov ◽  
...  

Sea radiance coefficient, defined as the ratio of the sunlight reflected by the water bulk to the sunlight illuminating the water surface, is one of the most informative optical characteristics of the seawater that can be obtained by passive remote sensing. We got the sea radiance coefficient spectra by processing the data obtained in measurements from board a moving ship. Using sea radiance coefficient optical spectra it is possible to estimate water constituents concentration and their distribution over the aquatory of interest. However, thus obtained sea radiance coefficient spectra are strongly affected by weather and measurement conditions and needs some calibration. It was shown that practically all the spectra of sea radiance coefficient have some generic peculiarities regardless of the type of sea waters. These peculiarities can be explained by the spectrum of pure sea water absorption. Taking this into account a new calibration method was developed. The measurements were carried out with the portative spectroradiometers from board a ship in the five different seas: at the north-east coast of the Black Sea, in the Gdansk Bay of the Baltic Sea, in the west part of the Aral Sea, in the Kara Sea with the Ob’ Bay and in the Philippine Sea at the coast of Taiwan. The new method of calibration was applied to the obtained spectra of the sea radiance coefficient that enabled us to get the corresponding absorption spectra and estimate the water constituents concentration in every region. The obtained concentration estimates were compared to the values obtained in water samples taken during the same measurement cycle and available data from other investigations. The revealed peculiarities of the sea radiance coefficient spectra in the aquatories under exploration were compared to the corresponding water content and some characteristic features were discussed.


The Holocene ◽  
2020 ◽  
pp. 095968362098168
Author(s):  
Christian Stolz ◽  
Magdalena Suchora ◽  
Irena A Pidek ◽  
Alexander Fülling

The specific aim of the study was to investigate how four adjacent geomorphological systems – a lake, a dune field, a small alluvial fan and a slope system – responded to the same impacts. Lake Tresssee is a shallow lake in the North of Germany (Schleswig-Holstein). During the Holocene, the lake’s water surface declined drastically, predominately as a consequence of human impact. The adjacent inland dune field shows several traces of former sand drift events. Using 30 new radiocarbon ages and the results of 16 OSL samples, this study aims to create a new timeline tracing the interaction between lake and dunes, as well, as how both the lake and the dunes reacted to environmental changes. The water level of the lake is presumed to have peaked during the period before the Younger Dryas (YD; start at 10.73 ka BC). After the Boreal period (OSL age 8050 ± 690 BC) the level must have undergone fluctuations triggered by climatic events and the first human influences. The last demonstrable high water level was during the Late Bronze Age (1003–844 cal. BC). The first to the 9th century AD saw slightly shrinking water levels, and more significant ones thereafter. In the 19th century, the lake area was artificially reduced to a minimum by the human population. In the dunes, a total of seven different phases of sand drift were demonstrated for the last 13,000 years. It is one of the most precisely dated inland-dune chronologies of Central Europe. The small alluvial fan took shape mainly between the 13th and 17th centuries AD. After 1700 cal. BC (Middle Bronze Age), and again during the sixth and seventh centuries AD, we find enhanced slope activity with the formation of Holocene colluvia.


Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1135
Author(s):  
Carolyn Payus ◽  
Lim Ann Huey ◽  
Farrah Adnan ◽  
Andi Besse Rimba ◽  
Geetha Mohan ◽  
...  

For countries in Southeast Asia that mainly rely on surface water as their water resource, changes in weather patterns and hydrological systems due to climate change will cause severely decreased water resource availability. Warm weather triggers more water use and exacerbates the extraction of water resources, which will change the operation patterns of water usage and increase demand, resulting in water scarcity. The occurrence of prolonged drought upsets the balance between water supply and demand, significantly increasing the vulnerability of regions to damaging impacts. The objectives of this study are to identify trends and determine the impacts of extreme drought events on water levels for the major important water dams in the northern part of Borneo, and to assess the risk of water insecurity for the dams. In this context, remote sensing images are used to determine the degree of risk of water insecurity in the regions. Statistical methods are used in the analysis of daily water levels and rainfall data. The findings show that water levels in dams on the North and Northeast Coasts of Borneo are greatly affected by the extreme drought climate caused by the Northeast Monsoon, with mild to the high risk recorded in terms of water insecurity, with only two of the water dams being water-secure. This study shows how climate change has affected water availability throughout the regions.


2021 ◽  
Author(s):  
Elin Andrée ◽  
Jian Su ◽  
Martin Drews ◽  
Morten Andreas Dahl Larsen ◽  
Asger Bendix Hansen ◽  
...  

<p>The potential impacts of extreme sea level events are becoming more apparent to the public and policy makers alike. As the magnitude of these events are expected to increase due to climate change, and increased coastal urbanization results in ever increasing stakes in the coastal zones, the need for risk assessments is growing too.</p><p>The physical conditions that generate extreme sea levels are highly dependent on site specific conditions, such as bathymetry, tidal regime, wind fetch and the shape of the coastline. For a low-lying country like Denmark, which consists of a peninsula and islands that partition off the semi-enclosed Baltic Sea from the North Sea, a better understanding of how the local sea level responds to wind forcing is urgently called for.</p><p>We here present a map for Denmark that shows the most efficient wind directions for generating extreme sea levels, for a total of 70 locations distributed all over the country’s coastlines. The maps are produced by conducting simulations with a high resolution, 3D-ocean model, which is used for operational storm surge modelling at the Danish Meteorological Institute. We force the model with idealized wind fields that maintain a fixed wind speed and wind direction over the entire model domain. Simulations are conducted for one wind speed and one wind direction at a time, generating ensembles of a set of wind directions for a fixed wind speed, as well as a set of wind speeds for a fixed wind direction, respectively.</p><p>For each wind direction, we find that the maximum water level at a given location increases linearly with the wind speed, and the slope values show clear spatial patterns, for example distinguishing the Danish southern North Sea coast from the central or northern North Sea Coast. The slope values are highest along the southwestern North Sea coast, where the passage of North Atlantic low pressure systems over the shallow North Sea, as well as the large tidal range, result in a much larger range of variability than in the more sheltered Inner Danish Waters. However, in our simulations the large fetch of the Baltic Sea, in combination with the funneling effect of the Danish Straits, result in almost as high water levels as along the North Sea coast.</p><p>Although the wind forcing is completely synthetic with no spatial and temporal structure of a real storm, this idealized approach allows us to systematically investigate the sea level response at the boundaries of what is physically plausible. We evaluate the results from these simulations by comparison to peak water levels from a 58 year long, high resolution ocean hindcast, with promising agreement.</p>


2017 ◽  
Vol 130 (4) ◽  
pp. 336 ◽  
Author(s):  
Eric A Parkinson ◽  
Chris J Perrin ◽  
Daniel Ramos-Espinoza ◽  
Eric B Taylor

The Coho Salmon, Oncorhynchus kisutch, is one of seven species of Pacific salmon and trout native to northeastern Pacific Ocean watersheds. The species is typically anadromous; adults reproduce in fresh water where juveniles reside for 1–2 years before seaward migration after which the majority of growth occurs in the ocean before maturation at 2–4 years old when adults return to fresh water to spawn. Here, we report maturation of Coho Salmon in two freshwater lakes on the north coast of British Columbia apparently without their being to sea. A total of 15 mature fish (11 males and four females) were collected in two lakes across two years. The mature fish were all at least 29 cm in total length and ranged in age from three to five years old. The occurrence of Coho Salmon that have matured in fresh water without first going to sea is exceedingly rare in their natural range, especially for females. Such mature Coho Salmon may represent residual and distinct breeding populations from those in adjacent streams. Alternatively, they may result from the ephemeral restriction in the opportunity to migrate seaward owing to low water levels in the spring when Coho Salmon typically migrate to sea after 1–2 years in fresh water. Regardless of their origin, the ability to mature in fresh water without seaward migration may represent important adaptive life history plasticity in response to variable environments.


2012 ◽  
Vol 16 (3) ◽  
pp. 649-669 ◽  
Author(s):  
G. H. de Rooij

Abstract. The increasing importance of catchment-scale and basin-scale models of the hydrological cycle makes it desirable to have a simple, yet physically realistic model for lateral subsurface water flow. As a first building block towards such a model, analytical solutions are presented for horizontal groundwater flow to surface waters held at prescribed water levels for aquifers with parallel and radial flow. The solutions are valid for a wide array of initial and boundary conditions and additions or withdrawals of water, and can handle discharge into as well as lateral infiltration from the surface water. Expressions for the average hydraulic head, the flux to or from the surface water, and the aquifer-scale hydraulic conductivity are developed to provide output at the scale of the modelled system rather than just point-scale values. The upscaled conductivity is time-variant. It does not depend on the magnitude of the flux but is determined by medium properties as well as the external forcings that drive the flow. For the systems studied, with lateral travel distances not exceeding 10 m, the circular aquifers respond very differently from the infinite-strip aquifers. The modelled fluxes are sensitive to the magnitude of the storage coefficient. For phreatic aquifers a value of 0.2 is argued to be representative, but considerable variations are likely. The effect of varying distributions over the day of recharge damps out rapidly; a soil water model that can provide accurate daily totals is preferable over a less accurate model hat correctly estimates the timing of recharge peaks.


2013 ◽  
Vol 9 (5) ◽  
pp. 2135-2151 ◽  
Author(s):  
C. Marzin ◽  
N. Kallel ◽  
M. Kageyama ◽  
J.-C. Duplessy ◽  
P. Braconnot

Abstract. Several paleoclimate records such as from Chinese loess, speleothems or upwelling indicators in marine sediments present large variations of the Asian monsoon system during the last glaciation. Here, we present a new record from the northern Andaman Sea (core MD77-176) which shows the variations of the hydrological cycle of the Bay of Bengal. The high-resolution record of surface water δ18O dominantly reflects salinity changes and displays large millennial-scale oscillations over the period 40 000 to 11 000 yr BP. Their timing and sequence suggests that events of high (resp. low) salinity in the Bay of Bengal, i.e. weak (resp. strong) Indian monsoon, correspond to cold (resp. warm) events in the North Atlantic and Arctic, as documented by the Greenland ice core record. We use the IPSL_CM4 Atmosphere-Ocean coupled General Circulation Model to study the processes that could explain the teleconnection between the Indian monsoon and the North Atlantic climate. We first analyse a numerical experiment in which such a rapid event in the North Atlantic is obtained under glacial conditions by increasing the freshwater flux in the North Atlantic, which results in a reduction of the intensity of the Atlantic meridional overturning circulation. This freshwater hosing results in a weakening of the Indian monsoon rainfall and circulation. The changes in the continental runoff and local hydrological cycle are responsible for an increase in salinity in the Bay of Bengal. This therefore compares favourably with the new sea water δ18O record presented here and the hypothesis of synchronous cold North Atlantic and weak Indian monsoon events. Additional sensitivity experiments are produced with the LMDZ atmospheric model to analyse the teleconnection mechanisms between the North Atlantic and the Indian monsoon. The changes over the tropical Atlantic are shown to be essential in triggering perturbations of the subtropical jet over Africa and Eurasia, that in turn affect the intensity of the Indian monsoon. These relationships are also found to be valid in additional coupled model simulations in which the Atlantic meridional overturning circulation (AMOC) is forced to resume.


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