Causes and effects of the water-level rise in the Caspian Sea

1996 ◽  
Vol 2 (1-2) ◽  
pp. 97-100 ◽  
Author(s):  
Jalal Shayegan ◽  
Amir Badakhshan
2021 ◽  
Author(s):  
Matthias Prange ◽  
Sri Nandini-Weiss ◽  
Thomas Wilke ◽  
Frank Wesselingh

<p>Continental drying in response to global warming will entail declining lake levels all over the world. Falling lake levels will have many far-reaching consequences that are underappreciated, but affect the livelihoods and economies of millions of people. A massive warning signal is the projected twenty-first century water level drop of up to 18 m in high emissions scenarios for the Caspian Sea, the largest lake in the world, which could hit stakeholders unprepared. Such a catastrophic drop in the Caspian Sea level would lead to a surface area decrease of 34% including the loss of the highly productive northern Caspian shelf and important wetlands such as the Volga Delta and other Ramsar sites. The disappearance of the vast shallow shelves, which are major food suppliers for fish and birds, will devastate native and endemic fish species, the Caspian seal and a richness of molluscs and crustacean species unique to the lake. The falling water level will not only threaten the unique ecosystem, but will also have severe impacts on regional economies and geopolitical stability.</p><p>In the first part of this presentation, we discuss the extent of twenty-first century projected continental drying on a global scale and its potential effect on worldwide lake levels. In the second part, we focus on the Caspian Sea and discuss the potential impacts of water level fall on biodiversity and ecosystem services. Finally, we address the question to which extent paleoclimates can be used as analogs for future global warming scenarios with respect to changes in the Caspian Sea level.</p>


Geografie ◽  
2007 ◽  
Vol 112 (4) ◽  
pp. 406-423
Author(s):  
Břetislav Svozil

This article deals with problems of variability level of the Caspian Sea. It brings a historical overview with an accent put on the 20th century. It points out causes of the decrease and the lift of the Caspian Sea level, mentions causes as well as consequences of these phenomena. It also deals with prognosticating: it examines whether an erroneous prognosis can influence solution of the problem and whether can cause huge damages. And it also mentions nonperiodical sea sway, increasing and decreasing water level fluctuations, which can cause short-time increases or decreases the Caspian Sea level, as well as the main causes of the Caspian Sea variability level, formulation of prognoses and impacts of the level fluctuation.


2021 ◽  
Vol 3 ◽  
pp. 53-63
Author(s):  
M.D Stambekov . ◽  

Atmospheric circulation processes that caused an extreme sea level drop in the area of the Kashagan offshore oil field in the northeastern part of the Caspian Sea in April 2019 are reviewed and analyzed. It is found that an increase in pressure and wind gradients over the Northern Caspian region led to the occurrence of the set of severe weather events related to each other. An extreme sea level drop caused by the downsurge driven by strong wind was recorded in the area of the Kashagan oil field. Behind the cold front, the cold advection occurred, causing a dramatic air temperature drop by 13 °С. A high temperature contrast and high relative humidity led to the abnormal amount of precipitation of 33 mm per two days. Keywords: water level, severe weather events, downsurge, northeastern part of the Caspian Sea


2012 ◽  
Vol 601 ◽  
pp. 280-288
Author(s):  
Mohammad Ali Lotfollahi-Yaghin ◽  
Roghayeh Rezaei

Jacket structures are designed for a specific water level (LAT). One of the important issues about these structures is the water level rise. For example, the level of water in the Caspian Sea has risen by 2.5m in the last fifteen years and is continuing to rise. The aim of this study is to investigate the behavior of one typical shallow or medium water jacket platform (a four-leg steel jacket platform in 55m water depth) under water level rise and to evaluate utilization factor of different element at different elevations. In this paper the finite element method (ANSYS) was used for the purpose of modeling of the structure. This paper discusses the effect of water level variation acting on the jacket structure and illustrates subsequent results of the stress utilization within the structure elements. The results of time history analysis show that the initial design water depth (before water level rise) has a basic role on the subsequent behavior of structural elements.


Author(s):  
Saule Zhangirovna Asylbekova ◽  
Kuanysh Baibulatovich Isbekov ◽  
Evgeniy Vyacheslavovich Kulikov

The hydrological regime of water reservoirs in different years has a decisive impact on the abundance of commercial fish stocks and the quality of ichthyocenoses. In this connection in 2015-2016 there was conducted a retrospective analysis and ranking of hydrological regime impact on these factors. The paper gives evaluation of catches and fish stocks under different scenarios of water availability in the main fishing ponds of the Republic of Kazakhstan that give about 80% of the annual fish catch of the country (except the Caspian Sea). There were analyzed 2000 factors of hydrological regime (water level, annual discharge) and 1845 factors of fishing stocks (catches, abundance, fish biomass). The paper determines the critical characteristics of water availability for fish stocks. There have been proposed a number of administrative decisions and actions in case if water content would approach to the critical level. Among them: limitation of fish catches in the following year; widening zones restricted for fishing; intensification of safety measures of the fish young in residual ponds during arid periods; introduction of catch standards for a unit of fishing effort in low-water years, high-water years and years with normal water level in rivers.


Author(s):  
Edward Vladimirovich Nikitin

Shallow coastal waters of the Volga river is a flooded feeding area for fish juveniles of nonmigratory fish species. There takes place annual downstream migration of fluvial anadromous fish species from spawning grounds of the Volga river to the Northern Caspian Sea. The most important factors determining the number and qualitative characteristics of fry fishes are the level of the Caspian Sea (currently having a tendency to the lowering), hydrological and thermal regimes of the Volga river. Researches were carried out in definite periods of time. In the summer-autumn period of 2012 fry fishes were presented by 19 species (13 of them were commercial species), which belonged to 9 families. The article gives data on all the commercial fish species. In the first decade of July the maximum number of fry fish was registered in the western part of the Volga outfall offshore - in box 247 (19.86 mln specimens/km2), in the eastern part - in box 142 (20.4 mln specimens/km2). The most populous were roach, red-eye, silver bream and bream; size-weight characteristics were better in the areas remoted from the Volga delta. In the third decade of July the quantitative indicators of fry fish on these areas decreased, size-weight characteristics greatly increased. In the second decade of October in the western part of the seaside there were registered increased pre-wintering concentrations of fish juveniles, their qualitative indicators increased, which is evidence to favorable feeding conditions in 2012.


Sign in / Sign up

Export Citation Format

Share Document