The geography of the Aral Sea basin is complex both topographically and politically. Both rivers that historically kept the lake full are the main freshwater sources for multiple countries.The lake itself is located in a geographically arid region, and the shrinking of the lake is causing the local climate to become even more arid.
The two main sources of water for the Aral, the Syr and Amu Darya rivers, originate hundreds of miles to the southeast in the mountains of Kyrgyzstan, Tajikistan and Afghanistan.
The areas the two rivers flow through rely solely upon them for their freshwater resources. The use of these rivers to develop central Asian countries has led to an increase in population in the area, and a heavy reliance on agriculture as an economic driver in the region. Human withdrawal of water from the Syr and Amu rivers has more than quadrupled in the last hundred years (Edelstein et al, 2012).
(Zmijewski, K. and Becker, R., 2014)
The Aral Sea watershed is very extensive, expanding
and bordering many countries in Central Asia. Anthropogenic manipulation, as
well as climate change, has altered both the Amu Darya River and Syr Darya
River, as well as the many other smaller rivers throughout the region. Populations
have increased greatly over the decades of development and development, and so
has the demand for water in the area, especially for agricultural cash crops like
cotton and rice. Multiple dams and reservoirs are implemented to supply water
to the many residence and irrigation canals, which account for about 70% of the
major rivers’ waters, such as Turkmenistan’s Karakum Canal and Kazakhstan’s Shardara
Reservoir, across the watershed (Zmijewski,
K. and Becker, R., 2014) .
(Cretaux, J., Letolle, R. Berge-Nguyen, M., 2013)
The Amu Darya and Syr
Darya Rivers supply groundwater and surface water to the aquifers and Aral Sea.
In 2001, the average annual flows of the rivers were recorded at approximately
80 km³ for the Amu Darya and 40km³ for the Syr Darya, which account ted for
55km³ to the sea (Zmijewski, K. and Becker, R., 2014) . However more noticeably,
diversions for agriculture have left the sea diminished and broken up into pieces;
recharges to the groundwater system are very small, as can be seen in the
following flow chart (Cretaux, J., Letolle, R. Berge-Nguyen, M., 2013) .
The precipitation, in
the form of glaciers, snow, and rain, flows from the Pamir and Tian Shan
Mountains in the southeast portion of the watershed (Zmijewski, K. and Becker, R., 2014) to the Aral in the
northwest portion. Precipitation and sea levels have fluctuated in the past;
however, over the past century, less and less precipitation is feeding into the
river systems and down to the Aral Sea. Losses from excessive use and climate
change are the major factors influencing the sea. Seasonal precipitation averages
have changed dramatically, with summer months receiving little to no rainfall,
and the wet, winter and spring months receive the majoring of accumulation in
the mountains to the rivers. NASA satellite images of the Aral Sea taken shows
the damages of what excessive human demand and lack of precipitation has had on
the sea (NASA, 2013) . An updated image
taken in August 2013 shows the broken up pieces that were once part of larger
portions of the sea.
References:
Edelstein, M.R.; Cerny, A. and Gadaev, A. Disaster by Design: The Aral Sea and its lessons for sustainability. Emerald Publishing, 2012. Web.
Micklin, P. and Aladin, N.V. 2008. Reclaiming the Aral Sea. Scientific American. 298:4, 64-71.
Cretaux, J., Letolle, R. Berge-Nguyen, M. (2013). History of
Aral Seal Level Variability and Current Scientific Debates. Global and
PLanatary Change, 1(2), 99-113.
NASA. (2013, August 25). Shrinking Aral Sea. Retrieved
from Earth Observatory:
http://earthobservatory.nasa.gov/Features/WorldOfChange/aral_sea.php
Zmijewski, K. and Becker, R. (2014). Estimating the Effects
of Anthropogenic Modifications on Water Balance in the Aral Sea Watershed Using
GRACE: 2003-12. Earth Interactions, 18(3), 1-17.
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