Impacts of climate change on water resources in Central Asia
43
Número 25, 2009
Hydrometeorological observations showed
that the asynchronous
course of atmospheric precipitation and air temperature in the high-
mountain zone of Tien-Shan negatively affects the balance of glaciers
and is reflected in the general water content of rivers, with a consider-
able glaciation of catchment areas (>10%). Thanks to negative trends
in precipitation and positive trends in temperatures in the rivers on
the northern slopes of Kyrgyz Ala-Too,
Terskey Ala-Too and large
inflows of the Sary-Jaz river, the flow for the period of 1963-1990 (in
comparison with the flow for 1930-1960) increased by 11.0-28.6% in
July, while annual values increased by 11.3-17.1%. The implemented
estimate of the change of volumes of glacial flow of the Naryn river
(being a basic component of Syr-Darya) by 2010, in conditions of
continuing warming, showed that they will increase in the basins of
all its main inflows that will lead to growth in the general flow (Podr-
ezov; Dikikh: Bakirov, 2003). This conclusion has been based on the
analysis of hydrometeorological conditions for 1991-2000, when av-
erage summer temperatures for a high mountain zone were above the
norm by 0.6 °C, and July temperatures by 0.9 °CС. The precipitations
here were lower than the norm by 22%, while in the mid-mountain
zone they were near the norm. Thanks to these conditions of warm-
ing
and humidity, the annual flow of the Naryn river exceeded its
average water content for 1991-1996 by 15.7%, thus a compensating
role of glacial flow was clearly shown here. According to data from V.
Kuzmichenok (2006), the total river flow in Kyrgyzstan increased by
6.2% from 1972 till 2000.
The dynamics of river flow during the decades (data from NHMS
of Tajikistan) shows that in Tajikistan
a general tendency was ob-
served of a decrease of surface flow during the period of 1971-1980,
in rivers with a snow-glacial source type within 11-14%, and snow-
rain 8-21%. In the following decade, 1981-1990,
the flow volume
in rivers with a glacial-snow source type decreased a little (1-10%),
and in rivers with snow-glacial and snow-rain source type it increased
Sulton Rahimov
44
Documentos CIDOB, Asia
Impacts of climate change on water resources in Central Asia
(5-25%). A mid-annual flow volume for the period of 1990-2000
rose with respect to the last decade because of an increase in pre-
cipitation and temperature rise. During the period of 1961-1990, the
total amount of the average annual flow
formed in the territory of
Tajikistan decreased by 4 km
3
/year, i.e. an annual reduction of flow
that represents 0.13 km
3
/year.
According to data from the Scientific-Information Centre of the Inter-
state Coordination Water Commission of Central Asia (SIC-ICWC) the
flow of the Syr-Darya river and its inflows for the last 17 years totalled
41.6 km
3
, that is, above the mid-long-term and annual volume for 1950-
1990 by 3.4 km
3
(or 8%). If we compare the average values of annual
flow of the Syr-Darya river for 17 years with the mid-long-term flow for
the entire period of observation of 1911-2007 (37.6 km
3
) then the flow
growth for 17 years will be higher (10%). The flow of the Amu-Darya
river and its inflows for the last 17 years totalled on average 69.2 km
3
,
that is, lower than the mid-long-term annual volume for 1950-1990 by
1 km
3
(1.5%), but it practically coincides with the mid-long-term flow
for the entire period of observation (1911-2007) –69.3 km
3
(Dukhovny
et alias, 2008).
Thus, it can be stated that in general, river flow did not undergo
special changes, though its interannual fluctuations with inconsider-
able deflections are obvious. At a given stage, both increase and lower-
ing of river flow is observed simultaneously, depending on the nature
of their nourishment. According to data from Agalceva (2002), a river
flow with a snow source type reduces faster according to rising tem-
peratures. The rivers with considerable contribution from glacial flow
are more “inert” in this plan, as temperature rise intensifies the thaw-
ing of high-mountain snow and glaciers, creating some compensation
conditions for flow formation. At the same time, in connection with
the continuing degradation of glaciation which progresses with rising
air temperatures, it is estimated that there will be flow reduction here
as well, probably, even more actively (Agaltseva, 2002).
Impacts of climate change on water resources in Central Asia
45
Número 25, 2009
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