IMPACTS OF DAMS BUILT IN TURKEY
Large annual and seasonal variations observed in the run-off of most large basins make it necessary for water resources management to store water in the upper catchements in order to allow regulated flows throughout the year and over the
 | years. Implications of dams on the Euphrates and Tigris Rivers must be viewed the context of the management of the whole Euphrates-Tigris basin. The extreme variability of the Euphrates and Tigris Rivers flow has been central water management problem for millenia. The Euphrates, along its entire course in the downstream countries, does not provide ideal sites for the creation of large dams and associated reservoirs. The largest dam in Syria (Tabqa) has only 9 BCM active storage capacity which accounts for 28 percent of the natural flow of the Euphrates. Main storage facilities on the Euphrates |
River in Turkey are Keban, Karakaya, Atatürk Birecik and Karkamis dams, of which largest three Keban, Karakaya and Atatürk dams are currently operating, Birecik and Karkamis dams are under construction. Since the active storage capacity
 | of these reservoirs are 47.6 BCM-1.5 times the annual mean flow of
31.6 BCM-the natural flow of this river is being regulated to a great
extent by utilizing the head of 503 m from Lake Keban to the border
over a distance of 468 km. Evaporation rates at the reservoirs in Turkey
compared to those at Tabqa, Quadisiyah and Habbaniya are much less,
due to the climatic conditions and the improved volume-to-surface
ratios of the Turkish reservoirs in the Euphrates gorge. On the other hand, absence of large reservoirs in Syria and Iraq indicates that little practical use has been made of reservoirs in these |
countries for storing water from high-flow years to low-flow years, and flood waters will continue to flow to the sea.
The Low-lying plains in Syria and Iraq form a natural expansion zone for high waters. The combined area of lakes and swamps
at the head of the Gulf varies from 8,288 sq.km at the end of dry season to 28,490 sq.km during the spring flood, covering the
area having irrigation facilities. During the 1946 flood, total inundated area reached 90,650 sq.km (Naff and Matson, 1984),
causing severe property damage and loss of life.
Downstream riparian countries have no over-year water storage capacities. Therefore Syria and Iraq are unable to store water
for later use as became clear in the dry, year of 1989. From the downstream riparian perspective, potential reductions in
natural Flow to provide for Turkey's need at full development of the Euphrates-Tigris basin could be greatly mitigated by water
savings that would come from evaporation savings and management of the waters in the basin. The reduction in system-wide
evaporation losses would mean that more water would be available for all riparian countries.
Quantity parameters of a river can be transformed by storaga reservoirs; in other words, the characteristics of a stream can be
dramatically altered with the help of storage facilities. Such a change could be depicted in a flow-duration curve. For this
purpose, a statistical analysis of the stream flow for the Euphrates at the Turkish-Syrian was carried out with and without of the
Keban Dam. The annual flow rate of 968 cubic meter per second, corresponds to 33 percent of the time span, Which has
increased to 46 percent after construction of the Keban Dam.
In conclusion, Turkey's dams would porvide Syria and Iraq with this much needed water security. Thus, if there were no dams
in Turkey, flood water would have reached the Gulf without being stored and causing great harm, and there would have been
serious water shortages in dry periods as it used to be in the past.
 | The management of dams in Turkey has always been in conformity with principles that ensure the benefits explained above. During the drought occured in 1989, inflows to Keban Reservoir in the most wet-months of April, May and June were only 42 %, 22 % and 28 % of the long- term averages, respectively. While the dam receives on average 9 BCM of water in these months, the total inflows reduced to only 4 BCM .Hence, were it not be the Keban Dam, only 20.8 BCM of water would have passed over to the Syrian side. Yet, thanks to the management of the Keban Dam, the actual amount of water reaching Syria was 25.5 BCM. These figures give annual totals. |
We can also take a look on the monthly distribution. In 1989 again, the volume of water received by Syria in July and August
when the need for irrigations is the greatest would have been 160 cubic meter per second (414 MCM in a month) under
natural conditions. However, the Keban-Karakaya system managed to deliver an extra water of 180 cubic meter per second
(467 MCM in a month) which raised the total volume of water crossing the boundary in these two months to 340 cubic meter
per second. This, of course, helped downstream countries to avoid the effects an otherwise inevitable drought.
In spite of all these realities, there are still examples indicating that in the Middle East every single event can be manipulated for
political purposes. One is the book titled "Water and Instability in the Middle East" in which N.Beschorner says "the fact that
flow regulation may be hydrologically beneficial but it was politically irrelevant."
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