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Istanbul’s Water Security depends on the rainy period to come  

• 22.09.2023
• Author:Dursun Yıldız
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Istanbul’s Water Security depends on the rainy period to come  

Dursun Yıldız

Director

Hydropolitics Association 

22 September 2023

There are two main causes for the present water situation in Istanbul. First of all, we need to separate Istanbul as an Asian side and a European side due to water shortage risk. There is no water shortage risk in the Asian side of İstanbul at all.

65% of Istanbul's population lives on the European side, but 35% of its water potential is located in this region. Since two-thirds of Istanbul's water demand occurs on the European side, the amount of water in the small-volume dam reservoirs of this side decreases rapidly in the drought period. In this case, most of the water needed must be supplied from the dams on the Asian side.

However, on the Asian side, the Melen dam in the Greater Melen water supply system, which also provides water to the European side, could not be put into operation. Due to the foundation ground problem, cracks occurred in the dam body. This completely changed the water supply plan of Istanbul. If the Melen Dam was put into operation, Istanbul's water storage capacity would increase 1.8 times.

Therefore, there are two main reasons for the water supply risk experienced these days. These are meteorological and infrastructural reasons. Firstly, the drought that has been going on on the European side since last year has caused a rapid drawdown of the water levels in the dams in this region. Secondly, since the Melen Dam could not be put into operation, sufficient water could not be stored for the needs of the European side.

 More storage capacity is required to provide approximately 3.3 million m³ of water used daily in Istanbul during the drought period. However, the fact that the Melen Dam was not completed and put into operation reduced Istanbul's water storage capacity by half and changed the water supply plan completely.

What could happen if no rain comes in the next month?

If there is no rain, as was the case last year, certain restrictions may have to be made on the European Side starting from the end of October. For this reason, the "Water supply risk management plan " should be implemented to ensure safe water supply to the European side in terms of both quantity and quality. All excessive water use should be prohibited.

If there is no rain next month, water will be drawn from the bottom area of the reservoir of the dams on the European side, which we call dead volume. This may lead to a decrease in the quality of water supplied to the water network on the European side. A limited water supply program may begin in some regions after October. This situation may last until the rains come.

The best measures to take  for sustainable water management

Istanbul's Drinking Water and Sewerage Master Plan 2053 was completed in the last month. This plan includes all the necessary measures to be taken in detail. However,  the classical water management approach must be changed radically to implement this plan effectively.

The best short-term measure for Istanbul's water management should be to convince water users to reduce their daily water use. As medium-term measures, I propose that Melen Dam should be completed quickly and a water demand management approach should be started in Istanbul. Reverse migration from Istanbul to Anatolia should also be encouraged. Istanbul is a megacity that supplies water to a larger population than many European countries. For sustainable water supply, a paradigm shift in water management and water use habits is mandatory.