14 May 2012Istanbul's rapid population growth, greater consumption associated with modern life, illegal housing around major reservoirs, pollution by industrial sites as well as large urbanisation projects are putting the city's water sources under pressure.
With the city's demand for water increasing every day, experts are sceptical of the capacity to meet it.
"Water sources in Istanbul and its surroundings don't seem able to respond to the city's population growth in the long run," Meric Albay, the dean of the Water Products Faculty at Istanbul University, told SES Türkiye.
The current policy of transporting water from distant reservoirs to Istanbul is a temporary and unsustainable one, he says.
The city of 15 million consumes an average of 820 million cubic metres of water annually, which is provided by a total of 12 water reservoirs. More than 32.6% of this is transported from the Melen Reservoir, located in Sakarya province, 185km from Istanbul.
There are 1-1.5 million people living in areas surrounding Istanbul's water basins, which puts pressure on water sources and their quality, says Tayfun Kahraman, the chairman of Istanbuls City Planners Chamber.
Albay says all of Istanbuls water basins are under the threat of different polluters. "This problem has become even more serious with the citys expansion towards the north and establishment of new settlements in that part of Istanbul," he explained.
According to existing legislation, housing is prohibited in areas up to 1,000m from water reservoirs, and settlement between 1,000 and 5,000m from basins can only be established with the permission of the Istanbul Metropolitan Municipalitys Assembly.
Many housing settlements within 5,000m of water basins were established before those zones became protected water basins, Ahmet Demir, the general director of Istanbuls Water and Canalisation Administration, told SES Türkiye.
"However, due to advanced construction methods, waste water from the housing settlements can be kept under control and ... be taken out of the reservoir [region], to then be subject to purification processes," he said.
As the number of industrial sites increases, pollution by industrial facilities is another serious threat for Istanbuls water sources. "It is a pity that industrial [sites] cannot or [mostly] do not purify the waste water they discharge to Istanbul's creeks," Beyza Üstün, a member of Istanbuls Environmental Engineers Chamber, told SES Türkiye.
Although this is forbidden by law for most creeks, facilities get informal permission from monitoring authorities to do so, she said, adding that most of the species living in creeks or basins where waste water is discharged are currently dying.
Istanbul's water purifying facilities are still insufficient and most of waste water gets discharged to deep sea waters through the Bosphorus Strait currents.
Meanwhile, large urbanisation projects, like the construction of the third bridge on the Bosphorus, pose another threat to Istanbuls water sources. Experts fear a third bridge and related highways and road extensions will destroy the citys northern forests -- often referred to as its "lungs" -- where much of its water sources are also located.
"The construction of the third bridge means at the same time more carbon emissions, less carbon reduction due to deforestation, more droughts and floods, and less and less clean drinking water," Esra Yazıcı Gökmen, an urban and regional planning expert at TEMA Foundation, told SES Türkiye.
Noting that Istanbul faced similar challenges after the construction of the second bridge, she urged authorities to give up on this and any other project that will cause the citys population to expand.