Istanbul's Water Pollution: Strategies And Solutions

Istanbul, Turkey's most populous city, is facing a water crisis. The city's water reserves are drying up, and its reservoirs, which supply water to its 17 million residents, were filled to only 19% capacity in January 2022. Istanbul's water supply and sanitation are stressed by the expansion of the city, and its reserves are polluted by settlements without adequate sanitation. The city's wastewater system is also contributing to the pollution of drinking water reservoirs. To address these issues, Istanbul has established a Water Control Center (ISKOM) and is developing the Melen System to meet the long-term water demand of the city. The city is also implementing a \rainwater collection system\ on the roofs of new buildings, and Turkey's Environment and Urbanization Ministry has made this system obligatory nationwide.

Istanbul's water reserves are drying up

Istanbul, one of the world's biggest cities, is facing a water crisis. The city's water reserves are drying up, and its residents are facing the threat of water scarcity. In January 2021, Istanbul's reservoirs were at shockingly low levels, with storage rates at just around 19% to 20% capacity, leaving less than one and a half months' supply for the city's 15 to 17 million residents.

The city's rapid expansion and growing population are putting enormous stress on its water supplies. Istanbul's reservoirs, almost half of which are located outside the city, are far from replenished, and water scarcity will soon become an even greater problem. The city's mean precipitation during the 1991 to 2020 climate period was 690.5 millimetres per year, which is above average for Turkey. However, the impact of climate change and urbanisation is exacerbating the water scarcity in Istanbul, with projections of a warmer and drier climate in the future.

The acute water shortage in Turkey's major cities has caused panic among residents. Istanbul's Mayor, Ekrem Imamoglu, acknowledged the severity of the situation, stating that the city was experiencing the aridest period in the last 91 years. In reaction to the water crisis, the city's water authority, İSKİ, has built dam infrastructure to bring water from villages hundreds of kilometres outside the city. However, this solution has come at a cost, as it has drained the water reservoirs of these villages and damaged agriculture, forcing residents to relocate to Istanbul, further exacerbating the problem.

To address the water crisis, several solutions have been proposed. One suggestion is for Istanbul to focus on demand-side water strategies rather than supply-side strategies. This involves implementing policies that conserve water and minimise loss, rather than solely relying on building more reservoirs. Other proposed solutions include improving desalination processes, planting less water-intensive crops, and implementing rainwater collection devices in households and businesses. Istanbul is also taking action by establishing a Water Control Centre (ISKOM) to monitor and address water-related issues. Additionally, following Istanbul's lead, Turkey's Environment and Urbanization Ministry made a "rainwater collection system" on the roofs of new buildings obligatory, recognising the potential for rainwater harvesting and greywater recycling to contribute to efficient freshwater use.

The city's water supply is stressed by its expansion

Istanbul is a megacity with a population of approximately 14 million, though some sources state the number is as high as 17 million. It is one of the most rapidly growing cities in Europe, with an annual population growth of 2.8%. This expansion of the city is putting a strain on its water supply.

In 2004, Istanbul's wastewater system consisted of 9,602 km of sewers, 17 pumping stations, 7 pre-treatment plants, and 5 biological wastewater treatment plants. 95% of the wastewater collected was being treated. However, there are still issues with untreated wastewater reaching stormwater drains and contributing to the pollution of drinking water reservoirs. In 1993/94, a severe water shortage occurred when health authorities forbade ISKI to use water from the Elmali reservoir due to its high concentration of ammonium caused by the discharge of untreated wastewater.

To address water supply issues, ISKI responded by planning and building new reservoirs located further away from the city, along with associated water treatment plants and pipelines. The Melen System is also being developed to meet the long-term water demand of Istanbul. The first stage, completed in 2007, increased the available water supply to 1,170 million m3 per year. The second and third stages are expected to bring a total of 1,180 billion m3 for all three phases, doubling the amount of water supplied prior to the Melen system.

Despite these efforts, Istanbul continues to face water supply issues due to its rapid expansion. The infamous Canal Istanbul project, a shipping route that will join the city's two seas, is expected to create adverse impacts on already stressed water basins. It will eliminate some of Istanbul's freshwater resources, pollute groundwater, and further increase the pressure on freshwater basins from urbanization.

To address these challenges, Istanbul should adopt demand-oriented water policies that are compatible with climate change. China's "sponge cities," which focus on storing precipitation and improving drainage and pollutant filtration, provide a positive example. Istanbul should also focus on reducing water loss and improving water management practices.

Istanbul's reservoirs are exposed to pollution from settlements without adequate sanitation

Istanbul is a large metropolitan city with a population of around 14 million, making it one of the world's 23 megacities. It is also one of the most rapidly growing cities in Europe, with an annual population growth rate of 2.8%. This rapid expansion has put a strain on the city's water supply and sanitation systems.

Nearly all of Istanbul's drinking water (97%) comes from surface water collected in reservoirs. The most important water sources are the Omerli-Darlik system on the Asian side and the Terkos-Alibeykoy system on the European side. However, many of these reservoirs are located within the metropolitan area and are vulnerable to pollution from nearby settlements that lack adequate sanitation facilities.

The reservoirs are surrounded by conservation zones that are meant to protect water quality by imposing restrictions on construction and industrial activities. These zones are divided into four concentric buffer zones with increasingly stringent regulations closer to the reservoirs. However, due to rapid and often unplanned urbanization, these regulations are not effectively enforced, resulting in the construction of homes without proper sanitation. Consequently, pollution from these settlements finds its way into the reservoirs.

The pollution carried by the water includes nutrients that serve as food for algae, leading to algal blooms (eutrophication). This process consumes oxygen, making the water unhealthy and unsuitable for a natural wildlife balance. It also increases the costs of monitoring and treating the water.

To address these challenges, Istanbul has taken several measures. The city has established a Water Control Center (ISKOM) to better monitor water quality. Additionally, Istanbul has developed a dual wastewater system to handle heavy storms and prevent contamination incidents. However, unauthorized sewer connections continue to be an issue, with untreated dirty water still reaching the reservoirs.

The establishment of the Water Control Center (ISKOM)

Istanbul, Turkey's most populous city, has been facing acute water shortages and water pollution issues. The pandemic and the lockdown that followed brought a significant decline in noise pollution and air pollution, but water pollution remains a pressing issue.

One of the key functions of ISKOM will be to separate rainwater drainage systems from sewage systems in residential units. This will reduce the load on treatment systems and promote the use of rainwater in daily life and industrial applications. By treating and reusing wastewater, Istanbul will be able to reduce water pollution and increase water availability for its residents.

Additionally, Istanbul is implementing other solutions to address water pollution and scarcity. These include the collection of roof and groundwater in underground cisterns in new buildings and the mandatory installation of rainwater collection systems on roofs by Turkey's Environment and Urbanization Ministry.

The future of Istanbul depends on how fast it can adopt demand-side water policies

Istanbul, Turkey's largest city, is facing a water crisis. The city's water reserves are drying up, and its reservoirs, which supply water to its 17 million residents, were only at 19% capacity in January 2022. The situation has been exacerbated by the impact of climate change, with extreme droughts becoming more frequent. Istanbul's water supply and sanitation are also stressed by the city's rapid expansion and population growth, which is almost twice the national rate.

The future of Istanbul depends on how quickly it can adopt demand-side water policies and improve its water management. The city's current supply-side approach is not sustainable and will only make the city more vulnerable to water scarcity in the future. Istanbul needs to move away from the dominant supply-side water management paradigm, which has been criticised for its inefficiency and inability to build resilience against climate change.

To address the water crisis, Istanbul should focus on reducing water loss and improving water efficiency. The city has already taken some steps in this direction, such as establishing a Water Control Centre (ISKOM) and implementing new zoning regulations that require rainwater harvesting and greywater recycling in all new buildings. Additionally, the city has been working to increase its water supply by developing new reservoirs and treatment plants, such as the Melen System, which aims to meet the city's water demand until 2040.

However, more needs to be done to address the underlying issues of water insecurity. Istanbul should learn from examples like China's "sponge cities", which use nature-based solutions to manage water in a circular and sustainable way. The city also needs to address the pollution of its water sources, as many of its reservoirs are exposed to pollution from settlements without adequate sanitation. Separating rainwater drainage systems and sewage systems in residential units, as well as better monitoring programmes, could help reduce the load on treatment systems and improve water quality.

The political will of local authorities is crucial in driving the necessary changes in water management. Istanbul's sustainability and resilience against climate change depend on how quickly it can adopt demand-side water policies and reduce its vulnerability to water scarcity.

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