Water supply and sanitation in Istanbul

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Water supply and sanitation in Istanbul is the responsibility of the public utility ISKI (Istanbul Su ve Kanalizasyon Idaresi) created in 1981.

Contents

Water sources

Nearly all of Istanbul's drinking water (97%) comes from surface water collected in reservoirs. Its most important water sources are the Omerli-Darlik system on the Asian side and the Terkos-Alibeykoy system on the European side. Both systems consist of dams, reservoirs, water treatment plants and pipelines. Many of the reservoirs that supply Istanbul are located within the metropolitan area and are exposed to pollution from settlements without adequate sanitation. Water quality is theoretically controlled by conservation zones around the reservoirs which limit construction and industrial activities in four concentric buffer zones with increasingly strict regulations the closer the zones are to the reservoirs. However, there is little enforcement of these regulations in the face of rapid and often unplanned urbanization. Illegal settlements sprang up around the reservoirs, fueled by land speculation. Subsequently they became de facto legalized with their own municipal administrations elected mayors. [1] [2]

Water pollution crisis and response

In 1993/94, a severe water shortage had occurred after health authorities forbade ISKI to use water from the Elmali reservoir because of its high concentration of ammonium caused by the discharge of untreated wastewater into the reservoir. [2] ISKI responded by planning and building new reservoirs located further away from the city and associated water treatment plants and pipelines, notably the Istranca dams in the Black Sea basin on the European side of the Bosphorus, and the Yeşilçay Regulator in the Black Sea basin on the Asian side. With these and other investments the available water supply was increased to 1,170 million m3 per year. [3]

The Melen system

However, given the growth of Istanbul, additional water resources were still needed. Therefore the Melen System is being developed to cover the long term water demand of İstanbul. The first stage supplying 268 million m3 was completed in 2007 with Japanese financing. A second and third stage are expected to bring a total of 1,180 billion m3 for all three phases to meet the water demand of the city until the year 2040, doubling the amount of water supplied prior to the Melen system. Also, a 5.5 km tunnel under the Bosporus will transfer water to the European side. [4] According to monitoring by four metropolitan agencies drinking water quality is good, reportedly surpassing Turkish as well as EU standards. According to a 2004 survey, 35% of customers stated that they drink water from the tap, up from only 10% in 2000. During that period water quality had improved due to network repairs and the completion of new drinking water treatment plants. [5]

Impact of climate change

Although the data do not indicate a clear declining trend in rainfall, extreme events – especially droughts – seem more pronounced than in the past. In 2006, rainfall of 67 mm was the record low for the previous 50 years, a period during which the average was 257 mm per year. Furthermore, the water level in reservoirs serving the city plummeted to around 25% of full capacity in 2007 and 2008. ISKI, using a scenario of a 2°C temperature increase by 2030, estimated that the city's water supply may decline by as much as 14% over the next two decades because of higher evaporation from reservoirs. [6]

Sanitation

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. Treated wastewaters are discharged into the Bosphorus. They are discharged into the lower layer, where the flow is towards the Black Sea in the North. The Black Sea has a much greater assimilative capacity than the ecologically more sensitive Marmara Sea to the South. For discharges into the Marmara Sea more expensive tertiary treatment is needed, while primary treatment is sufficient for disposal into the Black Sea. [5] The sewer system consists, in principle, of separate sanitary sewers and stormwater drains. However, in reality there are illegal cross-connections so that untreated wastewater reaches the stormwater drains and contributes to the pollution of drinking water reservoirs. [2]

See also

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Combined sewer Sewage collection system of pipes and tunnels designed to also collect surface runoff

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Water supply and sanitation in Turkey is characterized by achievements and challenges. Over the past decades access to drinking water has become almost universal and access to adequate sanitation has also increased substantially. Autonomous utilities have been created in the 16 metropolitan cities of Turkey and cost recovery has been increased, thus providing the basis for the sustainability of service provision. Intermittent supply, which was common in many cities, has become less frequent. In 2004, 61% of the wastewater collected through sewers was being treated.

History of water supply and sanitation The history of providing clean water and safe sanitation systems since the dawn of civilization

The history of water supply and sanitation is one of a logistical challenge to provide clean water and sanitation systems since the dawn of civilization. Where water resources, infrastructure or sanitation systems were insufficient, diseases spread and people fell sick or died prematurely.

Water supply and sanitation in Japan is characterized by numerous achievements and some challenges. The country has achieved universal access to water supply and sanitation; has one of the lowest levels of water distribution losses in the world; regularly exceeds its own strict standards for the quality of drinking water and treated waste water; uses an effective national system of performance benchmarking for water and sanitation utilities; makes extensive use of both advanced and appropriate technologies such as the jōkasō on-site sanitation system; and has pioneered the payment for ecosystem services before the term was even coined internationally. Some of the challenges are a decreasing population, declining investment, fiscal constraints, ageing facilities, an ageing workforce, a fragmentation of service provision among thousands of municipal utilities, and the vulnerability of parts of the country to droughts that are expected to become more frequent due to climate change.

Water supply and sanitation in Georgia is characterized by achievements and challenges. Among the achievements is the improvement of water services in the capital Tbilisi where the water supply is now continuous and of good quality, major improvements in the country's third-largest city Batumi on the Black Sea where the country's first modern wastewater treatment plant now is under operation, as well as a general increase in access to drinking water in the entire country. Water and sewer tariffs remain affordable, with the private water company Georgian Water and Power (GWP) serving the capital being financially viable and profitable, while the public water company serving most of the rest of the country remains financially weak. The improvements were achieved after the Rose Revolution of 2004 when the government decided to reform the sector and to invest in it after many years of neglect.

Water supply and sanitation in the Wellington region involves the provision of the "three waters" – drinking water, stormwater, and wastewater services in the Greater Wellington region.

References

  1. ↑ Ali Demirci and Anya Butt:Historical Overview and Current Trends in Istanbul's Water Supply Development, Globalization And Water Resources Management: The Changing Value of Water, August 6–8, Awra/Iwlri-University of Dundee International Specialty Conference 2001. Retrieved September 14, 2010.
  2. 1 2 3 (German) Şenda Kara and Frank Alleweldt:Trinwasserversorgung und Stadtexpansion:Der Fall Istanbul (Drinking Water Supply and Urban Expansion:The Case of Istanbul), in: Wasser - Abwasser 136 (1995), Nr. 7, pp. 345-353
  3. ↑ Istanbul Water Basin Management and European Union Water Framework Directive, 2007, International Congress on River Basin Management, by Dursun Ali Çodur, General Director, Istanbul Water and Sewage Administration (ISKI), Mehmet Patan, Planning Director, Istanbul Water and Sewage Administration (ISKI), İSKİ APK Director Nevzat Uyaroğlu, Research Director, Istanbul Water and Sewage Administration (ISKI), Orhan C. Gőktaş, Professional Environmental Engineer, Istanbul Water and Sewage Administration (ISKI), Deniz Aydin, Professional Environmental Engineer, Istanbul Water and Sewage Administration (ISKI). Retrieved September 14, 2010.
  4. ↑ XIVst Regional Directorate of State Hydraulic Works -Istanbul. Retrieved September 14, 2010.
  5. 1 2 Altinbilek, Dogan. "Water Management in Istanbul". International Journal of Water Resources Development. 22 (2): 241–253. doi:10.1080/07900620600709563.
  6. ↑ Waterwiki: Facing water challenges in Istanbul. Retrieved September 14, 2010.
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