The Bosphorus Water Tunnel ( tr, Boğaziçi Su Tüneli) or Bosporus aqueduct is an undersea aqueduct in

Istanbul ) , postal_code_type = Postal code , postal_code = 34000 to 34990 , area_code = +90 212 (European side) +90 216 (Asian side) , registration_plate = 34 , blank_name_sec2 = GeoTLD , blank_i ...

, Turkey, crossing the

Bosphorus The Bosporus Strait (; grc, Βόσπορος ; tr, İstanbul Boğazı 'Istanbul strait', colloquially ''Boğaz'') or Bosphorus Strait is a natural strait and an internationally significant waterway located in Istanbul in northwestern Tu ...

strait A strait is an oceanic landform connecting two seas or two other large areas of water. The surface water generally flows at the same elevation on both sides and through the strait in either direction. Most commonly, it is a narrow ocean chan ...

. It was constructed in 2012 to transfer water from the Melen Creek in

Düzce Province Düzce Province ( tr, ) is a province in northwestern Turkey. It is on the coastline of the Black Sea and is traversed by the main highway between Istanbul and Ankara. The main town is Düzce. There are ancient Greek ruins in the province. Düz ...

to the European side of Istanbul.

Need for the aqueduct

With a population of about 15 million, Istanbul is trying to secure its citizens' access to drinking water. Most

clean water Drinking water is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, ...

in Turkey (and, consequently, Istanbul) is located on the Asian borders of the country. Therefore, it is difficult to bring water to Istanbul's Asian side with hundreds of kilometres of pipelines, and another challenge to bring water to the European side of Istanbul with a tunnel dug 85 metres under the

sea bed The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most ...

(145 metres under the sea surface) atop an

active fault An active fault is a fault that is likely to become the source of another earthquake sometime in the future. Geologists commonly consider faults to be active if there has been movement observed or evidence of seismic activity during the last 10,0 ...

Commissioning and finance

The tunnel was commissioned by the Ministry of Forest and Water Management and constructed by an international consortium of Russian and Turkish companies (

Mosmetrostroy OJSC Mosmetrostroy ( rus, Мосметрострой, abbr. of "Moscow Metro Construction epartment) is a major Russian construction company, which deals with solving engineering problems related to performance of a wide range of under and above ...

, ALKE and STFA). The Melen Water Supply Project was funded mainly by JBIC (Japanese Bank for International Cooperation) and partly by DSI ( State Hydraulic Works).

Construction

There were two phases to the project: the underwater-tunnel phase and the land-tunnel phase. The underwater phase was done by the TBM (

tunnel boring machine A tunnel boring machine (TBM), also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They may also be used for microtunneling. They can be designed to bore thro ...

) method, and the land part by blasting. The TBM-drilling part of the project was complete in March 2009 and a ceremony was held, with the attendance of ministers, bureaucrats, Russian diplomats and

Kadir Topbaş Kadir Topbaş (8 January 1945 – 13 February 2021) was a Turkish architect, businessperson and politician who served as Mayor of Istanbul from 2004 to 2017. Biography He was born on 8 January 1945 in Altıparmak village of Yusufeli district ...

, the mayor of Istanbul. The TBM is specially designed and constructed for this project by the German firm

Herrenknecht Herrenknecht AG is a German company that manufactures tunnel boring machines, headquartered in Allmannsweier, Schwanau, Baden-Württemberg. It is the worldwide market leader for heavy tunnel boring machines. Roughly two-thirds of its 5,000 employ ...

, and is six metres in diameter. The average advancing speed of the TBM during the project was per day, with a maximum speed of 20.4 metres per day. After the tunneling works are finished, the tunnel is being lined by prefabricated concrete segments, after which come nine-metre-long steel pipes with an inside diameter of four metres.

Infrastructure

The tunnel is under the sea level, resisting a pressure of . It is a steel tube of in diameter, which is inside a hard-rock type tunnel of in diameter, bored with high-technology machinery. Situated between Ortaçeşme (

Beykoz Beykoz (), also known as Beicos and Beikos, is a district in Istanbul, Turkey at the northern end of the Bosphorus on the Anatolian side. The name is believed to be a combination of the words bey and ''kos'', which means "village" in Farsi. Bey ...

) and Derbent (

Sarıyer Sarıyer () is the northernmost district of Istanbul, Turkey, on the European side of the city. It consists of the neighbourhoods of Rumelifeneri, Tarabya, Yeniköy, İstinye, Emirgan and Rumelihisarı. Sarıyer also administers the Black Sea co ...

) under the Bosphorus, the long waterway tunnel has a water flow rate of . Being the first stage of the Melen System that cost 2 billion TL, the waterway tunnel was constructed in 1,756 days and completed on 19 May 2012 without any accident. It will transfer a daily rate of 2.8 million m³ of water, which is two and half times higher than Istanbul's current water consumption. The Melen System will bring the water of the Melen Creek in

from a distance of , and will ensure the needed water supply for Greater Istanbul until the 2060s. It is the first tunnel connecting two continents. There is a large railway project which will connect both sides of Istanbul as well, but it will be through submerged tubes placed on the sea bed and not by tunnelling. "Asia and Europa With a Water Conveyance Tunnel". Accessed January 29, 2011.

References

{{Tunnels in Turkey Water supply and sanitation in Turkey Buildings and structures in Istanbul Bosphorus Beykoz Sarıyer Tunnels in Istanbul Water tunnels Tunnels completed in 2012 Undersea tunnels in Europe Undersea tunnels in Asia 2012 establishments in Turkey

Need for the aqueduct

Commissioning and finance

Construction

Infrastructure

See also

References