A waterway of great significance

Turkey’s favourable geographical location makes it an important geostrategic player. This is owed mainly to the Bosphorus, a natural strait and internationally highly significant waterway.

The Bosphorus combines many unique characteristics; it divides the two continents of Asia and Europe, and it separates Turkey into a European and an Asian part. It cuts the country’s largest city, Istanbul, in half. It connects the Mediterranean Sea with the Black Sea, being the world’s narrowest strait used for international shipping with a minimum width of just 700 metres at some point. It is among the busiest natural straits in the world alongside the Strait of Dover or the Strait of Malacca in terms of the number of shipments crossing day-in, day-out. An average of 50,000 vessels transit the strait and more than 10 per cent of them are tankers. On a per-day average, this results in about 140 through-traffic vessels, including some 15 tankers, but without local traffic such as public transportation ferries, cruises and fishing boats. This means the Bosphorus is especially important for hydrocarbon shipments, a major transit way for crude oil and other petroleum products from Russia and other countries of the Commonwealth of Independent Nations, with around 2.5 million barrels a day of crude oil sailing through the strait.

Outstanding significance in history

The Bosphorus is 32km long and has a maximum width of 3.7km at its northern entrance. The depth ranges from 36m metres to 124m, the latter reached midstream of the S-shaped strait. Historically, the Bosphorus has always been of outstanding significance to all of the ruling empires in the region, namely the Ottomans who controlled the strait, and the Russians for whom it meant – and still means – the main maritime access to the outer seas and oceans. Additionally, the British, French, Germans and Italians were also interested in getting a gripon the sea lane, which was one of the reasons why negotiations on conditions for Turkey’s independence, which it reached in 1923, were complicated but eventually gave Turkey control over the Bosphorus, the Sea of Marmara and the Dardanelles. Detailed in the following 1936 Montreux Convention on the Regime of the Straits, merchant vessels enjoy complete freedom of transit and navigation through the Bosphorus. For warships there are special regulations, though.

Currently, two bridges connect the European and the Asian continents, and a third is in the making. The first bridge over the Bosphorus is simply called Bosphorus Bridge and was completed in 1973 and spans over 1,074m connecting the Asian and European urban centres of Istanbul. The second bridge, Fatih Sultan Mehmet Bridge, followed in 1988 5km north of the Bosphorus Bridge; it measures 1,090m and is part of the Trans-European Motorway. A third bridge, Yavuz Sultan Selim Bridge, is currently under construction and is located close to the northern mouth of the Bosphorus. With a length of 2,164m, it is set to become the world’s widest and longest combined road and rail bridge. Being a part of the North Marmara Highway project, it will provide a transit passage for people and freight transportation to and from the new Istanbul airport in the northwest of the city.

City of tunnels

The Bosphorus is also crossed by an undersea tunnel used for Istanbul’s urban rail transportation system, Marmaray. The tunnel is one of the most significant contributions to Istanbul’s railway network. Another tunnel for road traffic is currently under construction, the Eurasia Tunnel, set for completion in October 2016. The tunnel will enable motor vehicles to travel between Asia and Europe via a highway tunnel running underneath the seabed. The two-deck undersea tunnel will have a daily capacity of 120,000 vehicles.