Record: 45 km
The Istanbul Canal (Turkish: Kanal İstanbul) is a project for an artificial sea-level waterway, which is planned by Turkey on East Thrace, connecting the Black Sea to the Sea of Marmara, and thus to the Aegean and Mediterranean seas. Istanbul Canal would bisect the current European side of Istanbul and thus form an island between Asia and Europe (the island would have a shoreline with the Black Sea, Sea of Marmara, the new canal and the Bosporus). The new waterway would bypass the current Bosporus.
The canal aims to minimise shipping traffic in the Bosporus. It is projected to have a capacity of 160 vessel transits a day – similar to the current volume of traffic through the Bosporus, where traffic congestion leaves ships queuing for days to transit the strait. Some analysts have speculated that the main reason for construction of the canal is to bypass the Montreux Convention, which limits the number and tonnage of warships from non-Black Sea powers that could enter the sea via the Bosporus, as well as prohibiting tolls on traffic passing through it. In January 2018, Turkish Prime Minister Binali Yıldırım announced that Istanbul Canal would not be subject to the Montreux Convention.
The Istanbul Canal project also includes the construction of ports (a large container terminal in the Black Sea, close to the Istanbul Airport), logistic centres and artificial islands to be integrated with the canal, as well as the construction of new earthquake-resistant residential areas along the channel. The artificial islands are to be built using soil dug for the canal. Transport projects to be integrated with the canal project include the Halkali-Kapikule high-speed train, the TCDD train project, the Yenikapi-Sefakoy-Beylikduzu and Mahmutbey-Esenyurt metro lines in Istanbul and the D-100 highway crossing, Tem highway and Sazlibosna highway. Financing the canal is expected to be via a build-operate-transfer model, but could also be funded through public-private partnerships. The government is expecting to generate US$8 billion in revenue per year from Istanbul Canal, thanks in part to a service fee for transits. Critics, such as Korkut Boratav, have questioned this number and said that the net revenues could be negative. Other criticisms include the need to direct resources for focusing on earthquake readiness and addressing economic issues, and potential negative environmental impacts.