Turkey, with Bosporus and the Dardanelles, is home to the sole waterway straddling the Black Sea and the Mediterranean. From economy to military and security, the straits are critical not just for Turkey but for Black Sea countries as well. Being the main trade route that links the Black Sea countries to global markets, the straits have many characteristics unmatched by any other in the world.

The Bosporus, which meanders through the ancient city of Istanbul, is a UNESCO world heritage. The waterfront mansions are the most prestigious paragons of the Bosporus architectural style and they offer unrivaled beauty. In their original forms, most of the waterfront mansions are some of the most lucrative assets in Istanbul and all of Turkey. Among the most renowned waterfront mansions are Hasip Pasha Mansion, Muhsinizade Mansion, Ahmet Fethi Pasha Mansion, Tophane Field Marshal Zeki Pasha Mansion, Kıbrıslı Mansion, Tahsin Bey Mansion, Kont Ostrorog Manor, Şehzade Burhaneddin Efendi Mansion, Zarif Mustafa Pasha Mansion and Nuri Pasha Mansion.

Besides, a spate of spectacular palaces was also erected on the Bosporus during the Ottoman rule. These are Dolmabahçe Palace, Çırağan Palace, Beylerbeyi Palace, Küçüksu Pavilion, Beykoz Pavilion and Adile Sultan Pavilion. Some historical premises like Galatasaray University, the Consulate General of Egypt and the Sakıp Sabancı Museum are other highly popular and unique architectural wonders.

For the Black Sea countries, the Bosporus serves as an access point to the Mediterranean. It has hold of strategic importance since ancient times as a natural waterway between Asia and Europe.

The Bosporus is 29.9 kilometers in length and is as narrow as 4.7 kilometers at the Black Sea inlet and nearly 2.5 kilometers at the Marmara inlet, with the narrowest spot being 700 meters (Kandilli-Rumelihisarı-Bebek).

In addition to factors that restrict any safe passage from physical, oceanographic and meteorological perspectives, the Bosporus is home to waterborne traffic that is four times more than the Panama Canal and three times more than the Suez Canal.

Being quite narrow and meandering while being home to one of the world's busiest waterways, it is a strait that requires utmost reconsideration from the perspectives of geomorphology and hydrography as vessels need to make 12 highly critical maneuvers to change their course, making a 45-degree turn off the shore of Kandilli, and an 80-degree turn around Yeniköy despite some complicated currents that go as fast as 7 to 8 kph.

One can deduce from the underwater topography of the Bosporus that it is awash with a myriad of pits and sandbanks. The 50-meter long isobath (contour) that thoroughly covers the Bosporus from north to south creates a groove. One faces depths and pits out of nowhere at locations where the Bosporus becomes narrower.

It also houses extremely unique ecological conditions in terms of air masses that nautically influence it, and the diversity in plants and animals, and the terrestrial environment.

The current issue

Current is the most important oceanographic factor that concerns the Bosporus. Other oceanographic factors such as waves and tides are not as influential as currents are on the waterborne traffic in the Bosporus. It is also home to a surface current that streams at a speed of 6 nautical miles throughout the year, and eddy currents prevalent around Kandilli, Kanlıca and Yeniköy, and the undertow.

The physical characteristics of the Bosporus (being narrow and meandering) make currents even more relevant. The Bosporus current is formed under hydrological conditions with the effects of precipitation, vaporization and river streams just like it is the case for any other strait. The strength of the current depends on streams into the Black Sea by precipitation and rivers.

The regular current that streams into the Marmara Sea from the Black Sea is capable of changing course, making it from the Marmara Sea to the Black Sea because of winds blowing from the southwest. Colloquially known as "orkoz," the current makes it difficult for vessels to maneuver and navigate.

The surface current from the Black Sea to the Marmara Sea creates swirls in bays that it penetrates into, and there is an undercurrent streaming into the Black Sea from the Marmara Sea in locations near the shores. The depth of the undercurrent depends on the location and conditions. In some locations and cases, it can be 10 miles below the sea level. That is why the undercurrent adversely affects the course and maneuvers of heavy-lift vessels with a large draft survey.

The Black Sea region

The Black Sea is landlocked and the only way for water regeneration is through the Bosporus. The straits also serve as major biological corridors between the Mediterranean and the Black Sea. Depending on the season, aquatic creatures migrate from the Marmara Sea to the Black Sea and vice versa.

The Black Sea is connected to the Marmara Sea via the Bosporus, and to the Mediterranean via the Dardanelles and the Aegean Sea. Heavy rain, poor vaporization and excessive terrestrial freshwater inlets always make the water budget in surface waters of the Black Sea a surplus, and that is why surface waters stream into the Marmara Sea via the Bosporus. The countercurrent in the Bosporus carries salty Mediterranean water to the subsea basin of the Black Sea. When it comes to generic current systems, a large-scale cyclonic flow (counterclockwise), which thoroughly covers the Black Sea along the shore, manifests itself.

Adjacent or connected seas are under the influence of each other's hydrological characteristics through meteorological circumstances, surface and undercurrents. Any physical and chemical change in seas reverberates in all the others. Some 548 cubic kilometers of water make it from the Black Sea to the Marmara Sea in a year while 249 cubic kilometers of water from the Marmara Sea enters the Black Sea.

The Bosporus is one of the world's most challenging waterways in terms of navigation on the grounds of its physical characteristics. The strong currents in the straits, sharp turns and ever-changing weather conditions make it extremely difficult to navigate. However, the waterborne traffic is quite heavy in the Bosporus. 42,000 vessels on average go through the Bosporus a year, and more than 10,000 of them contain petroleum and petroleum-derived products. The cargo carried through the Turkish Straits weighs over 460 million tons a year, including 140 to 150 million of dangerous goods.

The Montreux Convention of 1936 entails that merchant ships can pass through the straits around the clock without having to undergo any procedure except for sanitation inspection. It is optional for them to be joined by a pilot boat or a tugboat when exposed to hazardous situations on the Bosporus.

Here are some major causes for maritime accidents: Heavy waterborne traffic, shipment of dangerous goods, ever-increasing vessel sizes, complicated traffic organization, challenging weather, maritime, current-related and climatic conditions, delicate environmental conditions, local hazards, other maritime operations with an impact on waterborne traffic, ever-rising number of maritime accidents, and narrow waterways that restrict vessels to move forward.

What are the risks?

The Bosporus runs the highest risk for an accident compared to other straits, coastal and inland waters around the world. That was why some major maritime accidents took place in the past, causing the loss of lives and property and doing environmental damage to a severe extent. Here are some major maritime accidents in the strait's history:

On Dec. 14, 1960, two tankers named Peter Verovitz (Yugoslavian) and World Harmony (Greek) collided with one another off the Bosporus shore of İstinye. As the tankers flared up, a devastating fire broke out, and tons of petroleum spilled into the water. It claimed 20 lives.

Following the collision of two Russian vessels on March 1, 1966, the fuel oil spilled into the sea, caught fire and burned the Kadıköy pier and the Kadıköy ferry down.

On Nov. 15, 1979, the Greek-registered tanker Evriali collided with the Romanian-registered tanker Independenta off the shore of Haydarpaşa spilling 95,000 tons of oil into the Bosporus. Having blown up, the tanker Independenta claimed 43 lives on board. The fire went on for two months.

The Greek-registered tanker Nassia collided with Sea Broker on March 14, 1994. The collision claimed 27 lives and 10,000 tons of crude oil burned out.

On Dec. 29, 1999, the Russian-based vessel Volgoneft-248 ran aground with the effect of southwest winds and split into two. 1,600 tons of fuel oil spilled into the sea, doing damage to scores of aquatic creatures and birds. It covered the 7-kilometer-long rocky, sandy and coastal line with oil.

On April 7, 2018, the 225 meter-long cargo vessel named Vitaspirit crashed into Hekimbaşı Salih Efendi Mansion of Beylerbeyi as its wheel got stuck as it was going under the Fatih Sultan Mehmet Bridge.

On Dec. 27, 2019, Liberian-registered dry cargo ship Songalridium 191 meters in length and 24,000 tons in gross weight crashed into the Bosporus bank off the shore of Rumeli Hisarı. Having witnessed the incident in broad daylight, it caused panic among the locals.

On Jan. 6, 2020, 186 meter-long Russian warship Marshal Ustinov was drawing near Kabataş when it became adrift due to heavy storm and rainfall, as a result of climate change which has made its presence felt in Turkey and around the world. The Coast Guard boats responded to the incident and prevented a major accident.

The past accidents on the Bosporus are likely to have caused large-scale environmental pollution, wildfires, mass deaths and extinction of aquatic creatures, and extend the period of time for waste to remain in the sea as four seas are landlocked and it takes a long time for water regeneration. The adverse effects are likely to last a long time.

In addition, the potential damage to historical sites done by such accidents is unimaginable given the history of Istanbul. Istanbul, a historical treasure and cultural heritage, will suffer substantial damage. The works that are shared cultural assets of mankind will cease to exist, and the long-established historical background will face the risk of annihilation.

Why Kanal Istanbul matters

Putting Kanal Istanbul into effect is important in making the Bosporus safe. The Dardanelles and Bosporus are natural canals formed over thousands of years. There are other man-made canals such as the Panama and Suez Canal. They are projects designed and put into practice to reduce costs in the aftermath of growth in global trade, and save time, as well. Kanal Istanbul is a man-made waterway in between the Black Sea and the Marmara Sea to mitigate the waterborne traffic in the Bosporus as it is an incomparable gateway between the Black Sea and the Mediterranean. The canal will make the whole cargo traffic flow without passing through the Bosporus.

In line with the growing economic activities around the globe, the number of vessels and the weight of goods going through the Bosporus keeps rising. While the number of vessels going through the straits in the 1930s, when the Montreux Convention was concluded, was 3,000, the average of the past 13 years has been 50.3 a year, and 20% of them are tanks carrying dangerous goods.

The Ministry of Transport and Infrastructure reports that 140 to 150 million tons of dangerous goods go through the Bosporus on an annual basis. This is nearly three times more than the amount of oil to be transported through the Baku-Tbilisi-Ceyhan pipeline, which has an annual capacity of 50 million tons.

The rise in waterborne traffic, growth in the size of vessels based on technological developments, and the increasing number of tankers carrying oil and derivatives put increasing pressure on the Bosporus and increase the risk of an accident. Official figures suggest that the waterborne traffic for container ships has declined by 11% since 2014 while cargo capacity of vessels has increased by 41%. This makes it essential to come up with a plan to build an alternative passageway to substitute for the Bosporus.

The Ministry of Transport and Infrastructure reports that it takes 14 hours on average for a regular ship to pass through while it takes 30 hours for vessels carrying dangerous cargo and that it costs up to $120,000 on average daily.

Of five potential ones, the corridor that is situated within the boundaries of Avcılar, Küçükçekmece, Başakşehir and Arnavutköy has been designated feasible based on the findings of studies conducted from 2011 to 2015 to set a route for the canal.

Kanal Istanbul is going to go through Küçükçekmece, Avcılar, Başakşehir and Arnavutköy on the European side of the city. The Environmental Impact Assessment (EIA) application for Kanal Istanbul was submitted to the Ministry of Environment and Urbanization on Feb. 20, 2018, and a public participation meeting was held in the town of Arnavutköy on March 27, 2018.

Comprising of more than 15,000 pages, the EIA report was drawn up by almost 200 academics from 33 scientific disciplines. On Nov. 28, 2019, a committee, which consisted of officials from 55 agencies and organizations, gathered and held a Review & Assessment Committee (RAC) meeting. The report was completed in the aftermath of the RAC meeting, and released on Dec. 23, 2019, for public opinion and was approved on Jan. 17, 2020.

As noted in the EIA report, the canal will be 45 kilometers in length, no fewer than 275 meters in base width, and 20.8 meters in depth. Auxiliary facilities such as two ports, one marina, one logistic center, seven bridges, dredging and coastal filling areas, two railways and two light rail systems will be built as a part of the project.

The project will also bring about a positive impact on employment. Additionally, the ports to be erected will pave the way for Istanbul to grow into a major hub for maritime trade.

Required to be completed in seven years, the project is estimated to serve Turkey for no fewer than 100 years.

Based on the studies over traffic for Kanal Istanbul, the scale of commercial container ships in the Black Sea currently stands at 3167 twenty-foot equivalent unit (TEU) increase and is estimated to increase to 3996 TEU by 2030, and to 5604 TEU by 2071. The ports of Marmara are equipped with a total of 11.4 million TEU cargo handling in theory. Based on the figures for the past four years, the average handling capacity is 5 million TEU a year.

The land-use plan will help the building stock located in settlements of Istanbul with risky buildings to exist on both banks of Kanal Istanbul. Any plan will be made in consideration of the city's natural, cultural, historical and social characteristics.

A canal to be built in Istanbul will save the Bosporus, which is a natural and historical asset, and the local people from a major hazard that they currently face day in and day out. Kanal Istanbul is poised to make sure that tankers, which currently pass through the Bosporus, make their way through the Canal, and to eliminate any risk.

* Deputy Minister at the Republic of Turkey's Ministry of Environment and Urbanization, Chief Climate Change Envoy