ISTANBUL — Turkish President Tayyip Erdogan on Saturday launched ‘Kanal Istanbul’, a $15 billion canal project aimed at relieving pressure on the busy Bosphorus Strait by laying the foundations of a bridge over the planned route. “We view ‘Kanal Istanbul’ as a project to save Istanbul’s future,” Erdogan told at the ceremony. “We are opening a new page in the history of Turkey’s development.” The government said it is increasingly hazardous for tankers to wind their way between Black Sea and the Sea of Marmara down the congested Bosphorous, which divides the European and Asian halves of Istanbul, a city of 15 million people. Already 43,000 ships pass through every year, far more that the 25,000 the government considers safe, causing longer waiting times. By 2050, it is estimated that the number will rise to 78,000. Critics of what Erdogan dubbed his “crazy project” when he revealed it a decade ago question the viability of a waterway running 45 km (28 miles) through marshland and farms on the western edge of Istanbul, and say it will damage the environment. Construction workers poured cement into the foundations of the 1.6 km bridge as a crowd waved Turkish flags. Erdogan said the canal would take six years to complete. Nevertheless, a survey suggests most citizens oppose the project, as does Istanbul Mayor Ekrem Imamoglu and the opposition CHP party, to which he belongs. Critics say it would destroy a marine ecosystem and endanger some of the city’s fresh water supply. Senior bankers told Reuters in April that some of Turkey’s biggest banks were reluctant to finance the canal due to environmental concerns and the investment risks. Russia is also concerned that the canal might not be covered by the 1936 Montreux Convention, which restricts the passage of non-Black Sea states’ warships through the Bosphorus. Imamoglu had dismissed Saturday’s ceremony as a face-saving stunt for a project that has been slow to materialize, partly due to economic difficulties. He said the bridge was part of a highway project unrelated to the canal. To its supporters, it means investment, jobs and safety for Istanbul, Turkey"s largest city. To its critics, it means an eco-catastrophe, a waste of precious funds and a threat to one of the most important treaties underscoring the country"s security. "Kanal Istanbul" — a scheme to dig a 45-kilometer long channel between the Black Sea coast and the Marmara Sea — is undoubtedly Turkey"s most polarizing project, running close to many of the country"s political fault lines, as well as its geological ones. With a new, canal-side city of about one million people also part of the plan — along with dozens of bridges and highways, marinas and malls — a 2018 estimate from the Turkish Ministry of Transportation and Infrastructure put the eventual cost at some $20 billion. An additional price, too, is the environmental damage, with the canal due to pass through some of Greater Istanbul"s most precious remaining green areas. According to the Istanbul Municipality — which strongly opposes the project — some 200,000 trees will be felled, 136 million square meters of agricultural land will be destroyed and 33 million cubic meters of the city"s water supply will be disrupted by the canal. Yet, the potential cost of this economic and political calculation may be much greater in the long run than even the $20 billion price tag. — Agencies