The two huge 3,000t steel gates across the main 900m wide navigation section of the St Petersburg flood barrier were successfully floated out of their dry docks and sunk as part of the test programme for the Russian city’s 25.4km long defence this week.
The barrier comprises 11 embankments, six sluices and two navigations and will protect the city from storm surges funnelling down the Gulf of Finland. These could inundate St Petersburg to a depth of 4.6m affecting around 3M people.
A motorway currently under construction along the barrier and then in tunnel under the navigation passes will be the final piece in the St Petersburg ringway. Total cost of the scheme is 87bn roubles (£1.8bn). UK consultant Halcrow has overall management and design responsibility for the project for client the ministry of regional development.