Flooding has been a continuing and even predictable problem in Saint Petersburg, ever since Peter the Great founded the city that became the Russian capital in 1703 on low-lying land within the Neva River estuary. Now, after 30 years of planning, construction and delays, a $3-billion barrier fitted with floodgates and carrying one of the city’s major ring roads is nearing completion.
The 25.4-kilometer-long embankment rises 5.5 meters above the normal water level of Neva Bay, protecting it from the Gulf of Finland to the north and east. At the northeast corner, it features a pair of 122-m-long pivoting, pie-slice-shaped gates that can swing shut to prevent rising gulf waters from overflowing the banks of the Neva River, which snakes through the historic city. Beneath the gates, a six-lane highway passes through tunnels that connect the ring road running atop the floodwall.