St Petersburg adapts to climate change

By Claire Ricklefs

Flooding in St Petersburg

The EBRD is helping deliver state-of-the-art flood defences to St Petersburg to protect the coastal city from flooding.

With recent research predicting a possible mean sea level rise of up to 1.9 metres by 2100, low-lying coastal cities are at an ever-increasing risk of flooding. And the rise is inevitable: no matter how successful global efforts to reduce emissions and greenhouse gases are, several centuries of rising sea levels are already built into the system due to melting ice sheets and glaciers, as well as the expansion of our warming oceans. Flood protection is therefore a vital investment for many cities.

Built on the flood plain of the River Neva at the extreme eastern end of the Gulf of Finland, St Petersburg is one of those cities at risk. In its 306-year history, the city has been flooded more than 300 times and has had to endure a notable increase in the frequency of flooding in recent years – a tell-tale sign of the effects of climate change.

But the good news is that the city and its rich cultural heritage are (almost) safe. After nearly 30 years of on and off construction, a state-of-the-art flood protection barrier that constitutes one of the largest civil construction projects in the world is due to be completed by the end of 2010.

A giant fortress

At 25 kilometres in length, the barrier cuts across the Gulf of Finland and Kotlin Island in the middle. It consists of 11 embankment dams and six sluice gates to allow water to flow through the barrier and prevent stagnation in the bay. It has two navigation openings for St Petersburg’s busy port traffic.

The total cost of the project is estimated at 87 billion roubles, equivalent to about €2 billion. In 2002 the EBRD signed a loan agreement of US$ 245 million with the Russian Federation, the largest ever EBRD loan at the time, to finance the construction of the flood protection barrier. Donors such as Japan, the Netherlands, Taipei China, the United Kingdom, the United States, the European Commission and the Northern Dimension Environmental Partnership contributed nearly €3.5 million in grants to fund project preparation and implementation consultancies. The European Investment Bank and the Nordic Investment Bank are also financing the project.

The EBRD loan is financing critical organs of the barrier: the heart (central control room), lungs (flood gates), blood (energy supply) and nervous system (computer automated control system),” says Evgeny Smirnov, the project's lead engineer. He has been monitoring and visiting the project almost monthly, working closely with the EBRD operation leader Susan Goeransson.

"Progress in the last two years has been immense,” says Ms Goeransson. “The barrier is now complete and the testing of the flood gates has gone well so far. Health and safety and management standards have also improved , largely due to the presence of international contractors which the EBRD has brought on board.”

Taming the beast

The barrier is so massive that it is clearly visible from space. Each of the six sets of sluices is as big as the Thames barrier and the two huge floating steel gates that close like doors to shut the main navigation channel each measure 122 metres long by 23.5 metres high by 4.7 metres wide. The second channel is closed by a 118m long steel barrier that rises from the sea and can punch through 600 mm of ice − the most that would be expected in a St Petersburg winter.

And there is more. The Russian Federation has used the opportunity to bridge a gap in the St Petersburg ring road, which will help to substantially reduce congestion and traffic in the main city. The barrier will now carry a six-lane highway that crosses one navigation channel via a bridge and passes beneath the main navigation channel in a 2 km-long, 26 metres-deep tunnel.

A priceless investment

A recent climate change adaptation analysis conducted by external engineering consultants Sinclair Knight Merz (SKM), confirmed that the barrier should withstand even the worst-case scenarios for climate change and sea-level rise.

"The barrier is designed to withstand a once-in-a-millennium flood of 4.55 metres but will provide protection for a once in 10,000-year flood of 5.15 metres,” says Mikko Venermo, the EBRD's Senior Environmental Adviser. That means the new barrier will protect the city’s inhabitants and its priceless treasures for at least the next century and probably much longer.