The word ‘delta’ often seems to go hand in hand with flooding, in countries like Bangladesh, Vietnam, Indonesia and Nigeria. But as well as threats, delta cities also face economic opportunities, says Paula Verhoeven, climate director of the Dutch delta port of Rotterdam.

Scientists, policy makers and entrepreneurs from delta cities all over the world are converging on Rotterdam for a three-day conference on Deltas in Times of Climate Change. They will be discussing the problems associated with living in a delta region, but also looking at the economic opportunities.

Rising sea levels
Delta cities everywhere are confronted by more or less the same issues. They lie at the mouth of one or more major rivers, often below sea level – which over the coming years will only go on rising. The rivers provide a handy transport link with the rest of the country, while the sea is the route to the rest of the world. This makes delta cities desirable places to live and work, and they often have populations well into the millions.

Because they face the same problems, delta cities can also learn from each other and work together to come up with solutions. Over the past two years, cities like Rotterdam, Jakarta and Ho Chi Minh City have been collaborating to explore possibilities. Paula Verhoeven sees economic opportunities for her city.

“Many different forms of architecture are being developed which allow you to live beyond the dykes in a traditional house, but have less trouble with flooding. For example, by raising the level of the living area so you don’t have water in your living room as soon as there’s a flood. Or by making buildings that can be temporarily sealed. And there’s a whole new sector emerging based on floating buildings.”

Finance
Of course, you can’t directly compare Rotterdam with cities like Jakarta and Ho Chi Minh City, which are often short of funds for investment. However, according to Paula Verhoeven it’s still important to invest now to avoid trouble in 20 years’ time.

Jos Dijkman, project manager at Deltares, an institute specialised in Delta issues, shares this view. He explains the problem facing Ho Chi Minh City in Vietnam.

“A large proportion of the drinking water is pumped up from deep groundwater and that causes subsidence, so the ground level is falling. This increases the danger of flooding. It’s the same story in Jakarta.”

Subsidence
Jakarta is subsiding by ten centimetres a year, says Mr Dijkman. “There are major plans to stop extracting groundwater and switch to supplying water via a mains network. At the same time, dykes need to be constructed because the subsidence won’t stop straight away. These are drastic but unavoidable measures,” he says.

Floating buildings
Nevertheless, for these deltas too the news isn’t all bad. They also face economic opportunities, says Paula Verhoeven.

“There too you see companies focusing on floating construction. There’s also an emerging industry associated with defence against water. There too you see companies investing in dykes and flood defences. Sometimes the companies are from the countries themselves, but they’re also from overseas."

The main aim of the Rotterdam conference is for participants to exchange knowledge and establish forms of cooperation, so in future it will still be possible to live in the world’s delta cities.