‘The loop is broken’

Professor of Hydraulic Engineering Han Vrijling is sad to see how attention for dikes is fading in the Netherlands. “Everyone talks about innovation like it’s a roast chicken that flies into your mouth of its own accord.”

The Netherlands is famous for its feats of hydraulic engineering. Do you think that is still justified today?

“It’s true in terms of our history. But if you look at the way water policy is developing at the moment … (Vrijling sighs). During my valedictory address (23 May, ed.) I talked about the Vice Minister for hydraulic engineering in Vietnam, Prof. Hoc. He wants to build dikes, because he no longer considers evacuations appropriate to the current level of affluence in his country. Before becoming Vice Minister, he was a professor of hydraulic engineering and the rector of a university of technology. When people without a solid background in hydraulic engineering come to visit him, he sees through them immediately. It’s just the opposite with us. Over here we no longer have any engineers at the top. The general thought seems to be that the entire delta programme can operate without engineers. The story in the Netherlands is that we need to work towards multi-layered safety. This implies that dikes are not sufficient. We should also build mounds and organise evacuations in case the dikes fail.”


What’s wrong with a good evacuation plan?

“The plan for multi-layer safety is contrary to the laws of economics. You have to spend your money where you’ll get the greatest bang for your buck. In this regard, prevention – raising and reinforcing the dikes – is the best option. It is relatively inexpensive. A third of our dikes are not in adequate shape. If something were to go wrong, the damage would be immense. A flood would mean an end to the world’s confidence in the Netherlands as an investment country. We saw it happen in 1995. In that year, there was not really a flood. Nevertheless, massive evacuations were conducted (in the provinces of Limburg, Gelderland and Overijssel, ed.) The computer company Compaq Computer, which had located its European distribution system in Tiel, decided to move to Germany as a result. We could also question whether evacuation plans actually work. When you’re in a storm at wind force 13, you’re really in trouble. The forces are enormous.”


In the early 1970s, you were involved in the design and construction of the storm surge barrier in the Oosterschelde (Eastern Scheldt). You have said that not much of any importance has happened in the Netherlands since then.

“The Maeslantkering came after that. But that was about it. When I was writing my valedictory address, I wanted to read my inaugural address again. In that address I also talked about living in an era in which we asked ourselves where we were going to go from there. That gave me a bit of a jolt. When I was in primary school, we were presented with two plans: the Delta Plan and the National Highway Plan. These plans involved the entire nation. We’ve not had such ambitious plans for a long time now. Some economists are saying that we need another great, compelling plan in order to pick us up out of the doldrums again. The construction of wind farms is one of the proposals. But I’m guessing that would not end well, because the farms would require continuous subsidies after they were built.”


Would reinforcing the dikes pull us out of the doldrums?

“Apart from increasing safety, it would create lot of jobs. In another era they created the Amsterdam Forest. This seems more useful to me.”


You speak out against what you call ‘the new hydraulic engineers’– people who do not attach as much value to dikes.

“Yes, those are the people who haven’t studied hydraulic engineering in Delft, but physical geography, biology or agronomy, and who now call themselves hydraulic engineering experts as well. They are all active in nature-related hydraulic engineering projects. A large part of the budget for flood control is being spent on new nature. And this while we aren’t even sure whether what they say is right. Nature lovers are not exempt from the laws of nature. Just consider the ‘Room for the river’ project. If you do the math, you find that both technically and economically it would be more efficient to raise the dikes than it would be to widen the river. Moreover, if the river is widened, it needs to be maintained as well. Wooded areas should be removed in order to prevent local flooding. Some farmers are still doing this, but they may well be gone in 10 years’ time. What will happen then?”


In the magazine De Ingenieur (The Engineer), you mentioned another possible explanation for why hydraulic engineering in the Netherlands has been at a standstill for so long. “Grandpa is dead”, you wrote.

“Grandpa, that was Rijkswaterstaat. In the past, this faculty received background support from Rijswaterstaat, the directorate responsible for public works. We had access to all the designs created by Rijkswaterstaat. The agency provided financial support for the student society known as the Society for Practical Studies. Someone from Rijkswaterstaat served on almost every graduation committee. The collaboration was very accessible and automatic. No one gave it a second thought. The Grandpa analogy is quite apt. Think about it. What was your grandfather doing way back when you were in secondary school? Nothing?! “No, it just looked that way. Grandpa told your mother, ‘You ought to give that lazy fellow a kick in the pants. And if he earns an eight, he’ll get ten bucks from me.” You had someone in the background whose influence on your life did not become apparent to you until later. Rijkswaterstaat has now pulled back. It no longer wishes to have anything to do with technology. The people there are now only concerned with management.”


I thought you were referring to the role that ‘Grandpa’ had played in your own career. You introduced probabilistic design methodology during the construction of the storm surge barrier in the Oosterschelde. In addition to the probability of flooding, this methodology considers the probability that a wide range of other conditions will combine to overwhelm the dike. You had been conducting research on it for three months, and ‘Grandpa’ embraced the plan.

“At that time, the organisation still had a management that understood the field; they could immediately recognise a ‘smart guy’ when they saw one.” I didn’t realise this until later. At the time, I thought, “Of course we’re going to do it this way. After all, I’ve done all the calculations. After the storm surge barrier in the Oosterschelde, we wanted to apply the same approach to the dikes. But that never happened. It was the end of an era, an era of which I was able to experience the very tail end.”

“We recently had a visit from the Delta Commissioner. He told us that he wanted to innovate. He knew the right words. He was looking for new ideas. I told him that he could begin to innovate by shifting to this risk approach for the dikes. That was a bridge too far for him. Everyone talks about innovation like it’s a roast chicken that flies into your mouth of its own accord. You sit back and ‘Bam!’ there comes innovation. But that’s not how it works. You have to be willing to take risks, as you may be investing in a washout.

“On another note, the Minister has recently said that she does indeed want to switch to probabilistic design methodology for the dikes. Now, 30 years after the Oosterschelde storm surge barrier. At the time I was a recent graduate, and now I’m a professor.”


Your departure also marks the end of an era. You are the last engineering professor to have worked on the Delta Works.

“Yes, the loop is broken. The chair has always been staffed by practitioners. We had people who had worked on the Afsluitdijk and then came to give lectures. Then came Professor Van de Velde from the Haringvliet sluices and Professor Glerum, who constructed sunken tunnels. These were people with considerable experience in construction. I wasn’t really in quite the same league with my storm surge barrier” (laughing).


They were classic hydraulic engineers in your eyes?

“Right. We’re seeing a trend now in which pure science is valued over practical experience. In the past, you could never became a professor if you had no practical experience. You had to have worked at Rijkswaterstaat, an engineering firm or for a contractor. Now the ideal career path consists in: PhD, assistant professorship, associate professorship, full professorship. It would be good if TU Delft had a better mix of professors with theoretical training and those with practical experience. I hope that TU Delft will never become a ski school in which neither the management nor the instructor has ever skied.”


You will be succeeded by two professors: Prof. Matthijs Kok and Prof. Bas Jonkman. Two researchers without practical experience. That’s less than ideal, right?

“Cook hasn’t had his feet in the water much, and Jonkman doesn’t have that much experience either. From that perspective, it’s not so good.”


But you’re happy anyway?

“Yes, of course. It’s better than not having any successors at all. I was afraid of that at first. Fluid mechanics, soil mechanics, mathematics and probability are of great importance to the chair. My two successors have all of that.”


Can you mention a few interesting research projects in hydraulic engineering that we should keep our eyes on?

“The study on multifunctional flood defences. Matthijs Kok has shown that it’s possible to make flood defences with parking garages inside.”

A brief silence follows…

“In my opinion, we didn’t really need research for that. These types of studies are often glorified delaying tactics. Policymakers say that they want a multi-purpose dike, but that TU Delft should study it first. If they really wanted it, I could ask two men I know from Royal Haskoning, and then I’d build them their dike tomorrow.”


One of the speakers at your valedictory symposium, your former student Suzanne van Kinderen, called you risk-adverse but also risk-seeking. That characterises you. You do not like to risk getting your feet wet, even though you make a lot of noise about things that you do not like. Is this accurate?

“Yes. I’m not an entrepreneur, like Van Kinderen. I’m a professor. There were 600 people at my farewell event, so I still have a lot of friends. Although I may have created some bad blood among the new hydraulic engineers.”


Another speaker, Peter Struik, an engineer AND director at Rijkswaterstaat (and also one of your former students) called you a persistent complainer.

“Yes. I do not know exactly what he meant. But if you have a responsible position at Rijkswaterstaat, you’re not going to be happy if someone is always reminding you that a third of the dikes are inadequate.”


But you don’t see yourself as a complainer?


CV Han Vrijling

Han Vrijling (65) graduated from TU Delft in 1974 with a degree in civil engineering (concrete structures). In 1980, he completed a degree in economics at Erasmus University. As a young engineering graduate, fresh from TU Delft, he worked on the construction of the storm surge barrier in the Oosterschelde. He introduced the use of probabilistic design methodology into the project. From 1984 until last month, he was Professor of Hydraulic Engineering and Probabilistic Design at TU Delft. During this period (1983 to 2010), he also worked for Rijkswaterstaat. He still does consultancy work for Horvat & Partners.

Editor Redactie

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