What I did on my holidays (IV) - Outside Amsterdam: Maeslantkering

One half of the great storm surge barrier across the estuary of the Maas (Meuse) at the Hook of Holland:

A model in the Keringhuis to show how it all works

The high point of this trip's watery theme was to see something of the massive flood control works across the different estuaries in the great delta across the south of the Netherlands.

Here at the Hook, these two great arms can, at a few hours' notice (automatically triggered by sensors out at sea), be floated in their dry docks, then out across the river to be sunk on to underwater sills, so as to hold back any anticipated storm surge, such as the one that caused such devastation in 1953. Once the danger is passed, the arms can be pumped out and floated back into their docks.

The Keringhuis is the information centre in that modest-looking grey shed, exploring and explaining (with a strong orientation towards engaging children) the problems and issues involved, not only in holding back flooding from the seas (something the inhabitants of the Netherlands have had to do since human habitation in the area first began), but also coping with flood waters coming down the rivers from elsewhere in Europe, and with periods of drought, and all while keeping open the trade routes into Rotterdam.

So it's a complex series of problems, with different answers for different locations, and not just in the different designs of massive barriers. Where once the answer was, almost, as many dikes as possible, now it's a matter of managing water in and out. Increasingly they look to work with nature, for example, encouraging the movement of coastal sandbanks so that beaches and dunes are built up, or in places "de-poldering" land so that surplus river water can be stored in lakes (which has meant re-settling people, the difficulties of which are rather skated over in the exhibition) and released as necessary, and other parts reverting to marshy nature; some dikes, being largely peat, dry out in increasingly hot, dry summers, so they have to be (perhaps counter-intuitively) watered to stop them crumbling away.

The statistics and superlatives of the engineering are impressive, especially if you book a guided tour, where the guide will take you under the main structure:

Those lower struts have to be regularly repainted on the inside as well as out - and the steel is apparently 7cm thick.

But what is even more striking is the way such a massive and complex long-term plan was developed and expanded over decades by (as far as possible) consensus across the different levels of government, with each having an agreed set of functions and responsibilities. It's a similar sort of long-term process as the development of cycling infrastructure across the Netherlands over the last 40 years or so. And now, they're developing an international network of those cities and countries that face similar problems (London, of course, where our own barrier wouldn't have been finished without Dutch expertise, New Orleans - no surprise there - St Petersburg, and so on). Which is rather encouraging as we face whatever climate change is going to bring us.