Sunday, July 26, 2009

The Maeslant Barrier

The main point of my bike trip yesterday was to see some components of the Deltawerken (Delta Works), a massive public works project designed to prevent flooding in the Netherlands. It was conceived after the great flood of 1953, in which massive property damage was done and more than eighteen hundred people were killed.

The ongoing battle between the Dutch and the sea is well documented. Some 27% of the land in the Netherlands is below sea level, including Delft. Much of this is polderland, meaning it has actually been reclaimed from the sea. In 1986, for instance, the province of Flevoland was established where previously only sea had been. You may have heard: God created the world, but the Dutch created Holland.

Compare the two maps of the Netherlands below; the first is a current map, and the other is what the Netherlands would look like without protection from the sea.

The Nieuwe Waterweg (New Waterway) connects the Europoort of Rotterdam - the second busiest port in the world after the Port of Shanghai - with the sea. Meanwhile, Rotterdam and the surrounding area must be protected from flooding. Dike reinforcements along the Nieuwe Waterweg were the original plan for protecting Rotterdam, but these were costly, slow, and in the 70's elicited protests from people who didn't want dikes in urban areas. So instead, in the 80's the idea of a moving storm surge barrier grew legs. In 1997, the Maeslantkering (Maeslant Barrier) was finally commissioned. You can see it below.

View Maeslant Barrier in a larger map

The Maeslant Barrier is a most impressive structure. When open as pictured above (which is 99% of the time since major storm surges happen only once every decade or so), the barrier sits in dry docks on both side of the shore. To close the barrier, the docks are flooded and the barrier itself floats. Each part of the barrier pivots closed around two massive (10 m in diameter) ball joints, the biggest in the world. (You can see it closed here.) Once the two sides of the barrier have met at the middle, compartments within them are flooded and the barrier sinks to the bed of the waterway, sealing it off. To reopen, the compartments are pumped dry and then the two barrier segments are pivoted back into their docking areas. (I learned all this from a very cool scale model at the Keringhuis, a museum located at the foot of the barrier.)

Finally, here are some pictures, which aren't very good because you have to be in a helicopter to have a prayer at getting this thing in frame...

Ball joint about which one side of the barrier pivots.

A look at the Maeslant Barrier down the Nieuwe Waterweg.

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