It seems to indicate that the sea level is higher than any time since it was constructed. There are significant winter storms in Northern Europe right now, so it’s not unexpected. However this is apparently a “once in a decade” occurrence so either the storms are very bad or the sea levels are unexpectedly high.
FYI closing this gate has a huge economic impact and is left over to machines.
The reasoning is a person living in the country would close this gate by fear of loosing families etc, here CODE decides when the time is right to close or stay open. It uses a lot of data to monitor and predict the weather.
> The reasoning is a person living in the country would close this gate by fear of loosing families
I don’t think that’s true. The official argument is that human operation wouldn’t reach the required reliability level (https://www.cs.vu.nl/~x/sil/sil.html: “The failure rate demands for this system were required to be 1:10000 for not closing when this was actually necessary, and 1:100000 for not opening the barrier when requested. This asymmetry is caused by the fact that if the sea surge barrier does not reopen, the river discharge can lead to flooding from the inside.”)
I think nobody knows for sure whether the conclusion that software alone would be more reliable than humans alone was correct (my money would be on “it wasn’t”). That’s hard to verify for such a system that “cannot be tested under the conditions for which it was designed” (https://www.researchgate.net/publication/220592956_Human_fac...).
You can’t do that statistically, either, as in real-world use it would take millennia to collect the necessary data, and that’s way longer than the design life of this structure.
Do you know of any good resources to see the water levels in such places? I know of some sites for example in California reservoirs, or Snotel and river gauges in the US. But I imagine the information is spread differently in these watersheds.
The title of this is slightly inaccurate. It’s the first time the barrier has closed at its default 300cm surge level. It has previously closed for testing with the level set down to 280cm to test it in storm conditions.
> During the evening of 8 November 2007, the barrier was closed due to a storm surge for the first time.
I also read the archived reference article [0]:
> In the Netherlands, maritime traffic in Rotterdam was halted as the authorities closed the giant Maeslant surge barrier, which guards the entrance to the largest port in Europe, for the first time since its construction in the 1990s
Is the title missing a [2007]? Or is there a current event happening as well that has been misidentified as the first occurrence of this?
Thank you for the explanation. Turns out I stopped reading a little too early:
> In order to test the barrier in actual stormy conditions, the water level threshold at which the computer system would start the closing procedure was lowered from 3.0 m over NAP to 2.6 m, for the duration of the 2007 storm season. On 8 November 2007, a storm from the northwest hit the Dutch coast. A storm surge, high enough to start the barrier's closing procedure, occurred.
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[ 3.9 ms ] story [ 39.2 ms ] threadI don’t think that’s true. The official argument is that human operation wouldn’t reach the required reliability level (https://www.cs.vu.nl/~x/sil/sil.html: “The failure rate demands for this system were required to be 1:10000 for not closing when this was actually necessary, and 1:100000 for not opening the barrier when requested. This asymmetry is caused by the fact that if the sea surge barrier does not reopen, the river discharge can lead to flooding from the inside.”)
I think nobody knows for sure whether the conclusion that software alone would be more reliable than humans alone was correct (my money would be on “it wasn’t”). That’s hard to verify for such a system that “cannot be tested under the conditions for which it was designed” (https://www.researchgate.net/publication/220592956_Human_fac...).
You can’t do that statistically, either, as in real-world use it would take millennia to collect the necessary data, and that’s way longer than the design life of this structure.
Which makes it all the more unique that it closed, because there's a lot of water coming down the Rhine and Waal right now.
Rijkswaterstaat (who manages all of this) prepared for this by making more space for the river water to flow and flood in other directions.
It's true! That's how big those arms are, and it's completely automated.
> During the evening of 8 November 2007, the barrier was closed due to a storm surge for the first time.
I also read the archived reference article [0]:
> In the Netherlands, maritime traffic in Rotterdam was halted as the authorities closed the giant Maeslant surge barrier, which guards the entrance to the largest port in Europe, for the first time since its construction in the 1990s
Is the title missing a [2007]? Or is there a current event happening as well that has been misidentified as the first occurrence of this?
* [0]: https://web.archive.org/web/20071109163913/http://news.bbc.c...
The other closes were "optional", mostly to check how it performed during a real storm.
> In order to test the barrier in actual stormy conditions, the water level threshold at which the computer system would start the closing procedure was lowered from 3.0 m over NAP to 2.6 m, for the duration of the 2007 storm season. On 8 November 2007, a storm from the northwest hit the Dutch coast. A storm surge, high enough to start the barrier's closing procedure, occurred.