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...indeed that was the tenor during the 'once-a-century' floods in the nineties:

River Rhine Floods 1995 | Background Information

...In February 1995, the Rhine and its tributaries (the Meuse and the Mosel), burst their banks in France Belgium, the Netherlands and Germany. Large areas of the Low Countries (Belgium, Luxembourg, the Netherlands) were flooded and many major towns were threatened.

The Dutch have defended themselves against the sea for centuries by an elaborate network of dykes 2,500 km (1,500 miles) long but, this time the floodwaters came from the rivers, from water flowing as a result of heavy rainfall in the Ardennes and a flood of melted snow in the Alps. For two years running, levels of flooding have occurred that, statistically, would normally happen only once a century. The flood waters swamped farmland, much of it in the polder regions, where the land had been reclaimed from estuaries and river basins.

...however, that flood led to measures:

Water Conflict and Cooperation/Rhine River Basin - WaterWiki.net

In 1995 in the Netherlands, some 200,000 people had to be evacuated because of imminent flood risks from the rivers Rhine and Meuse. Within months a lex specialis (special law) was passed to construct or improve about 750 km of dikes and levies before the year 2000.

...and Nomad's link was about further measures for the future, both in relation to seas and rivers, and specifically mentioning floodplains. In addition, the floodplain issue is specifically addressed by the separate Room for the River plan.

*Lunatic*, n.
One whose delusions are out of fashion.

by DoDo on Wed Dec 22nd, 2010 at 03:21:28 AM EST
[ Parent ]
Emphasis added:

For two years running, levels of flooding have occurred that, statistically, would normally happen only once a century.

And if the coin lands "heads" it MUST land "tails" in the next flip to Obey the Laws of Probability.

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre

by ATinNM on Wed Dec 22nd, 2010 at 01:22:07 PM EST
[ Parent ]
Sure, ask anyone in a casino.

Sweden's finest (and perhaps only) collaborative, leftist e-newspaper Synapze.se
by A swedish kind of death on Wed Dec 22nd, 2010 at 02:28:13 PM EST
[ Parent ]
Although I understand your sentiment of frustration, I'm not sure if that is just a goof stemming from mistranslation or unfamiliarity to the subject. The snippet is taken from a physical geography site; not a branch of study particularly rich in mathematics. In the Netherlands, the field of water management is dominated by civil engineers and mathematicians.

I do know that the Delta Committee and others have adopted a probabilistic approach, and that probabilistic methodology now provides the baseline for evaluating dyke safety - which was something I was doing earlier this year. It also is estimated that some 25% of all primary dykes currently still fail the safety test - which in the next round in 2011 will become even more stringent. This does not create major problems that have not been seen before (see recent Maas flooding) - and as DoDo writes upthread upgrades are in the work at all levels.

After the Delta Committee a National Water Plan was released in 2009 by the Balkenende government, which adopts major recommendations of the Committee - including plans for providing major rivers with space for large variations in river discharge, whereby the highest discharge scenario is taken as the baseline, and then a 5 - 10% extra is added.

After operating at the consultancy side in this particular branch, I have enough anecdotes that point at some flaws in the present regulatory framework of the Dutch waterboards, however, I have no doubts that the conservative and stringent safety conditions that need to be adhered to continue to make the Dutch safety system against flooding simply the safest in the world.

by Nomad (Bjinse) on Thu Dec 23rd, 2010 at 06:25:07 AM EST
[ Parent ]
Far be it for an American to tell the Dutch how to run their business.  :-)  I do get - too easily, perhaps - annoyed when long range planners naively apply Statistics and Probability.  Bit of boring personal history is involved, as well.

The Dutch planners need to junk history and do a re-think.  They need to take a hard look at what is going on as well as consider how to prepare for a relatively rapid, as such things go, sea level rise of 3 meters, conceivably more, over the next 20 years.  Expensive?  Yes.  But less so than having half of the Netherlands under water.  

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre

by ATinNM on Thu Dec 23rd, 2010 at 05:24:31 PM EST
[ Parent ]
ATinNM:
consider how to prepare for a relatively rapid, as such things go, sea level rise of 3 meters, conceivably more, over the next 20 years

Report of the Delta Committee - page 24 for scenarios which are considerably worse than the IPCC scenarios.

Unless you actually mean a sea level rise of 3 meters in the coming 20 years - which is in the range of possible as the sun not rising tomorrow and therefore can't be planned for.

by Nomad (Bjinse) on Fri Dec 24th, 2010 at 06:36:15 AM EST
[ Parent ]
Thanks for the links, DoDo.  Didn't mean to tee-off on your comment.  

It's just the inability of people to understand  what Probability and Statistics mean ... and it's not THAT hard ... drives me absolutely crazy.

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre

by ATinNM on Wed Dec 22nd, 2010 at 01:26:54 PM EST
[ Parent ]

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