Windmills

I think it's about time to take a brief look at how the Netherlands are coping with rising sea level. The Netherlands are famous for their low topography, half the country is less than one metre above sea level, and the highest point in the Netherlands is actually in the Carribean! Because of this the Dutch are the experts of mitigating against sea level rise, I mean I've been reading the IPCC's Assessment Report 5 ALOT recently, and I can't help but notice that 10/57 of the contributing authors for the sea level change chapter are from the Netherlands. Everyone knows about that little Dutch boy with his finger in the dam, but somehow I don’t think that's the secret of  the Netherlands' mastery of keeping the sea at bay.



Source: Flexitreks



The Netherlands is really interesting because not only do they have many types of coastal defence, but they have also been actively reclaiming land from the sea for hundreds of years. I want to use this post to look at windmills, for some reason I was convinced that these were an intrinsic part of the tulip growing process, but actually windmills have been instrumental in allowing the Dutch to live below sea level. This is definitely something that more countries and cities will have to start considering in the future.


It all started hundreds of years ago when the Dutch started draining marshland to make more farmland. They built canals and ditches to drain the land into rivers, but the land started to subside until it was the same sort of level as the rivers, and didn't drain any more and very liable to flooding (van Schoubroeck, 2010). Obviously this was a bit of a problem a so they made dykes to protect their land from the rivers, more ditches to divert the water, and windmills to pump the water out of the new farmland, to somewhere less annoying, usually a storage lake. The windmills either used a scooping wheel or an Archimedes screw to get the water to higher levels. This was the start of the typical polder system. I have found a little diagram here:



How windmills get water to go uphill (Source: iamexpat)



A really good example is Kinderdijk, a village below sea level that built 19 windmills, together with a combination of ditches and sluices, in the 18th century to pump water out of the land into a storage basin higher up. Who knew all you needed was a bit of wind and an Archimedes screw to live below sea level?


Sadly, the original wind-powered water pumps are no longer in use - but their steam then electrical pumping station descendants are still essential all over the Netherlands. In fact the Dutch pumps are so good, that when the Somerset levels flooded last year the Environment Agency borrowed 13 to try and reduce the water level (BBC News).

 

I love windmills, and I think that it's fantastic that it's possible to live several metres below sea level with a bit of ingenuity and wind power. I'm sure that something along these lines could be used elsewhere - I mean they have certainly proved that they work.