The Dutch versus the Ocean

I’ve chosen to research the Dutch “gracht” for my precedent study. The word “gracht” simply means canal and is prevalent in cities like Amsterdam. Although the scope of my study should focus on the city-scale canal infrastructure, as I was researching the topic, one question led me to another and I ended up going down the rabbit hole of how the Dutch were able to reclaim land and win out against the ocean. Since I’ve already learned so much about it, I thought it’d be a good idea to share what I’ve learned on Medium.

The Netherlands is a water-infused country, full of deltas and individual small islands. Year by year, the ocean eats away at the land, eroding more and more of the coast. The Dutch decided early on that they would construct a huge dam which would cut off Lake Ijsselmeer from the Ocean. This would not only prevent future flood events but also turned the saltwater into a fresh-water lake. In addition, it makes it easier for the Dutch to build additional dams in order to reclaim the land. But how were they able to drain water in such great quantities as early as the 14th Century?

After dissecting the methods they used, a lot of it becomes quite intuitive. First, they needed to build a dyke that surrounded the water that they wanted to drain out. Most times, they would establish ziplines and control a mechanism to drop huge boulders into the water at specific places. Normally, the current of the water would carry away any boulder that’s dropped, but because the lake has been dammed off, the velocity of the water was not great enough to carry the boulders away. Then, the Dutch would construct huge windmills that utilized the strong winds along the coast to pump water out from one side of the dyke into the other. This process may take months or years and hundreds of windmills were constructed.

After the water’s been drained, the soil won’t be compact enough for farming or infrastructure so they planted rough seeds of reed in order to toughen the soil. After the reed is fully grown and the land has been strengthened, the reed was burned which left nutrients and space for finer crops such as rapeseed and rye to grow. Depending on the specific situations of each patch of land, the richest (in nutrients) was set aside for vegetables, the satisfactory land was for rye and the land poor in nutrients was heavily planted on with trees and shrubs. The land was also now ready for the construction of infrastructure such as roads and houses.

Because the reclaimed land was several meters below the mainland, groundwater started to seep from the mainland into the reclaimed land, which created small scale flooding at its inception. To address this problem, all future reclamation was done with a thin channel that separated itself from the mainland, leaving the groundwater intact and away from the reclaimed land. This is visible from the 2 newest pieces of Flevoland. Obviously, there was a lot more engineering and complex systems at hand, but I wanted to share a simple rundown in case anybody else was interested.