The environment was very important too when considering the design of the Deltaworks. Some dams could only be closed during particular circumstances, i.e. when the tides and the winds were favourable. And you may almost forget: why were the Deltaworks built anyway? Exactly, because of flood disasters, caused by a combination of extreme weather conditions and spring tide. Knowledge of the weather and the climate is especially important when building something as large as the Deltaworks. The most advanced computer programmes were used to calculate the wind speeds and the currents, before the Maeslantkering and Oosterscheldekering could first be closed. Now the Deltaworks have been completed, research into (the change of) climates still has priority, since climate changes could have an effect on the sea levels. In the Netherlands, in which about half of the country lays below sea level, swimming is still a preferred solution to sinking.
Lastly, the Dutch landscape and some serious (global) environmental problems will be discussed. The Dutch landscape has been influenced particularly during the last two thousand years, since humans entered the area. Three prominent types of landscape will be described: the sea clay landscape, the river clay landscape and the dune landscape. Moreover, four environmental problems will be discussed: the rise sea level, the dangers to fish, the depletion of the ozone layer and water pollution. All these problems have (indirect) effects on us. It is not too late though and we can do a lot to help by treating our environment responsibly.