The terp mounds were a very resilient system against flood protection. However, the size of the constructed mounds was limited and they could only support small villages. With continued population growth and the need for more protected space in villages, the Dutch began building ring dikes around towns. As settlements continued to expand into the low, coastal areas, the land was drained using increasingly elaborate means (ditches, windmills, steam pumps). This drainage, coupled with peat harvesting and poldering (a method used to reclaim land from the sea), caused extensive subsidence, which increased flooding vulnerability. The increasing populations and value of property inhabiting lowlands required higher and stronger dikes, so much so that now most of the Dutch population and economic activity is supported by areas below sea level that are protected from floods by massive, nearly indestructible dikes and surge barriers. With such high consequences of flooding, dikes, and barrier structures for much of the country are designed to protect against a flood with a 1 in 10,000-year recurrence interval.
Learning Check Point
Objective: Understand the benefits of building with nature, and distinguish smart building approaches.
Although this Learning Check Point is not for credit, you will be expected to understand this material for the Module 10 Quiz.
Watch the required video Protecting Against Flooding: Holland's storm-surge barrier (9:43) about the “Deltaworks” flood protection system in the Netherlands. Answer the questions below.