The evolvement of dikes of carefully stacked clay to pile dikes into high-tech sensor dikes did not happen overnight. Already in Roman times, small dikes and dams were created. A look into the long Dutch tradition of dike building gives us insight on a deeply rooted culture of trial and error in a country where the sea level rises and the ground level is dropping. History shows that either a big flood or a tiny worm, but also national welfare can lead to big consequences and shifts in the flood protection system. Key moments in the ever evolving dike network are described over different dike periods.
Dike breach near Bemmel, 1799, Christiaan Josi, 1802
Coast Line Shortening
100 AD | 1,500 km coast line
800 AD | 2,300 km coast line
1500 | 2,600 km coast line
1850 | 2,100 km coast line
1950 | 1,600 km coast line
2000 | 880 km coast line
Dike Period until 700
The earliest indications of dike building date from the late Iron Age. During excavations of terps in the Frisian villages of Peins and Dongjum, among others, dike bodies were found – small dikes predating the building of the terp. These little dikes, no more than 70 cm high, were composed of neatly-stacked peat sods against a core of loose bulk material. Later on the structure was reinforced by adding an outer wall with a gentler gradient.
Excavation of an early sea dike – Original: E. Thoen e.a., Landscapes or seascapes? 2013
Dike Period 700 - 1200
The Netherlands witnessed little dike-building activity in the early Middle Ages. With the departure of the Romans began a period of political instability and population decline. From the eighth century we see renewed, if slow, population growth, after which the population of the Netherlands increased tenfold between 800 and 1250. Once again settlements were formed in the salt marshes, which abounded in fish and in grazing pastures for livestock. On a small scale, streams were dammed and low dikes built, following the contours of the existing differences in elevation.
Map of the dikes period 700 – 1200 (northern Netherlands)
Dike Period 1200-1500
In the fourteenth century, the combined effects of soil subsidence and rising sea levels meant, in many parts of the Low Countries, that sea level and ground level converged to the same height. This was the period that saw the first large-scale building of dikes. The population was falling in some parts of Europe, as a result of economic recession and a succession of epidemics, but the Netherlands, especially Holland, was doing relatively well.
The Saint Elizabeth’s Day Flood, Master of the St Elizabeth Panels, Anonymous, c.1490-c.1495
Dike Period 1500 - 1800
In the period between 1500 and 1800, the Netherlands became ever more prosperous and witnessed rapid population growth, although the graph displays peaks and troughs. The acme of the Golden Age was in the first half of the seventeenth century. Large-scale hydraulic engineering works such as land reclamation, polders and largescale peat extraction were organized by collectives, with interested parties joining forces for the purpose.
The prosperity of the Golden Age came to an abrupt end around 1730 with a major disaster: the advent of the naval shipworm. This mollusc, Teredo navalis, thrived in the climate of the Low Countries, and rapidly proliferated. The water republic of the Netherlands found that its very foundations were being literally eaten away. All the wooden structures along the coast, including the breakwaters of the dikes, were attacked and started to crumble. It was seen as divine punishment: God was visiting his wrath on the decadence of the Golden Age. In reaction to this plague, feverish efforts were made to find alternative materials and designs in the dike profile. In the end, the calamity provided a major impulse to the modernization of the dikes and dike management.
De slechte toestand van de Zeedijk vanaf Diemen, Jaap Hannes (second part) 1705, Anonymous 1705
Dike Period 1800-1950
After the disastrous damage wrought by the naval shipworm, dike builders had gradually switched to constructions with low-gradient outer slopes. To strengthen dikes, stony materials were added to the dike revetment. Most of the stone was transported from Norway by sea and from Belgium along the major rivers to the Netherlands. In addition, a great many dolmens or hunebedden were demolished to reinforce the coastal defences. From 1900 onwards, materials such as concrete blocks were developed, mass-produced and transported in large numbers. Advances in knowledge, technology and mobility made large-scale interventions in the water system possible, culminating in the Zuider Zee works.
Completion of the Wieringermeerdijk
Dike Period 1950 - 1985
The Zuider Zee had only just been closed off when the next calamity presented itself, this time in the southwest coastal region. In 1953, a rare combination of spring tide, a north-north-west storm and high water in the rivers caused a national disaster. In Zeeland, the islands of South Holland and West Brabant, there were widespread dike breaches. The North Sea Flood claimed more than 1,800 lives and caused immense damage. An area measuring some 1,650 square kilometres of land was flooded.
The North Sea Flood provided an impetus for a large number of new hydraulic works: the Delta Plan. The Netherlands must be protected from suffering any repeat of the disaster in the future. The sea inlets should be closed off, with the exception of the Nieuwe Waterweg and the Western Scheldt, thus making the coastline much shorter and far easier to defend. Parliament passed the Delta Act in 1958 and the construction commenced. The Act prescribed the criteria to be met by the dikes along the coast and rivers as well as their height. It was the beginning of an era of drastic and large-scale reinforcements of the dikes.
Construction of the Grevelingendam, 1958
Dike Period from 1985
A radical transformation in attitudes to water quality was triggered by an event that took place in 1986. Following a fierce fire at Sandoz chemicals factory in Basel, Switzerland, some twenty tonnes of pesticides became mixed with the water used to extinguish the fire and ended up in the Rhine. The toxic chemicals sowed death among fish for many hundreds of kilometres downstream. This was the era in which environmental activism came of age, with mussel farmers in uproar and nature conservationists staging furious protests against the closure of the Eastern Scheldt. There was also a slow change in attitudes to the country’s water defences. After the flooding of 1993 and 1995 – 240,000 people were evacuated in 1995 as a precautionary measure – the dikes were reinforced once again, but it also became clear that raising the prescribed norm was not the only solution. The policy document ‘Ruimte voor de Rivier’ (‘Space for the River’) advocated widening the riverbed instead of another largescale reinforcement of the dikes.