The Old Zuiderzee

I've long been fascinated by the geography and the history of the Zuiderzee. It was an arm of the North Sea which had gradually evolved with the rising sea levels caused by the slow global warming which melted ice sheets from the last ice age twelve thousand years ago. Global warming is not a new thing invented by pseudo-scientists and popularised by Al Gore; it's one of the natural cycles of the earth’s climate, just as is global cooling. This map from 1818 shows the inland sea in the early nineteenth century.

At the end of the last ice age, the area now known as the North Sea was dry land. Then about five thousand years ago, the rising sea levels from the melting and recession of the of the ice sheets which had covered northern Europe, created the North Sea. The melting polar icecaps gradually increased it to its current shape. The topography of the areas inland from the coast in what is now the northeastern portion of the Netherlands was a shallow depression. Drainage here was slow and the area filled with peat.

The continued warming trend caused the North Sea levels to rise further. Gradually there were inundations over the low lands inland, and flooding during major storms accelerated the erosion of the coastal dunes. The two maps above show the approximate land form of what is today the Netherlands. The one on the left shows the coastline during the first century AD, the one on the right depicts its shape in the tenth century.

Storms in 1282 and 1287 broke through the coastal barriers and the sea flooded inland. The name Zuiderzee entered general usage around that time. The size of the inland sea remained relatively stable from the fifteenth century onwards because of improvements in dikes. There were continuing disastrous floods, one in 1421 broke a seawall and incoming waters flooded seventy-two villages and killed about ten thousand people. This map from the Zuiderzee Museum shows the approximate shoreline in the fifteenth century.

Dikes and seawalls continued to be built and upgraded, and around the Zuiderzee, fishing villages sprang up and grew. Some of these developed into fortified towns, like Naarden in the Google Earth image above. The towns established important trade connections with ports around the Baltic Sea and in England. Kampen in Overijssel grew in prominence, as did several villages and towns in Noord Holland, such as Naarden, Amsterdam, Edam, Hoorn, and Enkhuizen.

The formation of the Zuiderzee had created many large, protected ports with easy access to the sea. This started the ascendancy of the Dutch to the status as the world's super power of the sixteenth and seventeenth centuries.

The Dutch continued to extend and reinforce its system of seawalls and dykes and look at ways to protect the land from the sea. In the seventeenth century there was a proposal to harness the waters, but its concept was too ambitious and impractical for the available technology of the time. In nineteenth century serious attention was given to controlling the waters and reclaiming land. Plans were proposed throughout the middle of the nineteenth century, then in 1886, Cornelius Lely began serious planning.

The map above was used to illustrate an article in the March 1893 edition of the Geographical Journal of the British Royal Geographical Society. The article explained plans developed by a technical research team under the guidance of Cornelius Lely, who in 1891 had become the Minister of Transport and Water Management for the Netherlands.

The plan called for the closing of the Zuiderzee with a dyke running from the tip of Noord Holland to western Friesland, making the contained waters into a freshwater lake. Once this was stabilised, internal dykes would be built encircling some of the shallowest areas and then draining these to reclaim the land. It was a very ambitious project.

The project sat on the shelf through the recession of the 1890s and continued to gather dust into the twentieth century. In 1913 Cornelius Lely regained his seat as Minister of Transport and Water Management. After severe flooding along the Zuiderzee coasts in 1916, the plans were resurrected and in 1918 the Zuiderzee Act was passed. Works began in 1920 and they progressed in stages. By 1924 the first dike, just 2.5 kilometres in length was completed. Between 1927 and 1932 the 23 kilometre Afsluitdijk was built between Noord Holland and Friesland, cutting off the newly formed IJsselmeer from the Noordzee. The polders were drained between 1930 and 1968.

The newly created lands of Wieringermeer were absorbed into the province of Noord Holland. Those of the Noordoostpolder and the Flevolands were united in 1986 to form the new province of Flevoland. A total of 1650 square kilometres of new land was created. About fifteen percent of this is now used as housing, nearly seventy percent is for agriculture use and the remainder is parks, nature preserves and infrastructure. The plans to dyke and drain the southwest portion of the old Zuiderzee to form a polder named Markerwaard was indefinitely postponed in the 1980s.

These two maps show the scale of the industry of the Dutch people over the last millennium as they reclaimed land from the sea. The map on the left is the current landform of the Netherlands. The one on the right shows the areas of the country that are below sea level.

Over the following while, I'll visit many of the towns and cities of the former Zuiderzee coast. Along the way, I'll pause in peaceful places to continue writing and editing.