The 20-mile-long 32-kilometer Afsluitdijk literally,closing-off dike, constructed from 1927 to
1932 between Wieringen now Den Oever and the west coast of Friesland, enabled the resourceful
Dutch to turn the saltwater Zuider Zee South Sea into the freshwater IJsselmeer and eventually to
create an entire new province, Flevoland. Like their successful responses to similar challenges before
and since, it was an audacious and farsighted feat of planning, hydraulic engineering, and reclamation.
Throughout their history, the Netherlanders have fought a battle against the water. Much of their tiny
country is well below average sea level, in places up to 22 feet 7 meters. The threat of inundation
comes not only from the sea but also from the great river systems whose deltas dominate the
geography of Holland. Over centuries, literally thousands of miles of dikes and levees have been
built to win agricultural land back from the water, and having gained it, to protect it. From the
seventeenth century Amsterdam merchants invested their profits in building the North Holland
poldersBeemstermeer, the Purmer, the Wormer, the Wijde Wormer, and the Schermerreclaimed
through the ingenious use of the ubiquitous windmill.
In 1250 the 79-mile-long 126-kilometer Omringdijk was built along Frieslands west coast to
protect the land from the sea, and as early as 1667 the hydraulic engineer Hendric Stevin bravely
proposed to close off the North Sea and reclaim the land under the Z uider Z ee. His scheme was then
technologically impossible. The idea was revived in 1891 by the civil engineer and statesman
Cornelis Lely. Based on research undertaken over five years, his plan was straightforward: a closing
dike across the neck of the Z uider Z ee would create a freshwater lake fed by the River IJssel and
allow the reclamation of 555,000 acres 225,000 hectares of polder landin the event, 407,000
acres 165,000 hectares were won. Despite Lelys assurances about the feasibility of the plan, his parliamentary colleagues were
unenthusiastic. But attitudes changed after the region around the Z uider Z ee was disastrously flooded
in 1916 moreover, World War I in which Holland remained neutral convinced the Dutch
government that internal transportation links needed to be improved. The Z uiderzee Act was passed
The Z uiderzeeproject commenced in 1920 with the construction of the Amsteldiepdijk, also known
as the Short Afsluitdijk, between V an Ewijcksluis, North Holland, and the westernmost point of the
island of Wieringen. There were some initial foundation problems and a financial calamity for the
contractor, but the dike was completed in 1926. There followed the construction of the small test
polder Andijk 1927 and the Wieringermeer 1927?1930.
The key element in the daring plan was the construction of the Afsluitdijk across the Waddenzee, an
arm of the North Sea. The project was undertaken by a consortium of Hollands largest dredging
firms, known as N. V . Maatschappij tot Uitvoering van de Z uiderzeewerken. All the work, involving
moving millions of tons of earth and rock, was carried out manually by armies of laborers working
from each end of the structure. Built during the Great Depression, the Afsluitdijk was a welcome
source of employment. It was completed on 28 May 1932. It was intended later to build a railroad
over the broad dike, but as the volume of road traffic increased in Holland, priority was given to a
four-lane motorway. The railroad was never built, although adequate space remains for it.
The closure of the Afsluitdijk enabled the eventual reclamation of three huge tracts of land formerly
under the sea: the Noordoostpolder 1927?1942, East Flevoland 1950?1957, and South Flevoland
1959?1968. They were later combined to become a new province, Flevoland, with a total area of
over 500 square miles 1,400 square kilometers. Its rich agricultural land supports two cities,
Lelystad and Almere, although the latter is more properly a dormitory for Amsterdam. Flevoland is
on average 16 feet 5 meters below sea level. The great freshwater body south of the Afsluitdijk was
renamed IJsselmeer. Its balance, carefully controlled through the use of sluices and pumps, is
determined by inflow and outflow rates, rainfall and evaporation, and storage level changes. With a surface of nearly 500 square miles 131,000 hectares, it is the largest inland lake in the Netherlands.
A proposal to reclaim a fifth polder, the 230-square-mile 60,300-hectare Markerwaard, behind a
66-mile-long 106-kilometer dike between Enkhuizen and Lelystad was not pursued, mainly
because of ecological concerns.
In February 1998 the Dutch Ministry of Transport, Waterways, and Communication published the
Waterkader report, setting out national water-management policies until 2006. Aiming to keep the
Netherlands safe from flooding, it presents a case for reserving temporary water-storage areas
controlled floodingagainst times of high river discharge or rainfall. The government,
recognizing that raising the dikes and increasing pumping capacity cannot continue forever, has
adopted the mottoGive water more space. The document Long-Range Plan Infrastructure and
Transport of October 1998 promised to invest 26 billion guilders approximately U.S.$13 billion in
the nations infrastructure before 2006. Part of the money is earmarked for waterways, including
links between Amsterdam and Friesland across the IJsselmeer.