8 - Draining and staying dry: dikes and pumping stations
The final decision to construct the Noordoostpolder was made in the mid-1930s. The decision had been postponed for a number of years, due to a severe global economic crisis which caused the government to cut costs. Towards the end of the year 1935, when the budget for the Zuiderzee Fund was being discussed, an amount of two million guilders (approximately 0.9 million euros) was allocated for the initial work to construct the dikes.
Costs
There were neither extensive reports on the environmental impact available at that time, nor any possible influence on the planning and no options for objections or appeals against the government decision. However, there was a cost-benefit analysis. During the discussion in the House of Representatives, a “Note concerning the N.O.-polder” was submitted which showed that the costs of reclamation, construction and cultivation were approximately equal to the desired amount of 2,500 guilders (approx. 1,150 euros) per hectare. The total costs were estimated at 126.1 million guilders. The austerity of the design which was applied in order to match the intended costs caused disadvantages for the water management organization. The construction of a broad boundary lake between Lemmer and Blokzijl, for example, was not deemed necessary.
Video: "How it started: The Noordoostpolder". The video shows the reclamation and drainage of the Noordoostpolder in the 1940s.
Approximately ten million drainage pipes, ready to be used for draining the Noordoostpolder. This photo was "blocked" by the censorship, 1940.
Dikes
The very first task that started in 1936 was the construction of a working port at Urk.This working port formed an integral part of the construction site for the Vissering pumping-station and the lock at Urk. Working ports were needed to provide a safe berth for the vessels which were used to construct the dikes. A canteen and a management office were also erected. The dike construction was started in 1937 from Urk and Lemmer. The last opening near the current Rotterdamse Hoek was closed on 3 October, 1939. Urk turned into a peninsula then. Later, the dike sections south of Urk were also constructed. From Vollenhove and Blokzijl, the dike sections along the boundary lakes and the Zwarte Meer were started.
Construction of the dike from Lemmer to Urk in connection with the construction of the Noordoostpolder on 21 June 1938.
The mayor of Urk (right) and the mayor of Lemmer shake hands at the Lemmerkant, after the last soil had been deposited in the IJsselmeer, so that Urk is no longer an island and the drainage of the Noordoostpolder can begin, October 12, 1939.
The last opening of the ring dike around the Noordoostpolder was located about one kilometre west of Schokkerhaven. Harmen Smit, whom the fishermen called “the last king of Emmeloord”, left the port of Schokland.
The last opening was closed on December 13, 1940, at 1.52 pm. As a result of a heavy west wind, the water level in the polder was about thirty centimetres higher than the engineers of Zuiderzee Works had wished for. As a result, an additional 150 million m³ of water had been enclosed which largely needed to be pumped out.
The unveiling of a model of the Noordoostpolder on the dike at Nagele, opposite Havenweg / Sluitgatweg, in memory of the fact that fifty years ago, the last dike section around the Noordoostpolder was closed. Left: B. Blikman (deputy), right: C. van der Wildt (chief engineer-director of the Flevoland board of Rijkswaterstaat), 1990.
The dikes of the Noordoostpolder proved to be strong and solid. The first dike reinforcement activities after the construction were necessary at the end of the last century because safety standards had been changed. Not until 60 years later! The structure of the dikes remained virtually unchanged. Respect for the dike builders of the last century!
The arrival of polder workers at the Ramspol in 1941.
Drainage
The intention was that the three pumping-stations that would drain the polder and keep it dry, would be ready at the time of the closure of the ring dike. Unfortunately, the electrical pumping-station Buma at Lemmer was the only one ready for the task. The pumping-station Vissering close to Urk was delivered and ready for use much later due to war-related circumstances and did not participate in the drainage of the polder. The electric pumping-station Smeenge close to Kadoelen partly contributed to the drainage. As a result, the drainage took nearly a year longer than planned.
Water levels and dried surface during the drainage.
The pumping-stations are named after the members of the Zuiderzee Association. Age Buma was a Member of Parliament. He was chairman of the Zuiderzee Association and one of the main advocates in favour of creating polders in the Zuiderzee. Gerard Vissering was president of De Nederlandse Bank and also chairman of the Zuiderzee Association. Politician Harm Smeenge was one of the great champions and vice-chairman of the Zuiderzee Association. Buma hailed from Friesland, Smeenge from the East and Vissering from Amsterdam. The distribution of the names was not entirely coincidental.
Condition of the newly dry land after rainfall. Schokland in the background.
Dry
On 7 January, 1941, pumping-station Buma started draining the polder. On 9 September 1942, an average water level of 4.40 m below NAP was reached.
On that water level, the lowest sections of the polder were dry and that date was therefore used as the milestone for when the Noordoostpolder, the first polder in the IJsselmeer, was drained. Due to the war-related circumstances, there was often too little electricity available to maintain the correct polder levels after the drainage. Higher water levels occurred at times, with temporary quays being built to protect the areas that had already been cultivated.
Left in the foreground, a pile of drainage pipes; on the right, a portable construction shack. In the background, some barns. Drawing Henk Rotgans 1943-1947.
Keeping dry
The areas in the eastern part of the polder have a higher altitude than the western parts. Trenches were dug out as soon as an area started to dry. Fuel shortages mandated a lot of manpower. The ditches were mostly hand-dug as well. Many people in hiding worked on this project during the Second World War (see also window 10).
The trenches were dug with draglines. When the polder was still under water, trenches had already been dredged that would later form the canals. After drainage, the sludge that had built up in these channels had to be dredged again. The complete drainage system was therefore dug out: the water flowing from the plots needed to be channelled to the pumping-stations. The dewatering of the plots was done by installing drainage. This was first done by hand and later on with machines (see window 9).
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Electric Pumping Station Smeenge (name since 1950) at Kadoelen. Pumping station Buma at Lemmer. Pumping station Vissering on Urk.
Pumping stations
After the Second World War, the three main pumping- stations were fully commissioned to keep the polder dry. The pumping-stations have now been modernized and pumping-station Vissering also functions as a combined heat and power plant, a unique concept.
The total drainage capacity of the Noordoostpolder allows for draining an amount of water comparable to about fifteen millimetres of precipitation, about seven million m³ per day. The seepage (inflow of water via the subsoil) already causes a daily inflow of water that is comparable to one millimetre of precipitation every day. This must be drained every day. The Noordoostpolder has a small area (about one percent) of open water. The excess water must therefore be pumped out quickly, and that is possible only due to the relatively high drainage capacity.
Flood
The tight water system reacts strongly to heavy precipitation. Local flooding can occur during periods of heavy rainfall and high water levels. In the autumn of 1998, thousands of hectares of agricultural land were flooded. Harvests were lost massively. Queen Beatrix and the prime minister at the time, Wim Kok, visited Tollebeek, the lowest place in the Noordoostpolder, to witness the disaster with her own eyes. The government offered (financial) aid.
In recent years, the municipality of Noordoostpolder and Waterschap Zuiderzeeland have been working hard to drain excess water more quickly, through drainage, infrastructure and wider watercourses.