Kaagpolder auxiliary pumping station
In the open West Frisian meadow polder area between Opmeer and Obdam, the metre chimney stands out. It belongs to the former auxiliary steam pumping station of the Kaagpolder. Together with the adjacent Kaagmolen windmill and the electric pumping station, they provide a wonderful picture of the development of drainage technology from wind power to motor power. Both the pumping station and the mill are listed buildings.
Kaagpolder
The auxiliary pumping station is located in the Kaagpolder (approx. 355 ha), formerly known as the Spanbroekerkaag. Originally, it was a marshy peat area that would have disappeared under water without intervention. Therefore, in the 16th century, it was decided to reclaim the area and build a windmill for drainage. In 1654, the current Kaagmolen was built with a wingspan of 26.28 metre, which was very large for that time. The mill pumped water to the Raaksmaatsboezem and was fitted with a screw pump around 1850 to replace the original paddle wheel. The mill is still operational and now serves as an aid in draining the polder.
Switch to steam drainage
After the mid-19th century, wind-powered drainage became increasingly ineffective due to land subsidence, which meant that water had to be pumped higher and higher. Moreover, the wind was always an uncertain factor. In 1879, the polder board decided to build an auxiliary steam pumping station. At the time, switching entirely to steam was not financially feasible due to the high price of coal. When there was no wind and heavy rainfall, the pumping station was a real godsend as a supplement to the windmill. On March 12, 1879, the tender for the pumping station took place in the Town Hall in Spanbroek.
The design came from the Amsterdam engineering firm W.C. and K. de Wit, which specialized in pumping stations. The building was constructed by contractor J. Kooten from Wognum. Unfortunately, a calculation error by the engineering firm resulted in an unexpected additional cost of almost 1,000 guilders.
The auxiliary steam pumping station consisted of two parts: a boiler house on the north side and a machine and pump building on the south side. A small 16 hp steam engine drove the centrifugal pump. Next to the pumping station stood a chimney and a coal shed, where the coal that was delivered by barge was stored. A bridge over the water was only installed later. Starting up the steam engine was a time-consuming task. When it was necessary to assist the mill, the chairman of the polder board would notify the engineer one day in advance. During the firing process, the engineer remained with the machine at all times and temporarily lived with his family in the building.
End of the coal era
After decades of loyal service, the steam pumping station proved to be outdated and inefficient in the 1950s. Maintenance costs were rising and the pump was also in poor condition. In 1958, the steam engine was replaced by a 37 hp Deutz diesel engine. This engine had several advantages: it was more efficient, quicker to deploy (without the long process of heating up steam), and consumed about 50% less fuel. This modernization brought an end to the era of coal-fired drainage. The space under the steam boiler was then closed off. The original steam engine and pump were given a new home in the Cruquius Museum in Haarlemmermeer.
Monument status
In the mid-1980s, the diesel installation was also due for replacement. Electric drainage offered a better solution, but installing a new system in the existing building was difficult. Plans for land consolidation in the De Gouw area, which would lower the water level, required major modifications. It was therefore decided to build a new electric pumping station next to the existing one, rendering the old pumping station obsolete.
In 1994, an electric pumping station with a screw pump was built next to the auxiliary steam pumping station. The transformer required for this was housed in the auxiliary steam pumping station. Later, the electric pumping station was replaced by a fully automatic screw pump with a separate transformer. The transformer in the auxiliary steam pumping station was removed and a few control cabinets remained in place.
In 1988, the auxiliary steam pumping station, the chimney, the coal shed, and the Kaagmolen windmill were designated national monuments. The coal shed, which collapsed due to storm damage in the same year, was rebuilt a few years later.
Extra
Cycling
- Polder mill route from Hoogwoud (Routiq)
- Hoogwoud bike ride 30 km (Westfries Genootschap)
Kaagmolen (Mill Database)