Mills on the Air: Kinderdijk

On Saturday May 9, Rob PA3BXR and Elmar PD3EM will be active on HF for the Mills on the Air Event from the Unesco World Heritage Kinderdijk.
This year they'll activate the Pumping station Wisboom which is part of the windmill complex.
They will use the special event callsign PA6MK (Mills Kinderdijk). QSL via PD3EM.

In the Alblasserwaard, the area to which Kinderdijk belongs, problems with the water level became more and more apparent from the 13th century. To get the rid of the excess water in the poldes, long canals were duged. These canals are called "weteringen" and you can find them all over Holland. This method remained sufficient for only a few years. The ground level fell yet again because of a structural issue (veen) and the level of the river rose at the same time, soan additional way of keeping the correct level of the water in the polders was required.
It was decided to buid a series of windmills which would pump the water into a reservoir (boezem) until the level of a nearby river has reached a level that pumping the water into that river was possible again.

In 1868, the windmills received support in the form of two steam pumps. The Wisboom pumping station, named after the chairman of the Overwaard board at that time, served the Overwaard. Four water wheels pumped water from the low storage basin of the Overwaard to the high storage basin. The windmills continued working as well. The steam pump in the Nederwaard has been dismantled. The foundations of the old steam pump now stand beneath the J.U. Smit pumping station.

The steam pumping station was converted to electricity in 1924, and the steam works and the large chimney were torn down. The former boiler room housed the transformer room, the engine room and a workshop. New side wings housed two Pannevis double-suction centrifugal pumps. Two three-phase motors with a horsepower of 115-195 kW powered the pumps. In 1953, a supplementary electric pump was built beside the Wisboom pumping station, although it was later demolished.

In 1995, the current auger pump De Overwaard (ir. G.N.Kokgemaal/Overwaard pumping station) commenced operation and the Wisboom pumping station was shut down. The Wisboom pumping station and its systems are listed historic buildings and have been restored to working order by the Kinderdijk World Heritage Foundation. Besides its protected status, it also has a new lease on life as a visitors’ centre.

Step into the Wisboom pumping station for a unique glimpse into the world of water management and control. The vacuum pumps against the front wall are used to create a vacuum in the housing of the centrifugal pumps. This causes the water level in the housing to rise. Once the water has risen to a sufficient level, it can be pumped out. The electromotors at the back of the room run the big belts that turn the water wheel inside the housing.