Monday, May 2
Fascinated by Holland’s history with water, I walked 3 miles south from Haarlem to visit one of the 3 pump houses that drained a major area of Holland from 1849-52. The journey entailed taking a free ferry across what I later learned was part of the “Ring Canal” built to drain a lake.
In prehistoric times, what is now the North Sea was largely land: one could walk from present day Holland to England. Rising ocean levels gradually covered the land, but even as recently as the Roman era, much of present day Holland was comprised of low lying land interspersed with lakes. However, the shoreline became an increasingly changing and dangerous landscape as the ocean continue to rise and storms battered the coast. Early inhabitants started living on mounds (whether natural or man made) called terps, to which they retreated when the inevitable floods occurred. The first known dike was constructed around the time of Christ.
Inland from the ocean were mounds of peat standing higher than the surrounding bogs. In the 10th century humans began moving from the coast into this area, and found that by digging trenches and draining water from the sodden peat domes, they could farm the land. The problem was that drying the peat causes it to lose its ability to hold back the rush of storm water; as it dries it shrinks, becomes fluffy, and the top layer oxidizes and turns sour. Once the old land becomes too sour for farming, the inhabitants looked to new peat mounds to drain.
Compounding the problem, peat became an important commodity: it was used for heating, to fire brick-making kilns, to dye cloth, to brew beer. The more the peat was harvested, the more the ground sank, and the less resistant to flooding it became. In response, towns that had ruined the land with their appetite for fuel, started to build dikes and dams to protect themselves; Amsterdam was one such town. Yet the peat harvesting continued.
(An aside to this story is described in an interesting recent book given to us by our friend Ginger, “The Edge of the World” by Michael Pye, describing the influence the North Sea has had on western civilization. After the peat became unsuitable for agriculture, it was used for cattle grazing. Families began keeping cows, and to eke out a living on the infertile land they produced butter for export. Butter requires immaculate conditions or it will spoil; it is far less forgiving than cheese. The Dutch reputation for cleanliness began with the requirement that the dairy barn, usually an extension of the house, be kept immaculate.)
With land that was now below sea level in many areas, Holland developed techniques to pump it out. In one of the most significant developments of the time, windmills previously used for grinding grain were set up to raise water over dikes and into drainage ditches. Windmills sprouted up everywhere, and enabled the inhabitants to keep their feet dry on land situated below sea level.
Model of a ’tjasker’ which could pump water into a ditch, where a larger windmill would pump it into a canal to carry it to the ocean.
Nevertheless, terrible storms occurred from time to time over the centuries, causing catastrophic damage and destroying entire cities.In 1506 and 1509 there were terrible storm surges which broke through ditches and canals and formed a huge new lake south of Amsterdam, called the Haarlemmer (you can seethe beige expanse of the “Groote Haarlemmer” in the middle of the map below). By 1647 this lake had grown to 66 square miles, swallowing towns as it expanded.
Map of Haarlemmer Lake
Pumping out the Haarlemermeer was originally proposed in the 1600s, but there was widespread public resistance, especially by the fishermen. But in 1836 massive storms devastated the region. In November a hurricane drove water to the gates of Amsterdam, and on Christmas Day the water was driven in the opposite direction, flooding the streets of Leiden. It became clear something had to be done: The lake needed to be pumped out. There was natural sentiment to do the job by traditional windmills, but it would have taken 160 windmills 30 years to do the job. King Willem I pushed The Netherlands to advance its technology and insisted that steam engines be used.
The first step was to build a 61 km (38 mile) elevated ring canal to carry the pumped water away, and to carry ship traffic which previously would cross the lake. It took 8 years to build, as the work was done entirely by hand. The earth that was removed was used to build a 120 ft wide dike around the entire lake.
Three pumping stations were built. The pump at De Cruquius, with a cylinder diameter of 12 feet, was the largest Watt style steam engine ever built.
Each stroke raises 8,000 liters 5 meters high. There are 8 levers. They run at 5 strokes per minute. The water is raised to the ring canal, from which it flows to the Spaarn River and eventually to the Zuider Zee and out to the ocean.
One of the valves which let water enter the chamber on the downward stroke and closed on the upward stroke:
They were paid by the stroke. A meter counted them out:
Pumping began in 1848 and the lake was dry by July 1852. In the end, 800 million tons of water were removed.
Holland carefully monitors water levels to this day. Using more modern pumps, they pump out the lowlands when it rains through a vast network of drainage ditches and canals. Since there is still salt in the land left over from prehistoric times, they intentionally flood areas of land occasionally to freshen the soil. Massive dikes and dams have been built in recent decades, some of which have been designated amongst the most impressive modern engineering wonders if the world. I felt fortunate to visit this one and look forward to seeing others.