Dam Cities

Many towns and cities in the Netherlands, and certainly in its western part, Holland, bear a name ending in "dam". Among them are of course Amsterdam, and the harbour city of Rotterdam, but also numerous much smaller towns, such as the charming little towns Edam, Monnikendam, the brandy city of Schiedam, and villages such as Maasdam and Alblasserdam; in the North of the Netherlands: Appingedam. The photo shows the river Alblas and the dam at Alblasserdam in the background.


To the right you see the town of Alblasserdam from a satellite. The dam in the river Alblas is at the centre of the picture. The name of the street at that location is "Dam" obviously. To the right of the dam you see the inner part of the river. The harbour is at the left side of the dam; originally it was the outer part of the river Alblas.

These "dam" towns all derive their name from the way they originated. They developed according to a common pattern which can be recognized even today. However also many other towns show that same pattern, e.g. Gouda, Hoorn, Schoonhoven, Gorinchem, Muiden. If you want to see the pattern at its clearest do not go to one of the larger cities, but visit for instance the tiny town of Nieuwpoort where everything is present and at only a few minutes walking distance. Before telling the story of the history of the "dam" cities it is good to know a little bit about the previous situation. A fact startling to most other inhabitants of the world is that a considerable part of the land is below sea level, and that the famous landmarks such as windmills and dikes are needed to keep the feet of the Dutch people dry. A thing that not so many people know is that activities of these same people are the cause of the fact that the land has become so low.

Two thousand years ago when the Romans visited the region for a few centuries, most of Holland was a large swamp, filled with peat, with a few rows of sandy dunes along the coast. The first parts to be inhabited were the dunes. Still today the inner side of the dunes is densely populated and much sought after. Gradually the people started colonizing the swamp land and after some time started to live there permanently, often on small artificial hills because the land was flooded frequently. Some farms or villages are still built on such a hill which is called "wierd" or "terp" depending on the region where they are located. The farm shown on the photo is built on a hill appr. 1 m above the surrounding terrain.


In order to make the land suitable for farming, mainly cattle, the water table had to be lowered; this was done by digging ditches. The long straight parallel ditches are still typical of the Dutch landscape.
This worked but it had an unwanted effect: the very soft peat slowly subsided, and after one or two centuries the positive effect was lost. Thus the flooding frequency increased dramatically in the 12th century, necessitating drastic measures.

The frequent flooding was detrimental also for agricultural activities and people started surrounding pieces of land with dikes. The diking schemes became bolder and ever larger areas were protected. The dikes followed the larger rivers such as the Rhine branches in the SW of the Netherlands. Smaller rivers had to be closed off with a dam. To get rid of excess water from the inner area there was a culvert in the dam with a door to prevent flow from the outside water body to the inner area.

Once the land was protected the average water level did become lower, but the price paid was that the peat continued shrinking. The land subsidence can be observed in many places. Thus it became difficult again to keep the land dry, particularly in winter. Also a lot of peat was taken away for fuel which resulted in a number of large lakes, some of which are now favoured for recreation. Improving technology was needed to keep the land inhabitable. The first windmills were introduced in the 15th century. Using ingenious schemes it became possible in the 17th century to reclaim a number of the lakes of which the bottom was up to 2 m below sea level. In the 19th century steam power became used to drive the pumps, and in the 20th century electrical pumps got used; present polders now are up to 6 m below sea level.

Water protection authorities were founded by progressive rulers. They were among the first democratic organisations in the world, where the voting depended on the amount of land owned. The organisations were called Hoogheemraadschappen and they were powerful which they expressed by building impressive offices. Such offices can still be seen in Delft, Leiden, Edam and Rotterdam (on the photo you see the building of the water authority for Schieland, now museum). Many of the major dikes were built in the 13th century, and the office buildings dated from the 16th or 17th centuries.

Traffic in the early days was mainly by boats because of the muddy state of the land, and the dams were a considerable obstacle. If goods had to cross a dam there were two ways to do this. One was to unload the ship, carry the goods over the dam and load them into another ship. The other way was to tow the (small) ships with goods and everything over the dam. In both cases many helping hands were needed so that a village developed. Since the procedure of transferring the goods was time-consuming there was also an inn near the dam. The place where people built their houses was along the dike because it higher than the rest and thus safer. This street which often is called Hoogstraat (High street) is the oldest street of the city and still an important shopping street usually; in Rotterdam and Schiedam this is the case and also in Amsterdam where the street is called Nieuwendijk (New dike). The inn is still found at its proper place in Nieuwpoort. The place where the dam was built often simply is called Dam, and similarly the dam still bears this name in e.g. Alblasserdam, Schiedam and Amsterdam.

The part of the river at the inner side of the dam usually retains its original name, Amstel in Amsterdam, Rotte in Rotterdam, Schie in Schiedam. The part at the outer side was connected to a larger body of water, an estuary, so here larger ships boarded and the place became the harbour (Haven), or outer harbour (Buitenhaven).

Obviously the water flowing down the once open river could not simply be stopped so in the dam there was a wooden sewer. In Rotterdam where a railway tunnel was built along the track of the former Rotte river the remains of such sewers were digged up. At those times windmills were not yet used to pump water, they were even hardly known in Holland. At low tide the sewer was opened and at high tide it was closed again. In winter however this drainage system was often insufficient and the land was flooded for months.

When the traffic became more important a sluice was built through the dam or parallel to the dam. A particularly beautiful sluice complex can be found in Muiden, near Amsterdam. The sewer was not only used to let water out; in war situations water was let in to inundate the land to keep the enemy out. In Nieuwpoort the city hall was built over the sewer so that protesting farmers could not easily prevent the flooding. In addition Nieuwpoort was built as a fortress to protect the sewage system from enemy attacks.

Many of the towns prospered and acquired city rights allowing them to build a defense system around the city. Traditionally it consisted of a wall and moat. Now this presented a problem since the moat had to cross the dike at two places while at the same time the inner and the outer water had to be separated. This problem was solved by building a "beer" across the moat. This is a brick wall with steep sides and a sharp upper edge; on top there often were two small turrets. This made it very difficult for intruders to cross the moat over this wall. Nieuwpoort still has one, although it is covered on one side by the roadway crossing the town. The fact that this road is close to the "beer" is not surprising since the road follows the dike on which the town was built.

The first generation of flood prevention structures were culverts in a dike, usually built of wood. There was a wooden door inside which could open only to one side. Thus flow from the inner area to outside is allowed whereas flow from outside is prevented. This structure made use of the tidal motion in the larger rivers; at low tide when outside the level was below the level inside, water could flow out. At high tide the door closed due to the water pressure. Water levels in the polder could not be more than a few tens of cm below the average sea level.

Later on windmill power was used to move the water. In the 19th century steam engines started to be used to pump the water from the low areas.

  ©: Nico Booij (2012)