Maps reveal the historical path of the Rhine
Below the rivers they say 'friet', above they say 'patat'. In the 15th century BC, this boundary was quite different - and not only because the potato was not introduced to the region until the 18th century AD. In the 15th century BC, the tail of the Rhine was located much further south than it is now. It was only around 800 AD that the Rhine, under human influence, moved to its current position where it now guards the boundary between 'friet' and 'patat'. Using about 40 old maps of the Netherlands, researchers Jana Cox and Maarten Kleinhans (Utrecht University) and curator and map expert Marco van Egmond (University Library), among others, were able to detail the history of the Rhine and the Haringvliet rivers. This research shows the importance of historical archives and human activity in a system.
How did the Rhine change between 1500 BC and today?
Both the mouth and the tail of the Rhine have moved locations throughout history. In the past, the beginning of the Rhine was closer to The Hague and the tail was further south. Through natural avulsions, whereby the river spills out of its banks, and through human activity the Rhine has wandered and become narrower over time.
Between 3500 and 2600 BC, people first settled in the area, and they did so especially around tidal streams. Between 800 BC and the year zero, people also settled in surrounding peatlands. After that time, until about 500-1000 AD, Roman settlements drained a lot of this peatland. Partly due to this reclamation, the Rhine and Meuse rivers came to lie in their present position around 1050-1350 AD. The Biesbosch wetlands later came into being during the Saint-Elisabeth floods of 1421-1424.
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The huge influx of trade around Rotterdam by, among others, the East India Company and, later on, modern cargo ships, ensured that the river was constantly under development.
Why does the Rhine have such an extensive history?
Both as a result of natural avulsions and human (inter)action, the river has long been in motion. From the Roman occupation, the founding of Rotterdam and the port of Rotterdam, the Saint-Elisabeth flood and the peak of maritime trade to the more recent construction of the Nieuwe Waterweg, the damming up of the Zuiderzee and the Delta Works - man and nature have been influencing the area around the rivers for more than 2000 years.
Using landmarks such as existing churches, you can compare old maps to current maps.
What types of maps did you have at your disposal for this research?
We used geological maps and old maps. Geological maps are based on geological deposits and archaeological finds, so you can see where the land and the rivers likely used to run in the past. Geological maps show the history since about 9000 years ago. We did not use the whole collection of geological maps for this research, only maps between 1500 BC, when the mouth of the Rhine stabilised, and 1500 AD.
Old maps are maps created by people, the first one is from 1558 AD. From then on, we started using existing old maps instead of geological maps.
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How do you know if those old maps from the sixteenth century are accurate?
With the help of landmarks such as existing churches, you can compare old maps with current maps. That way you know exactly which ones are accurate. Whether an old map is accurate or not also depends on the source(s) of the map. If a land surveyor was involved in making the map, it is usually geometrically reliable. Other maps may have been copied from that reliable map and will therefore also be correct, although sometimes there is some time lag between these copies. In this research, we have mainly used such accurate prototypes or derivatives. Sometimes these maps have been published by well-known mapmakers, but not always.
What makes this research so unique?
Many of the old maps we used were river and sea maps. Skippers, for example, had to be able to see exactly where they would be able to moor. Many maps were also made to improve the navigability of rivers or to prevent dike breaches. This is unique to the Netherlands: the importance of the rivers has ensured that the Netherlands is very rich in cartographic data about them. All these maps were already available, and the enormous work of cataloguing, digitising and georeferencing the maps had already been done by the University Library. That greatly facilitated the research. In addition, a previous PhD student developed a tool that uses maps of aerial photographs to determine how the estuary looks like under water. So the way really was paved for us: everything was already there and we could get straight to work.
J.R. Cox, J.R.F.W. Leuven, H.J. Pierik, M. van Egmond, M.G. Kleinhans, Sediment deficit and morphological change of the Rhine–Meuse river mouth attributed to multi-millennial anthropogenic impacts, Continental Shelf Research, Volume 244, 2022, 104766, ISSN 0278-4343, https://doi.org/10.1016/j.csr.2022.104766.