GIS reconstruction of the palaeogeography of the Holocene Rhine-Meuse delta

Since 1999, Utrecht University maintains a reconstruction of the channel belt network of the Rhine-Meuse delta in the Holocene, stored in GIS. The rivers Rhine and Meuse split in various branches today and have done similarly in the past. New channels have formed and older channels have been abandoned through natural sedimentary processes such as avulsion and transgression. The resulting Holocene delta substrate can be seen as a spaghetti of channel belts, composed mainly of sand, that dissect flood basin sequences of clay and peat. These features are mapped at very high resolution, and for the great majority of the channel belts direct age control on their beginning and abandonment is available. Utrecht University keeps a series of databases for this type of research. Of borehole descriptions and of 14C datings obtained on relevant sediments, for example, these being the primary raw data. The GIS of the Rhine-Meuse delta channel belt fragments is our database storing the mapping and dating of recognized channel belt features and is our tool for iterating to the optimal palaeogeographical reconstruction. I will discuss the functional setup of the GIS for delta network reconstruction and the philosophy behind it (Berendsen et al., 2007). In a single map-layer we store channel belt fragments in a mosaic map, and use a small number of polygon attributes to label geological-geomorphological meaning. The digital map is linked to a table storing ID’s and reconstructed ages for individually distinguished channel belts. This data structure allows checking for internal consistency of the implemented reconstruction, enabling iterative improvement while digitizing and labeling. Palaeogeographical maps for any given time during the Holocene result from GIS-database queries. The reconstruction result is typically visualized as a time series of maps showing delta network change, and as static map showing age of preserved channel belts fragments (Berendsen et al., 2001). I will give a few examples of the way the database is presently used in archeological, geological and physical geographical applications. The reconstruction is a widely used resource in the 'Malta' archeological practice in the Netherlands today. It is highly successful, also because it was launched digitally early in the 21th century when many archeologist were making their digital transition. But the original digital map is now over 10 years old and in detail in many locations the reconstruction has significantly changed (improved, we think). I will highlight the progress in recent years, including our extensions into the Niederrhein area in Germany.
 References: Berendsen, H.J.A., K.M. Cohen, E. Stouthamer (2001) Maps and cross-sections. p. 49-55 + addendums. Chapter in: Berendsen & Stouthamer (2001) Palaeogeographic development of the Rhine-Meuse delta, The Netherlands. Assen: Van Gorcum 268 pp + color maps and cross-sections Berendsen, H.J.A, K.M. Cohen & E. Stouthamer (2007). The use of GIS in reconstructing the Holocene paleogeography of the Rhine-Meuse delta, The Netherlands. Int. J. of GIS, 21, 589-602.