High tides and low sites: the effect of floodplain creation on the archaeological and cultural heritage in the ‘Wijmeersen 2’ area (lower Scheldt basin)

ERWIN MEYLEMANS, YVES PERDAEN, INGE VERDURMEN
Flemish Heritage Institute

From 2009 onwards several areas in the lower Scheldt basin will be developed as flood basins. The main objectives are enhancing safety against uncontrolled floodings, and the creation of nature reserve areas (mainly with tidal flats and marches).

This creation of ‘controlled flood areas with tidal influence’ will have a significant impact on the geological and cultural heritage values in these wetlands, of which the main negative factors are: -The construction of a number of new dykes; -The complete erosion of the historical landscape structure and its relics within these new floodplains; -Renewed erosion over a longer time period through the formation of new gully systems.

Because of the enormous archaeological and cultural historical potential and significance of these areas on the one hand, and the relative lack of palaeo-environmental and archaeological knowledge due to masking overburden sediments on the other, the Flemish Heritage Institute is conducting a ‘pro-active’ screening of these areas. The main aspects of this research are the diachronical reconstruction of the palaeo-environment (based on a geological survey and the reconstruction of the palaeo-environment through mainly pollen analysis), archaeological prospection and evaluation, and historical research.

The goal of this interdisciplinary approach is the assessment of the impact of these large scale infractructural works on the geological and cultural heritage, and the formulation of mitigation strategies (preservation in situ when possible, preventive research if necessary).

In 2008 this research was mainly focussed on the so called Wijmeersen 2 area, alongside the river Scheldt. Based on the palaeo-environmental reconstruction of the area a number of zones were subjected to an archaeological borehole survey and subsequent evaluation research through test pitting. This revealed important archaeological sites in all these zones. In one area a number of prehistoric occupation phases (early Mesolithic; early to late Neolithic) are situated on a system of point bar deposits from lateglacial origin. Probably the most surprising find however was the discovery of an intensive and rich Roman (end of 1st - beginning of 3th century) occupation of the area. Moreover, due to the clay cover and permanent wet conditions organic material is very well preserved.

The cultural historical research of the Wijmeersen 2 area shows a parcel and drainage pattern that reflects the historic land use and development as can be seen on historical maps from the 16th century onwards. Archives furthermore demonstrate that this systematic drainage and organisation of these wetlands commenced at least in the 13th century. For this purpose the Wijmeersen were provided with a number of dykes and ditches. Several of these, of which some can be traced back to at least the 18th and in some cases the 16th century, are still visible in the area.

The research thus shows that the Wijmeersen 2 area has a very rich and well preserved geologic, palaeo-environmental and cultural heritage record. It is not as yet fully clear what the long term impact of the floodplain development on this record will be. Since a ‘full scale’ excavation is unrealistic, due to the stratified character, depth and (horizontal) extent of the archaeological deposits, a balanced compromise needs to be found. This includes further evaluation and prospective research, working out strategies for in situ preservation (synchronized with the envisaged nature development), and in the long term the development of a monitoring strategy.