They did not Live by Grass Alone: the Politics and Palaeoecology of Animal Fodder in the North Atlantic Region

Abstract

A five year research project was set up to monitor soil moisture and groundwater levels of an extensive buried, mainly alluviated landscape located at the interface between the lower Great Ouse valley and the fen-edge in western Cambridgeshire. The intention was to monitor changes in hydrology, soil structure and geochemical status before, during and after large scale gravel extraction. The results presented here concern the pre-extraction monitoring period over three years. The project has identified three major landscape zones – shallowly buried former dryland, several sets of relict palaeochannel systems which still remain waterlogged, and a marginal zone between these where the monitored parameters fluctuate on a seasonal basis. The moisture levels of the alluvial overburden, buried soils and infills of the palaeochannel systems appear to act independently of each other, controlled by a combination of rainfall, agricultural land management, height above sea level and depth of burial. It is predicted that the removal of 1–3m of overburden accompanied by water abstraction when gravel extraction commences will lead to changes in the moisture regime of the immediate area and therefore of any contained archaeological contexts and the superficial sediments in this river valley/fen-edge landscape.     

Hydrological monitoring of an alluviated landscape in the lower Great Ouse valley at Over,Cambridgeshire: the quarry restoration phase

Abstract

This paper sets out the results of the last phase of the hydrological monitoring programme conducted at the Hanson Over quarry in Cambridgeshire, during the first full year (March 2004 to March 2005) in which the area of the first phase of gravel extraction was reinstated as reed beds under the management of the Royal Society for the Protection of Birds. It follows on from the studies of the pre-extraction and extraction phases, both published previously in Environmental Archaeology (French et al. 1999; French 2004). It is reassuring to report that the groundwater table in the formerly quarried area and the landscape immediately upstream and downstream has ostensibly been restored to pre-extraction levels, along with a return to previous pH, conductivity, redox and dissolved oxygen values in the groundwater system. Significantly, the continuing gradual fall in groundwater levels observed beyond 500 m from the quarry face for a distance of at least 1·5 km was seen to be arrested, although these had not quite recovered to pre-extraction levels downstream to the northeast. In addition, the soil moisture within the alluvial overburden and the buried palaeosol has also almost returned to pre-extraction levels. This indicates that the clay bunding of the formerly quarried areas acts as an effective barrier against further water abstraction, both inside and outside the sealed area, and allows the natural aquifer to begin to return to its previous levels of influence.

The study dramatically indicates that both the mineral operator, drainage authority and archaeological curator need to collaborate from the outset of any quarrying operation to ensure the continuing maintenance of the groundwater and soil moisture system regardless of how well the combined gravel and water abstraction processes are conducted, and how successful the post-quarry conservation is. As every site's landscape dynamics contribute to its individual hydrological setting, each case is different and requires tailored monitoring programmes to protect the archaeological and palaeo-environmental record from the adverse effects of water abstraction associated with development schemes.