MoLAS 2005: annual review

Spitalbrook Water Park, Broxbourne

Clients: Alan Conisbee and Associates on behalf of the Lee Valley Park

The Lee Valley Park lies to the east of Broxbourne station between the River Lea and the railway line. Its redevelopment will include the creation of new landscaped nature reserves and the construction of a canoe course, as well as a number of buildings with roads and parking. The site, which extends to over 1km², is in an area of historic gravel pits. Old Ordnance Survey maps suggest that most of it had, in fact, been quarried away and backfilled or turned into reservoirs.

It was this gravel extraction, however, that led to the discovery in the early twentieth century of the Lea Valley Arctic Beds within the gravels, and of Mesolithic flint scatters in the overlying alluvium that are today considered to be of National importance. The Arctic Beds contain the remains of the animals (mammoth, woolly rhinoceros, reindeer and lemming) and plants (arctic willow and mosses) that existed in the valley around 20,000 years ago, close to the height of the last Ice Age. The Mesolithic flints comprised several hundred flakes and cores found in two small areas at the interface of a sandy soil and the overlying peat. Their depositional context makes them of great importance, as they each represent a single ‘event’: a temporary knapping site, retaining a representative assemblage of flint artefacts and the debris of their manufacture.

The flints were excavated during visits to examine exposures in the gravel pits by SH Warren, the well-known local antiquarian, assisted by his wife and garden boy. Pioneering work on pollen analysis, a technique now used routinely in reconstructing past environments, was carried out on samples taken from the quarries by Professor Harry Godwin, of Cambridge University, who was at the time working on his pollen zonation scheme that was to form the basis of our present understanding of vegetation change from the end of the last Ice Age to modern times. Subsequently (in the early 1950s) some of the first radiocarbon dates ever obtained were made on samples taken from the Arctic Beds. This legendary work was undertaken in the quarries of the St Albans Sand Co. on Nazing Mead and in Rikof’s Pit, which lay in the south east corner of what is today the Lee Valley Park. If similar deposits survive on the site it would offer the opportunity for their examination and excavation using modern techniques.

Geoarchaeological monitoring of geotechnical site investigations was undertaken in October 2005. As expected, most of the site was found to have been disturbed by quarrying. However, in situ alluvial deposits were identified close to the former Rikof’s Pit and a geoarchaeological borehole was drilled in this area to obtain core samples for off-site examination. Although this work is still in progress, radiocarbon dates have been obtained from peat within the alluvium that show it is indeed of Early Mesolithic date and contemporary with that found in Rikof’s Pit. Whether these deposits will be preserved in situ or will be the focus of further excavation is not yet known, but as a result of the geoarchaeological investigation it is now known that the potential exists for modern study of these sites that were investigated when the techniques of archaeology and past landscape reconstruction were in their infancy.

This site report is extracted from MoLAS 2005: annual review