Deepham’s Sewage Works Edmonton London Borough of Enfield

In September 2011 Oxford Archaeology South (OAS) were commissioned by GBMJV Ltd, to maintain an archaeological watching brief during the creation of a
new pumping shaft facility at Deepham's Sewage Works, Edmonton, Greater London. The purpose of the field investigation was to mitigate the impacts of the
development.
Previous investigations at the site have including floodplain modelling and deskbased assessment, which suggested that the area has a high archaeological and a
palaeoenvironmental potential. However, subsequent targeted field evaluations to the south of the site and small scale watching briefs within or close to the site have
failed to identify any signs of significant archaeology. Instead large areas of ground disturbance and truncation have been identified associated with the construction of
the Sewage works.
The more recent watching briefs undertaken at the site have identified preserved floodplain deposits, including peat and alluvial deposits sealed under thick Victorian
made-ground deposits. An updated deposit model has also been produced and has indicated areas of preserved floodplain deposits exist to the east and south of the
site, with signs of higher truncation on the gravel terrace to the west. The results of previous work on site have helped to confirm the high level of ground disturbance
and truncation identified in the west, with only a few shallow archaeological features
surviving here. The most significant of these were medieval and post medieval features and structures associated with the pre-sewage works, Deepham's Manor Farm.
No archaeological features or deposits were identified during the current watching
brief located to the east of the sewage works, where an intact alluvial silts and organic deposits overlie sandy gravel deposits. The organic sequence was identified
at a depth of 3.62m to 3.05m (8.39m and 8.96m OD) and potentially represents part of the prehistoric peats known from the surrounding area. These peats were overlain
by a sequence of alluvial silty clays that represent increasing water and river-levels in this area. These deposits were found to have high potential for
palaeoenvironmental assessment and dating. Two organic units were also identified interstratified within the Pleistocene gravels at depth of 6.5m (5.51m OD), which
may represent the Late Glacial Arctic Bed deposits.
The absence of archaeology within this area of the site may potentially relate to the buried palaeotopography of the area, which the updated deposit model indicates is
close to a large late Pleistocene channel that likely continued into the Holocene. The waterlogged nature and potentially early inundation of this area of the site may
suggest that it was less favourable for human activity, compared to other locations like the terrace edge or floodplain islands that were also identified in the site model.