An array of twenty evaluation trenches, each measuring 30m x 2m, was excavated across the route, representing a 4% sample of the area (Fig. 4). The trenches were positioned to investigate the potential impacts along the route of the pipeline. The aims of the trial trenching was to investigate fully and expose the entire vertical extent of all trenches to this depth. The trenches were excavated using a mechanical excavator under archaeological supervision and were positioned on anomalies identified from the geophysical survey, in order to establish the date, nature, vertical and horizontal extent and significance of any archaeology. A proportion of the trial trenches were also located to investigate areas without geophysical anomalies in order to test the efficacy of the geophysics and ensure that the issue of the presence/absence of archaeological remains was resolved. Some trenches were split into sections in order to maintain stability, reduce flooding and minimise risks to personnel. In particularly deep deposits such as the crossing of the Red Rhine (DX6) and roads (RDX1 and RDX2) depths were anticipated be at least 4m and consequently a series of four test pits and four boreholes was undertaken to evaluate the deeper impact areas. The boreholes were drilled using a terrier rig with continuous sleeved core recovery. The test pit were dug with the mechanical excavator. In June 2015 Oxford Archaeology undertook an archaeological evaluation along the route of the proposed Severnside Pipeline Diversion, South Gloucestershire. The work was commissioned by Jacobs on behalf of the National Grid. The primary purpose of the evaluation was to assess the archaeological potential of the route of the proposed pipeline diversion. The site lies upon extensive estuarine alluvial deposits known as the Wentlooge Formation, which underlie large areas of both the English and Welsh sides of the Severn Estuary. In the Enron site to the south, a thin peat layer containing a comminuted charcoal in-wash was radiocarbon dated to the early Bronze Age. Although no evidence of human activity accompanied this deposit, previous work to the north-east of the site had provided evidence of Romano-British settlement. A geophysical survey was undertaken prior to the intrusive works that suggested low archaeological potential, with mainly services and geological changes revealed. The archaeological evaluation comprised the mechanical excavation of 20 trenches measuring 30m by 2m, compr...