Site Event/Activity record ECH7190 - Chester Northgate Redevelopment: Phase 1 Post-Excavation Assessment Report

Post excavation results and analysis for the programme of archaeological mitigation (Phase 1) in support of the Chester Northgate scheme, a mix of retail, residential and leisure development. The site lies in the heart of the historic city centre, bounded by Watergate Street and Northgate Street on the south and east, and by Hunter Street and St Martin’s Way, to the north and west (NGR centred on SJ 40367 66480). Significantly, the Phase 1 site overlay the area of the central range (Insulae XXII, XXI and XVI) of the Roman legionary fortress. Fieldwork involved monitoring of all groundworks undertaken in respect of the Phase 1 scheme, including the construction of structural elements, such as pile caps, lift pits, and drainage and utility service runs, as well as modern topsoil/overburden stripping and breaking-out of existing slabs. The key mitigation strategy adopted was one of in situ preservation. In the limited areas where disturbance was unavoidable, strategies of archaeological excavation, strip-and-record and watching brief were adopted. This assessment also includes monitoring of two ‘off-site’ features associated with the wider Northgate development, including a drain to remove surface water from the site by means of a tunnel to the River Dee, also two electricity cable routes, extending from the main redevelopment down St Martin’s Way and Nicholas Street, with one extending to the west along Grey Friars, whilst the second extended to the east along Weaver Street. The mitigation methodology was successful in limiting the archaeological disturbance to less than 3%. Notable areas where archaeological excavation and recording were required during the most recent phase of mitigation in 2020-1 include the surface-water drainage trench on the south side of Hunter Street, another service-diversion trench on the west side of Northgate Street, the lower foundation pile mat for the new market and cinema, within the former bus exchange, and an area on the southern edge of the grassy knoll (on the north side of Princess Street), known as Core Base 1, which was required for a lift shaft and stairwell associated with a new multi-storey car park. The archaeological works extended across three insulae located on the west side of the fortress’s central range: Insula XXII containing barrack blocks and centurions' quarters; Insula XXI occupied by a building/buildings, of uncertain purpose (possibly a stores/workshop complex); and Insula XVI containing a substantial courtyard building, the function of which is also unclear. Elements of several of the barracks and also a centurion’s quarters, furnished with plastered walls, were recorded, together with small fragments of buildings and associated deposits in the other two insulae. The identified stratigraphy on-site included the following:- - Natural geological deposits. - Buried soils surviving in patches, also a probable tree bole, which pre-dated the establishement of the legionary fortress (Period 1). - Remains of the fortress dating to the late first/second century AD (Period 2), also the later phases of occupation dating to the third-fourth century (Period 3), and the abandonment of the fortress (Period 4). Elements of the fortress barrack blocks, including the centurion's quarters with plastered walls, were recorded, together with fragments of buildings and associated deposits. - A few post-Roman features including pits and other cut features. Also, over much of the site, a thick accumulations of dark soil dating to the early medieval, later medieval and early post-medieval periods (Period 5). This is consistent with the earliest maps of Chester, which suggest that, away from the main street frontages, much of the Northgate area remained open as late as the nineteenth century. - Evidence for nineteenth-century occupation including a few poorly preserved walls and associated deposits (including part of a cellar on Princess Street), and the remains of Victorian buildings that had fronted the adjacent streets, cleared during the later twentieth century (Period 6). The mitigation works also collected 38 bulk soil samples, from largely Roman contexts, producing an assemblage of palaeoenvironmental remains - animal bones, fish bones/scales, marine mollusc shells, charred plant remains and charcoal. The report includes the results of the analysis of the samples. (1) See also the following for earlier individual stages in the Phase 1 mitigation:- ECH 6891: Supplementary DBA, May 2019 ECH 6893: Hunter Street Evaluation, Aug 2019 ECH 6895: Grassy Knoll, Strip, map and record, Aug 2019 ECH 6894: Watching Brief, Sept 2019 ECH 6897: Off Site Drainage, Watching Brief, Oct 2019 ECH 6898: Grassy Knoll and Bus Station, Watching Brief, Dec 2019 ECH 6899: Watching Brief, Jan 2020