SDO21043 - Poole West Quay. Marine Archaeology Heritage Assessment

‘Wessex Archaeology was commissioned by Ramboll to provide consultancy services in relation to the marine archaeological environment for the Poole West Quay development (the Site). This document comprises the marine archaeological heritage assessment and the geoarchaeological review of Ground Investigation (GI) data. The aim of the document is to assess the known and potential marine archaeological resource within the study area, comprising a 500 m buffer around the Site, up to the Mean High-Water Spring (MHWS), and to assess the likely impacts of the development proposals on this resource. The effect of the development proposal on the marine archaeological environment will be a material consideration in the determination of the planning application. This assessment has established that there are the following marine archaeological environmental assets: • potential for prehistoric archaeological material, with two peat deposit identified; • three records of find spots within the study area; • 12 known shipwrecks and obstructions within the study area. There is also potential for additional currently unknown sites to exist; • No recorded wreck locations within the study area, as above there is potential for additional unknown sites to exist; • 19 records related to waterfront activity including wharfs, slips, boat houses, and a bathing hut; • no known aircraft lost while in military service, though the potential for aircraft is extremely low, because of their status they are automatically protected under the Protection of Military Remains Act 1986; and • The historic seascape character of the area comprises the following character types: coastal infrastructure; ports and docks; recreation; communications; cultural topography; fishing; industry; military; and navigation. The geoarchaeological review comprised the assessment of 41 GI boreholes to a maximum depth of 20.42 mbgl (metres below ground level) and has enabled the lithological characteristics of the deposits beneath the Site to be identified; stratigraphic units to be defined; and an initial assessment of the geoarchaeological potential to be made. Overall, data coverage across the Site was good and the modelled sediments fit well with the recognised sediment sequence for the area (BGS, 2021) comprising; Palaeogene bedrock (Oakdale Clay Member) overlain by Holocene tidal flat deposits reaching up to 16.40 m in thickness along the western margin of the Site and capped by made ground up to 4.60 m in thickness. Peat was also encountered in two locations at 12.60 mbgl (-11.31mOD) in the southern part of the Site and 13.00 mbgl (-11.18mOD) in the central part of the Site and reached up to 1.80 m in thickness. Peat deposits have a high geoarchaeological potential, containing a stratified range of palaeoenvironmental waterlogged remains informing on past physical vegetation and environmental change (and the impact of humans on the landscape). Poole West Quay Marine Archaeology Heritage Assessment iv Doc ref 244280.1 Issue 2, August 2021 In terms of the geoarchaeological potential of the deposits encountered beneath the Site, bedrock (Oakdale Clay Member) deposits have low potential. The fine grained tidal flat deposits also have low geoarchaeological potential but may contain layers of peat or buried archaeological remains. Peat was recorded in CP110 located within 15 m of the new quay wall. Given there are no GI data directly available in the location of the new quay wall, there is potential for peat to be present. The elevation of any peat deposits is expected to be around -11 mOD. If any proposed piling exceeds this depth, further geoarchaeological works at the location of the quay wall may be required. The wider cultural heritage resource of the area is defined by its use as an anchorage and commercial port, with a variety of known archaeological sites across the wider area. Overall, the potential resource may be characterised by a scattered palimpsest of archaeological features, with significant gaps in the record where the area has fallen out of use, or potentially been inundated due to sea level changes within the harbour. There is therefore the potential for deposits within the site to preserve evidence of the prehistoric landscape, allowing an insight into the wider paleoenvironmental history of the Site, in addition to further Roman material from the use of the area as a port and local manufacturing centre. The need for, the scale, scope, and nature of any further assessment and/ or archaeological works should be agreed through consultation with the statutory authorities. The recommended procession of mitigation, if required, would be avoidance, reduction via appropriate mitigation, remedying and offsetting the potential harm, and finally the recovery of the identified archaeology as appropriate.’