York Historic Environment Record

As part of the planning application a borehole survey with subsequent dynamic sampling survey and programme of hydrological monitoring were carried out to provide information on the nature and preservation of buried archaeology at the site. The sedimentary sequence extends from glaciogenic till through river channel deposits to organic muds associated with the King’s Fishpool, which in turn are overlain by post-medieval deposits and modern concrete. Radiocarbon dates on waterlogged wood within interbedded organic deposits suggest flooding of the site in the post-Roman period. There is organic preservation at the site, however it has been subject to considerable humification. Below 5.80m aOD, the stratigraphy is waterlogged. On 17 April 2019 technicians from Van Walt Ltd installed Keller PR-36 XiW groundwater monitoring sensors in the four cable percussion drilled boreholes (BH) and in two of the three window sampling (WS) holes (WS02 and WS03) that had been drilled for geoarchaeological purposes. Sample Minimum Mean SD Maximum WS02 +7.51m OD +7.65m OD ±0.10m +8.37m OD WS03 +7.02m OD +7.24m OD ±0.13m +8.20m OD BH01 +7.43m OD +7.53m OD ±0.07m +7.79m OD BH02 +7.44m OD +7.52m OD ±0.04m +7.64m OD BH03 +7.54m OD +7.67m OD ±0.10m +8.10m OD BH04 +7.45m OD +7.68m OD ±0.10m +8.15m OD