York Historic Environment Record

3 dipwells installed for 6 month pre-planning monitoring programme. 2 pressure transducers were also installed. Water level movements across the site as logged in both boreholes were broadly identical in pattern, with a maximum elevation of 8.70m AOD recorded in BHO2 and a minimum of 7.64m AOD in BH06. The range at each was also very similar, 0.46m in BH02 and 0.42m in BH06. The limited data confirms the concept model that groundwater flow is eastwards towards the River Ouse. Because the majority of the site is concrete and tarmac surfaces, localized infiltration of precipitation will be limited, and therefore recharge of the watertable is likely to be due to influences from the river as well as precipitation events throughout the catchment area. The evidence from this limited program of deposit monitoring suggests that conditions within the sediments below the watertable are predominantly reducing and therefore support preservation of organic archaeological and bioarchaeological materials. The results of the assessment of twenty-six sub-samples from the borehole survey support this conclusion. Furthermore, there is no evidence to suggest that conditions had changed over time, or are now in a state of flux, which could compromise the continued survival of these vulnerable organic remains.