Anaerobic Digestion Plant, Royston Road, Baldock, Hertfordshire: Archaeological Field Evaluation and Monitoring of Geotechnical Test-Pitting

BiogenGreenfinch are preparing a planning application for the construction of an anaerobic digestion plant on land adjacent to Royston Road, in Wallington parish, north-east of Baldock, Hertfordshire. An archaeological desk-based assessment was carried out by Albion Archaeology that demonstrated that the area had the potential to contain sub-surface archaeological remains. Following approval of a written scheme of investigation for these works, a geophysical survey was carried out (Stratascan 2010). This identified a single anomaly considered worthy of specific targeting during trial trenching. Following the geophysical survey, a series of geo-technical test-pits were opened and observed by Albion; these did not reveal significant archaeological remains. A trial trench plan was agreed with the CPA. It was designed to target the square anomaly identified by geophysical survey and to target other, apparently blank, parts of the area. These evaluative techniques showed that the area was largely blank of archaeological features. Two seemingly unrelated ditches were excavated 200m apart. The date and function of the ditches is unclear. They may be part of a prehistoric/Roman or medieval field system. The remains of a palaeochannel were recorded. In Trenches 11 and 12 the underlying chalk at the base of the palaeochannel contained several compact flint deposits; these may account for the geophysical anomaly highlighted within the survey. The anomaly was not caused by human activity.