Geophysical Survey, Magnetometry Survey at Pelham Spring Solar Farm, Essex

The survey was undertaken using four Bartington Grad601 sensors mounted at 1m intervals (1m traverse interval) onto a rigid frame. The system was programmed to take readings at a frequency of 10Hz (allowing for a 10-15cm sample interval) on roaming traverses (swaths) 4m apart. These readings were stored on an external weatherproof laptop and later downloaded for processing and interpretation. The system was linked to a Trimble R8s Real Time Kinetic (RTK) differential Global Positioning System (dGPS) outputting in NMEA mode to ensure a high positional accuracy for each data point. MLGrad601 and MultiGrad601 (Geomar Software Inc.) software was used to collect and export the data. Terrasurveyor V3.0.37.0 (DWConsulting) software was used to process and present the data. The survey has recorded anomalies indicative of significant and extensive archaeological activity at three locations in the proposed development area (PDA) all of which are interpreted as highly likely to be foci of settlement activity, possibly of different periods. AAA1 comprises a series of fields and smaller enclosures extending for approximately 500m along the western edge of the PDA in F1. The most concentrated and extensive area of activity is in F4 (AAA2 North and South) where a moated site is confirmed with outlying fields. North of this, along the northern edge of the PDA in F4, a second area of activity is identified. Although many of the anomalies here are low magnitude this complex area of enclosures is also clearly defined and extensive. However, given the extensive nature of, and proximity between, the two areas of activity it is difficult to be certain where one area finishes and the other starts or indeed whether they overlap. A third, isolated enclosure complex, AAA3, is also recorded in F4 bordering the north-west corner of Battle's Wood. Despite the level of archaeological activity described, parts of the PDA are devoid of anomalies. No anomalies of archaeological potential are recorded in F2 and F3 with very few recorded in F5 and F6 and the eastern half of F1. Many of the recorded anomalies are very weak responses although mostly easily discernible against the relatively homogenous magnetic background. It is therefore possible there may be other features that cannot be detected. Nevertheless, it is considered highly likely that the extent of all the areas of significant remains have been identified and their extent defined by the survey.