Poole Flood Defence - Archaeological Assessment of geophysical data

Wessex Archaeology

Wessex Archaeology were commissioned to undertake an archaeological assessment of geophysical data, acquired in November 2022 by Channel Surveys Limited over the proposed site of the Poole Flood Defence project.

This report comprises of an assessment of geophysical data acquired by Channel Surveys Limited over the proposed Poole Flood Defence study area. The geophysical data comprises of a multibeam echosounder data set. This was used to assess the presence of seabed features of archaeological potential within the study area.

The assessment of the proposed site of the Poole Flood Defence project resulted in a total of 21 seabed anomalies being identified as being of possible archaeological interest. There are summarised as follows

• A total of 11 anomalies were assigned an A2_h rating; anomaly of likely anthropogenic origin but of unknown date; may be of archaeological interest or a modern feature;
• A total of 9 anomalies were assigned an A2_l archaeological rating; anomaly of possible anthropogenic origin but interpretation is uncertain; may be anthropogenic or a natural feature;
• One anomaly was assigned an A3 archaeological rating; Historic record of possible archaeological interest with no corresponding geophysical anomaly.

For the anomaly assigned an A3 archaeological discrimination rating, an Archaeological Exclusion Zone of 50 m is recommended by applying a buffer on the recorded position. For all anomalies assigned an A2_h or A2_l archaeological discrimination rating, no archaeological exclusion zones are recommended at this time but avoidance of all features by micro-siting is recommended if they are proposed to be directly impacted by development in the future. If micro siting is not possible, then further assessment to ascertain the nature of the features may be required – this may particularly be the case for anomalies classified as A2_h.

It is recommended that if any objects of possible archaeological interest are recovered during any groundwork operations, that they should be reported using a pre-agreed reporting protocol. This will establish whether the recovered objects are of archaeological interest and recommend appropriate mitigation measures.