Archaeological Geophysical Survey

Specification for Archaeological Geophysical Survey

  1. Introduction

    1. This specification, prepared by the Devon County Historic Environment Team (HET) sets out the scope of the archaeological works required to better understand the presence, absence and significance of heritage assets with archaeological interest within a proposed development site.
    2. This work is usually undertaken in support of and to inform a proposed development that will be subject to a later planning application, but can also be required as a first stage of archaeological work undertaken through the application of an archaeological condition applied to a planning consent granted by the Planning Authority. The usual wording of such a condition is as follows: “No development shall take place until the applicant has secured the implementation of a programme of archaeological work in accordance with a written scheme of investigation which has been submitted by the applicant and approved by the Local Planning Authority. The development shall be carried out at all times in strict accordance with the approved scheme, or such other details as may be subsequently agreed in writing by the Local Planning Authority.”
    3. A geophysical survey is defined in the Chartered Institute for Archaeologist (CIfA) standards and guidance as the use of “non-intrusive and non-destructive techniques to determine the presence or absence of anomalies likely to be caused by archaeological features, structures or deposits, as far as reasonably possible, within a specified area or site on land, in the inter-tidal zone or underwater. Geophysical survey determines the presence of anomalies of archaeological potential through measurement of one or more physical properties of the subsurface.” (CIfA Standard and Guidance for Archaeological Geophysical Survey).
    4. The survey work must be carried out in accordance with current Historic England and CIfA guidance.
    5. The results of the survey along with any intrusive investigations may lead to one or more of the following:
    6. The formulation of a strategy to ensure further recording, preservation or management of the resource
    7. The formulation of a strategy to mitigate a threat to the archaeological resource
    8. The formulation of a proposal for further archaeological investigation within a programme of research
    9. If, in the light of the results of the geophysical survey, intrusive archaeological works are required the requirement and scope of such works will need to be agreed with the HET. The specifications for the range of works that may be required can be found on the Devon County Historic Environment Teams webpage – Environment and Planning.
  2. Written Scheme of Investigation

    1. This Specification sets out the requirements for archaeological geophysical surveys that may be undertaken at the request of the HET and will form the basis of the agreed Written Scheme of Investigation to be prepared by the geophysical contractor and submitted for approval by the HET.
    2. In advance of the survey commencing the geophysical survey contractor must agree with the HET:
      1. The geophysical technique(s) to be employed in the survey, and
      2. The areas to be subject to any geophysical survey.
      3. The Written Scheme of Investigation should contain, as a minimum, the following elements:
      4. Non-technical summary of proposed survey methodology
      5. Site location (including map) and description of site.
      6. Designations (Scheduled Monument number(s))
      7. Context of the project
      8. Geological/geomorphological and topographical background
      9. Archaeological and historical background to include an examination of historic maps of the site to assist in the interpretation of any anomalies identified by the survey, as well as a consideration of any desk-based historic environment research must be consulted
      10. General and specific aims of the survey
      11. Survey methodology
      12. Report preparation (method) including data presentation
      13. Publication and dissemination proposals
      14. Copyright
      15. Archive deposition
      16. Timetable for fieldwork, reporting and archive deposition
      17. Staffing
      18. Health and Safety considerations
      19. Monitoring procedures
    3. The Written Scheme of Investigation must include the OASIS reference number for the project as well as a copy of the quotation from the Archaeology Data Service for the digital archiving of the data generated by the survey.  This quotation can be obtained online from ADS Easy for surveys of sites of up to ten hectares in size. For surveys of sites over ten hectares in area a quote should be obtained by contacting the Archaeology Data Service.
  3. Fieldwork

    1. The field survey will be undertaken in accordance with this Specification and with the Written Scheme of Investigation which will be prepared by the geophysical survey contractor and submitted for approval by the HET.
    2. The survey grid locations should be accurately plotted, typically with ±0.1m accuracy and geo-referenced so that the grid can be-located by other parties.
    3. Should concentrations of artefacts or other anthropogenic material be noted during the course of the survey the character and location of any such material must be noted and recorded in the final report. Any artefact recovered from the site should be handed over to the overarching archaeological consultant or the HET.
  4. Reporting

    1. The report shall be prepared collating the results of the geophysical survey.
    2. It is advised that a draft version of the report is submitted to the HET for comment prior to its formal submission.
    3. The archaeological consultant shall complete an online OASIS (Online AccesS to the Index of archaeological investigationS) form in respect of the archaeological work. This will include the uploading of a digital version of the report and this version of the report will be downloaded by the HET on the understanding that it will in future be made available to researchers via a web-based version of the Historic Environment Record. The report to the Historic Environment Record will also include the OASIS ID number.
    4. The Archaeology Data Service advises that “Good data management from the very beginning of a project can be key to its success and makes preserving data and preparing it for deposit with ADS much easier”.  The Written Scheme of Investigation must include reference to the geophysical contractor’s Data Management Plan.
    5. Reports should contain as a minimum:
      1. Non-technical summary
      2. Introductory statements
      3. Aims and purpose of the evaluation
      4. Methodology
      5. Results, including a confidence rating for the results and their interpretation
      6. Conclusion
      7. Plans/plots, including interpretative plans of the results
      8. Anomalies identified must be numbered in plans/plots and these should be referred to in the text description of the survey results
      9. The plans/plots of the survey results should be overlaid on the OS grid showing the grid references.  Any plots that are illustrated without an OS grid must include at least two points annotated with their GPS coordinates.
      10. Index to and location of digital archive
      11. References
    6. The results section of the report should “demonstrate that the archaeological potential of all anomalies located during the survey has been considered and the maximum use should be made of data plots and interpretation plans in this regard. Since the cause of anomalies often cannot be unambiguously determined based on geophysical measurements alone, the text should also be clear about the degree of uncertainty pertaining to inferences drawn from the results.” (Annex 2 – CIfA Standard and Guidance for Archaeological Geophysical Survey – updated 22nd November 2013).
  5. Personnel

    1. The work shall be carried out by a recognised archaeological consultant, agreed with the DCHES. Staff must be suitably qualified and experienced for their project roles. All work should be carried out under the control of a specified Member of the Chartered Institute for Archaeologists (MCIfA), or by a specified person of equivalent standing and expertise. Any WSI or PD will contain details of key project staff and specialists who may contribute during the course of the works – excavation and post-excavation.
    2. All staff, including subcontractors, must be fully briefed and aware of the archaeological work required under the specification and written scheme of investigation, and must understand the aims and methodologies of the project.
    3. Health and Safety matters, including site security, are matters for the consultant. However, adherence to all relevant regulations will be required.
  6. Deposition of Archive and Finds

    1. Completion of the project is dependent on the compilation of an ordered and integrated project archive by the archaeological consultant in accordance with this Specification, the CIfA Standard and guidance for the creation, compilation, transfer and deposition of archaeological archives and with Management of Research Projects in the Historic Environment (MoRPHE). The archive must also be transferred for long-term curation to a recognised, accredited or trusted repository. An archive is defined as “all records and materials recovered during an archaeological project and identified for long term preservation, including artefacts, ecofacts and other environmental remains, waste products, scientific samples and also written and visual documentation in paper, film and digital form” (ARCHES).
    2. It is anticipated that the archive will consist only of born-digital data created by the survey and the final report production. However, surface finds may be recovered during the survey work and any such material may also need to be deposited as part of the overarching site archive that includes any further archaeological works. All data generated from the survey should be included in the project archive.
    3. The Written Scheme of Investigation must set out a timetable for the deposition of the archive. The HET would normally expect this to be completed within six months of completion of the fieldwork element of the project.
    4. Deposition of the archive
      1. The collecting museums in Devon (Royal Albert Memorial Museum Exeter, Museum of Barnstaple & North Devon and Plymouth City Museum & Art Gallery) require that the digital archive (consisting of born-digital data produced during fieldwork) must be transferred into the care of a Trusted Digital Repository (see ‘Deposition of the digital archive’ – below) and not to the museum.
      2. Deposition of the digital archive
        1. The digital archive will consist of all born-digital data (images, survey data, digital correspondence, site data collected digitally etc.).
        2. The digital archive must be deposited with a Trusted Digital Repository and thus made publicly accessible, in accordance with the National Planning Policy Framework (2021). It is understood that the only suitable repository for digital archaeological archive is the Archaeology Data Service (ADS). The digital archive must be compiled in accordance with the standards and requirements of the ADS, which may be accessed through the ADS website.
        3. Guidance on selection for the archive is also provided.
        4. It is expected that depositors will sign an Archive Level Common Deposit Agreement for digital archiving purposes.  Depositors are encouraged to read ADS Guidelines for Depositors at an early stage in project planning. This must be stated within the Written Scheme of Investigation, which should also identify the recipients of each element of the documentary archive.
        5. Further guidance can be found at Work Digital/Think Archive: A guide to managing digital data generated from archaeological investigations (Digventures, 2019).
        6. The archaeological consultant must notify the HET upon the completion of the deposition of the digital archive with the ADS and completion of an OASIS entry.
  7. Monitoring by the Historic Environment Team

    1. The archaeological consultant shall agree monitoring arrangements with the County Historic Environment Team and give two weeks’ notice, unless a shorter period is agreed with the HET, of commencement of the fieldwork. Details will be agreed of any monitoring points where decisions on options within the programme are to be made.

Revised: 24th November 2022