What’s the Difference between an Archaeological Watching Brief and an Archaeological Evaluation?

We sometimes get asked by clients how an archaeological watching brief differs from an archaeological evaluation.

The short answer is that a watching brief is monitoring work carried out during a development or scheme of works. An evaluation is part of preliminary work required either in support of or following determination of your planning application and generally well in advance of any development.

Whether you’re asked to commission one or the other depends on where you are in the planning process and the likelihood of your proposed works uncovering archaeological remains.

Why have I been asked to commission an archaeological evaluation?

If you’ve been asked to commission an archaeological evaluation on your site it means you’re probably at the beginning of the planning process. That’s because it is part of the data collection phase of works, designed to help the Local Planning Authorities understand whether your site needs further archaeological works as part of planning consent.

The archaeological evaluation provides information on the nature, extent, quality and significance of archaeological remains present on a site. Based on the results of the evaluation, the Local Planning Authorities will decide whether further archaeological work is needed.

An evaluation will typically involve the excavation of trial trenches or test pits sited strategically across the site, while fieldwalking, geophysical survey, boreholes and deposit modelling may also be required. The evaluation strategy should ensure that enough information is recovered to fulfil the planning conditions. Sometimes it may be possible to combine the archaeological site investigations with the work of the appointed geotechnical engineers – so it’s worth raising this with your archaeological consultant at an early stage since it could save both time and money.

Archaeological Evaluation in the Choir, Presbytery and Aisles of Exeter Cathedral

Archaeological Evaluation in the Choir, Presbytery and Aisles of Exeter Cathedral. Oakford Archaeology.

Why have I been asked to commission an archaeological watching brief?

A watching brief is usually the final stage of archaeological investigation, and may follow on from desk-based studies, evaluation trenching or excavation. It is usually applied to schemes where the potential for archaeological remains is low.

During a watching brief an archaeologist works closely with the groundworkers and visits the site when excavation work is being carried out in the area of interest. The archaeologist monitors the groundworks, which could be foundation trenches, services, drainage or landscaping, and records any archaeological remains that are exposed.

An archaeological watching brief might require just one visit or it might be several, depending on the scale of the project. If it is a small project you would want to make sure all of your groundworks happen on the same day to save time and money.

Monitoring a geotechnical borehole survey in July 2016, at Rougemont Gardens, Exeter, Devon.

Monitoring a geotechnical borehole survey at Rougemont Gardens, Exeter, Devon. Oakford Archaeology.

Does the size of the development or scheme of works make any difference?

Both watching briefs and evaluations can be required on schemes of any size. They might be stipulated on a large development site or pipelines, or they might be applied to a small house extension or development within a conservation area. The size of the project makes no difference, it’s purely down to whether your proposed development is located within or near an area of potential archaeological interest.

What happens if archaeological remains are found?

A worry for many clients is what happens when archaeological remains are found and whether it will stop the job.

If archaeological remains are found during an evaluation your archaeological contractor will produce a report detailing the results of the evaluation and the nature of the archaeology on the site. The report will help the planners to decide whether subsequent mitigation work is needed or whether the risk to archaeology is minimal enough to warrant planning consent without any further archaeological conditions.

It’s rare that significant archaeological remains are found during a watching brief. A watching brief is only ever stipulated if the potential for archaeological remains is low. It’s almost always the case that you will see your contracted archaeologist during initial groundworks and that’s it. On the rare occasions significant archaeology is exposed, it will be dealt with as quickly as possible to limit any delays to the groundworks.

If you have any queries about archaeological watching briefs or evaluations or have been asked to commission an archaeological consultant or contractor for your project, we’re happy to provide a free quote or answer any questions you might have.