When archaeology conditions appear on a planning consent, applicants often ask which kind of fieldwork will follow. The three terms heard most often are watching brief, evaluation and excavation, but they are not interchangeable. Each one serves a different purpose, and the type required depends on how much is already known about the site and how significant the likely archaeology may be.
What each type of fieldwork is designed to do
The simplest way to distinguish the three is by their purpose within the decision-making process.
- A watching brief monitors development groundworks and records archaeological remains if they are exposed during those works.
- An evaluation usually tests the site in advance, often through trenching, to establish the nature, extent and significance of any remains.
- An excavation is a fuller programme of investigation and recording where archaeology is known or strongly expected to be affected.
- Each stage may stand alone or form part of a sequence depending on the site and planning advice.
How the appropriate approach is chosen
The level of fieldwork depends on the available evidence and the amount of uncertainty that remains after earlier assessment.
- If a desk-based assessment indicates potential but not enough certainty, evaluation may be the next logical step.
- If the archaeology risk appears limited and tied directly to construction works, a watching brief may be considered sufficient.
- If important remains are known and cannot reasonably be avoided, excavation may be required before or during development.
- The approved WSI explains the agreed method and helps the project team understand why that route has been chosen.
Why understanding the difference helps clients
Treating all archaeology work as one generic process usually creates confusion around cost, programme and site expectations.
- A watching brief is not simply a smaller excavation, and an evaluation is not just a formality before every project.
- Knowing the distinction helps clients understand the likely level of site activity and reporting involved.
- It makes condition discharge discussions clearer because the required scope is defined more precisely.
- Most importantly, it helps the project team coordinate archaeology with construction in a more realistic way.
Frequently asked questions
Can a watching brief turn into further work?
Yes. If significant remains are encountered, additional recording or mitigation may be needed depending on the agreed procedure and the findings.
Is evaluation always done before excavation?
Often, but not always. On some sites enough is already known for excavation or other mitigation to be agreed directly.
Which option is usually cheapest?
That depends on the site, but the right question is not which is cheapest in isolation. It is which is proportionate and appropriate for the evidence and planning condition.
Need advice on this type of project?
AS Archaeology & Heritage Services can advise whether a site is likely to require a watching brief, evaluation or excavation and prepare the WSI needed to take that work forward.
Related links: Archaeological Fieldwork | Written Scheme of Investigation | Contact AS Archaeology