Evaluation
The purpose of an archaeological evaluation is to gather sufficient information about the scale, importance and density of archaeological features that might be present on a site. A distinction is often drawn between the research that can be conducted without needing to dig test pits and trenches (the ‘desk-based’ assessment), and the more intensive works that take place in a field evaluation.
These field evaluation works have three main purposes:
- They provide detailed information about how important and vulnerable the archaeological remains might be, allowing a Local Planning Authority to make an informed decision about whether or not a development should be permitted (for full Details on these procedures see Planning Policy Guidance note 16).
- They allow archaeologists to draw up a detailed programme of how to protect any surviving remains, or otherwise to complete their excavation and study (a ‘written scheme of investigation’ in the terminology of Planning Policy Guidance).
- They allow developers and their advisors to work out how expensive and how time consuming it might be to excavate and/or conserve the archaeological remains, reducing – and ideally eliminating altogether – the element of risk that unexpected discoveries might introduce.
There is a difficult balance to be struck between minimising unnecessary disturbance and expense, whilst maximising the amount of information that is recovered. The main objective is to emerge from the process with a clear idea of what works are required, and to satisfy the proper authorities (usually the local planning authority) that this is the case. The scope of works for an evaluation will usually need to be agreed with the local planning authority.
Typically the main element of the evaluation exercise will involve machine dug trial trenches, followed by hand excavation and recording of the deposits and sections exposed. Some County Archaeologists have preferred sample densities – and will invite a trenching layout involving the study of three or four percent of the development footprint. In other circumstances test-pits are sometimes more appropriate, and it can sometimes be possible to undertake a full archaeological evaluation in association with the excavation of engineering test-pits. This can only be achieved, however, where the archaeologists are closely involved in planning, excavating and recording the test-pits.
Careful negotiation is required in order to ensure that the archaeological investigations take place in the most appropriate areas, and to the appropriate survey density. It is often possible to reduce the amount of work required by first undertaking geophysical or topographic survey, making it possible to locate the field investigations more precisely.
Archaeology South-East has a wealth of experience in the design and implementation of cost-effective evaluation exercises that give architects and developers the information they need, whilst satisfying the concerns of local planning authorities.
Our careful attention to providing the most accurate possible survey data has considerable benefits for the longer term management and development of the archaeological features encountered, since it allows for a seamless integration of the evaluation exercise with any subsequent excavation works that might be required and in the construction process itself.
Some recent evaluation exercises:
Land north of Bersted, West Sussex.
Pan Urban Extension, Isle of Wight
Land north of Horley, Surrey.
Contacts: Darryl Palmer, Jon Sygrave & Neil Griffin
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