Archaeological evaluation | trenching and test pitting. Professional service.

Archaeological evaluation is usually required at the pre-app or pre-determination stage of the Planning Process, in line with Section 16 of the National Planning Policy Framework.  

Evaluation involves taking a look below the surface of the ground to ascertain the presence, nature and preservation of any archaeological remains within a development area. This will be undertaken in accordance with a specification of works provided by the Local Authority archaeological team, or in accordance with a Written Scheme of Investigation approved by the same team. 

The process usually takes the form of a combination of geophysical survey (where appropriate and which Vindomora Solutions Ltd subcontract out) with trenching and/or test pitting. In most cases, the Local Authority has set guidance as to the amount of trenching required: usually between 3 and 10% of the development area as appropriate.

The results of the evaluation will then decide the level of mitigation (if any) that will be imposed as a planning condition on the site in question.

Often, these trenches are excavated in the first instance by a mechanical excavator, such as a JCB, under archaeological supervision. The archaeologists then take over with hand tools as soon as the first archaeological horizon (or undisturbed geology) is uncovered. The trenches are cleaned of debris (even if no archaeology is present), features investigated and in some cases environmental samples taken and artefacts retained to be sent to specialists where necessary. 

Where working space is restricted or only small areas of excavation required by the Local Authority, archaeological test-pitting can be used for evaluation, rather than large trenches. These test pits are a quick way of evaluating an area though their window on any archaeological remains is much smaller and more can be missed. Test-pitting is also often used on sensitive areas such as graveyards when attempting to find wall foundations for repair or replacement. Where possible, test-pits are usually excavated purely by hand, though in cases where tarmac or other modern overburden has to be removed a small mechanical excavator is often used.