What is an Archaeological Evaluation?
An Archaeological Evaluation is frequently required as a condition of planning where intact archaeological remains are known or suspected. One or more of a range of techniques may be employed to determine the level of archaeological survival and whether there is a need for more detailed investigation.
Geophysics may be considered sufficient in itself but the variable quality of results mean it is more often used in combination with Trial-trenching and/or Geoarchaeology:
What is a Geoarchaeological Survey?
Geoarchaeology may form part of the fieldwork requirement on sites where an assessment of lower-lying soils and sediments is thought likely to produce detailed evidence for the reconstruction of past landscapes and environments.
A geoarchaeological survey is a rapid and cost-effective method of mapping buried landscapes and deposits, comprising a series of auger transects or boreholes designed to reach deeply buried deposits, generally within alluvial floodplains or estuarine environments.
The resultant cores are then subject to specialist sedimentological and palaeoenvironmental analysis for the reconstruction of ancient landscapes. These will show how deposits formed and changed over time whilst pollen, spores and microalgae preserved within the sediment are indicative of environmental conditions.
The survey results will often take the form of a ‘deposit model’.
Generally, not an end in itself, the geoarchaeological survey will be used to inform subsequent stages of a more comprehensive fieldwork programme and mitigation strategies.
What is Trial-Trenching?
Trial-trenching establishes the depth and character of any surviving archaeological deposits or features.
Trenches are usually opened by machine and toothless ditching bucket and may be of varying size, although dimensions of 30m × 1.8m are common. Where remains are present, the aim is to excavate only as much as is required to determine their date, function and condition.
How many trenches will I need?
Based in most cases on a sample of 2-5% of the proposed development area.
What Happens Next?
The results will inform planning of the need to consider further mitigation, such as full excavation and recording or preservation in-situ, depending on the significance of the remains