Methods of excavation

The timbers at Testwood wrapped in polythene to prevent them from splitting and warpingThe timbers at Testwood wrapped in polythene to prevent them from splitting and warpingThe excavation at Testwood Lake of the oldest bridge in England presented archaeologists with an interesting challenge
 
The timbers were found during the excavation of a temporary lagoon which would be flooded with water two weeks after they were found. The team needed to act quickly because the force of the flooding would damage the timbers, and chemicals in the water could start their decay. They rapidly cleaned and recorded the exposed timbers, removing some for examination and to provide samples for tree-ring and radiocarbon dating.
 
Spraying the timbers to keep them wet and prevent damage from drying outSpraying the timbers to keep them wet and prevent damage from drying outThose timbers that remained were carefully wrapped in layers of protective polythene and textiles and then covered with gravel. A year later, in 1999, the temporary lagoon was drained dry in preparation for it being removed and the Testwood Lakes excavated on its place.
 
The team were then able to work again on the timbers. They decided they must be recorded and then removed as the construction of the reservoir would destroy them if they were left where they were. The project manager, Andrew Fitzpatrick, decided to cut a section parallel with the row of stakes to expose them fully.
 
Cleaning the timbers after excavationCleaning the timbers after excavationOne again, the timbers needed to be protected against drying out – once their protective layer of gravel and textiles was removed, they were in danger of turning quickly to dust. The team wrapped them in polythene and sprayed them three times a day with a water spray to keep them moist.
 
The next stage was to number and record the size and position of each of the timbers. This was done digitally using an EDM (electronic distance measurer). The data was created in a way that would allow the archaeologists to construct a three-dimensional map using computer software.
 
Once this had been done, the timbers were taken out and put in a small lagoon to keep them wet. They were drawn, photographed and samples taken to date them before they were wrapped again in polythene and stored.