Preservation in Situ
This remarkable monument has only survived because of the wet, peaty soil in this area. The high water table ensures that oxygen cannot get to the wood. The water effectively replaces the cellulose structure in the wood and prevents rot.
When the water table drops, oxygen can get to the wood and decay begins immediately. Research has shown that with six weeks of oxygen exposure, timbers are so degraded as to be archaeologically worthless – no information can be gleaned. For this reason, it is essential to keep the site waterlogged to preserve the monument.
At Flag Fen, we have two methods for helping with this:
- Sprinkler systems – in the Preservation Hall, exposed wood is sprinkled with cooled, filtered water to slow decay
- Artificial lake – our mere has been created over the largest portion of the ceremonial platform. It is topped up with water on weekly basis and leaks at a rate of 1cm per day. This, in effect, keeps the water table around the platform artificially high; thus preserving it.
How can we be sure this is working? We can’t. The site is drying out as drainage and increased development around us dries out the land surrounding the monument. In 2008 we embarked on a programme of water monitoring with Atkins Construction and Peterborough City Council following a smaller survey in 2002. We need to ensure we find out as much as possible about the site through excavations and research before the remains are lost and also continue to slow down decay by employing methods to ensure the site is kept water logged.
