Page 112 - Manual for Activities directed at the Underwater Cultural Heritage

iV. Objective, methodology and techniques
For every activity directed at underwater cultural heritage the project’s objectives should be very clear and the methodology
and techniques should be chosen accordingly. This applies to safeguarding, consolidation and research alike.
Matching objectives with methodology and techniques
Rule 16. The methodology shall comply with the project objectives, and the techniques em- ployed shall be as non-intrusive as possible.
An underwater archaeological site is an extremely fragile historical record that is a repository of information about developments in human history. The potential historical information it contains varies enormously. The objects a site contains may have been designed to be used outside, on or under water. They were submerged accidentally or on purpose. They
range from religious and ritual deposits, bridges, dockyards, light-houses, dykes and ports, settle- ments, towns and necro- polises to fishing insta- llations, naval, merchant and fishing vessels, and other anthropogenic evi- dence. Locations may vary as well, from sea-shore, to lake or river, and from an aquifer of a few cen- timetres to depths of thousands of metres be- low the surface of the sea.
Threats to sites
Underwater archaeological heritage is exposed to the following threats, among others:
• Physical-mechanical: Erosion and abrasion by currents, tidal movements or changes in water circulation; erosion/mechanical deterioration due to dredging, fishing, anchoring.
• Biological: Marine borers (especially Teredo navalis or shipworm), fungi and bacteria, for the most part dependent on the presence of oxygen.
• Chemical: Oxidation reactions of organic material and corrosion of metals.
• Human: Treasure hunting, souvenir collecting, fishing, dredging, infrastructural or development works, pollution, ship movements, archaeology, oil drilling and pipeline laying.
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Objective, methodology and techniques