The knowledge of underwater cultural heritage exists and persists because of documentation. In order for current and future generations to learn from archaeology, the information gained in the course of an archaeological project must be documented and made available in an organized form. Archaeological documentation thus gathers information on prehistoric and historic sites in a systematic, professional way. The destruction of submerged archaeological sites through salvage, fishing, pipe laying and other activities has heightened the need for documenting. Two rules of the Annex are devoted to documentation, Rule 26 and Rule 27.
As has already been stated, the production of archaeological knowledge and understanding is an iterative process. Field-data from earlier work will be reconsidered in preliminary studies for future projects or management plans. This data is also, however, the primary source to refer to if new interpretations of the past produce new scientific questions that were not answered at the time, simply because they were not yet formulated or asked. It is for this reason that documentation aims at objectively recording all observations, findings and activities as accurately and completely as possible.
The nature and level of documentation is dictated by the specific circumstances of a site and is guided by the objectives and methods employed. It is thus consistent with planning decisions.