What happens to a site after it's discovered?
In Situ preservation
British Star Fort preserved in situ at Ninety Six National Historic Site. (Southeast Archeological Center, NPS)
We cannot assume that we who are alive today can know precisely which questions we need to ask about the past, and which we do not. New questions about the past are always developing and old questions are being answered. Answering old questions usually generates new ones. As new questions are asked, different kinds of information become important, and information may need to be examined in new ways. At the same time, techniques of field study and analysis are constantly being developed and improved, making it possible to address questions that could not be addressed using older techniques. Thus, there is a danger that if only those archeological properties we see as valuable today are protected, we will allow the destruction of properties that will be of great value in the future.
Accordingly, it is appropriate to preserve in place as large a range of archeological properties as possible, even if we cannot define precisely how we would use the information they contain. There are obvious practical limits to the application of this principal, but as a rule, if an archeological site can practically be left in place and preserved from damage, it should be. There is a large number of ways in which this may be done.
Stabilization preserves the site by supporting or strengthening it to reduce the possibility of deterioration. Backfilling—covering an archeological site with fill—is an effective treatment, provided caution is exercised to limit compaction, disturbance of the soil, chemical changes, and changes in soil structure. As well, access must be assured within reason for future research. Designing construction projects so as to leave an archeological site in a reasonably protected open space, designing structures over archeological sites in such a way as to minimize subsurface disturbance, and protecting archeological sites from damage through fencing, berm construction, shoreline armoring and rerouting construction activities are all potential impact avoidance treatments.
Archeological resource protection may be attained by establishing protective covenants or other arrangements with residents, operators, or users of constructed facilities to control the archeological resources within their domain. Site banking preserves archeological resources in an undisturbed state for future archeologists who will most likely have more advanced questions and techniques than we have today. Examining existing assemblages and collections to answer research questions may also be an effective alternative to excavation.
For your information
NPS Technical Briefs on Site Stabilization