On-Site Conservation Surveys

Abstract

Conditions often exist in underwater environments that favor the long-term preservation of archaeological remains, and valuable information regarding our past can be gained through comprehensive archaeological investigation of these submerged sites. In more recent times, the archaeological community has moved away from the more traditional excavation and recovery methods and further towards on-site examination and in situ preservation of underwater cultural heritage sites. This chapter discusses the use of in situ preservation techniques in the form of on-site conservation surveys conducted on 15 WWII submerged sites in Saipan.

Appendices

Appendix A: On-Site Conservation Survey Data Sheet

• Date of survey

• Time of survey

• Aim of survey

• Personnel

• Site (name, date and type)

• Location

• Distance from land/reef

• Site classification

• Site dimensions (length, width, area)

• Site orientation

• Seabed topography

• Marine macrofauna and flora (type and abundance) (photograph)

• Wreck-specific types of marine life (photograph)

• Composition of dominant wreck material (in situ observation, cargo influence)

• Exposed artifacts (type, material, apparent condition, degree of completeness, distribution)

• Degree of site exposure (area, height above seabed)

• Evidence of seasonal exposure

• Evidence or potential for storm, cyclone influence

• Evidence of human disturbance (salvage, pollution, modern contamination, water activities)

• Weather conditions

• Sea conditions

• Swell

• Current (rate, direction, speed)

• Tidal information

• Freshwater/saltwater influence (rivers, springs, seawater)

• Water temperature (surface, at depth)

• Salinity/conductivity water (surface, at depth)

• Dissolved oxygen content water (surface, at depth)

• pH water (surface, at depth)

• Redox potential water (surface, at depth)

• Water depth (minimum, maximum)

• Visibility (material type in suspension)

• General sediment composition (in situ observation)

• Mobility of sediment surface (rippling, direction and frequency)

• Sediment slope

• Probe depth to wreck material (extent of burial)

• Depth to stable seabed (evident by black/anaerobic layer)

• Sediment gradation (changes in color)

• Sediment photography (surface, gradation, at depth)

• Sediment sampling (sample all significant layers)

• Sediment analysis (particle size distribution, inorganic elements, organic content, nutrients, microorganisms)

• pH sediment (measure all significant layers)

• Redox potential sediment (measure all significant layers)

• Timber infestation by marine borers (active, depth to non-activity)

• Probe depths of timbers (exposed, buried)

• pH profiles of timbers (exposed, buried)

• Timber samples (wood identification, maximum water content, FT-IR, ¹³C-NMR, Py-GC-MS)

• Corrosion potential metals (concretion/metal interface)

• Surface pH metals (concretion/metal interface)

• Depth of concretion and graphitization

• Depth of concretion

• Depth of graphitization

• Sample concretion (optional)

• Sample metals (optional)

Appendix B: On-Site Corrosion Survey Data Sheet

Date of survey:______________________________________________________

Time of survey:_____________________________________________________

Personnel:_________________________________________________________

Site (name, date and type):____________________________________________

Location and GPS co-ordinates:________________________________________

Weather and sea conditions:___________________________________________

Swell and tidal information:___________________________________________

Current (rate, direction, speed):_________________________________________

Water temperature:__________________________________________________

Water depth to wreck (minimum, maximum):_____________________________

Visibility (meters):___________________________________________________

Distance and direction from land/reef:___________________________________

Freshwater influence (e.g. rivers, springs, rainwater runoff):__________________

Site dimensions (length, width, area):___________________________________

Site orientation (e.g. upright, list to port or starboard, upside down):____________

Composition of dominant wreck material (e.g. iron, aluminum):______________

Dominant encrusting organisms on surface (type, abundance and photograph):____________________________

Evidence of active corrosion (depth, position and photograph): Y/N ______________________________________________________________________________

Evidence of dynamite and/or storm damage (depth, position and photograph): Y/N __________________________________________________________________

Evidence of structural collapse (depth, position and photograph): Y/N ____________________________________________________________________________

Evidence of human disturbance (e.g. salvage, pollution) (depth, position and photograph): Y/N ________________________________________________________