Archaeological monitoring of the dredging for the
immersed tunnel, Oslo, Norway.2005-2008
A balance between rescuing cultural heritage, cost and effort.
Tori FalckJostein Gundersen
PIANC, 2013-11-20
Constructing the immersed tunnel
The immersed tunnel project 2005-2008
• Tre entrepriserHavnelageret, Sjødelen, Sørenga
Sørenga
Open water enterprise
Havnelageret
Planning - scoping
• Results of analyzing core samples for dinoflagellate cysts and spruce pollen.
• Indicating precence of sediments from warm period in medieval times (AD1000-1300)
Pockets of ballast sand and flint deep down in the clay
Coerced situation – from surveying to monitoringResults from mapping:1)Acoustic sub-bottom profiler fails to define the contents of the sediments.2)Core samples concludes that the sediments consists of layers from the medieval period.Conclusion: 1) There is a potential for archaeological remains in large parts of the tunnel route (shipwrecks).2) There is no secure evidence to divide between high potential and low potential.3) The archeological project is defined as monitoring: Salvage of archaeological remains emerging in the process of dredging.
Archaeologists monitor the work on site.
Requirements:The archaeologist require direct visual and physical access to all dredged sediments.The archeologist has the power put the work on temporary hold if there are finds or to rule out possible finds.
Basic needs and resources:Enough crew for the continuous monitoring and for readiness if there are finds.
Method and basic requirements:
Dredging: Different situations
Dredging: Different situations
Dredging: Different situations
Custom made sieve
Health and security: Balancing on the barges
Boat: ca.1620
Results: Mass material – harbour finds
Type NumbersCeramics 3811Glass 2072Clay pipes 743Shoes 349Other 185Totale 7160
Results: Boats
Conclusion – Lessons learned
• Best practice is to finish the archaeological work before the construction work starts
• Adequate mapping should be a piority.• Achieve a good understanding of the
stratigraphic situation.• Priority on health and security. • Good communication between participators in
all chains of the work process.
Boat: 1789/90
Boat: ca 1800
Boat: ca 1840
Boat: ca.1665