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