This study analyzed stratigraphic and geotechnical data from boreholes and other tests in Como, Italy to reconstruct the historical shoreline evolution and identify remnants of the ancient Roman harbor. Organic silty layers 2-4 meters thick with poor mechanical properties were found, representing a sheltered harbor environment. Reworked brick fragments in the layers suggest a historical age. The integration of geological, geotechnical, and archaeological data helped reveal the former position of the shoreline and Roman harbor structures underneath the current city.

1. Historical shoreline evolution and the Roman
Harbour in the Como urban area: results from
stratigraphic and geotechnical analyses
Ferrario M.F., Brunamonte F., Castelletti L., Livio F., Martinelli
E., Michetti A.M. & Motella S.
Università dell’Insubria, Dipartimento di Scienza e Alta Tecnologia
Via Valleggio 11, Como
Francesca.ferrario@uninsubria.it

2. Medolo Group
(pelagic
limestones, Early
Jurassic)
Gonfolite Group
(conglomerates
and
sandstones, Oligo
Gonfolite
Backthrust

3. Stratigraphic database
Piazza Verdi
Piazza Verdi drillings
- 2 boreholes (65 – 70 m)
- Physical parameters
- Shear tests, triaxial tests
- Permeability tests
- Macroremains and
palynological analyses
- Gamma-Ray analysis
- Carbon dating

4. Subsidence
• Natural: soft sediments (few mm/y)
• Anthropic: ground water overexploitation (up to cm/y)
• Increased risk of inundation
• Building damages
Photo by Valerio Comerci

5. LGM - Maximum extension of Adda glacier
and water outflow
Modified after
Bini et al., 1993

6. Lateglacial
270 m asl
220 m asl

7. 1st appearance organic substance
ca. 18 kyr BP
215 - 220 m asl

8. Coastline (18.000 BP)
Delta progradation
Proto-historic settlements

9. Shoreline
I century BC
City walls (I century BC)
Archaeological
findings: Roman
quay
Archaeological
findings: ship remains
(Piazza Mazzini)
Prehistorical drainage network
Drainage modified by the Romans

10. Archaeological findings
In 1964, in Piazza Mazzini a
marble block and ship
remains were discovered at
4,60 m below the ground
surface.

11. Shoreline
1858
1722
1871
2013
I century BC
City walls (I century BC)
City walls (IV-V century AD)
Historical coastline position

12. Catasto Teresiano, 1858
Catasto Teresiano, 1898
Piazza Cavour

13. 1997 campaign
- 10 drillings (60 m deep)
- 5 CPTU
- lab tests
2013 campaign
- 3 drillings (30 – 40 m deep)
- 2 drillings (10 m deep)
- 10 DPSH
- cross-hole seismic tests
- In progress: radiocarbon
dating, plant macroremains and
diatoms analyses

14. Pile-dwellings
Gas-emission features
Leather tiers (depth: 13 m)

15. The cross-disciplinary integration of the various
datasets enables to:
- Identify an organic silty layer ca. 2-4 m
thick, with very poor mechanical
properties, related to a closed low-energy
environment, such as a sheltered harbour or a
dock;
- Sparse reworked bricks fragments suggest an
historical age;
- Reconstruct the isopachs of this layer

17. Geologic section

18. SW NE
wn = 60 – 90 %
LL = 55 – 70 %
Qc = 0,2 – 0,5 MPa

19. SE NW
Man-made fillings
Organic siltsAlluvial sands
Organic clayey silts

20. Conclusions
A multidisciplinary approach, involving data
coming from both geology and
archaeology, can lead to a more accurate
knowledge of an area, thus allowing to
understand present-day natural and
anthropic dynamics and to better plan
future urban development.

21. Thank you
This research was realized in
collaboration with Comune di
Como and Georicerche srl