Coastline regression of the Romagna region, Italy, due to sea level rise and
natural and anthropogenic land subsidence
G. Gambolati, P. Teatini, L. Tomasi
Dept. Mathematical Methods and Models for Scientific
Applications, University of Padova, Padova, Italy
M. Gonella
Med Ingegneria S.r.l., Ferrara, Italy
ABSTRACT
The Romagna coastal area in the Northern Adriatic Sea has experienced in
recent times continuous changes because of its precarious environment
and low ground elevation above mean sea level (msl).
Major processes which may influence the stability of the coast profile
include land subsidence of both natural and anthropogenic origin and the
msl rise caused by global climate change.
According to the most accredited modeling predictions msl is expected to
rise by almost 0.5 m over the next century due to greenhouse effect.
Natural land subsidence is the result of deep downward tectonic
movement and consolidation of geologically recent deposits. It may be
estimated in the range of 2-2.5 mm/y in the Ravenna area and
twice as much in the Po river Delta.
Anthropogenic land subsidence is primarily related to groundwater pumping
from the upper fresh water aquifer system and gas production from
Plio-Pleistocene reservoirs.
Geodetic surveys from 1953 to 1990 provide documentary evidence of
cumulative land settlement exceeding 0.8 m and 1.2 m at Marina di
Ravenna and Cesenatico, respectively.
In this study we estimate both natural and anthropogenic land
subsidence for the years 2015, 2050, and 2100
with the aid of ad hoc finite element simulation
models.
The use of these predictions together with the expected msl rise shows
that many present lowlands may be permanently submerged at the end of
the next century. The extent of the flooded area of the
Romagna coastal region can be as much as 690 and 910 km2, using an
optimistic
and a pessimistic land subsidence scenario, respectively.
A local detailed analysis indicates that the areas around the cities of Ravenna and
Cesenatico may be seriously affected by sea water ingression while the
city of Rimini is well protected because of its relatively high
elevation above msl.
