U.S.- Italy Research Workshop on the
Hydrometeorology, Impacts, and Management
of Extreme Floods
Perugia (Italy), November 1995
THE NOVEMBER 1994 FLOOD
EVENT ON THE PO RIVER:
STRUCTURAL AND
NON-STRUCTURAL MEASURES AGAINST INUNDATIONS
Enrico Marchi, Giorgio
Roth, and Franco Siccardi
Istituto di Idraulica
Universita di Genova
Via Montallegro 1, 16145
Genova
ITALY
This paper discusses the major features of the Po River
basin and the actions undertaken to mitigate the effects of extreme flood
events specially those related to the 1994 disastrous flood event.
The river drains the largest morphological unit of the Italian territory.
River training works started in the Lower Po during the Roman Age and
developed upstream, first as discontinuous systems, then connected to form
two uninterrupted belts, which have reduced the overflow frequency but also
the carrying capacity of the river channel.
The outcome has been increasing values of flood peak quantiles in the
Lower Po, which is the reach with the highest risk of flooding.
On the other hand, the upstream catchment, where partial embankments
are available, experienced recent flooding events, including that of November
1994, and requires protection. The
risk mitigation policy designed by the Italian National Department of Civil
Protection, takes into account all the components of the river system. It is clear that the development of traditional
structural protection along the Po River has reached a critical stage; a further
expansion of the existing levee system will increase the downstream flood
risk. Furthermore, it appears that
non-structural measures, such as the coordination of the existing flood warning
systems, may be suitable for protecting communities that are affected by such
food occurrences along the Po River. In addition, a reduction of the flood discharge entering the Lower
Po is needed in order to decrease the risk of flooding to acceptable levels.
This paper shows that this goal can be accomplished only by diverting
the higher part of the flood from the river immediately upstream of the Lower
Po, allowing the inundation and the temporary storage of the diverted water
on pre-designed large agricultural areas.
Implementing such a policy will require a reliable flood warning system
and, above all, a sound regulatory authority.