| dc.description.abstract | Italy and, in particular, the Campania region, has been exposed to
Hydraulic Risk since long ago. In hydraulic risk analysis the definition of
maximum flood discharge with a specific return time (T) is crucial and,
to this aim, the VAPI- Campania procedure (1995) was adopted in the
Campania region. The VAPI method is based on a geo-morphoclimatic
model, identifying 7 climatic homogenous areas with respect to the
rainfall probability density function and 3 classes of permeability for the
rainfall-runoff transformation model. At the XXX National Congress on
the Hydraulic and Hydraulic Engineering (IDRA 2006), the hydrological
working group of Salerno University (Rossi and Villani (2006)), pointed
out guidelines for up-dating the VAPI-Campania and, in particular the
role of: orographic barriers in the evaluation of intensity and persistence
of the extreme rainfalls; and the individuation of hydro-geomorphotypes
for the rainfall-runoff modeling at the catchments and sub-catchments
scales. In this framework, the present thesis gives a contribution to a
hydro-geomorphological approach to achieve the two guidelines
mentioned above. This research focuses first on the automatic
individuation and objective delimitation of the orographic barriers in
order to upgrade the heuristic delimitation (expert judgment) used in the
simplified model of orographically induced rainfall of Rossi et al. (2005).
The proposed procedure is based on the basic concepts of the hierarchic
orometry (hierarchical mountain geomorphometry), prominence and
parent relationships, to delineate the 'orographic mountain' in various
spatial scale (hierarchical- multiscale approach). Also, the procedure
defines the 'morphologic mountains' and its components (ridge, plain
and hillslope) using slope, altitude, relief ratio and exposition with
respect to the dominant perturbation fronts and its moving direction.
The second topic of research deals with the individuation of the hydrogeomorphotypes.
To this aim, the prototypal work of Guida et al. (2007),
was taken into account as a guideline in the identification of the hydrogeomorphotypes
and the decisional scheme of Scherrer and Naef (2003),
here modify, allowed the identification of the three dominant runoff
mechanisms on the Campania region. In particular, the prototypal
procedure of Guida has been here objectified and automatized, defining
the 9 elementary landscape forms (Troch et al., 2002), characterized in
terms of sub-surface flow and soil moisture storage, under an objectbased
GIS environment. The procedure here presented allowed
identification on the hydro-geomorphological map, and of the runoff
mechanisms: Hortonian overland flow for excess of saturation, subsurface
flow, and deep percolation.
In order to test the procedure some hydro-geomorphological analysis
have been carried out based on data from two instrumented
experimental catchments and on rainfall data from the Regional
Functional Center of the Campania Civil Protection Sector. The results
allowed to calculate the hydrologic index named Runoff Index, which
improves the evaluation of the runoff coefficient (Cf) for un-gauged
basins. Other analyses were performed on further 4 catchments with
similar hydrologic and geologic behavior in order to extended the
procedure to the whole Campania region. Also, conceptual discussions
on the implementation of the Runoff Index in the rainfall-runoff
transformation operated with a largely used hydrologic software, HECHMS,
was made, in order to evaluate the feasibility of the procedure
proposed in the present research and improve the RI in hydraulic risk
evaluation at a regional scale. [edited by author] | en_US |
