| The expected value of the annual flood is always needed for attaining
reliable estimates of the return period of floods. In particular, the
accuracy of its estimate is crucial for ungauged basins, where regional
analysis is to be invoked.
The main goal of this research was to search for an index flood formula
suitable to explicate the influence of basin characteristics such as
geomorphology, vegetation, soil and climate. This formula, due to
unavoidable overparameterization, more than being suggested for technical
use, allows sensitivity analyses of simpler formulae to basin features.
This study was mainly based on the theoretical distribution of floods
developed by Iacobellis and Fiorentino (2000). In particular, the
relationship that they derived for the first order moment was analyzed and
simplified by assuming the Gumbel distribution as a first order
approximation for the distributions of floods and rainfall intensities. The
results were validated with regard to data recorded in some basins located
in Southern Italy, in a climatically end geologically heterogeneous
territory. |