Testing empirical and synthetic flood damage models: the case of Italy
In: Natural hazards and earth system sciences: NHESS, Volume 19, Issue 3, p. 661-678
ISSN: 1684-9981
Abstract. Flood risk management generally relies on economic assessments performed by
using flood loss models of different complexity, ranging from simple
univariable models to more complex multivariable models. The latter account for a
large number of hazard, exposure and vulnerability factors, being
potentially more robust when extensive input information is available. We
collected a comprehensive data set related to three recent major flood events
in northern Italy (Adda 2002, Bacchiglione 2010 and Secchia 2014), including
flood hazard features (depth, velocity and duration), building
characteristics (size, type, quality, economic value) and reported losses.
The objective of this study is to compare the performances of expert-based
and empirical (both uni- and multivariable) damage models for estimating the
potential economic costs of flood events to residential buildings. The
performances of four literature flood damage models of different natures and
complexities are compared with those of univariable, bivariable and
multivariable models trained and tested by using empirical records from
Italy. The uni- and bivariable models are developed by using linear,
logarithmic and square root regression, whereas multivariable models are
based on two machine-learning techniques: random forest and artificial neural networks. Results provide important insights about the choice of the
damage modelling approach for operational disaster risk management. Our
findings suggest that multivariable models have better potential for
producing reliable damage estimates when extensive ancillary data for flood
event characterisation are available, while univariable models can be
adequate if data are scarce. The analysis also highlights that expert-based
synthetic models are likely better suited for transferability to other areas
compared to empirically based flood damage models.