Development, application and validation of a flood damage model for multi-year crops (vineyards and orchards).

Floods are one of the most frequent and widespread natural hazards globally. Over the past 20 years, the number of floods has more than doubled from the previous two decades, resulting in annual losses of around $40 billion worldwide. Among the various sectors exposed, agriculture is certainly the most vulnerable to events of this type, given its close dependence on weather conditions. However, although floods constitute the second most serious threat to agricultural areas, causing total production losses of up to 20%, their impacts are still difficult to assess. The perceived minor importance of agricultural losses compared to those of other assets (e.g. infrastructures, residential and industrial buildings, cultural assets), together with a lack of observations, have led to development of few approaches for crop damage assessment in case of floods, in most of the cases also characterized by considerable imprecisions. In compliance with the requests of the Floods Directive (Directive 2007/60/EC), a model has been developed to quantify the direct and tangible flood-related damages to the multi-year crops (such as vineyards and orchards). The loss of perennial plant material in the years following the flood and thus, the expected damage, is evaluated based on hazardous variables (e.g., water depth, inundation duration, season of occurrence, etc.), crop (e.g., typology, technological solutions, yield, etc.) and economic conditions (product price, production costs, etc.). The model relies on several damage curves, by means of which it is possible to estimate the total absolute damage for each flooded agricultural portion. The expert-based model has been developed referring to the Emilia-Romagna region (Northern Italy) and validated using real damage records collected after the flood of the Secchia river (2014). Results are convincing, reproducing the damage suffered by farmers with a good approximation (errors of about 12-20%).