Improving flood damage assessment models in Italy

Environmental Economics and Investment Assessment, 2006

Floods are a very common natural process in Italy. In the 20-year period from 1980 to 2000 the State set aside 7,400 million euro for flood damage, or roughly one million euro per day. With this study we developed a flood damage estimation model which land administration bodies and insurance companies could find useful in the management of flood-related damage data. The model simulates event scenarios and evaluates expected economic losses. Potential economic loss assessment implies knowledge of the event, exposed asset values and the degree of damage. Following a widely shared simplifying assumption, flood water level was taken as the only factor indicating event magnitude. The model incorporates the following steps: a) event description: definition of flood parameters (flooded area and water level), utilizing real-time measurements or data from event simulation with a hydraulic model; b) asset damage and identification of the affected population; c) evaluation of the degree of damage as a function of event magnitude; d) attribution of an economic value to different exposed assets; e) quantification of economic loss by multiplying economic losses and damage severity. The method could be used either as a forecasting tool to define event scenarios or for "real-time" damage assessment after a catastrophe. The approach is suitable primarily to large-area damage assessment but could also be appropriate for land use planning, civil protection, and risk mitigation.

Sustainability

In recent decades, floods have caused significant loss of human life as well as interruptions in economic and social activities in affected areas. In order to identify effective flood mitigation measures and to suggest actions to be taken before and during flooding, microscale risk estimation methods are increasingly applied. In this context, an implemented methodology for microscale flood risk evaluation is presented, which considers direct and tangible damage as a function of hydrometric height and allows for quick estimates of the damage level caused by alluvial events. The method has been applied and tested on businesses and residential buildings of the town of Benevento (southern Italy), which has been hit by destructive floods several times in the past; the most recent flooding occurred in October 2015. The simplified methodology tries to overcome the limitation of the original method—the huge amounts of input data—by applying a simplified procedure in defining the data of the...

Natural Hazards and Earth System Science, 2010

ABSTRACT Damage assessments of natural hazards supply crucial information to decision support and policy development in the fields of natural hazard management and adaptation planning to climate change. Specifically, the estimation of economic flood damage is gaining greater importance as flood risk management is becoming the dominant approach of flood control policies throughout Europe. This paper reviews the state-of-the-art and identifies research directions of economic flood damage assessment. Despite the fact that considerable research effort has been spent and progress has been made on damage data collection, data analysis and model development in recent years, there still seems to be a mismatch between the relevance of damage assessments and the quality of the available models and datasets. Often, simple approaches are used, mainly due to limitations in available data and knowledge on damage mechanisms. The results of damage assessments depend on many assumptions, e.g. the selection of spatial and temporal boundaries, and there are many pitfalls in economic evaluation, e.g. the choice between replacement costs or depreciated values. Much larger efforts are required for empirical and synthetic data collection and for providing consistent, reliable data to scientists and practitioners. A major shortcoming of damage modelling is that model validation is scarcely performed. Uncertainty analyses and thorough scrutiny of model inputs and assumptions should be mandatory for each damage model development and application, respectively. In our view, flood risk assessments are often not well balanced. Much more attention is given to the hazard assessment part, whereas damage assessment is treated as some kind of appendix within the risk analysis. Advances in flood damage assessment could trigger subsequent methodological improvements in other natural hazard areas with comparable time-space properties.

Journal of Flood Risk Management, 2017

This article analyses the assessment of economic damages in urbanised flooded areas by testing the use of reimbursement data to obtain damage curves. Data coming from field observation of the 2000 flood in Piedmont, Italy, are used and the influence of local features and topography, as well as urban patterns are studied. Our starting point is the assessment of individual flooded elements, whose damages result from slightly more than 7000 refund claims. Damage functions estimation is carried out by using water depth and flow velocities obtained by 2D inundation model. Results show the relationship of damage versus water depth and versus flow velocity are strongly nonlinear and urban patterns playing a major role in explaining the amount of damage under given conditions. Moreover, results provide useful information for future ex ante estimation of potential flood damages and rewarding risk reductions and management actions.

Natural Hazards and Earth System Science, 2012

There is a wide variety of flood damage models in use internationally, differing substantially in their approaches and economic estimates. Since these models are being used more and more as a basis for investment and planning decisions on an increasingly large scale, there is a need to reduce the uncertainties involved and develop a harmonised European approach, in particular with respect to the EU Flood Risks Directive. In this paper we present a qualitative and quantitative assessment of seven flood damage models, using two case studies of past flood events in Germany and the United Kingdom. The qualitative analysis shows that modelling approaches vary strongly, and that current methodologies for estimating infrastructural damage are not as well developed as methodologies for the estimation of damage to buildings. The quantitative results show that the model outcomes are very sensitive to uncertainty in both vulnerability (i.e. depth-damage functions) and exposure (i.e. asset values), whereby the first has a larger effect than the latter. We conclude that care needs to be taken when using aggregated land use data for flood risk assessment, and that it is essential to adjust asset values to the regional economic situation and property characteristics. We call for the development of a flexible but consistent European framework that applies best practice from existing models while providing room for including necessary regional adjustments.

SSRN Electronic Journal

This paper estimates the direct and indirect socio-economic impacts of the 2000 flood that took place in the Po river basin (Italy) using a combination of Computable General Equilibrium (CGE) model and Spatial and Multi-Criteria Analysis. A risk map for the whole basin is generated as a function of hazard, exposure and vulnerability. The indirect economic losses are assessed using the CGE model, whereas the direct social and economic impacts are estimated with spatial analysis tools combined with Multi-Criteria Analysis. The social impact is expressed as a function of physical characteristics of the extreme event, social vulnerability and adaptive capacity. The results indicate that the highest risk areas are located in the mountainous and in the most populated portions of the basin, which are consistent with the high values of hazard and vulnerability. Considerably economic damages occurred to the critical infrastructure of all the sectors with the industry/commercial sector having...

2021

Flood damage assessment to economic activities is affected by a general paucity of data to both describe the strong diversity that characterises this sector and validate existing flood damage models. This study aims to assess the applicability, the validity, and the transferability of the methodology for the estimation of flood damage to economic activities developed in France by the working group GT AMC, led by the Ministry of Environment. The method was tested in two case studies: the flood that affected the Île-de-France Region in 2016 and the 2002 flood in the city of Lodi, Italy. Flood damage estimates were compared to observed losses in order to appraise their uncertainty range, to define a methodology of application that reduces such an error, and to supply an evaluation of the methodology transferability.

Research Square (Research Square), 2024

The increasing frequency of floods in recent decades has highlighted the pressing need for effective flood management to mitigate damages. Precisely identifying flood-prone areas and quantifying flood damage is of utmost importance, especially in developing countries. In the current study, a 2D hydraulic modeling approach using HEC-RAS is adopted to simulate flood characteristics and flooded area. This research centered around 2 objectives: (1) the development of a regional model for estimating flood damage in residential and commercial zones; (2) the assessment of global depth-damage functions in a western region of Iran. The findings indicated a strong correlation (correlation coefficient > 0.81) between modeled and observed damage losses in residential, commercial and agricultural areas. In situations where observational data were lacking, the Asia and Global depth-damage curves proved to be valuable tools for estimating flood damages in these areas. Furthermore, the evaluation of methods for converting relative damage into monetary value demonstrated that incorporating spatial variations in building size significantly reduced the error in damage estimation caused by floods, by approximately 77%. Although, the use of the reconstruction/renovation cost coefficient tended to underestimate damages in areas with depths exceeding one meter, it showed acceptable performance in estimating flood damages for depths below one meter (absolute relative error = 7.1%). In summary, the Asia and Global depth-damage curves can serve as suitable functions for estimating economic losses in floods, especially in data-limited areas or regions lacking standardized damage functions like Iran. This can provide more reliable estimates of flood damages and aid in better flood management strategies, thereby contributing to improved disaster preparedness and response.

Procedia Engineering, 2014

Flooding damage appraisal can been obtained by interpolating real damage data caused by historical flooding events or accounting the effects of a flood in terms of the depreciation of assets. Most often, the expected damage is evaluated by means of damage functions describing the relationship occurring between the damage and hydraulic characteristics of flood. The present paper aims to evaluate the uncertainty linked to the choice of the depth-damage function adopted in the flood damage analysis. Several possible depth-damage function formulations were selected in literature and applied to historical flooding events monitored in the "Centro Storico" catchment in Palermo (Italy).

E3S Web of Conferences, 2016

Flooding and flash floods that cause significant economic and social damage have been widely studied in the last few decades. The European Commission Flood Directive 2007/60 Flood Risk Management Plans require the assessment of potential damage to give an appreciation of the magnitude of the consequences of a flood event and so help stakeholders to use a cost benefit approach to planning flood mitigation measures. This paper evaluates the direct tangible flood damage applying the JRC water depth-damage functions for the European territory to estimate the potential economic damage. Intangible damage is evaluated with the Life Safety Model (LSM) to study the dynamic interactions among people, vehicles, buildings and the flood wave. LSM assesses potential flood damage and allows the development of a Flood Evacuation Plan in case of an emergency, underlining the evacuation routes adopted by people and vehicles. This enables emergency managers to avoid evacuation bottleneck problems and identify areas of potential high mortality. The impact of changes such as road network improvements, the location of safe havens and timing of flood warnings can be assessed in terms of potential loss of life. The developed methodology has been applied on the Sardinian Flood Risk Management Plan pilot basin, the Coghinas river lowland basin.