*4.3. Depth-Damage Curves for Other Spanish Municipalities*

As an example, Table 7 presents the regional indexes (RI) corresponding to some of the most damaged municipalities in Spain (Figure A1) due to flooding, which allows for constructing their own depth-damage curves (Figure 12).

**General sector Asset Barcelona Orihuela Los Alcázares Vera Murcia San Sebastian Málaga Valencia San Javier Zaragoza Lorca** Residential & Others Build. 1.00 0.42 0.30 0.29 0.26 1.11 0.50 0.44 0.30 0.39 0.23 Furnit. 1.00 0.59 0.59 0.61 0.75 0.70 0.73 0.82 0.67 0.78 0.59 Commercial Build. 1.00 0.39 0.31 0.30 0.28 0.75 0.51 0.40 0.31 0.34 0.25 Furnit. 1.00 0.37 0.40 0.32 0.55 0.69 0.44 0.55 0.40 0.74 0.43 Invent. 1.00 0.41 0.37 0.33 0.45 0.49 0.44 0.57 0.37 0.49 0.38 Industrial Build. 1.00 0.47 0.25 0.31 0.22 1.13 0.53 0.48 0.25 0.31 0.20 Furnit. 1.00 0.37 0.35 0.27 0.51 0.73 0.39 0.55 0.36 0.81 0.39 Invent. 1.00 0.37 0.40 0.32 0.55 0.69 0.44 0.55 0.40 0.74 0.43

**Figure 12.** Depth-damage curves for some of the most damaged municipalities in Spain due to flooding (pluvial and fluvial) for the 2020 reference year.

The literature is scarce on the spatial transferability of damage curves, but a similar study by the IBI Group for Alberta (Canada) [16] uses the results of a local consumer price index survey to transfer damage to all economic sectors. Therefore, although limitations still exist, the present study represents an improvement on the current state of the field.

#### **5. Conclusions**

The use of depth-damage curves is globally accepted, even acknowledging the omission of other relevant variables, such as the water velocity or the floodwater residence time. A number of flood damage models are based on the use of these water-damage relationships. One of their major limitations is their site-specific nature, which means they cannot be applied in other regions. Moreover, the need of price updating may be considered a limitation, too. These issues are discussed in the literature and there is broad agreement about the better performance of relative depth-damage functions that remain static at least in time. Their shape, though, in terms of regional transferability, is more dependent on the style and typology of construction, which could be assumed to be fairly uniform at a national level. Maybe, for these reasons, standardizing a methodology of curves at a European level does not seem feasible yet, as some authors indicate discrepancies among computed and actual damage when using these continent-wide curves. Besides, countries such as the United Kingdom (Multi Colour Manual) and the United States of America (HAZUS-MH) apply their own nationwide depth-damage curves, and they have been well accepted for many years.

Barcelona is one of the case studies of the EU-funded RESCCUE project, whereby a comprehensive analysis of its climate resilience has been carried out. The impact of increasingly frequent pluvial floods has been analyzed. Namely, a detailed flood damage assessment has been conducted for the entire city, focusing primarily on properties. Due to the lack of existing detailed depth-damage curves for Barcelona, a tailored approach has been used, considering the 14 types of properties commonly found in highly urbanized cities. These developments were based on a sample of actual damage records; when insufficient or when the correlation between the damage and water depth was poor, the contribution of a flood expert surveyor was essential. Therefore, as in many other previous studies, expert opinion was included, resulting in the construction of semi-empirical depth-damage curves for Barcelona. In addition, this paper offers a methodology to obtain the depth-damage curves for any Spanish municipality, which provides standardization of depth-damage curves at a national level.

The methodology to standardize the construction of depth-damage curves in Spain presented here will contribute to enhancing cost-benefit studies in flood damage assessments at a micro scale and will allow for the comparison of results between different regions of the country. This could take on special relevance for future reviews and updates of flood risk management plans in Spain in the framework of the European Directive 2007/60/CE, included in the Spanish legislation through the Royal Decree 903/2010.

**Author Contributions:** Conceptualization, E.M.-G. and M.G.-H.; methodology, E.M.-G., M.G.-H., E.F.-O. and S.C.; validation, E.M.-G. and M.G.; formal analysis, E.M.-G.; investigation, E.M.-G., E.F.-O. and M.G.-H.; resources, S.C.; data curation, S.C. and E.M.-G.; writing—original draft preparation, E.M.-G.; writing—review and editing, M.G.; visualization, E.M.-G.; supervision, M.G.; project administration, E.M.-G.; funding acquisition, E.M.-G. and M.G.-H. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Horizon 2020 Framework Programme, Grant Agreement No. 700174.

**Acknowledgments:** The authors thank the Spanish insurance company Consorcio de Compensación de Seguros (CCS) for its important role in this research. Without its collaboration by providing claims data the damage model would have not been calibrated properly.

**Conflicts of Interest:** The authors declare no conflict of interest.
