During the year 2018 several flood events hit Badalona (Province of Barcelona) and several other areas of Catalonia. Generally, these events attract significant public and media attention. Are we experiencing more extreme rainfall events due to the effect of climate change during the last years?
The BINGO project helps us answering this question. The project provided two different predictions of future rainfall intensities useful for flood analysis: one for the period 2015-2025 and the other one for 2051-2100. The 2015-2025 prediction did not show significant variations of future rainfall intensities whereas the 2051-2100 predictions showed significant uncertainty with both an overall decrease according to the climate scenario RCP 4.5 and an overall increase according to RCP 8.5. Nevertheless, both of the latter climate scenarios showed an increase of rain event intensity up to 2-year return period. The project also analysed observed rainfall intensities in Badalona since 2013. Figure 1 (left) shows all the rainfall events in Badalona from 2013 that exceeded either the 20 or 60 minute rainfall intensity of 1-year return period. The selected indicators are useful for flood analysis and are common in urban drainage engineering. The figure shows that Badalona experienced rainfall events of intensities up to approximately 5-year return period since 2013. Moreover, the year 2018 experienced 4 events exceeding the 1-year return period. Figure 1 (right) shows a flood event that occurred in Badalona the 16
Overall, the analysis of both the rainfall observations since 2013 and the 2015-2024 predictions of Badalona does not seem to show an increase of the latest year and near future rainfall intensities. However, there can be a significant increase for the period 2051-2100, particularly probable for events up to a couple of years return period.
Furthermore, the 2018 was an exceptional year that experienced 4 significant rainfall events. Moreover, since 2013 the observations did not show extreme events (extreme events could be defined as the ones having a return period higher than 5-10 years). This suggest that Badalona seems to experience flood hazard due rain events smaller than 5-10-year return period (that is usually the design criteria of the urban drainage system) and these few-year return period events are likely to get more frequent due to climate change.
In Badalona, the CoP has been working together now for almost 4 years, looking at BINGO's resultsfor the research site, understanding them in their own context and trying to come up with solutions. Check out the aftermath in this video: