# Mobile Augmented Reality Application to Evaluate the River Flooding Impact in Coimbra
## 2 Case Study of the City of Coimbra  
Coimbra is a city that receives variable amounts of rain, which has historically led to occasional floods. The river front in Coimbra is populated by parks, cafes, restaurants, public infrastructures and residences. Flooding from the overflow of the Mondego river has an impact on the social, economical and environmental system. It is important to know and visualise which buildings are impacted in case of different possible floods to prevent and invest in solutions for avoiding damages. Many buildings that are far away from the river are still within the first two metres from the reference point of the overflow of the river [5]. Table 1 shows the historical flood events in the city. As the table shows, the risk of flood is real. The construction of a dam upstream and dykes along the river has contributed to a better management of the flow and the minimisation of losses. Nonetheless, incidents still happen, and as recently as 2019, there were broken dykes that caused the evacuation of two thousand people and resulted in significant economic losses.  
The analysis of the rain through time in Coimbra helps to identify and notice the risk of floods. This has been conducted for each unit of time (hour, day and month) over 24 years. An import remark is that the rain precipitation values are low due to Coimbra having, on average, several days without rain.  
Figure 1 shows the hourly precipitation average. Most of the rain precipitation occurrences appear to have between 10 h and 18 h. Figure 2 shows the monthly average amount of rain. Most of the flood records happened from November to March [5]. The plot below shows the months that average most of the rain precipitation. From June to September, a dip occurs, reducing the likelihood of rain precipitation as a cause of flooding incidents for these months.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Year** & **Precise Date** & **Main Consequences** \\ \hline
1331 & N/A & Coimbra city isolated \\
1520 & Mar & Coimbra city isolated \\
1656 & Feb & Coimbra city isolated \\
1708 & Feb 17 & Coimbra city isolated \\
1739 & Dec 3–6 & Indeterminate casualties \\
1764 & Jan 19 & Coimbra city isolated \\
1788 & Feb 23 & Indeterminate casualties \\
1804 & Jan & Coimbra city isolated \\
1821 & Jan & Coimbra city isolated \\
1843 & Mar 27 & Coimbra city isolated \\
1850 & Jan 18 & 12 casualties \\
1852 & Nov & Coimbra city isolated \\
1857 & Dec 18 & Coimbra city isolated and without flood \\
1860 & Dec 27–28 & 8 casualties \\
1872 & Jan 26–27 & Max. peak flow of 5317 m\({}^{3}\)/s \\
1876 & Jan 23 & Coimbra city isolated \\
1878 & Dec 18 & Coimbra city isolated \\
1900 & Feb 12 & Coimbra city isolated \\
1915 & Jan 19 & Coimbra city isolated \\
1924 & Mar 25 & Coimbra city isolated \\
1949 & Jan 29 & Max. peak flow of 4147 m\({}^{3}\)/s \\
1955 & Jan 19 & Significant economic losses \\
1962 & Jan 1 & Significant economic losses \\
1977 & Jan 14 & Significant economic losses \\
2001 & Jan 27–28 & Rupture of dykes and isolated villages \\
2016 & Feb 13–14 & Significant economic losses \\
2019 & Dec 21 & Rupture of dykes, evacuation of 2 k residents \\ \hline \hline \end{tabular}
\end{table}
Table 1: Main historical flood events in Coimbra [5] between 1331 and 2019.  
Figure 1: Hourly average of all hours in the day (2000–2024).