Vulnerability Assessment of Potable Water Supply Network to Flood Risk in the Grand Casablanca, Morocco

Understanding the vulnerability of critical urban infrastructure to climate change hazards is essential to enhance their resilience. To recommend a successful adaptation strategy, this study intends to evaluate the vulnerability of potable water supply network to flood risk in seven residential districts of the Grand Casablanca region. ArcGIS Online was used to acquire the map of the Grand Casablanca region. The public service operator “Lydec” was required to provide the following information for the vulnerability assessment: (1) the distribution of drinking water pipes throughout the study area; (2) the presence of unfixed leaks in service lines and distribution; (3) the series of pipes responsible for overflows; (4) data regarding retention basins, pumping stations, and booster pumps existing in the area; and (5) the report on the drinking water quality analysis by urban areas from the Lydec website in the public section. The method used was “Impact and Vulnerability Analysis of Vital Infrastructures and Built-up Areas—IVAVIA.” It started with the impact chain, which established the cause-and-effect relationship between the hazard and the exposed object, considering sensitivity and response capacity indicators. Using the Min–Max approach, those indicators should be normalized to ensure comparable values within a 0 to 1 scale. Then, the reliability analysis is applied to verify the indicators’ consistency. The next step involved weighting the indicators through the Principal Component Analysis method (PCA) and integrating them into the two vulnerability components using the Weighted Arithmetic Aggregation method. As a result, the potable water infrastructure in the Ain Chock, Hay Hassani, and the Nouaceur province is the most vulnerable, while the El Fida-Mers Sultan area exhibits very low vulnerability. The urban areas of Ben M’sik-Sbata, Moulay Rachid-Sidi Othmane, and the Mediouna province demonstrate a high vulnerability, with a value of 0.52. The potable water infrastructure’s vulnerability in the other areas is between 0.29 and 0.42. Three elements can explain these results: The lack of robustness due to the fragility of the drinking water pipes, the unrepaired leaks, and the malfunctioning of some electrical components in case of immersion. The insufficient recovery capacity due to the inaccessibility of sites requiring intervention, the unavailability of human or material resources, or the lack of alternatives in the event of a facility failure and the functional dependence on electricity. In conclusion, the areas with the most vulnerable infrastructure would be prioritized for intervention through medium and long-term adaptation measures.