Browsing by Author "Bchari, Fatima El"
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- Flood susceptibility assessment through statistical models and HEC-RAS analysis for sustainable management in essaouira province, MoroccoPublication . Khouz, Abdellah; Trindade, Jorge; Santos, Pedro Pinto; Oliveira, Sérgio; Bchari, Fatima El; Bougadir, Blaid; Garcia, Ricardo; Reis, Eusébio; Jadoud, Mourad; Saouabe, Tarik; Rachidi, SaidFloods are natural disasters that often impact communities living in low-lying areas in the northern and central parts of Morocco. In this study, our aim was to create a flood susceptibility map using three methods; the hierarchy process (AHP) frequency ratio model (FR) and the weights of evidence (WoE) model. We extensively examined the area identified by these approaches using a hydraulic analysis software called HEC-RAS (version 6.3.1). Our analysis focused on the Essaouira watersheds in Morocco, where we identified around 197 flood locations. Out of these, we randomly selected 70% for modeling purposes while the remaining 30% were used for validation. Ten factors that influence floods were considered, such as slope, elevation, proximity to rivers, drainage density, stream order, land use patterns, rainfall data, lithology (permeability level) index (TWI), and curvature. We obtained these factors from data sources. Finally, we generated a flood susceptibility map and evaluated its accuracy by calculating the area under the curve (AUC). The validation results confirmed that all three models were robust and effective with an AUC of 90. Moreover, the research uncovered a trend of vulnerability with the most susceptible area being in close proximity to the city of Essaouira along the Oued Ksob. A detailed analysis using HEC-RAS was conducted at this identified location, pinpointing the village of Diabat as highly exposed. These findings hold significance for flood management, empowering decision makers, scholars, and urban planners to make informed choices and implement strategies that can minimize the impact of floods in susceptible regions while minimizing potential damages.
- Geospatial modelling for sinkhole hazard in the coastal area of Safi, MoroccoPublication . Bchari, Fatima El; Trindade, Jorge; Charif, Abdessamad; Chaibi, Mohamed; Khouz, Abdellah; Malek, Halima AitCollapse sinkholes represent a geological hazard that is particularly associated with karst regions, characterized by the dissolution of soluble rocks leading to the formation of voids. This phenomenon is significantly more prevalent in areas with evaporate terrains, wherein the rapid dissolution of soluble rocks facilitates the swift alteration of gap locations and sizes. The ensuing discussion explores the distinctive nature of collapse sinkholes, emphasizing their occurrence in karst and evaporate terrains, shedding light on the factors contributing to their formation and frequency. The coastal region of Safi is characterized by abundant karst features overlying evaporitic rocks, along with historical and recent sinkhole collapse events. Our current investigation aims to develop a susceptibility map for sinkhole collapse in the Safi region. Initially, a comprehensive inventory map of collapse occurrences was created through meticulous fieldwork and the integration of remote sensing data. Nine predisposing factors were identified and incorporated into a Geographic Information System (GIS), including elevation, lithology, curvature, slope, aspect, drainage density, lineament density, topographic wetness index, and land use. To assess the relationship between these factors and sinkhole collapse, statistical analyses were conducted using spatial analysis based on the Frequency Ratio (FR) and Analytical Hierarchy Process (AHP). The FR analysis revealed that high and very high susceptibility zones constitute 14.19% and 6.89% of the region, respectively, while moderate, low, and very low susceptibility zones occupy 23.07%, 26.12%, and 29.74%, respectively. Utilizing the AHP method, it was determined that high and very high susceptibility zones cover 20.32% and 12.01% of the region, respectively, with moderate, low, and very low susceptibility zones encompassing 19.38%, 27.55%, and 20.74%, respectively. To compare and evaluate the outcomes of the AHP and FR methods, the Area Under the Curve (AUC) approach was employed. The success rates, as indicated by AUC, demonstrated that FR (90.5%) exhibited higher accuracy than AHP (73.5%). The validation of the landslide susceptibility map confirmed the acceptability of the methodologies employed. These results can be effectively utilized for hazard mitigation and land use planning in the coastal area of Safi.