Investigation of groundwater potential using geomatics and geophysical methods: Case study of the Anzi sub-basin, western Anti-Atlas, Morocco
Hasna El Ayady, Kevin Mickus, Said Boutaleb, Zine El Abidine El Morjani, Mustapha Ikirri, Fatima Zahra Echogdali, Armel Zacharie Ekoa Bessa, Kamal Abdelrahman, Mouna Id-Belqas, Sara Essoussi, Mohammed S. Fnais, Mohamed Abioui
Abstract
The mapping of water potential in arid regions holds crucial significance for the sustainable management of water resources in these vulnerable environments. The Anzi sub-basin in Morocco is confronted with water scarcity, presenting a significant challenge. The region's arid climate and limited accessibility to groundwater resources further exacerbate this scarcity, ultimately constraining the region's socioeconomic development, heavily reliant on agriculture. To address this issue, the current study employs mathematical modeling, specifically the frequency ratio (FR) method, and geomatics tools such as remote sensing (RS) and geographic information systems (GIS) to map and assess potential groundwater zones. The study considers multiple factors influencing water availability, including the density of drainage nodes, lineament density, permeability, slope, NDVI, curvature, distance to drainage, topographic wetness index (TWI), sediment transport index (STI), distance to lineament, and rainfall. The investigation identifies 45 wells, of which 70% are used for model application and the remaining 30% for validation. The model application results in the identification of five potential zones: very high, high, moderate, low, and very low, encompassing 3.97%, 10.11%, 23.38%, 35.02%, and 27.53% of the total study area, respectively. Furthermore, the model's validity is confirmed through the ROC (receiver operating characteristic) curve analysis, indicating a reliability value of 82.5% for the FR method in mapping groundwater potential. These findings align with the results obtained from geophysical prospecting in the region. Notably, the locations of high-flow wells generally correspond to moderately to highly conductive anomalies of resistivity, primarily attributed to the presence of quaternary formations, geological faults, and geophysically derived faults. These results are further validated by proton magnetic resonance surveys.