Analyse de sensibilité d’un modèle de potentiel aquifère élaboré àl’aide de l’analyse multicritère au niveau du Moyen Atlas tabulaire (Maroc)

article publié en français (p.31-41), avec un résumé étendu en anglais (p.42-43), et 6 planches couleur hors-texte (p.66-71)International audienceThe evaluation of groundwater potential appears to be an effective tool for the management of water resources, particularly in arid and semi-arid regions such as the Middle Atlas plateaus. This region consists essentially of dolomites and dolomitic limestones of the Lower and Medium Lias, favoring a large amount of groundwater above the impermeable substratum formed by Triassic red clays. These groundwater karstic origins play a crucial role for drinking water supply of the big cities (Meknes, Fes) and irrigation of surrounding areas. It is located between the Lambert Conformal Conic (Merchich Morocco) coordinates: 480 Km 15 l / s) are divided into 38% on the very high and high potential area, 33% on the medium potential zone and 29% on the low potential area very low. Drilling at low to very low flow rate (Q< 10 l / s) are distributed into 21% on the very high and high potential area, 24% on the medium potential area and 55% on the low to very low area. The groundwater potential of Middle Atlas plateaus is more important in the northwest because of its lithology in dolomitic limestones and calcareous more fractured and high degree of karstification. It is also important to note that more detailed field verification is required to validate and complement the results of this study and to develop a detailed mapping of discontinuities and geological units within sectors supposed to be potentially suitable for groundwater prospecting.L’évaluation du potentiel aquifère est un outil efficace pour la gestion des ressources en eaux, en particulier dans les régions arides à semi-arides. L’objectif principal de cette étude est d’identifier le potentiel aquifère en appliquant la méthode AHP de Saaty et en utilisant une analyse de sensibilité pour apprécier l’effet de chaque paramètre de recharge en eaux souterraines sur la carte de potentialité aquifère finale. L’analyse multicritère a été utilisé dans le but de localiser les zones potentielles de l’aquifère du Moyen Atlas-tabulaire. En effet, le potentiel aquifère a été subdivisé en 15% (très élevé), 31% (élevé), 19% (moyen), 18% (faible) et 14% (très faible). La validité du modèle développé a été testée par lesdonnées de forages. Cet aquifère karstique à un potentiel d’emmagasinement des eaux souterraines plus important dans la partie nord-ouest en raison de sa lithologie en calcaires dolomitiques plus fracturés et à karstification élevée

Groundwater potential of Middle Atlas plateaus, Morocco, using fuzzy logic approach, GIS and remote sensing

Groundwater is a most important resource in arid and semi-arid regions and is required for drinking, irrigation and industrialization. Assessing the potential zone of groundwater recharge is extremely crucial for the protection of water quality and the management of groundwater systems. To identify the groundwater potential zone in the study area, thematic layers of lithology, slope, karst degrees, land cover, lineament and drainage density were generated using topographic maps, thematic maps, field data and satellite image, and were prepared, classified, weighted and integrated in a geographic information system (GIS) environment by the means of fuzzy logic. The fuzzy membership values have been assigned to different thematic layers according to their classification on respect for their contribution and their occurrence in groundwater. Based on the generated groundwater potential map, it was found that about 8% of the investigation area was categorized as very high potential for groundwater recharge, 31% as high, 28% as moderate, 17% as low and 16% as very low potential for groundwater recharge. Finally, the results were verified using well-yield data. The highest recharge potential area is located towards the downstream regions related to more fractured and karstified limestone