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Copper mineralization in the Lower Paleozoic sedimentary cover of the Anti-Atlas (Morocco) is continually being revised not only to improve its mining capacity, but also to determine its origin, which remains a matter of debate. As evidenced by the various models proposed, the related research is fragmented, localized, and confusing. The origin of the Anti-Atlas Lower Paleozoic copper mineralization is shared between synergistic and epigenetic processes or a superposition of the two processes. Based on new tectono-magmatic data and a reinterpretation of the ore structural arrangement, we propose a link between the last concentration of copper deposits and the Late Triassic–Early Liassic CAMP (Central Atlantic Magmatic Province) tectono-thermal event, as evidenced by the significant concentration of copper mineralization in the three NE–SW corridors affected by extensional faults, some of which are filled with dolerite CAMP magma. The heat flow generated by the mafic dykes within these reactivated corridors causes mineralized fluids to up well into the sedimentary layers, depositing material rich in juvenile or leached copper, or even a mixture of the two. In some cases, these fluids are trapped by fracture systems that accompany passive folds initiated on normal faults. In other cases, these fluids can infiltrate bedding planes, and even karst caves, formed during carbonate exhumation. Notably, extensive NE–SW faults systematically cover the early Hercynian structures, suggesting that they belong to a post-Hercynian extensional episode. During the Late Triassic, the global fragmentation of the Pangaea supercontinent was manifested by the stretching of the continental crust at the margin of northwest Africa, with the simultaneous opening of the Central Atlantic Ocean and emplacement of CAMP magmatism. This last and often overlooked tectonothermal event must be considered in the remobilization and reconcentration of copper mineralization and other mineralization in Morocco.

This article has been accepted for publication in Geocarto International, published by Taylor & Francis. Mineral prospectivity mapping (MPM) based on the principle of geometric mean was applied to stream sediment geochemical, fault density, and aeromagnetic data from Tagmout basin, Morocco to determine new areas for optimizing copper exploration. The application of a fuzzy operator using stream sediment data, factor analysis, and fault density map, allowed weights to be assigned to these parameters so that the MPM function can process them to indicate the most favorable zones of copper mineralization. The model's accuracy as evaluated using a normalized density index (Nd with value 1.22) shows the reliability of the method. The potential copper concentration areas represent 8.22% of the entire basin of which 30% are concentrated in the western portion of the basin and other significant areas are in the southwest and northeast portions. The results indicate that MPM is a powerful technique for planning exploration programs that aim for sustainable mining activities.

Groundwater potential delineation in the Akka basin, southwest Morocco, has been determined through the combination of geospatial techniques and geological data. The geometric average and expected value are two multi-criteria approaches used to integrate a set of factors–data for which the weights of each factor are assigned using the fuzzy logic function, which transforms values of factors influencing groundwater presence in a range of [0, 1]. The efficiency factors used in this study are the lineament density, node density, drainage density, distance from rivers, distance from lineament, permeability, slope, topographic witness index, plan curvature, and profile curvature. Thereafter, the groundwater potential map was generated in a GIS environment. To assess and compare the efficiency of the two models, the well data existing in the basin were used to choose the most efficient model. For that reason, the prediction area (P–A) graph, the normalized density (Nd), and its weight (We) were applied to estimate the capacity of each model to predict the target area. The analysis shows that the expected value model (Nd = 1.86 and We = 0.62) is more efficient than the geometric average model (Nd = 0.96 and We = −0.04). The results of the expected value model can be used in the future planning and management of water resources in the Akka basin.

Floods are among the most important natural disasters in the world. These phenomena are due to climate changes, which have caused natural hydrological events such as heavy rains. This study develops two methods applied to the watershed of the Ifni River, which is a hydro system located in the southwest of Morocco. The main objective of this chapter is to compare the flood risk determined using the Flood Hazard Index (FHI) method with the hydraulic model of HEC-RAS/WMS. This approach makes it possible to visualize and quantify the spatial distribution of floods in this basin. The FHI method makes it possible to map flood-prone areas throughout the basin while the HEC-RAS/WMS model allows it to map areas at risk of flooding downstream of the Ifni River basin due to the presence of a single station in this basin. ISBN för värdpublikation: 9780128221846; 9780128232651

This research work is intended as a contribution to the development of a multicriteria methodology, combining several factors to control the availability of groundwater resources, in order to optimize the choice of location of future drilling and increase the chances to take water from productive structures which will satisfy the ever-increasing water demand of local population (Arghen basin in the Western Anti-Atlas chain of Morocco). The geographic information system is used to develop thematic maps describing the geometry and the hydrodynamic functioning of the aquifer. In this study, 11 factors including geology, topography, and hydrology, influencing the distribution of water resources were used. Based on the Analytical Hierarchy Process (AHP) model, GIS, and remote sensing, the study mapped and classified areas according to their hydrogeological potential. The favorable potential sectors cover 17% of the total area of the basin. The medium potential sectors account for 64%, while the unfavorable areas cover 18% of the basin area. The groundwater potential map of the study area has been validated by comparing with data from 159 boreholes scattered throughout the basin.

The cartography of floods by two different approaches enabled us to determine the limits and the advantages of each one of them. This cartography has been applied to the El Maleh basin situated in the South-East of Morocco. The HEC-RAS approach consists of a combination of the surface hydrologic model and the digital terrain model data. This combination allows thereafter the mapping of the flood zones by the use of the WMS software. Thus it can predict the probability occurrence of floods at various frequency times and determine the intensity of the flood (depth and velocity of flood water) inside the El Maleh river by using the existing hydrological data. Otherwise FHI method approach introduces a multi-criteria index to assess flood risk areas in a regional scale. Six parameters (flow accumulation, distance from drainage network, drainage network density, slope, land use, and geology) were used in this last method. The relative importance of each parameter for the occurrence and severity of flood has been connected to weight values. These values are calculated following an Analytical Hierarchy Process: AHP, a method originally developed for the solution of Operational Research problems. According to their weight values, information of the different parameters is superimposed, resulting to flood risk mapping. The use of the WMS model allowed us to accurately map the flood risk areas with precisely flood heights in different levels. However, this method is only applicable for a small portion of the basin located downstream of the hydrological station. Otherwise, the FHI method allows it to map the entire basin but without giving an indication of the water levels reached by floods. One method does not exclude the other since both approaches provide important information for flood risk assessment.

Groundwater, in the Souss-Massa Basin (South western Morocco), occurred under unconfined conditions in the Pliocene and Quaternary formations of the plain, often overlying one or several confined sub-aquifers, such as Neogene and Turonian deep aquifer. The ensemble constituted the multi-layer aquifer system of Souss-Massa Basin. The El Gouna springs emergence, flowing from the Turonian deep aquifer, was one of the natural outlets of the system, with a low flow rate in the downstream part. This study focused on the El Gouna springs area and aimed to understand its hydrogeological functioning based on geological structures and their role in the appearance/disappearance of springs in this area, then studied the relationship between deep and shallow aquifers. For this reason, vertical electrical soundings (VES) using the Schlumberger array and seismic sections using were carried out in the study area. All geophysical data were calibrated by mechanical well logging and geological outcrops, and used to build geoelectrical and seismic cross-sections and structural map. The geoelectrical results showed the alternance of conductive and resistive zones related to the Plio-Quaternary deposits. This alternance followed by a conductor layer ( Senonian marl and marly limestones. The deep resistant layer corresponded to the Cenomano-Turonian limestone aquifer (170 Ωm) with a thickness of about 95 m. Seismic sections showed that the fault pattern in the studied area was mainly concentrated along corridors with a major direction of ENE-WSW and secondary direction of NNE–SSW. The first one constituted an extension of regional faults such as the El Klea and Agadir faults. The highlighted structures bringing the two aquifers into contact, allowing the emergence of some springs in the area. These resurgences came from the Turonian limestone and dolomite deep aquifer. Despite deepening of the impermeable covering deposits (Senonian marls), the water was forced to flow along higher permeability paths of the fault zone. This upward flow was controlled by structural discontinuities in the impermeable Senonian marls. This hypothesis could explain the spatial variation of salinity in the El Gouna area.

Aeromagnetic data were analyzed, constrained by geological and ore deposit mapping to investigate possible regions within the Igherm inlier region of the Anti-Atlas in western Morocco that are favorable for more detailed copper exploration. The aeromagnetic data were investigated by creating reduction to the pole (RTP), upward continuation and tilt-angle anomaly maps. Additionally, depths to magnetic susceptibility sources were estimated using three-dimensional Euler deconvolution and tilt-angle depth methods. The RTP map indicated several anomalous regions where magnetic maxima can be related to Paleoproterozoic and Neoproterozoic metamorphic and volcanic rocks located between the uplifted regions in the northern portion of the Igherm inlier region. The western portion of the study area is characterized by short wavelength, NE-trending magnetic maxima that are related to Pan-African orogeny volcanic units. Derivative maps indicate that the majority of the lineaments are NE-trending probably related to post Pan-African rifting. However, there are several NW- and E-trending lineaments related to the Variscan orogeny. The depths of the sources of these lineaments range between 100 m and 5200 m, with the deeper depths mainly trending toward the northeast. Using the derivative analysis, RTP, magnetically determined depth estimates and the nature of known copper deposits in the region (e.g., Tizert deposit), several regions were determined to be favorable for more detailed mineral exploration. These regions are located along the edges of Proterozoic uplifts where paleobasins containing Basal Series sediments have been affected by mainly NE-trending faults that act as conduits for deeper magmatically formed ore-rich fluids.

In Morocco, iron deposits of sedimentary origin are mainly developed in the Ordovician where they are interbedded at different levels of the stratigraphic column. A detailed analysis of the sedimentary facies shows that the iron ores are not randomly distributed but are concentrated at omission surfaces of the sequences thus raising the question of their sedimentological significance within the sequences that shelter them. This study determines three morphological types of ore, which provide a possible avenue for economic exploitation. These morphological types are: firstly, from metric to decametric bodies of regional extension (examples are “Caid Rami” and “Tachilla”), consisting of a set of detrital facies organized in two stratigraphic stages that cyclically recur to form genetic sequences. Within each sequence, the maximum mineralization is at the top of the prograding basal stage and is expressed by diagenetic iron cement and at the base of the regressive stage in the form of strata of iron oolites, or in massive beds. Secondly, lenses with a thickness up to 30 m over a kilometer width (example of “Imi n’Tourza” field), corresponding to incisions cut along the ravinement surfaces. The maximum mineralization of this second type is within the median sandstone stage in connection with a large transgressive event. Thirdly, there is a type of reworked material consisting of discontinuous layers of ferruginous conglomerates and bioclastics lining the ravinement surface that separates the higher order sequences. It is this third type that has generated the most economic interest. The iron-bearing mineral phases identified are: magnetite, hematite, iron chlorite, maghemite, iron hydroxides (goethite, lepidocrocite) and siderite. The ultimate source of iron would probably be the large reserves of banded iron formation of the West Africa Craton (Mauritania in particular). Intense tropical weathering would have leached the silica and left a highly enriched iron residuum that was carried as particulate iron to shallow marine shelf environments where Fe3+ was converted to Fe2+ during early diagenesis. This reduced iron was recycled into the water column by tidal currents or storm waves where it precipitated as ferric oxide or ferrous silicate ooliths. This depositional mechanism accounts for the positioning of ironstone beds at times of stasis and reworking.

Reliable estimates of river stream flow and flood zoning maps are needed for water resources management such as flood mitigation, water supply, dam construction and irrigation. The flood hazard caused by Tata River in the Southeast of Morocco Kingdom, is assessed using statistical modeling technique (Weibull), hydraulic modeling with HEC-RAS and the Geographic Information Systems (GIS). Four flood maps for return periods of 20, 50, 100 and 500 years are generated. For the four return periods the maximum depth of water reached by the river and extent of flooding are estimated. For 500 year return period (Q=860 m3/s), water average depth on the left river (Teghremt) and right one (Tata) is 2.20 m and 3.05 m, respectively. The flood hazard modeling reveals that the flooded zone is more significant out of the left (east) tributary (Teghremt) than out of the right (West) Tata river. Through lateral flood zoning maps, areas that are vulnerable to flooding hazards have been identified. This information is useful in defining the minimum height of flood protection structures such as dikes to protect the area from flooding. The results can be useful for evacuation planning, estimation of damages and post flood recovery efforts.

In the Ziz Basin, located in arid area in southeastern Morocco, surface waters are scarce and local populations are entirely dependent on groundwater resources for drinking and irrigation. In order to evaluate the main factors controlling the origin and salinization of groundwater resources, we have investigated the chemical and stable isotope compositions of groundwater and surface water in different areas in the Ziz basin, upstream and downstream from the Hassan Addakhil dam, which is the major man-made reservoir in the basin. A large variation in water quality was observed, specifically an increase in salinity from north (upstream to the reservoir with TDS ~ 460 mg/L) to south (downstream; TDS ~ 16,000 mg/L). In the northern portion of the basin, the low saline groundwater is composed primarily of Ca2+ and Mg2+ due to dissolution of carbonate formations in the High Atlas Mountains. In contrast, the major dissolved consequents of saline waters are Cl−, SO4 2− and Na+, apparently due to dissolution of evaporite minerals (gypsum and halite). In some areas elevated nitrate contents imply anthropogenic contamination derived from local agriculture. The stable isotopes data (δ18O = −8.6 to −8.3 ‰ and δ2H = −55.7 to −53.8 ‰) indicate that the High Atlas Mountains, upstream of the reservoir constitute the major source of water to the Ziz Basin. Given that this arid basin is entirely dependent on groundwater resources, long-term salinization of groundwater in the Ziz Basin could lead to negative effects and reduction of the local agricultural productivity in addition to the degradation of drinking water quality in this region.

This article presents research and development of an interoperable platform to facilitate, monitor and coordinate groundwater data sharing. This system was orchestrated by a number of services described by Open Geospatial Consortium (OGC) such as Sensor Observation Service (SOS) and other services for the use of mapping data, Web Feature Services (WFS), Web Map Service (WMS), and catalogue services (CSW). An important activity for our project was the establishment of a portal for geographic data and services. Geoportal developed for this project will promote and facilitate access to groundwater data and share theme more openly. Otherwise our system has been designed to provide a powerful tool that enhances the ability of regional staff to monitor near real-time groundwater data (i.e. piezometric level) and as a result will help provide a more effective response to environmental upsets.

The construction of small dams and hillside reservoirs is a common practice for dealing with erratic and unevenly distributed rainfalls in arid and semi arid areas. Moreover, these small hydraulics structures are recommended as a solution to adapt to climate change in rural areas. They are fundamental for the sustainability of the water resources. However, these dams are potential sinks for upstream sediment. Therefore, it would be useful to monitor and measure the amount of sediments in small dams because it is necessary to understand siltation and better functioning of these vital structures. This control and these measurements require the application of the bathymetry or topography surveys which is too expensive for the responsible of these small dams. In this context, this paper proposes a simple and low cost method called: Triangulation of the estimated silted level. This method is based on direct measurement of the accessible silted level in dam. This new method is compared with another method based on the initial Elevation-Capacity curve of dam, usually used when the bathymetry is not attainable. The results of both of them have been verified with those of the bathymetry and electrical tomography methods and validated the proposal method as the most approximate. Therefore, this method is recommended as a new direct and simple technique to evaluate the amount of silting in small dams and hillside reservoirs.

In the arid sub-Saharan of southern Morocco, groundwater salinization poses a direct threat for agricultural production in six oases’ basins that are irrigated by water imported from the High Atlas Mountains. Here the geospatial distribution of salinity is evaluated in shallow groundwater, springs and surface waters in the Drâa Basin, integrating major and trace element geochemistry and isotopic tracers (O, H, Sr and B). The data show that water discharge from the High Atlas Mountains to the Upper section of the Drâa Basin is characterized by both low and high salinity, a distinctive low δ 18 O and δ 2 H composition (as low as −9‰ and −66‰, respectively), typical for meteoric water from high elevation, a 87 Sr/ 86 Sr range of 0.7078–0.7094, and δ 11 B of 12–17‰. The Ca–Mg–HCO 3 , Na–Cl–SO 4 , and Ca–SO 4 compositions as well as the Br/Cl, 87 Sr/ 86 Sr, and δ 11 B values of the saline water suggest dissolution of Lower Jurassic carbonates and evaporite rocks in the High Atlas Mountain catchment. Storage and evaporation of the imported water in a man-made open reservoir causes an enrichment of the stable isotope ratios with a δ 18 O/δ 2 H slope of 18 O and 2 H (as low as −9‰ and −66‰, respectively) and higher 87 Sr/ 86 Sr ratios (∼0.7107–0.7115) relative to irrigation water and groundwater flow from the Upper Drâa Basin. This newly-discovered low-saline groundwater with a different isotopic imprint flows from the northeastern Anti-Atlas Jabel Saghro Mountains to the northern oases of the Lower Drâa Basin. This adjacent subsurface flow results in a wide range of Sr isotope ratios in the shallow oases groundwater (0.7084–0.7131) and appears to mitigate salinization in the three northern Drâa oases. In contrast, in the southern oases, the higher salinity suggests that this mitigation is not as affective and increasing salinization through cycles of water irrigation and salt dissolution appears inevitable.

The present work was conducted in the basin of Laayoun-Dakhla (South Morocco) to: 1) identify the recharge and flow characteristics of the Lower Cretaceous aquifer (LC); and 2) provide information about the mineralization of aquifer’s water. Isotopic and hydrochemical compositions combined with the geological and hydrogeological settings were used for this purpose. The principal changes in chemical composition of LC groundwater result from mixing with water of deeper circulation. Closer analysis of available chemical data reveals the importance of dissolution/precipitation processes in evolution of groundwater chemistry. Piezometric levels, as well as chemical and isotopic composition of groundwaters, confirm hydraulic connection between the LC and the others aquifers. Overlap of some major characteristics (δ18O, δ2H, Cl-) in this aquifer suggests that mixing processes considerably influence the hydrochemical evolution of water. The surface electrical resistivity does not indicate any freshwater-saltwater interface in the coastal aquifer and the relationship between 18O and Cl allows us to reject the hypothesis of a seawater intrusion.

This chapter presents synthesis results of physical geography, geology, and water resource availability of the Souss-Massa River Basin. The geomorphology and geology are very complex in detail. The actual valleys of Souss and Massa are due to erosion processes caused by floods. The Souss-Massa plain is a narrow fainting zone with recent sedimentary deposits, embedded between the High Atlas in the north and the Anti-Atlas in the south. The calibration of electrical soundings with deep boreholes allowed understanding of the geometry and the structure of the aquifer of Souss-Massa plain.

Argania spinosa (the argan tree) is a slow-growing tree endemic of Morocco, growing on semi-arid areas where no other tree species can live. With the aim of predicting temporal changes in A. spinosa woodlands under a probable increase in aridity, we set off to investigate these questions: how do A. spinosa physiological attributes respond to variations in climatic conditions and seasonality, and which is the set of attributes that most affects tree response to environmental conditions? In three study sites, Beni Snassen (North), High-Atlas (Mountain) and Admine Forest in Agadir (Coastal), gas exchange measurements, photochemical efficiency, leaf water potential and different leaf attributes were monitored in February, July and November of 2006. The Mountain site presents the most continental climate. Trees in this site were the most stressed in summer, having the lowest midday leaf water potential values, photochemical efficiency and assimilation rates. We found a Ψmd threshold around -4 MPa, below which stomatal conductance responds linearly to Ψmd. Plants from the North area never reached this threshold during the study period. Although leaf pigments presented a clear seasonal pattern, leaves from Coastal trees exhibit the highest content for each season. The three study sites were separated by two discriminate functions obtained by canonical discriminant analysis. In summer, the Mountain population is separated from the other sites mainly by assimilation rate and Fv/Fm, while in winter transpiration rates and chlorophyll content are the main discriminant variables. Our study shows that A. spinosa trees adjust their physiological status and leaf attributes to environmental conditions allowing plants to thrive under a dry climate. Under a scenario of global change, the distribution of the argan tree likely shifts to milder areas.

The study of spatial and temporal variations of some hydrochemical properties in the Oued Issen watershed, Morocco, has revealed their close relation to the area's lithologic and geologic characteristics and to variations in hydroclimatological cycles. High concentrations of sodium chloride are measured during flood periods, when the outcrops of the basin are leached by streams draining the rather dense hydrographic network.

The main objective of this paper was to look into the morphological differentiation patterns and phenotypic plasticity in four populations of Argania spinosa with environmentally contrasted conditions. Mean response, magnitude and pattern of morphological intra- and inter-population plasticity indexes were measured and analyzed in order to identify which characters contribute the most to the acclimation of this species. Populations growing in the ecological optimum of the species presented the lowest plasticity, while those growing in the most stressed habitats showed an increased morphological variability. The study of four populations showed that human pressure seems to play an important function in the regulation of morphological characters. However, climatic conditions seem to play a significant role in the increase of morphological plasticity.

Argania spinosa is an example of an avoider tree growing under semi-arid conditions in Morocco. To assess what are the physiological strategies of this species, different variables were measured through an annual cycle in two populations located in the species' main distribution area. Results show the expected decrease of leaf water potential (psi) with an increase of water-use efficiency (A/gs) with the onset of the dry season. In summer, leaf conductance (g(s)) was sensitive to vapour pressure deficit (VPD), and stomatal closure occurred over 30 mbar of VPD. Surprisingly, carbon isotope discrimination (delta13C) maintained very low values over the year, with almost no relationship with any physiological or morphological variable. Hence Argania spinosa presents a complex set of mechanisms to avoid water deficit, but delta13C cannot be used as an ecological tracer of long term WUE.

Summary Groundwater in many arid basins, particularly in developing countries, is the only available water resource that sustains local communities. Yet, information on the basic hydrological parameters and the sustainability of the groundwater exploitation are often lacking. This study investigates the origin of groundwater from the Lower Cambrian carbonate aquifer of the Lakhssas Plateau in the Anti-Atlas Mountains of southwestern Morocco. The study aims to reveal the origin of the groundwater, salinity sources, and the residence time of the water. The study is based on a comprehensive geochemical and isotopic (oxygen, hydrogen, carbon, and strontium) investigation of groundwater from different parts of the basin. The hydrochemical and isotopes results indicated three types of groundwater in the Lakhssas Plateau: (1) thermal water in the southern part of the basin with solute composition that reflects dissolution of calcium–sulfate and calcium carbonate minerals; (2) low-temperature groundwater at the southern margin of the basin with low salinity (chloride content up to 100 mg/L) and chemical composition that is expected from equilibrium with limestone–dolomite rocks; and (3) low-temperature groundwater in the northern, western, and eastern margins of the basin with a wide range of salinity (chloride up to 800 mg/L). The different water types had also different stable isotope composition; the thermal water was depleted in 18 O and 2 H (δ 18 O as low as −7.6‰) relative to the southern (−5.9 to −5.3‰) and northern waters (−5.7 to −3.8‰). The differences in δ 18 O and δ 2 H between the southern and northern waters are related to elevation that induced fractionation of oxygen and hydrogen isotopes in recharge water originated from coastal moisture. The data suggest that the high salinity in groundwater from the northern, western and eastern margins of the Lakhssas Plateau is related to the presence of schist rocks in these areas. The distinctive low Na/Cl and Br/Cl ratios, coupled with high silica contents and high 87 Sr/ 86 Sr ratios (up to 0.713) in the saline groundwater provide additional evidences for the link between salinity and the schist rocks. In contrast, the thermal water had relatively low 87 Sr/ 86 Sr ratio (0.7089), which is identical to the secular seawater Sr isotope ratio during the Early Cambrian period and presumably reflects interaction with the Early Cambrian carbonate and sulfate aquifer rocks. In the northern and southern groundwater, the 87 Sr/ 86 Sr ratios were higher and correlated with the Mg/Ca ratios, inferring mixing between the Early Cambrian limestone and other rocks with higher 87 Sr/ 86 Sr, such as the schist rocks. The radiocarbon data showed 14 C activities ranging from 6 pmC in the thermal water to 62 pmC in the southern water. Age-modeling, corrected for dissolution of the carbonate rocks with dead carbon, simulated mean residence time of 10–15 ka BP for the thermal water and a range of 0 to 3 ka BP for the northern and southern waters, depending on the used models. The integration of the data enables us to establish a conceptual model for the origin of groundwater in the Lakhssas Plateau: (1) recharge to the aquifer from relatively heavy-isotope depleted recharge water, presumably during wetter conditions about 10–15 ka BP. The recharge water interacted at high depth with limestone and calcium sulfate minerals and emerged to the surface as thermal water at the southern part of the basin; (2) more recent recharge from coastal moisture originated from the Atlantic Ocean. The stable-isotope composition of groundwater was controlled by the elevation of their recharge areas: recharge at higher elevation, particularly in the southern margin resulted in lower δ 18 O and δ 2 H values; (3) the recharge water interacted with the carbonate aquifer rocks, particularly with calcite and dolomite minerals. In areas of exposure of schist rocks, the water–rock interaction induced salinization of the groundwater. Overall, our data reveal that the limited water resources in this semi-arid zone of Morocco could be in some parts less renewable and also saline. Future exploitation of this basin will have to account the salinity factor and the suggested contribution of water recharged some thousands years ago.

In spite of its geographical situation on the Atlantic and Mediterranean coast, Morocco is one of the most arid areas of the world; it experiences highly variable rainfall and recurrent droughts. The limited water resources are threatened by increasing demands and accelerated quality degradation. In addition, the Intergovernmental Panel on Climate Change (IPCC) predicts in its 4th Assessment Report that “Annual rainfall is likely to decrease in much of Mediterranean Africa and northern Sahara, with the likelihood of a decrease in rainfall increasing as the Mediterranean coast is approached” (IPCC 2007) Chapter 11, p. 866). The fact that climate is changing has become increasingly clear over the past decade. This prediction is based on several climate models thatsimulate global and regional mean precipitation. While the multi-model predictions show confl icting results for some areas, in the Mediterranean and Northern Africa the multi-models show consistent results of signifi cant reduction in precipitation (IPCC 2007). The Intergovernmental Panel on Climate Change reports that heat waves have been increasing towards the end of the 20th century and are projected to continue to increase in frequency, intensity and duration worldwide (WHO 2009; Baccini et al. 2008; IPCC 2007; Meehl et al. 2007; Robinson 2001). Climate change is caused by the combined impact of growing human population and economic activities (WHO 2003b). The IPCC has developed a series of 40 scenarios of plausible future trajectories for population growth, economic and technological development (IPCC 2000). Each scenario gives estimates for greenhouse gas emission levels, and predicts the changes in the temperature ( Campbell-Lendrum and Woodruff 2007). For example, temperature may be estimated to increase by 0.54C (scenario B2 – low emission scenario), 0.84C (scenario A1B – middle emission scenario) or 1.02C (scenario A2 – high emissions scenario) in 2030, relative to the baseline period (WHO 2009).

Determination of the origin of recharge of the unconfined aquifer in the right side of the Souss wadi between Agadir and Taroudant (South-western of Morocco) was based on the use of hydrochemical and isotopic analysis of groundwater, surface water and springs of the contact zone between the High-Atlas Chain and the Souss plain.The correspondence in the space evolution of the various chemical elements of evaporitic origin (SO42-, Cl-, Sr2+) in groundwater, piedmont springs, and surface water reveals the existence of recharge water from the adjacent High-Atlas Chain.The various recharge modes of the different aquifers (High Atlas and Souss plain) determined by isotopic analysis, shows that the source of groundwater for the unconfined Souss aquifer seems to be composite between a direct infiltration on the High-Atlas tributaries and a remote recharge from the bordering High Atlas aquifers.La determinación del origen de los aportes de agua de la capa freática de la ribera derecha del rio Souss entre Agadir y Taroudant (Suroeste de Marruecos) se ha basado en la hidroquímica y el análisis isotópico de las aguas subterráneas, aguas superficiales y manantiales de la zona de contacto entre el Alto Atlas y la llanura de Souss.La correspondencia en la evolución espacial de los diferentes elementos químicos de origen evaporítico (SO42-, Cl-, Sr2+) en las aguas subterráneas, manantiales de pie de monte y aguas superficiales, revela la existencia de una recarga de agua procedente de la cadena del Alto Atlas. El análisis de los modos de recarga de los diferentes acuíferos (Alto Atlas y llanura de Souss) determinado por análisis isotópico, demuestra que la alimentación de la capa freática de Souss a partir del Alto Atlas parece ser mixta, compuesta por una infiltración directa de los afluentes del Alto Atlas y una alimentación lejana desde los acuiferos que limitan con el borde del Alto Atlas.

Malgré le grand nombre de puits et forages d’eau réalisés dans les différentes régions karstiques du Maroc, de nombreux inconnus subsistent encore concernant les critères d’implantation et le coût final des ouvrages. Afin d’optimiser les campagnes de forage à venir, une méthodologie de prospection multicritère a été adoptée dans la région karstique nord‑orientale du Maroc. Elle s’articule selon trois axes, à savoir : 1) détermination des linéaments hydrogéologiques à partir du traitement et interprétation des images satellitaires radar SAR ERS-1 et Landsat ETM+; 2) application de la géophysique électrique par (a) sondages électriques pour la détermination des épaisseurs des niveaux d’altération et de fracturation et par (b) trainées électriques pour la localisation précise de la zone de passage des linéaments hydrogéologiques, et finalement 3) application des techniques de Sondage par Résonance Magnétique (SRM) pour la vérification de la présence d’eau. Les différents résultats de sondages mécaniques réalisés à la suite de cette campagne de prospection montrent un taux de réussite très satisfaisant., In spite of the great number of water wells and drillings carried out in various karstic areas of Morocco, many unknown factors still remain concerning criteria for installing such works and for the final costs. To optimize future drilling campaigns, a multi-criteria method of prospecting was adopted in the karstic area of north-eastern Morocco. It is presented according to three axes: 1) the determination of hydrogeologic lineaments based on the analysis and interpretation of SAR ERS-1 and Landsat ETM+ images; 2) the application of electrical resistivity methods by (a) vertical electric soundings (VES) for the determination of the thicknesses of weathered layers and of fractures, and by (b) electric resistivity profiling for the determination of the exact location of hydrogeological lineament zones; and finally, 3) the application of Magnetic Resonance Sounding (MRS) for the verification of the presence of water. The various results of mechanical drilling carried out following this prospecting campaign show a very satisfactory rate of success.