Détermination des écoulements préférentiels en zone karstique (Tafrata, Maroc), Apport des données satellitaires SAR ERS-1 et Landsat ETM+ et de la prospection géophysique

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

Understanding the trade-offs between climate change-induced aridity and agricultural water demand in the Souss basin, Morocco

The concept of integrated water resource management requires an in-depth analysis of water inflows into a river basin. Population growth and the uncertainties associated with climate change are causing increased water stress and droughts, which are impacting agriculture. Hence the need for studies on the impact of climate change on demand-supply interactions in river basins. In this study, a generic decision support system, ModSim, was used; for the first time in the region; to examine the agricultural water usage and demands over Souss basin in Morocco. ModSim was calibrated over the period from 1990 to 2019 using recorded data about physical processes and hydraulic infrastructures features and management. The simulations succeeded in replicating different deficit episodes at the various irrigated perimeters. During the simulated period from 2012 to 2019, it was observed that the water supplies for the different dams in the basin experienced a decline ranging from 38% to 89%. As a result, the average total unmet demand for surface water from reservoirs in irrigated areas reached 201 mm3 between 1990 and 2019 and the monthly average demand increases by 55% in the dry season, compared to the demands in the rest of the year. The significant amount of unmet demand across all sites suggests that demands are satisfied by the withdrawal of water from groundwater resources. The adopted approach has proven to be a useful decision support tool to understand water resources planning challenges. Water managers require such reliable tools to represent the basin's water trade-offs. Thus, additional investigation to improve the representation of groundwater/surface water interaction approaches is required to enhance the evaluation of the consequences of different uses, especially in arid and semi-arid regions with significant water stress such as Souss. A conceptual framework as well as a detailed discussion have been produced in order to guide efficient water management and governance

A Network of Transdisciplinary Observation Mechanisms as a Digital Source of Knowledge on Rangeland, to Communicate and Exchange at Local, Regional and Global Scales

For several decades, interventions geared towards the development of drylands have been the catalysts of much change in a rapidly evolving world, and learning how to build sustainable trajectories that take into account both cultural and contextual variations is becoming of increasingly great import. As local problems become intertwined, and given the difficulty of large-scale collective action, understanding these dynamics requires cognizance of all levels of knowledge governance systems and their interactions. So far as rangelands are concerned, the lack of easily accessible documentation encompassing all knowledge to date is a major impediment to their sustainable development. With this in mind, polycentric governance would allow for centralized decision-making, which would then give rise to solutions that could be adapted to local conditions. Recent advances in technology and the proliferation of data are creating new opportunities for monitoring the progress and performance of multi-scale development efforts, and indeed new and non-traditional data sources will be paramount to the success of such endeavours. For instance, participatory observation is an emerging example of a non-traditional data source that is already making a significant contribution, and has fostered engagement at the community level. We seek to demonstrate the value of implementing transdisciplinary observation mechanisms—here, in relation to Southern Countries’ pastoral systems—and to provide concrete examples of how such mechanisms can be adopted for mainstreaming the use of data from a variety of sources, thereby facilitating the implementation of a sustainable development agenda as part of a continuous learning process. This project has been managed within the framework of the Agadir Platform, infrastructure supported and implemented by Ibn-Zohr University, Morocco