Assessment of changes in MEdiTerranean HYdro-resources in the South: river basin Trajectories – AMETHYST

The AMETHYST project has an approach based on three research axes:
The main goal of the first research axis “Present” is to understand and analyze the current interactions between the water cycle and the combined environment and human drivers of change; the ultimate goal is to build an integrated modeling platform which will be used as a quantitative tool to analyze the past and forecast the future. The work is organized around different tasks: data collection concerning physical and socio-economic data; remotely sensed data production; modeling of the hydrological functioning; and validating the integrated platform.
This second axis “Past” develops an interdisciplinary and holistic vision of the continuous interactions between human and environmental components of the water system over the last five decades. This analysis will later help for defining realistic scenarios to be tested in the third axis «Future«. The work is organized around different tasks: gathering the pre-existing information about the major socio-environmental and technological factors involved in the evolution of water systems; confronting interpretations of physical transformations, based on observations and modeling, with past human activities; analysis of historical interactions between social and environmental conditions, with a special task focused on the impacts of droughts on the water systems.
The thirst axis “Future” forecasts the future of water resources, considering the plausible changes in the main drivers identified in the first and second axes. The forecast horizon is twenty years, while the climatic simulation goes over fifty years in order to identify clearer long-term trends. The work is divided into four main tasks: gathering of the climate scenarios and downscaling to the regional or local scale; building several local socio-economic scenarios to conceive future trends of water uses; running of the integrated models and proposition of comprehensive water scenarios.

• The establishment of a data exchange system among the project partners is necessary. In the case of geographical information and forecast data, a web devise allows to visit the information available (metadata).
• A strong experimental action took place during the first 24 months with different types of measures and surveys.
• follow up of the surfaces with spacial teledetection : different tasks allowed the developement and methodological evaluation for the Mapping of biophysical variables of the surface
• modelling of the process : the validation of different types of models for the assessment of surface flow. (physical models of type SVAT, models of energy results, models based on the FAO-56 and other models of culture.
• Understanding of the resource management of water for the irrigation with the SAMIR model.

Two model types were chosen at the time of submission,
-For Integrated SIM physical modeling: the model is installed on a sub-basin of the Tensift, difficulties in connection with forcing (calibration) still exist.
-For the conceptual integrated modeling: the model is installed and functional on the plain of Tensift, an activity is launched to broaden the application of the model to the mountain component. The model is installed on the site of Merguellil,
• Evolution of water resources in the past: Various activities have addressed this evolution (analysis of satellite time series for monitoring the snow on the Tensift, analyzes the outputs of the ISBA model on Merguellil and Tensift.
• Drought indicators: Analyses of drought events are available from measurements of precipitation and series of spatial measurements. Software is developed ‘MDI’ to calculate different stress indices based on satellite data.
• Climate scenarios are proposed on the two study sites as part of the CDD of Camille Szczypta.

• finalize the development of the integrated models;
• starting the development of anthropogenic scenarios on the two study sites.
• starting the interaction between 3 axes (integrated modelling, climatic scenarios, anthropogenic scenarios)
• analyzing the interaction between resource evolution of extreme events and their interaction with the socio-economic environment;

34 papers in international journals
53 communications in international congres and symposuims

As pointed out by international organizations and an abundant scientific literature, water is a strategic issue in the Mediterranean region, mainly because of the rarefaction of the resources, in quantity and/or quality, facing the ever increasing demand and the problem of sharing water scarcity. Vulnerability linked with water is paramount in the semi-arid North Africa, where climatic hazards and environmental changes induced by human activities reinforce the likelihood of crises, and where the unequal distribution of resources contributes to increasing the competition between water uses and users. The AMETHYST project aims to analyze the co-evolutions of the water resources under the influence of global change (climate and anthropogenic changes) and of the water uses trajectories. We focus our work on the Maghreb because a large range of evolutions is still possible in this region, far from the extremely severe situations of coastal Spain or Israël on one side, from the reasonably comfortable situations of northern Italy or south-eastern France on the other side. Two case studies will be considered, the Merguellil catchment (near Kairouan, in central Tunisia) and the Tensift region (near Marrakech, Morocco). They are emblematic of water scarcity issues, with rich complementarities in terms of environmental context, water uses, sector competitions, hydraulic history and current water policies. They can also provide large sets of data because of previous long-term research works.
We propose an inter-disciplinary project combining physical, social, economic and political sciences, with three research axes: (1) A numerical platform of the integrated functioning of the water resources evolution will be developed, based on models driven by in-situ, reanalysis or scenario data as well as satellite products and anthropogenic constraints arising from the study of the reciprocal impacts of water uses and policy regulations on water resources. (2) Based on a diachronic data analysis and a diagnostic run of this platform, we will analyze the evolution of water resources in the past fifty years in relation to many environmental social, economic, political and technological factors that have interacted. We’ll not only look at trends but also at the way the system reacts after events such as drought or social upheavals. (3) Various scenarios, based on climate and anthropogenic modifications associated with socio-economic projections, will be tested to anticipate effects on water resources trajectories in the next twenty years (extended to fifty years for climate change scenarios), by numerical modeling and by participative approaches.
The high ambition of this project is to enhance exchanges between environmental and human sciences at every step of the research, from the acquisition of data to the common definition of prospective scenarios. This shared approach seems the best answer to the urgent water issues in the region, and in particular for providing concrete elements of information to water managers, authorities and stakeholders with whom we will work for the whole duration of the project.