In Morocco, establishing an Integrated Water Resource Management System is fundamental for sustainable development. With regards to its mission CRTS is carrying numerous actions through the country to demonstrate the role of the rapidly evolving earth observation programs for collecting and disseminating water related information in cost effective and sustainable ways. In this paper, parts of the results from these actions will be presented from different applications in different water contexts.
The first case study aims at developing, in the Souss-Massa hydraulic basin, an integrated approach including the exploitation of the satellite data, the pre-existing data and the Geographical Information Systems (GIS) as sources of information and tools of analysis within the water management process. This region has continuous aquifers that are facing a severe depletion because of intensive irrigated activities. The use of multi-sensors and multi-temporal satellite images (optics and radar) enables to highlight new practices on the current situation of the land use, particularly in the irrigated areas during the last decades. The land use changes analysis shows the surface expression of the groundwater over-exploitation by generating an intensive dynamic, with regards to different aspects of land use changes, in particular in terms of irrigated zones extension. These changes are of two forms, closely related to the reduction (disappearance) or the extension (appearance) of irrigated agricultural activities. In the first case, they are essentially related to the urbanization pressure, soil degradation, and groundwater overexploitation. In the second case, considered as more dominant, these changes take form of appearance of new irrigated farms where groundwater is still more available. Although the general trend at the basin scale shows a continuous increase in irrigated surfaces, locally these irrigated zones are disappearing. The extension seems to be more generalized for the whole plain region and not simply limited to the upstream as it was expected.
The second case study concerns Ighrem region which is facing a critical situation with regards to potable water resources sustainability. This region has a discontinuous aquifer systems and week surface water contributions because of its arid climate. This area belongs to the Anti-Atlas Mountains considered as part of the Panafrican chain with complex and intensive deformations and a large lithological variability; witch makes more difficult the characterization of its hydrogeologic context. The approach was based on the integration of multi-sensors earth observation data, the existing data and the field truth in order to contribute to the groundwater prospecting process. This allows us to produce details information from lineament and lithological mapping in order to better characterize the aquifer system. In particular, radar imagery had been used for mapping zones with high recharge potential. On the other hand, the integration of these information in a quantitative approach known as Weight of Envidence Modelling for combining evidence in support of an hypothesis. This method has been used based on key hydrogeologic predictors for groundwater prospecting: geology, geomorphology, hydrology and recharge potential. This enabled us to identify and locate the zones presenting high aquifer potentials. These zones are supposed to guide geophysical prospecting to better refine the location of productive drilling in the future.
The third case study concerns the Sebou hydraulic basin which is receiving more than 1/3 of Moroccan surface water potentialities per year. The aim of the study is to demonstrate the use of earth observation data to better characterize the key hydrologic parameters for water balance evaluation. Actual evapotranspiration (AET) and rainfall are the elements in water balance estimation that give sound information on water availability. At this stage of the work rainfall products were taken from ground meteorological stations and the AET was estimated from remote sensing and GLDAS global meteorological data using the Surface Energy Balance System (SEBS) model. On the other hand, to better refine the calculated daily average of the evaporative fraction a detailed land use map from very high resolution imagery were used for surface parameters. Furthermore, climatological water balance estimation was done over rainfed and irrigated croplands for a specific period in 2010 and 2011.
