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Moroccan karst has been the subject of study over the last two decades as a system, where landforms interact with groundwater, springs and human action. The literature review gone through in this article focuses on international publications, including French journals. It shows the complexity of the karst area and its local model diversity. The regimes of the aquifers, landforms and springs were reported in most mountain terrains and the local interactions between the karst aquifer, karst springs, landforms and human action were discussed. Even the Rif Mountain presents some karst aspects, mainly in its central part, the Atlas domain is more dominated by karst. The substrate types, tectonics, altimetry, climate, and vegetation roles are important in karst dynamics. Human factors impact the landscapes and the equilibrium of the hydrokarst system via resources overuse and management. Indicators of the present-day disequilibrium were evoked (turbidity of water in karst springs, geotechnical problems, erosion of the soil, etc.). These problems will be more complex in the future due to the human density increase and probable intense human activity in the rural areas. Sustainable management is therefore a challenging priority in the karst domain.

After the brief presentation of the major karstic areas in Morocco, the article focused essentially on the Atlas mountains to investigate the impact of the agriculture on the natural systems equilibrium. Socio-economic changes (demographic pressure, escalation of the landscape use, utilisation of new techniques in water harvesting, etc... ) have sometimes fathered mechanisms of degradation. Many indicators seem to reflect these mechanisms. The pedologic indicators, soil erosion, the hydrologic and geomorphic indicators, are apprehended to demonstrate existent correlation between different variables and the often negative impacts of land over-use in the karstic domain of the Middle Atlas.

In Morocco, hydric erosion is the main factor in soil degradation. It is a dynamic and very complex phenomenon, linked to natural and anthropic factors that are difficult to control in time and space. Land degradation has visible impacts on the environment and hinders economic and social development. The consequences of erosion, both upstream and downstream of watersheds, are costly for the Moroccan economy. The Oued Isly watershed is an elongated mountan basin with an area of 1312km2. It is part of eastern Morocco. It is located in the south of Oujda city. Wadi Isly is characterized by irregular flow. Its flow increases during the winter and early spring. Extreme flows are recorded after exceptional and very intense rain in the Touissit and Guenfouda mountains. The watershed of Wadi Isly knows currently a very active erosive dynamic that affects all the slopes on both banks of the Oued Isly. Several factors contribute to the processes of soil degradation, such as climatic aggression and anthropogenic action. The objective of this study is to estimate soil losses at the Wadi Isly watershed by the application of the universal soil loss equation (USLE) and the use of GIS and Remote sensing. This study also aims to discuss the amplifying factors of the erosive phenomenon in this semi-arid environment.

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