The Tangérois region is into full socio-economic evolution with the development of free zones and the establishment of a new population. The requirements of water and agricultural produce increase. The urbanization and industrialization cause the land to change use and function. These changes would affect the hydrological behavior of Tleta watershed (17 700 ha), which feeds Ibn Batouta dam; a significant source of water for the Tangérois. The assumption sit for is that these landscape changes affect the production of water, soil erosion and the productivity of land. It is the principal purpose of the ALMIRA research project, within which this study is being implemented. It aims at contributing to check this assumption by analyzing agrarian and landscape dynamics in Tleta. The diagnosis of the Tleta watershed allowed the agroecological zoning of land and the description of the agricultural farming systems (56 surveyed farms). Eight quadrats (of 1,75 km² on average) were selected to analyze the dynamics of land use and parcellar between 2000 and 2015 starting from the exploitation of land use maps produced on different dates and Google images of quadrats selected for 2003, 2009 and 2015. For each quadrat, the parcellar was digitalized. The study confirmed the intense evolution of spaces in Tleta. The significant factors of change are the economic development, the establishment of the new city of Chrafate, the contributions of external capital, the exodus of young people, the development of tree crops (Morocco Green Plan) and the valorization of matorral. The analysis of quadrats showed that the share of parcels with built environment varies from 0 to 30%; those with hedge from 0 to 90%; the median size of the parcels is lower than 0.5 ha but varies from some m² to 2 ha; the share of matorral varies between 2 and 57%. The dominating farming system is the mixed-farming-livestock. The average size is 7.7 ha, distributed on six parcels. 50% of the farms have a size from 5 to 10 ha. They produce cereals (wheat, barley, oats), sorghum and leguminous plants (beans, lentils, chickpea), intended for auto consumption and livestock. Dominant crop rotation is cereal/fallow, used as pasture for livestock. The olive-tree plantation is recently developed. The average animal herd is composed of four cattle, three sheep and three goats. This study posed the bases of a prospective analysis of the watershed: How these evolutions will combine by 2040? What would be the impacts on agricultural economics, erosion and the supply of water for the dam?

Key words: Agrarian dynamics, Landscape dynamics, Tleta watershed, Western Rif, Morocco