Soil erosion by precipitation, rainfall and runoff is a widespread phenomenon in different countries of the world. It becomes disastrous in particular on the slopes because of the torrentiality of the flow, of the strong vulnerability of the grounds (soft rocks, fragile grounds, steep slopes). The present study has for objective: The analysis of the data of concentrations of sediments in suspension are measured at the station of the rivers highlights relations, linking the concentration (or the solid flow) of the sediments in suspension to the liquid flow and to quantify the seasonal, monthly and interannual and intra annual variation of the surface degradation. Annual tonnage estimates of solids loads to the Mé were derived from the power law for all seasons. From this deduction, the annual quantities of sediment transported by the Mé from 2015/2017 is 7.06.106 t/year, or a specific degradation of 1.79.103 t/km2/year. On the other hand, in 2017, the value of this solid input is 3.06.106 t/year. However, the annual solid input is estimated at 7063.03.103 t/year with a specific degradation of 1784.47 t/km2/year at the Mé from 2015 to 2017.

The Aghien lagoon watershed is located in peripheral north-east areas of Abidjan. This space is accelerated population growth more than more important. The rate of urbanization is higher than 60% in 2014 (RGPH, 2014). Also, does the acceleration of urbanization result in vegetation cover degradation for the benefit of the built environment and a peri-urban agriculture. Also, does the acceleration of urbanization result in vegetation cover degradation for the benefit of the built environment and a peri-urban agriculture. This study aims to analyze in part one the diachronic evolution of vegetation cover between 1987-2000 and 2000-2015, and second part its takes stock of this dynamic between 1987 and 2015. Thus, the analysis of land use dynamics in the Aghien basin is based on the the vegetation mapping of landsat images. The methodology is based on the supervised classification by maximum likelihood of landsat images The results of the dynamics of land use in the basin in 1987, 2000 and 2015 indicate a decline in forest cover and perennial crops in favor of built environment and bare soil (+10.98%), subsistence crops and fallow (+11.37) over the period (1987-2015). Urbanization and increase crops are caused modifications of vegetation cover in outskirt of basin. These changes are mainly due to demographic pressure and unsustainable agricultural practics.