The lake system of Taabo watershed contributes at 35% in the country electrification. Besides this use, water is also used in agriculture, fishing and for drinking water. The increasing human activities in its basin led to siltation of Kossou's Lake and eutrophication of 26% of Taabo's Lake total area. However, no study has yet been performed to protect or prevent this resource against pollution. This study is the first in Ivory Coast intending to delineate three protection areas around the watershed lakes. It tries firstly to define all parameters involved in the surface water intrinsic vulnerability. Their integration in multicriteria analysis coupled to use of Geographic Information System (GIS) has then used to delineate protection area around the basin lakes. Three zones were proposed: (1) the immediate protection zone, with a radius of 2000 m around the lake including water, its islands and coastal strip; (2) the near protection perimeter, limited to intense vulnerability zones in the immediate sub-basins of lake; (3) the distance protection perimeter has been estimated to the whole catchment in order to take into account diffuse pollution. As conclusion of protection perimeters elaboration, assistance must be provided for restoring quality and quantity of basin water.

The objective of the study is to set up and calibrate a model using the soil and water assessment tool (SWAT) in order to simulate the water flow in the Buyo Lake located in west of Cote d'Ivoire and to test and evaluate the usefulness and the performance of the model. In this study, we had used the ArcSWAT graphical user interface to manipulate and execute the major functions of SWAT model from ArcGIS tool. Hydrological modeling of Buyo Lake Basin was carried out with the ArcSWAT interface for SWAT 2009. The analysis shows that the surface water flow in the basin is less sensitive to the parameters linked to groundwater flow. Therefore, the water flow was tributary to the surface runoff. The calibration model of the flow in the watershed was performed by running about 500 and 1000 runs in SUFI2 on the period 1985-1988. The statistics showed that there is a good correlation between the monthly observed and simulated river discharge. The obtained results are generally acceptable, and the ability of the SWAT model to simulate the flow in very large complex and heterogeneous watersheds like those of Buyo Lake was highlighted.