Due to climate change, which has caused the scarcity of rainfall and the depletion of water resources in recent decades, Côte d'Ivoire has embarked on a planning program for the integrated management of its water resources. The present study is carried out on the Lobo watershed in Nibéhibé, located in the western part of Côte d'Ivoire (between 6°17' and 6°44' W longitude and between 6°46' and 7°41' N latitude). Indeed, the multisectoral use, the impact of climate, the demographic growth on water resources as well as the uncoordinated management lead to a crucial water shortage in the basin. The objective of this study is to propose optimization scenarios for the use of water resources for planning and sustainable management. To this end, field surveys were carried out among the state structures and the populations of the basin to acquire the socio-economic data necessary for the simulation of future water demand. The product of the specific consumptions by the levels of activities allowed to estimate the needs by sectors of activities (water supply, agriculture, and breeding) and consequently the global needs of the basin in 2021. The Water Evaluation And Planning (WEAP) model, which is a water resources management tool, was used to simulate the future water demand of the basin under different scenarios. The results show that the water demand for 2021 is 30 180 588 m3. The water demands by 2050 under the reference, low population growth rate, high population growth rate, improved standard of living and climate change scenarios are 83,700,000 m3; 57,700,000 m3; 114,100,000 m3; 107,600,000 m3 and 114,100,000 m3 respectively. As a result, the unsatisfied water demands for the same scenarios are 23,700,000 m3; 10,700,000 m3; 38,600,000 m3; 34,300,000 m3 and 38,600,000 m3 respectively. The reduction of these unsatisfied demands for the well-being of the basin populations requires the implementation of planning and integrated management systems of the basin water resources through optimization scenarios.