The drinking water needs of the populations of the localities of Bébouo-sibouo, Zaliouhan and Krébleguhé are increasingly accentuated and constitute one of the major problems in this area of west-central Côte d’Ivoire. The aim of this work is to strengthen the drinking water supply system in order to meet the needs of the population. To solve this problem, the methodology was based on simulating the operation of existing and complementary networks using Epanet software. The results show that the population’s needs in 2019 are estimated at 400,032 m3/d and 685,406 m3/d in 2031. The pipes selected after sizing are all in PVC with nominal diameters of 10 bar, and comprise a PVC DN 200 mm for delivery, a PVC DN 90 mm for supply pipes (main pipe) and another PVC DN 53 mm for distribution. Simulation of the network shows that there is a malfunction in the existing system, which can be explained by the low or even zero pressures recorded only after 1 h of distribution throughout the existing network. Even if pressure results are good on the complementary network, low flow velocities are recorded on the whole network. As a result, further boreholes need to be drilled to boost production. This model will therefore be retained and used to support the implementation of this water supply project.

The construction of hydraulic structures on watercourses modifies the flow conditions and the extent of flood propagation zones. To do this, the installation of the structures must be preceded by models ensuring the correct dimensioning of the structures and their influence on the hydrological functioning of the watercourse. This study used hydrometric data, satellite images and cartographic data to design a run-of-river dam and model its influence on the propagation of floods from the Davo River to the drinking water production station in Gueyo (Côte d'Ivoire). The dimensioning of the weir gave the following main characteristics: 2.5 m heigth, 1.3 m wide at the crest, 3.8 m right-of-way and 177 m long. The retention created by the presence of this weir answer the population's water needs, which are estimated at 0.19 m3/s, or 16,800 m3/day. Simulation of the behaviour of the Davo River during high water periods shows that the presence of the weir does not have a significant impact on the extent of the floodplain area.