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.

In Côte d'Ivoire rice cultivation is practiced in rainy conditions and remains sensitive to climatic uncertainties. This study is conducted to analyze the variation of climatic parameters and their impact on rice production in the high Sassandra region. The daily climatic parameters (rainfall and temperature) recorded over the period from 1976 to 2005 and the agronomic characteristics of two rice varieties (NERICA 1 and IDSA 85) were used for yield simulation using SARRA-H model. The results showed that the rainy season generally begins in March while instability is observed at the end of the rainy season (between 15 July and 9 October). Overall, the annual rainfall recorded remains potentially appropriate to meet rice water requirements. However, rice cycle shortens when the temperature rises; besides it lengthens when the photoperiod is high. Regardless of sowing date, the total requirements are essentially the same for both rice species. The best yields, 17,161 kg/ha for NERICA1 and 20,048 kg/ha for IDSA85 are obtained when sowing on 5th April. On the other hand, the date of 15th March gives the lowest yields. These results constitute a significant contribution in the redefinition of the rice agricultural calendar in the high Sassandra region.

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.

This work aims to test the polygons' method of Thiessen, initially used to evaluate the average rainfall for assessing a groundwater recharge. The study concerns the groundwater of Terminal Continental, the main source of water alimentation of Abidjan population. The database is constituted by rainfall (three stations) and piezometric data (ten piezometers). This method has been tested on both cases: in surface for calculating the total recharge and in saturated zone for assessing the true recharge. The results showed that the ground water of Abidjan total recharge is estimated to 252 mm.year-1; the one estimated in saturated zone is equivalent to 158 mm.year-1 in 2006, that is to say 12 pc of the total infiltration. The taking account of "land use" factor in the approach underlined the fact that the quick ongoing urbanization of Abidjan city is reducing the infiltration zones.