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.

Since the crisis that happened in 2002, artisanal gold panning activity is practised on the minor and major bed of Cavally river in Zouan-hounien (Côte d'ivoire). This generating activity of income to the populations is done without respecting the environmental and social measures. However the water of the river is used by this population for food, bodily, agricultural needs. This study aims at evaluating the impacts of artisanal gold panning on the morphology and the quality of water of the Çavally river. Thus, the treatement of satellite images by teledetection software ang geographics informations systems, the analyze and the treatement, with SEQ-Water tool, for samples taken are used. It comes out from this study that surfaces of the sections of the river evolved/moved from 5,68%, in 1986, to 16,31%, in 2011. Between 2011 and 2018, surfaces of the sections increased by 16,39% to 55,93%. This study raises too that water of the Çavally river is of average quality. It thus allowed to propose an action plan to fight against the impacts of the artisanal gold panning on the quality of water while being based on the classification carried out according to the uses.

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.

Extreme flow events have had a significant impact on populations and their activities in recent decades. To reduce the impacts associated with their advent a analysis between extreme hydrological phenomena and climate variability is necessary. However, qualitative data accessing difficulties and explanatory variable definition of extremes hydrological phenomena limit extreme flows rate studies. This study proposes the analysis the variability of the floods and the low flows at the Bianouan hydrometric station. Thus, five (5) floods characteristics variables (QCX5, QXJA, F90p, F95p and F99p) and three (3) for, the low flows (VCN10, QJNA and F10p) were extracted daily flows from the Bianouan hydrometric station from 1 January1962 to 31 December 2005. The variability of these extremes has been studied by the trend analysis (linear regression) and of the stationarity (Pettitt and Hubert tests). The results show that for flood variables the negative trend is very significant and ruptures are observed in 1980. For low flow variables the negative trend is significant and the ruptures are observed in 1981. From this study, we can deduce that the ruptures observed in the rains and flows average in the end 1960s and early 1970s have affected later the extreme flows around the 1980s.

The prevention against the pollution of groundwater has been over three decades a major concern for the specialists of the field of water. To that purpose, many methods that use intrinsic parameters have been adopted since 1987. For this study, two methods have been adopted to enhance the robustness of results. It is about DRASTIC and SINTACS who use both the intrinsic features of aquifers. The errors margins have been calculated for both maps so as to appreciate their veracity rate. Finally, these maps have been superposed to translate an infiltration on the salts content map which is supped to translate an infiltration from superficial origin. The results clearly indicate that whatever the method, three classes of vulnerability have been identified: the strong vulnerability class, the average vulnerability and the low vulnerability classes. Globally, the area remains moderately vulnerable. Whatever the errors margin that was determined shows the respective values: 16,74 % and 18,04 % for the DRASTIC and SINTACS methods. The superposition of the salts content map shows that the pollutant found in groundwater might have an origin that might not be from a superficial origin infiltration. The use of statistical tests as contribution to this study could lead to determine the origins of these pollutants.