This study is part of a critical assessment of the conformity of the environmental rehabilitation plan applied in the context of a semi-industrial gold mining operation. The study aims to assess the relevance and effectiveness of the actions implemented with regard to the Ivorian mining code of 2014, interministerial decree n° 0026/MINEDD/MMG/2019 as well as international standards. The methodology adopted combines field observation, local survey, semi-structured interviews, regulatory analyses and GIS processing. The analysis is structured around three axes: the initial state of the site, the impacts of mining activities and the technical quality of the rehabilitation measures. The results reveal that only 32% of pits are properly backfilled, with signs of erosion, partial revegetation of the soil, and poorly recycled waste. Deficits in environmental monitoring and the low involvement of authorities constitute major limitations. This work proposes technical and institutional recommendations for better post-exploitation ecological governance. It is part of a dynamic of continuous, practical and rigorous strengthening of the regulatory, normative, operational, scientific, environmental, socio-economic and cultural framework of contemporary, inclusive and truly sustainable semi-industrial gold mining in Côte d’Ivoire.

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 study aims to assess the evolution of water balance parameters watershed Comoe in a context of climate change. Using the GR2M hydrological model, climate data from the climate model RegCM3 under the A2 emission scenario were simulated to get infiltration, runoff and evaporation and plant transpiration for the periods 1991-2000, 2031-2040 and 2091-2100. Similarly, monthly hydrological and climatic data were used to calibrate the parameters of GR2M hydrological model over the period 1961-1990. The calibration of the hydrological model gave Nash values between 57% to 72%. At validation, Nash criterion varies from 51% to 75%. The results of projection, revealed a decrease in runoff of 18.8% to 34% in 2031-2040 and 40% to 73% in 2091-2100 horizon in different localities. Refills of sheets that are through infiltration could decrease by 7% to 13% in 2031-2040 horizon and 49.3% to 70% in 2091-2100. The decrease in these two consecutive hydrological parameters is, firstly, to falling precipitation of 7.17% and, secondly, an increase in the evaporation and plant transpiration via the temperature increase of 3.6