For several decades, the N'zi region has been experiencing increasing climatic disturbances, characterized by decreasing rainfall, increasing droughts, and growing anthropogenic pressures such as urbanization and land-use changes. This study aims to analyze the impacts of climate change on water resources in the N'zi watershed in Côte d'Ivoire. The data used for this research includes rainfall, relative humidity, and river flow. Rainfall and hydrometric indices were calculated using the weighted moving average method or Nicholson's method to identify the main trends in the time series. The research results revealed a gradual transition to drier conditions since the 1970s, marked by frequent and severe droughts. Before this period, years were characterized by alternating wet and dry episodes, with mostly positive SPI indices. After the breakup years (1969-1975), moderate to severe droughts became predominant, affecting river flows and the availability of water resources. The application of remote sensing normalized difference water index (NDWI) highlights a significant reduction in the surface area of the Kongobanadougou reservoir between 1988 and 2014, followed by a slight recovery in 2024, underlining the impact of climatic variability and human interventions. Measuring stations show spatial and temporal variability of droughts, with more frequent droughts downstream and decreasing moisture indices over the decades. Despite recent improvements in some regions, droughts remain a major challenge, exacerbated by climate change and human pressures. This situation calls for proactive and sustainable management of water resources in order to anticipate and mitigate the effects of future droughts. The study highlights the need to implement adaptation strategies to cope with climate change's impact on the watershed's ecosystems and populations.

 

Key words: N'zi in Côte d'Ivoire, watershed, water resources, impacts, climate change evolution.