Characterization of Climate Change and Aquifer Recharge in Three Localities in the South-West of Côte d’Ivoire

Located in the southwestern part of Côte d'Ivoire, the study area's economic activity is rainfall-dependent agriculture and facing climate change impact on water resources. This study aims to improve the resilience of water users based on a better understanding of the recent manifestation of climate change. Specifically, it is to determine the episodes of rainfall variability and estimate the effective rainfall and groundwater recharge. The hydro-climatic database for this study covers more or less the period from 1977 to 2021. The characterization of rainfall variability was highlighted by the calculation of rainfall indices, while effective rainfall and recharge values were determined using the ESPERE (Estimation of Effective Rainfall and Recharge) software according to different mathematical methods. Using the non-parametric Pettitt test was possible to detect years with significant rainfall breaks. Thus, there was an alternation of deficit and surplus periods at different scales in the three localities. However, a break in the rainfall pattern occurred in 1989 in San Pedro, whereas this event took place a year later, in 1990, in the other two localities. The effective rainfall and annual recharge closely followed the rainfall evolution in the three localities at different scales. This acquired knowledge of hydrological and hydrogeological rainfall, dynamics can be used to better educate the resilience and climate change adaptation habits of the populations in the southwest region of Côte d'Ivoire.