Mapping and Surface Evolution of the Bacon Reservoir Using Satellite and Uav Imagery (Southeast Côte D’Ivoire, West Africa)

Surface water resources are fundamental to human survival and socioeconomic development, providing water for domestic consumption, agriculture, aquaculture, and hydroelectric energy production. In West Africa, and particularly in Côte d’Ivoire, small reservoirs constitute vital infrastructures that support rural livelihoods, sustain dry-season farming, and enhance water security. However, these systems are increasingly threatened by climatic variability-especially prolonged droughts and irregular rainfall patterns-as well as by anthropogenic pressures such as land-use change, deforestation, and agricultural expansion. This study focuses on the Bacon Reservoir, located in southeastern Côte d’Ivoire, with the objective of assessing the spatiotemporal dynamics of its surface area between 2016 and 2023. Multi-temporal Sentinel-2 satellite imagery and high-resolution unmanned aerial vehicle (UAV) data were processed and analyzed using geographic information system (GIS) and remote sensing techniques. The results show significant interannual variations in the reservoir’s surface area: from 74,840 m² in 2016, it decreased to 67,900 m² in 2018 (a reduction of -9.27%) before recovering to 80,900 m² in 2023 according to Sentinel-2 observations. UAV-based measurements for 2023 yielded a slightly higher estimate of 87,404 m², representing an approximate 8% difference compared to satellite-derived values. This discrepancy highlights the importance of integrating high-resolution UAV imagery with freely available satellite data to enhance accuracy in monitoring small water bodies, whose spatial variability may be underestimated by medium-resolution sensors. The observed recovery trend of the Bacon Reservoir after 2018 reflects a certain degree of resilience, possibly linked to improved rainfall conditions or local management interventions. Overall, the study demonstrates the relevance of combining multi-source remote sensing data for long-term monitoring of small reservoirs in tropical regions. These findings provide essential insights for water resource managers and policymakers seeking to promote sustainable water use, strengthen climate resilience, and ensure the long-term viability of small-scale reservoirs across Côte d’Ivoire and West Africa.