Hydroclimatic Projections for the Mouhoun Basin in Burkina Faso by the Year 2100

This study assesses the potential impact of climate change on streamflow in the Mouhoun River Basin, Burkina Faso. Eight downscaled global climate models (GCMs) from CMIP6, provided by the NEX-GDDP-CMIP6 program (ACCESS-CM2, ACCESS-ESM1-5, MIROC6, MIROC-ES2L, MPI-ESM1-2-HR, MPI-ESM1-2-LR, MRI-ESM2-0, and NESM3), were employed. The ensemble mean of these models was considered for the historical period (1960–2014) and for future projections (2015–2100) under three Shared Socioeconomic Pathways (SSPs): SSP1-2.6 (optimistic), SSP2-4.5 (intermediate), and SSP5-8.5 (pessimistic). These climate data were used as inputs to the GR6J hydrological model to simulate streamflow up to 2100. The analysis focused on the interannual mean of hydro-climatic projections for three time horizons: near-term (2025–2054), mid-term (2055–2084), and long-term (2071–2100), compared with the reference period 1981–2010. Results show a general increase in streamflow across all scenarios. Under SSP1-2.6, anomalies reach +43.4% in the near term but gradually decline (+22.4% and +12.9%), indicating a tendency to return toward historical conditions. SSP2-4.5 exhibits a stronger increase (+51.2%, +36.2%, +35.3%) but also a progressive decline. In contrast, SSP5-8.5 reveals a sharp intensification of flows, with anomalies of +78.7%, +107%, and +110%, highlighting an increased risk of long-term hydrological imbalance. Regarding rainfall, an increase is observed in the northern basin under SSP1-2.6 and SSP2-4.5 (+95 mm, +60 mm, +40 mm; and +115 mm, +105 mm, +90 mm across periods), with an overall trend returning to historical levels. A similar pattern is observed in the south, with temporary increases followed by a downward trend. However, under SSP5-8.5, rainfall rises sharply in both the north (+150 mm, +210 mm, +230 mm) and the south, suggesting a sustained intensification. These results underscore the strong hydro-climatic variability across scenarios and time horizons. They highlight the urgent need for integrated water resource management strategies, particularly in the agricultural sector, to meet the growing demands of an expanding population and to mitigate risks associated with future hydrological excesses or deficits.