Assessing the Influence of Climate Change and Anthropogenic actions on Water Resources in the Wami River Catchment, Tanzania

Abstract Understanding the trend, extent, and effect of climate change and anthropogenic activities are globally important for monitoring river catchments water resources. Due to the majority of river catchment from developing countries like Tanzania experiencing insufficient time series data, the long-term ERA5-Land (1960–2021) reanalysis was used to assess the influence of climate change and anthropogenic actions on water resource in the Wami river catchment. The Mann-Kendal Sneyer test revealed a change that reflects the effect of anthropogenic actions on runoff in 1992, hence the mean annual runoff, precipitation, and actual evapotranspiration decreased by 19%, 9.7%, and 8.9%, respectively, while potential evapotranspiration increased by 5% after the change. Budyko decomposition and climate elasticity methods illustrated that climate change caused a notable contribution to the reduction of Wami River runoff. Hydrological sensitivity analysis revealed that variability of climate is a primary factor that reduced runoff with a contribution of 69%, while anthropogenic actions are 31%, this illustrates runoff in the Wami River catchment is more vulnerable to climate variability than anthropogenic actions by considering that the majority of the catchment are classified as arid or semi-arid. Our study emphasizes the significance of adopting a Nature-based Solution (NbS), participatory integrated planning (PIP) approach for sustainable water resources within the Wami river catchment.