Evolving Streamflow Extremes in a Changing Climate for a Peninsular River Basin

Due to the adverse impacts of climate change, which have elicited global attention and concern, there is a pressing need to understand and address the multifaceted challenges of changing climatic conditions. The direct influence of changing climate on precipitation patterns and temperature significantly impacts streamflow dynamics through modifications in the peak and low flow conditions. The current study employs daily discharge data from ten stream gauge stations situated within the Narmada River basin, which is a prominent west-draining peninsular basin. This study examines gradual and abrupt changes in extreme streamflow indices, encompassing vital hydrological variables such as peak flows, low flows, and streamflow volumes. The study employs two robust non-parametric tests: the Modified Mann–Kendall test (MMK) for trend identification and the Pettitt test for detecting abrupt shifts. Furthermore, the true magnitude of trends is assessed using Sen’s slope (SS) estimator. The analysis reveals a consistent decreasing trend in peak flows and a significant change point across all stations. However, contrasting trends are observed in the annual streamflow volume and low flow days, indicating a mixed pattern of change, thus highlighting the complex dynamics of streamflow variations. The research aims to understand better the hydrological dynamics within the study area for efficient water resources management and flood mitigation.