Reevaluating streamflow declines across the middle East and central Asia with insights from change point detection

Change point detection (CPD) methods are widely used to identify abrupt shifts in streamflow, often linked to human activities. This study assesses the effectiveness of CPD techniques across countries in the Middle East, Central Asia, and Pakistan—regions vulnerable to water scarcity and climate variability. Analysis of annual streamflow data (1970–2018) revealed that 1998 was the most frequent breakpoint, coinciding with a major El Niño event, suggesting climatic anomalies were key drivers of the initial change. The coherence of breakpoints across the region highlights the influence of large-scale climate signals. However, comparison of pre- and post-break conditions indicates that the magnitude of hydrological shifts cannot be explained by climate alone, highlighting the limitations of CPD methods in distinguishing climatic from anthropogenic drivers. To explore these dynamics in more detail, the Karkheh River Basin (KRB) in Iran was examined. A marked change in streamflow patterns around 1998 was observed, along with shifts in temperature and precipitation. These results underscore the need for cautious use of CPD methods when attributing hydrological changes to human versus climatic factors.