Streamflow projections for the Jhelum River basin under climate change

Abstract High Asian mountain water resources, which serve as a lifeline for downstream communities, are vulnerable to warmer future climates. Following the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) 3b protocol, the future changes in the mean and extreme streamflow of the Jhelum River under the shared socioeconomic pathways (SSPs) of SSP1-2.6, SSP3-7.0, and SSP5-8.5 were quantified. For this, successful calibration and validation of the eco-hydrological Soil and Water Integrated Model (SWIM) against observed streamflow for 1999–2004 and 1994–1999, respectively was completed. Then, the SWIM was forced with bias-adjusted ISIMIP3b historical (1985–2014) and future (2016–2100) datasets. Climate change analysis suggests a warming of 0.9 ºC, 5.7 ºC, and 7.5 ºC per century under SSP1-2.6, SSP3-7.0, and SSP5-8.5, whereas substantial wetting of 329 mm, 665 mm, and 1258 mm per century under SSP1-2.6, SSP3-7.0, and SSP5-8.5, relative to the historical period. Seasonal temperature changes reveal that during the monsoon temperature increase was more pronounced specifically 5.78 ºC whereas precipitation also increased markedly 20.84% during the monsoon season for the far future climate under the high-end warming scenario of SSP5-8.5. Subsequently, the mean ensemble changes suggest an increase in low flows (89% in February) but a decrease in high flows (37% in June) under all SSP scenarios, more pronounced under the high-end warming scenario of SSP5-8.5. Further, the 30-year return level will decrease for the near-future (2016–2043), mid-future (2044–2071) and far-future (2072–2100) climates under SSP1-2.6, ranging from −7.01% to −9.87%, under SSP3-7.0, ranging from − 7.22% to − 13.35%, and under SSP5-8.5, ranging from − 9.41% to − 26.60% for the ensemble of five models under consideration which imply a reduction in the likelihood or magnitude of extreme river flow events. The outcomes of this study will advance our knowledge of the discharge dynamics of the Jhelum River Basin under climate change, which will facilitate the better management of precious water resources.