The 24th IAHR-APD Congress (24th IAHR-APD Congress)

54 / 2023-12-25 16:31:49

Evaluating Climate Change Impact on Hydrology under CMIP6 Climate Scenarios for the Old Brahmaputra River Basin, Bangladesh

Climate Change,CMIP6,SWAT,Streamflow,Bangladesh,trend analysis

Climate change poses unique challenges to hydrological systems, necessitating a particular examination of its impact on water resources. This study focuses on the Old Brahmaputra River Basin in Bangladesh, employing data from five prominent climatic models (GFDL.CM4, GFDL.ESM4, MIROC6, MPI.ESM1.2.HR, and MPI.ESM1.2.LR) sourced from the CMIP6 dataset. The Soil and Water Assessment Tool (SWAT) model is utilized to assess future streamflow trends, shedding light on the interactions between climate variables and hydrological processes. The analysis reveals that despite a positive trend, estimated streamflow does not exhibit a significant increase in either the near or far future across all five climatic models. This challenges conventional expectations, prompting a reevaluation of assumptions about the hydrological response to climate change. Notably, simulations under the high radiative forcing scenario, ssp585, indicate a two times more significant increase in streamflow for two models compared to the lower radiative forcing scenario, ssp245. This underscores the sensitivity of streamflow patterns to emission scenarios. Precipitation trends in the Old Brahmaputra River Basin show a lack of significant increase in the near or far future, raising questions about the resilience of water resources. In contrast, both maximum and minimum temperatures exhibit a substantial and consistent rise across all models, particularly in the near future. The influence of ssp585 is evident in higher temperatures compared to ssp245, emphasizing the critical role of emission scenarios in shaping future climate conditions. This study contributes to the understanding of climate-induced hydrological changes in the Old Brahmaputra River Basin. The observed streamflow trends, coupled with temperature and precipitation dynamics, carry significant implications for water resource management, agriculture, and ecosystem sustainability. The absence of a clear upward trend in streamflow despite positive trends underscores the complexity of hydrological responses to climate change. This study contributes valuable insights to the broader discourse on climate change impacts, urging policymakers and stakeholders to consider the intricate relationships between climate scenarios and hydrological responses for effective long-term planning and sustainable water resource management in the Old Brahmaputra River Basin, Bangladesh.