High-resolution gridded streamflow data for Ganges-Brahmaputra-Meghna River Basins in Bangladesh (1951-2023).

A 9-km daily gridded streamflow dataset is generated using the Variable Infiltration Capacity-River Routing Model (VIC-RRM) across the Ganges-Brahmaputra-Meghna River basins over 1951-2023, forced by the ERA5-Land reanalysis data for naturalized streamflow. Physically consistent streamflow forecast data is also generated forced by the ECMWF S2S forecasts. The performance of the dataset is evaluated using observed streamflow data from three gauge stations in Bangladesh along the streams of Ganges, Brahmaputra, and Meghna Rivers, calculating the modified Kling-Gupta Efficiency (mKGE) metric for the 365-day climatology. For Ganges, Brahmaputra, and Meghna Rivers, the mKGE values of reconstructed streamflow data are 0.50, 0.75, and 0.25, respectively. Comparing with the reconstructed streamflow data, the streamflow forecasts show a good agreement with mKGE values of 1.00, 0.97, and 0.91 at three gauge stations, respectively. This dataset provides physically consistent reconstructed and forecasted streamflow data at high resolution, offering a valuable resource for the assessment of climate variability and change and the development of river basin-specific water management strategies in the Ganges-Brahmaputra-Meghna Rivers in Bangladesh.