Improvements in streamflow predictions occurred because DA decreased streamflow compared to the CTRL run, reducing its positive bias. This situation was observed particularly during the wildfires of 2018 for both basins, but also in 2019, 2020, and the four-year period for PGRB. The overall decrease in positive bias by DA is noticeable in Figure 4, in which the CRTL streamflow (red) appears distinctly larger than the DA streamflow (blue) in years that improvement was observed, except for 2021 in PGRB when CTRL streamflow was higher than DA. The reason for the overall DA decrease in streamflow predictions will be further discussed in section 5.4.3.