The study looked at how changes in riverbeds affect flooding in the Pearl River Delta from 1999 to 2008. By using a mathematical model, researchers found that the riverbeds getting deeper helped the area handle floods better. Water levels during a big flood in 2008 were lower than before, with the biggest drop at Makou station. Tides got stronger, moving the tidal limit further up the river. The Xijiang river network saw more changes than the Beijiang network. This uneven deepening of riverbeds led to more water being diverted during floods, reducing flood risk in the area.