Fig. 1. Locations of the Huaihe River Basin, selected hydrological stations, dams and sluices

Fig. 2. Hierarchical clustering results presented by black, red, yellow, blue and green colors for all the flood events named by station name+ event sequence which is sorted in chronological order (e.g., ZiLS01 means the first event at ZiL station)

Fig. 3. Classification performance assessment using the Goodman-Kruskal index (GKI), C index (CI) and minimum cluster for different total class numbers

Fig. 4. Normalized flood hydrographs of individual flood event classes (a-e) and their frequencies of flood events in the pre-flood, flood and post-flood seasons

Fig. 5. Variations of individual flood behavior metrics among different classes. Median values are defined by the solid dot symbols, respectively. Each black box illustrates the 25th and 75th percentile values, and the vertical line defines the minimum and maximum values without outliers. The white dot means the 50th percentile value and the violin shape means the frequency distribution of flood behavior metric.

Fig. 6. Spatial variations of different flood event classes

Fig. 7. Interannual distributions of flood event classes from 2006 to 2015 in the Shaying River, Hongru River, Southern mountainous rivers, Huaihe mainstream and for all the flood events

Fig. 8. Correlation coefficients between impact factors and flood behavior metrics (the blank column means insignificant impact factor)

Fig. 9. Contributions of impact categories and their combinations on the regional and interannual variations of individual flood event classes