Flood is more likely in areas with a bigger TWI (Mojaddadi et al. 2017). Lower TWI zones, on the other hand, are less vulnerable to flooding (Figure 3 (l)). The higher value was assigned for the higher TWI and the lower value was assigned for the lower TWI, respectively. As a result, the downstream of the Bilate catchment has the highest TWI and has a larger probability of flooding than the upstream of the catchment, which has the lowest TWI and has a lower probability of flooding. The lowest TWI covers an area of 265.9 km² (4.7%) in class between 6.8 and 8.3 whereas the highest TWI cover an area of 2,077.2 km² (36.9%) in class between 12 and 14, respectively (Table 14).