The potential use of the SCS-CN method to estimate extreme floods in the West Bank data-scarce catchments

In the West Bank, extreme floods are becoming more frequent. This can be attributed to the expansion of urban areas together with the climate change impacts (the increasing rainfall intensity). This situation worsens given the lack of proper hydraulic infrastructures required to safely dispose of the accumulated floods. Thus, it becomes essential to estimate extreme flood values so as help decision-makers in formulating proper corrective and preventive strategies. This study utilizes the SCS-CN approach to estimate extreme flood values at the different West Bank data-scarce catchments. Maximum annual daily rainfall (MADR) values were used to obtain extreme rainfall daily grids for different selected return periods (10, 25, 50, and 100 years). The GIS was heavily used to apply the SCS-CN method for the entire West Bank catchments. Results show that extreme daily rainfall values are increasing with the increase of the return period. Further, catchments draining into the west (into the Mediterranean Sea) have more extreme daily rainfall values than those draining to the east (into the Dead sea and the Jordan river) and as such, the expected extreme floods in these catchments are high for the selected return periods. Moreover, based on the average expected extreme flood values, a flood hazard map was developed that classifies West Bank catchments into 5 flood hazard zones. By area, about 42% of the total West Bank catchments are under high to very high flood hazard zone. The results of this research can be adapted to realize any administrative strategy changes for cohesive catchment-based extreme flood hazard management and to prioritize flood remedial plans at the different West Bank catchments.