Extent and Evaluation of Factors Causing Flash Floods in Watalai Khwar, District Bajaur, Pakistan

Abstract

This study was designed to identify the potential causes of flash floods in the Watalai watershed District of Bajaur, Khyber Pakhtunkhwa, Pakistan. The study used both primary and secondary data to achieve the study's main objectives. The five most frequently flood-affected villages were selected for the data collection. To investigate the anthropogenic causes of flash floods 310 carefully designed questionnaires were filled by the representatives of different sections of the local community. The study finds that in the opinion of 33% of the respondents’ intense rainfall in the watershed mainly causes flash floods in the area. Similarly6% of the investigated people claim that flash floods in the area are due to heavy thunderstorms in the spring and summer seasons. About 33% of the inquired community is of the view that human encroachment and unplanned infrastructure are the main causes of flash floods in the Watalai floodplain. Likewise, 8% of the sample population reveals that flash floods are caused in the area due to an increase in population. However, in addition to the responses regarding the causes of flash floods from the community, other factors like the piped culverts and low height bridges are also causes of flash floods in the study area. The analysis of the study area's spatial images shows that the water channel's sharp angles, the low permeable mountainous region, steep slopes and the deposition of sediment load were the reason for high flow and flash floods.