Flood probability analysis for different return periods in District Peshawar, Pakistan

Floods are the most destructive among all hazards across the globe. Research revealed that there is a marked increase in frequency and intensity of floods. Therefore, it is important to assess flood risk and reduce its probability and negative consequences. Assessment of flood probability helps to identify those areas which are very likely to be flooded in future. The current study attempts to assess the probability of floods by studying the causes, nature and intensifying factors in district Peshawar. In order to achieve the desired objectives, primary data regarding flood hazard were collected in a questionnaire survey, field observation and interviews of the relevant community and departments. Whereas secondary data were taken from Satellite images, irrigation department and Pakistan Meteorological Department. Flood hazard probability was determined for different return periods by developing flood scenarios. The Flood-2008 in the study area was considered as a landmark event for these scenarios. For visual interpretation, four different return periods of 5, 10, 50 and 100 years were mapped. Fast expansion in the built-up areas and other developmental works, violation of landuse planning and presence of bottlenecks (flood intensifying conditions) were found as main causative factors for the probability of flood hazard in the area under investigation. On the basis of findings from this study, it is recommended to build check dams or reservoirs in the upstream area, and a proper flood forecasting and warning system must be established. Furthermore, it is also recommended to implement the landuse planning regulations in the flood plain, in order to reduce the probability of flood.