Flood Hazard Mapping using Hydraulic Model and GIS: A Case Study in Mandalay City, Myanmar

摘要

This paper presents the use of flood frequency analysis integrating with 1D Hydraulic model (HECRAS)and Geographic Information System (GIS) to prepare flood hazard maps of different return periods inAyeyarwady River at Mandalay City in Myanmar. Gumbel’s distribution was used to calculate the flood peak ofdifferent return periods, namely, 10 years, 20 years, 50 years, and 100 years. The flood peak from frequencyanalysis were input into HEC-RAS model to find the corresponding flood level and extents in the study area.The model results were used in integrating with ArcGIS to generate flood plain maps. Flood depths and extentshave been identified through flood plain maps. Analysis of 100 years return period flood plain map indicatedthat 157.88 km2 with the percentage of 17.54% is likely to be inundated. The predicted flood depth ranges variesfrom greater than 0 to 24 m in the flood plains and on the river. The range between 3 to 5 m were identified inthe urban area of Chanayetharzan, Patheingyi, and Amarapua Townships. The highest inundated area was 85km2 in the Amarapura Township.