Urban Flood Simulation in Erbil City by Using Storm Water Management Model (SWMM)

Abstract

One of the worst and most frequent natural disasters is flooding. Due to changes in precipitation patterns brought on by global climate change, flash floods are a threat to most cities. When it rains heavily, infrastructure capacity could be insufficient, and flash floods occur at weak points. This study evaluates the drainage system network capacity of the worst flood risk area using the Storm Water Management Model (SWMM). The study area is around the Council of Ministers, which is divided into 23 sub-catchments, and maximum daily rainfall data was collected from the Erbil Directorate of Meteorology and Seismology. This study analyzed three maximum daily rainfall events in three different decades of rainfall data from 1992–2022 to estimate the likelihood of flooding. The three events associated with maximum daily precipitation were 103.9 mm, 79.0 mm, and 71.8 mm on February 3, 2006, November 21, 1992, and January 28, 2013, respectively, using the Indian Meteorological Department (IMD) method to convert daily rainfall data to hourly rainfall. The dynamic wave routing method is used for flow routing, and the Horton equation is used to measure infiltration. The flood rate amount in the nodes is classified into three stages: moderate flood (0.001 - 0.1 m³/s), high flood (0.1 - 0.5 m³/s), and very high flood (more than 0.5 m³/s). The results showed that the number of flood nodes is (14, 10, and 10) for each of the three events, with (4, 3, and 3) nodes experiencing moderate floods, (5, 6, and 6) nodes experiencing high flood rates, and (5, 1, and 1) nodes experiencing very high flood rates. It is indicated that the drainage system networks in the study area are unable to handle the amount of runoff and are poorly constructed.