Estimation of flash flood in urban area of Dubai using Hydrologic Modeling System (HEC-HMS)

Dubai is categorized as an arid region, and over the years with the increase of population, the built-up area is also increasing. Due to the specific type of dry climate, rainfall is very scarce. The rainfall event mainly occurs between January and March and intensity of these rainfall is so high that it causes floods. Flooding is the most devastating types of hydrological events which are triggered by excess precipitation. The objective of this study was to estimate runoff as a result of March 2016 rainfall in Dubai. The precipitation from Global Precipitation Measurement (GPM) was studied using HEC-HMS. DEM was used to delineate subbains for Dubai. SCS Curve Number was used as a loss method in the HEC-HMS. Since the subbains differs in their land use characteristics, therefore weighted curve number was calculated for each subbasin. The land use type was obtained from LULC map. The results showed that highest flooding of 2802 m3 in subbasin 3 which is largest subbasin having an area of 330 km2. The results also depicted that subbasin having larger area produce highest runoff. These results were validated with Rational Method and previous studies. The comparison of peak discharge from HEC-HMS with Rational Method showed R2 of 0.88. The peak discharge was also consistent with previous studies of UAE and Egypt. Since there are no active flow gauges in Dubai, these studies are important for stakeholders in their decision making for future development projects.