Flood analysis using HEC-RAS model: a case study for Hafr Al-Batin, Saudi Arabia

Abstract

Hafr Al-Batin is a Saudi Arabian city located in the northeastern part of the kingdom. The city lies in the dry valley of Wadi Al-Batin, part of Wadi Al-Rummah, which leads inland towards Medina and formerly emptied into the Arabian Gulf. Hafr Al-Batin is located in an area where three valleys meet, which makes the city under high risk of flooding, especially when intense rain occurs during short duration as in the case of arid and semi-arid regions. The yearly average rainfall intensity of Hafr Al-Baten is estimated to be 125 mm. Recently, extreme rainfall events occurred, generating flood water to flow from all valleys towards the city, causing serious damage to public and private properties. In this study, HEC-HMS and HEC-RAS models are used to simulate flood occurrence in the city. The results indicate that the average flow depths within the part of the main channel passing through Hafr Al-Batin city were 3.02 m, 3.26 m, 3.45 m, 3.76 m, 4.04 m and 4.34 m for the simulated 2, 5, 10, 25, 50 and 100-year design floods, respectively. Flood hazard maps are also generated to identify the areas within the city with high risk of flooding.