Physically, Fully-Distributed Hydrologic Simulations Driven by GPM Satellite Rainfall over an Urbanizing Arid Catchment in Saudi Arabia

Hatim Sharif,Almoutaz Hassan,Muhammad Al-Zahrani

doi:10.3390/w9030163

Abstract

A physically-based, distributed-parameter hydrologic model was used to simulate a recent flood event in the city of Hafr Al Batin, Saudi Arabia to gain a better understanding of the runoff generation and spatial distribution of flooding. The city is located in a very arid catchment. Flooding of the city is influenced by the presence of three major tributaries that join the main channel in and around the heavily urbanized area. The Integrated Multi-satellite Retrievals for Global Precipitation Measurement Mission (IMERG) rainfall product was used due to lack of detailed ground observations. To overcome the heavy computational demand, the catchment was divided into three sub-catchments with a variable model grid resolution. The model was run on three subcatchments separately, without losing hydrologic connectivity among the sub-catchments. Uncalibrated and calibrated satellite products were used producing different estimates of the predicted runoff. The runoff simulations demonstrated that 85% of the flooding was generated in the urbanized portion of the catchments for the simulated flood. Additional model simulations were performed to understand the roles of the unique channel network in the city flooding. The simulations provided insights into the best options for flood mitigation efforts. The variable model grid size approach allowed using physically-based, distributed models—such as the Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model used in this study—on large basins that include urban centers that need to be modeled at very high resolutions.

Highlights

Storm events that result in catastrophic floods are rare but do occur in arid environments, especially in urban centers
Analysis (GSSHA) model used in this study—on large basins that include urban centers that need to be modeled at very high resolutions
The main hydrological simulations of this study were driven by satellite rainfall

Summary

Introduction

Storm events that result in catastrophic floods are rare but do occur in arid environments, especially in urban centers. With increasing population and urbanization, the public susceptibility and economic impact of flooding in these areas will be increasing [1] Since these events do not occur frequently, there may not be enough pressure on decision makers to invest in the development of robust hydrometeorological observing systems or hydrologic/hydraulic flood control structures. The dramatic societal impacts of these events motivate researchers to perform studies aimed at developing science-based recommendations on best approaches to help decision makers address this issue [2]. Such information can lead to solutions that help save lives and resources and provide opportunities to harness floodwaters and turn them into a resource that can benefit the society.

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