Flood hazard mapping and assessment in data-scarce Nyaungdon area, Myanmar.

Zaw Myo Khaing,Zaw Myo Khaing,Zaw Myo Khaing,Kazuhiro Nakamura,Badri Bhakra Shrestha,Takahiro Sayama,Ke Zhang,Ke Zhang,Hisaya Sawano,Guy J-P Schumann

doi:10.1371/journal.pone.0224558

Abstract

Torrential and long-lasting rainfall often causes long-duration floods in flat and lowland areas in data-scarce Nyaungdon Area of Myanmar, imposing large threats to local people and their livelihoods. As historical hydrological observations and surveys on the impact of floods are very limited, flood hazard assessment and mapping are still lacked in this region, making it hard to design and implement effective flood protection measures. This study mainly focuses on evaluating the predicative capability of a 2D coupled hydrology-inundation model, namely the Rainfall-Runoff-Inundation (RRI) model, using ground observations and satellite remote sensing, and applying the RRI model to produce a flood hazard map for hazard assessment in Nyaungdon Area. Topography, land cover, and precipitation are used to drive the RRI model to simulate the spatial extent of flooding. Satellite images from Moderate Resolution Imaging Spectroradiometer (MODIS) and the Phased Array type L-band Synthetic Aperture Radar-2 onboard Advanced Land Observing Satellite-2 (ALOS-2 ALOS-2/PALSAR-2) are used to validate the modeled potential inundation areas. Model validation through comparisons with the streamflow observations and satellite inundation images shows that the RRI model can realistically capture the flow processes (R2 ≥ 0.87; NSE ≥ 0.60) and associated inundated areas (success index ≥ 0.66) of the historical extreme events. The resultant flood hazard map clearly highlights the areas with high levels of risks and provides a valuable tool for the design and implementation of future flood control and mitigation measures.

Highlights

Due to rapid socioeconomic development and associated intensifying anthropogenic activities along with climate changes, losses of human lives and properties resulting from floods are increasing in many Asian countries in recent decades [1,2,3,4]
The modeled streamflow discharges at the Zalun station matches well with the observations indicated by high R2 (0.90) and Nash-Sutcliffe model efficiency coefficient (NSE) (0.85) values (Fig 5a)
The RRI model is generally able to capture the temporal variablity of the streamflow processes (Fig 5a)

Summary

Introduction

Due to rapid socioeconomic development and associated intensifying anthropogenic activities along with climate changes, losses of human lives and properties resulting from floods are increasing in many Asian countries in recent decades [1,2,3,4]. Flood hazard mapping and assessment (http://www.fao.org/soils-portal/soil-survey/soilmaps-and-databases/faounesco-soil-map-of-theworld/en/), and MODIS flood inundation image (http://floodobservatory.colorado.edu/Events/ 2016Myanmar4365/2016Myanmar4365.html)

Objectives

Methods

Results

Conclusion