Flood Mapping and Flood Dynamics of the Mekong Delta

ISSN 2072-4292

Flood Mapping and Flood Dynamics of the Mekong Delta:

ENVISAT-ASAR-WSM Based Time Series Analyses

Claudia Kuenzer 1,*, Huadong Guo 2, Juliane Huth 1, Patrick Leinenkugel 1, Xinwu Li 2

and Stefan Dech 1

1 German Remote Sensing Data Center, DFD, German Earth Observation Center (EOC), German

Aerospace Center (DLR), Oberpfaffenhofen, D-82234 Wessling, Germany;

E-Mails: juliane.huth@dlr.de (J.H.); patrick.leinenkugel@dlr.de (P.L.); Stefan.dech@dlr.de (S.D.)

2 Center for Earth Observation & Digital Earth (CEODE), Chinese Academy of Science,

Beijing 100094, China; E-Mails: hdguo@ceode.ac.cn (H.D.G.); xwli@ceode.ac.cn (X.W.L.)

* Author to whom correspondence should be addressed; E-Mail: claudia.kuenzer@dlr.de;

Tel.: +49-8153-28-3280; Fax: +49-8153-28-1458.

Received: 20 November 2012; in revised form: 1 February 2013 / Accepted: 1 February 2013 /

Published: 5 February 2013

Abstract: Satellite remote sensing is a valuable tool for monitoring flooding. Microwave

sensors are especially appropriate instruments, as they allow the differentiation of

inundated from non-inundated areas, regardless of levels of solar illumination or frequency

of cloud cover in regions experiencing substantial rainy seasons. In the current study we

present the longest synthetic aperture radar-based time series of flood and inundation

information derived for the Mekong Delta that has been analyzed for this region so far. We

employed overall 60 Envisat ASAR Wide Swath Mode data sets at a spatial resolution of

150 meters acquired during the years 2007–2011 to facilitate a thorough understanding of

the flood regime in the Mekong Delta. The Mekong Delta in southern Vietnam comprises

13 provinces and is home to 18 million inhabitants. Extreme dry seasons from late

December to May and wet seasons from June to December characterize people’s rural life.

In this study, we show which areas of the delta are frequently affected by floods and which

regions remain dry all year round. Furthermore, we present which areas are flooded at

which frequency and elucidate the patterns of flood progression over the course of the rainy

season. In this context, we also examine the impact of dykes on floodwater emergence and

assess the relationship between retrieved flood occurrence patterns and land use. In addition,

the advantages and shortcomings of ENVISAT ASAR-WSM based flood mapping are

discussed. The results contribute to a comprehensive understanding of Mekong Delta flood

dynamics in an environment where the flow regime is influenced by the Mekong River,

overland water-flow, anthropogenic floodwater control, as well as the tides.

Keywords: flood; flood dynamics; flood progression; water detection; inundation; radar;

Envisat; ASAR; WSM; feature extraction; time series; Mekong Delta; Vietnam

City of Water