Channel braiding and stability of the Brahmaputra River, Bangladesh, since 1967: GIS and remote sensing analyses

Takagi, Tetsuya; Oguchi, Takashi; Matsumoto, Jun; Grossman, Michael; Sarker, Maminul Haque; Matin, Mir A.

doi:10.1016/j.geomorph.2006.03.028

Cited by 81 publications

(66 citation statements)

References 42 publications

(44 reference statements)

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“…Moreover, remote sensing from satellites can capture recurrent images and have multi-spectral sensors, becoming a powerful tool to monitor changes on the earth's surface over a large area. Satellite images can couple with GIS tools to analyze changes in braid index and channel width [10] or apply supervised/unsupervised classification to monitor channel numbers and bar changes [11,12].…”

Section: Introductionmentioning

confidence: 99%

Channel Planform Dynamics Monitoring and Channel Stability Assessment in Two Sediment-Rich Rivers in Taiwan

Chen

Yang

et al. 2017

Water

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Recurrent flood events induced by typhoons are powerful agents to modify channel morphology in Taiwan's rivers. Frequent channel migrations reflect highly sensitive valley floors and increase the risk to infrastructure and residents along rivers. Therefore, monitoring channel planforms is essential for analyzing channel stability as well as improving river management. This study analyzed annual channel changes along two sediment-rich rivers, the Zhuoshui River and the Gaoping River, from 2008 to 2015 based on satellite images of FORMOSAT-2. Channel areas were digitized from mid-catchment to river mouth (~90 km). Channel stability for reaches was assessed through analyzing the changes of river indices including braid index, active channel width, and channel activity. In general, the valley width plays a key role in braided degree, active channel width, and channel activity. These indices increase as the valley width expands whereas the braid index decreases slightly close to the river mouth due to the change of river types. This downstream pattern in the Zhuoshui River was interrupted by hydraulic construction which resulted in limited changes downstream from the weir, due to the lack of water and sediment supply. A 200-year flood, Typhoon Morakot in 2009, induced significant changes in the two rivers. The highly active landscape in Taiwan results in very sensitive channels compared to other regions. An integrated Sensitivity Index was proposed for identifying unstable reaches, which could be a useful reference for river authorities when making priorities in river regulation strategy. This study shows that satellite image monitoring coupled with river indices analysis could be an effective tool to evaluate spatial and temporal changes in channel stability in highly dynamic river systems.

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Section: Introductionmentioning

confidence: 99%

Channel Planform Dynamics Monitoring and Channel Stability Assessment in Two Sediment-Rich Rivers in Taiwan

Chen

Yang

et al. 2017

Water

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“…Takagi et.al. [11] analyzed the spatial and temporal changes in the channels of Brahmaputra. Sarker et.al.…”

Section: Introductionmentioning

confidence: 99%

Analysis on River Bank Erosion-Accretion and Bar Dynamics Using Multi-Temporal Satellite Images

Rahman¹,

Yunus²

2017

AJWR

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Dudhkumar River flows from upstream of India Border at Bhurungamari to the confluence with Brahmaputra River at Noonkhawa of Kurigram district having a stretch of 64 km in Bangladesh. Due to onrush of water from upstream in monsoon, erosion in Dudhkumar River takes a serious turn, threatening collapse of Sonahat Bridge in Bhurungamari, embankment on its right bank, dykes and several dwelling houses in recent years establishing the river as a destructive one. Thus study aiming at computing the long and short term bank line shifting along the river is of great significance. In this study, images of Landsat MSS and TM acquired from the year 1973 to 2015 have been used to investigate the riverbank migration pattern, accretion-erosion, rate of change of width, sinuosity and island dynamics of Dudhkumar River. For the short term analysis, migration rates are calculated from one Landsat image to the next. For long term analysis, the migration rates are calculated based on the difference between the 1973 image as the reference and subsequent images. From the short-term analysis, the mean erosion and accretion rate have been estimated as 128 m/y and 194 m/y on the left bank, and 141 and 176 m/y on the right bank indicating the accretion rate as greater than the erosion rate. Erosion rate has been found as greater in right bank rather than left bank and accretion rate is much more in left bank than the right bank. Due to high discharge, maximum erosion and accretion have been found as 349 m/y and 410 m/y respectively at left bank in 2013-2015 indicating the bank protection measures vulnerable. Computations on sinuosity of the river Dudhkumar River show that the sinuosity ranges from 1.36 to 1.53 showing significant increase in year 1989, 1997 and 2011 due to active erosion and deposition induced by monsoon flood. Analyses on island dynamics reveal that the island area started increasing after 1973 and maximum island area found in 2001. The analysis divulged that the Dudhkumar River is a highly meandering river with several critical sections where the river has been suffering enormously with erosion problem and shifting.The present study also identifies steadfast evidence on the dynamic fluvio-geomorphology of Dudhkumar River depicting urge for execution of erosion control schemes.

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“…Alternatively, it develops toward meandering when the sediment supply equals approximately the sediment-carrying capacity of the flow. River channel changes, such as downcutting and aggradation in channel bed (e.g., Moshe et al 2008;Zahar et al 2008), erosion and accretion at channel banks (e.g., Takagi et al 2007;Kummu et al 2008;Baki and Gan 2012), and transformations of channel patterns (Wang and Li 2011), are natural processes for an alluvial river (e.g., Kummu et al 2008;. Numerous studies have indicated that channel change for different rivers, or for different river patterns in a river, can be induced by diverse driving factors.…”

Section: Introductionmentioning

confidence: 99%

Spatial and temporal variations of channel lateral migration rates in the Inner Mongolian reach of the upper Yellow River

Ran

Yan

2016

Environ Earth Sci

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Channel variations of the Inner Mongolian reach in the upper Yellow River are very complicated because of diversity of channel patterns, intense changes in water and sediment, and enhanced human activities in the last decades. It is important to examine the channel migration rates in this river reach. Based on channel planform changes at 236 digital channel cross-sections, the present study estimated the channel migration rates in terms of mid-channel line shift at the digital channel cross-sections during the periods 1975-1990, 1990-2000, 2000-2006, 2006-2010, and 2010-2011. The results show that the average channel migration rate for the whole river reach is 5.0, 7.9, -5.9, 8.6, and -1.0 m -1 in the five different periods, respectively. In both directions to the right and to the left, the highest channel migration rate was always observed in the meandering channels, while the lowest channel migration rate was in the whole Inner Mongolian reach except the Sanhuhekou-Zhaojunfen (S-Z) sub-reach. The temporal variation of channel migration rate was mainly controlled by changing sediment concentration in river flow, while the spatial variation along the straight, braided, and meandering channel reaches was largely affected by material differences of channel banks as reflected by different channel patterns. With the highest average lateral migration rate to the left bank, the meandering channel reach is extremely vulnerable to lateral migration and needs to be protected with engineering practices, because a large population and wide farmland are located on its left floodplain.

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Channel braiding and stability of the Brahmaputra River, Bangladesh, since 1967: GIS and remote sensing analyses

Cited by 81 publications

References 42 publications

Channel Planform Dynamics Monitoring and Channel Stability Assessment in Two Sediment-Rich Rivers in Taiwan

Channel Planform Dynamics Monitoring and Channel Stability Assessment in Two Sediment-Rich Rivers in Taiwan

Analysis on River Bank Erosion-Accretion and Bar Dynamics Using Multi-Temporal Satellite Images

Spatial and temporal variations of channel lateral migration rates in the Inner Mongolian reach of the upper Yellow River

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