Bank Protection and River Training Along the Braided Brahmaputra–Jamuna River, Bangladesh

Bank Protection Structures along the Brahmaputra-Jamuna River, a Study of Flow Slides

Water ◽

10.3390/w12092588 ◽

2020 ◽

Vol 12 (9) ◽

pp. 2588 ◽

Cited By ~ 1

Author(s):

Maarten van der Wal

Keyword(s):

Slope Failure ◽

Research Question ◽

Failure Mechanisms ◽

Flood Plain ◽

Design Guidelines ◽

Test Facility ◽

Training Structures ◽

Bank Protection ◽

Flow Slides ◽

River Training

The planform of the Brahmaputra-Jamuna River followed its natural path in Bangladesh until the construction of bank protection works started to save Sirajganj from bank erosion since the 1930s. Several so-called hardpoints such as groynes and revetments were constructed in the period 1980–2015 and the Jamuna Multipurpose Bridge was opened in 1998. The Brahmaputra Right Embankment and other projects had saved the western flood plain from inundation during monsoon floods. These river training works experienced severe damage by geotechnical failures, mostly flow slides. A flow slide is an underwater slope failure because of liquefaction or a breaching process in the subsoil or a combination of both. The design of most of these training works did not consider the risk of damage by flow slides. All descriptions of the observed damages show that scour phenomena in the channel close to a river training work are a cause of flow slides, besides pore water outflow. The research question was: how can the design of river training works be improved to reduce the risk of damage by flow slides? The main part of the investigation was focussed on reducing local scour holes near river training works. The most promising results are river training works with gentle bank slopes, permeable groynes, bed protections in dredged trenches with gentle side slopes, and methods to increase locally the bearing capacity of the subsoil. It is recommended to increase the knowledge of the failure mechanisms in the Brahmaputra-Jamuna River by improved monitoring in the field, the setup of a database with descriptions of all observed flow slides and the circumstances in which they occur. In addition to these recommendations, a field test facility is proposed to verify the knowledge of the failure mechanisms in that river. These activities will optimise the design of new river training structures with a very low risk of damages by flow slides and geotechnical instabilities and they will contribute to an improvement of the current design guidelines for river training structures.

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Identification of channel diversion and bank protection techniques for toorsa river

Indonesian Journal of Innovation Studies ◽

10.21070/ijins2020546 ◽

2020 ◽

Vol 9 ◽

Author(s):

Monika Thapa ◽

Nimesh Chhetri ◽

Jigme Yoezer ◽

Leki Tenzin ◽

Narendra Chhetri ◽

...

Keyword(s):

Soil Compaction ◽

Flood Frequency ◽

Flood Frequency Analysis ◽

Sieve Analysis ◽

Sheet Pile ◽

Bank Protection ◽

Arc Gis ◽

River Training ◽

The Stability

This project aims for desigining of flood embankment structures to accommodate both normal flows as well as the highest designed flood for the return period of 100 years form flood frequency analysis. The new channel dimensions are being determined and embankment protection works for the floods are being designed and recommended. Having found steel sheet pile more advantages and safety, the same is recommended for the river training works. The focus of the project was confined to the channel diversion along with proper embankment works. The methodology included the usage of several approaches such as ARC –GIS to obtain catchment area and cross section of the river,and hydraulics analysis was done using HEC-RAS and the slope/W analysis check was done for the stability of the embankment works. The laboratory test such as sieve analysis, bulk density test, specific gravity test was done to determine the classification of the soil, compaction of the soil, to use different parameter for the desigini g works.

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Review on the Field Applications of River Training Structures for River Bank Protection

The Ganga River Basin: A Hydrometeorological Approach - Society of Earth Scientists Series ◽

10.1007/978-3-030-60869-9_8 ◽

2021 ◽

pp. 115-133

Author(s):

Alok Kumar ◽

C. S. P. Ojha

Keyword(s):

River Bank ◽

Training Structures ◽

Bank Protection ◽

River Training

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Performance of alternative methods of bank protection

Canadian Journal of Civil Engineering ◽

10.1139/l92-125 ◽

1992 ◽

Vol 19 (6) ◽

pp. 1049-1061 ◽

Cited By ~ 1

Author(s):

P. F. Doyle

Keyword(s):

Bank Erosion ◽

Alternative Methods ◽

Channel Stability ◽

Severe Attack ◽

Gravel Bed ◽

Training Structures ◽

Bank Protection ◽

River Training ◽

Riprap Protection ◽

Large Floods

The durability of several common bank protection methods used as less expensive or environmentally acceptable alternatives to toe-trenched angular rock riprap has been documented during the 1980s at seven typical bank erosion sites in British Columbia. Since the sites were uncontrolled examples of actual river training works in operation, natural events hindered a precise comparison of each scheme with toe-trenched angular rock riprap protection. However, of the four alternatives investigated – gravel dykes, tree revetments, riprap with toe apron, and semi-round riprap – all but semi-round riprap performed less than satisfactorily over the years of observation. Documentation of performance is sufficient to conclude that on steep gravel-bed rivers, gravel dykes do not endure; tree revetments require constant maintenance and will not endure large floods, unless extremely well-constructed; toe aprons are not as reliable as toe trenches for the same volume of rock; and well-placed, large semi-round rock performs well under moderately severe attack. Key words: erosion, bank protection, channel stability, river training structures, gravel-bed.

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Experimental Study on Backflow Patterns Induced by a Bilateral Groin Pair with Different Spacing

Applied Sciences ◽

10.3390/app11041486 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1486

Author(s):

Cuiping Kuang ◽

Yuhua Zheng ◽

Jie Gu ◽

Qingping Zou ◽

Xuejian Han

Keyword(s):

Cross Sections ◽

Large Scale ◽

Recirculation Zone ◽

Flow Direction ◽

Wake Flow ◽

Zone Length ◽

Array Configuration ◽

Contraction Ratio ◽

River Training ◽

Spanwise Velocity

Groins are one of the popular manmade structures to modify the hydraulic flow and sediment response in river training. The spacing between groins is a critical consideration to balance the channel-depth and the cost of construction, which is generally determined by the backflow formed downstream from groins. A series of experiments were conducted using Particle Image Velocimetry (PIV) to observe the influence of groin spacing on the backflow pattern of two bilateral groins. The spacing between groins has significant effect on the behavior of the large-scale recirculation cell behind groins. The magnitude of the wake flow induced by a groin was similar to that induced by another groin on the other side, but the flow direction is opposite. The spanwise velocity near the groin tip dictates the recirculation zone width behind the groins due to the strong links between the spanwise velocity and the contraction ratio of channel cross-sections between groins. Based on previous studies and present experimental results, quantitative empirical relationships are proposed to calculate the recirculation zone length behind groins alternately placed at different spacing along riverbanks. This study provides better understanding and a robust formula to assess the backflow extent of alternate groins and identify the optimum groins array configuration.

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Stream-barb installations for narrow channel bends — a laboratory study

Canadian Journal of Civil Engineering ◽

10.1139/l04-017 ◽

2004 ◽

Vol 31 (3) ◽

pp. 478-486 ◽

Cited By ~ 14

Author(s):

Troy Matsuura ◽

Ronald Townsend

Keyword(s):

Laboratory Study ◽

Phase 1 ◽

Rectangular Channel ◽

Field Tests ◽

Narrow Channel ◽

Secondary Currents ◽

Stream Bank ◽

Low Profile ◽

Bank Protection ◽

Bed Scour

Phase 1 of an ongoing laboratory study of a novel form of stream-bank protection structure is described. "Barbs" are dike-like stone structures designed to protect the (usually unstable) outside-bank regions of channel bends. These low-profile structures point upstream into the flow and typically extend to about 1/4-way across the channel. By disrupting near-bank velocity gradients they promote sediment deposition along the eroding outside-bank region. Their presence also modifies the "helicoidal"-type flow pattern of the bend such that secondary currents, which would otherwise attack the outside-bank, are redirected towards the center of the channel. This novel form of bank protection structure is currently undergoing field tests on selected bends on a number of shallow "wide" streams in Illinois, USA. While initial results are encouraging, additional studies are necessary to develop design criteria for their wider application. In phase 1 of this study, the effectiveness of different arrangements of barb groups, in both 90° and 135° moveable-bed bend sections of a hydraulically "narrow" rectangular channel, are investigated. For each hydraulic condition considered, the channel-bed scour profiles generated by the different barb groups are compared to corresponding "reference" profiles generated in the absence of barbs. Judging the effectiveness of the different barb groups in promoting long-term stability of the outside-bank region is based on two criteria: (i) percent reduction achieved in scouring in the vicinity of the outside-bank and (ii) degree to which the channel thalweg (deepest portion) is moved from the outside-bank region towards the center of the channel.Key words: barb, channel bends, local scouring, bank erosion, bank protection, secondary currents.

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