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The major sea port of Bangladesh is the Chittagong port located on the right bank of Karnafuli river of Bangladesh. This river port is considered as the lifeline of the economic activities of the country due to its increasing trade demand. Many port facilities have been planned to be implemented in future to meet this increasing demand. Due to manm...
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... river , which is the major river of Chittagong, originates from Lushai hills in Mizoram state and flows about 270 km south and southwest through the southeastern part of Bangladesh to reach the Bay of Bengal. During this course this meandering river passes Kaptai hydroelectric power plant, Halda-Karnafuli confluence and several bridges ( Fig. 1). The length of the river from Kaptai Dam to Halda-Karnafui confluence is about 45 km and from Halda-Karnafuli confluence to BN Academy is about 30 km. Karnafuli river is a tidal river having semi-diurnal characteristics. During flood period the flow travels long distance in the upstream direction of Halda river and very near to Kaptai Dam in upper Karnafuli river. This study mainly focuses on the lower part of Karnafuli river spanning from Kalurghat to Khal no-18. Lower Karnafuli river is the most important portion of the whole river due to the vast economic activities. Regular maintenance of this portion of river is necessary to keep it navigable for safe transportation of vessels. Recently capital dredging work at Sadarghat area is running to maintain sufficient draft. Thus the application of a 2D mathematical model to assess the effect of capital dredging at this location is highly envisaged. A 2D model Delft3D has been applied to simulate the hydrodynamic and morphological processes of Karnafuli river. Delft3D consists of different modules such as Flow, MOR, Wave, WAQ. For this study the Flow module is used which is a multidimensional (2D or 3D) hydrodynamic and transport simulation program. This module is capable of calculating unsteady flow and transport phenomena resulting from tidal and meteorological forcing on curvilinear grid. It is also possible to take into consideration some other parameters such as temperature, salinity and different constituents and observe the 2D or 3D distribution of the results. To know and predict the navigability and erosion/deposition pattern it is important to know the hydrodynamic and morphological characteristics of the river which is reflected by its flow velocity, shear stress and sediment transport. Earlier in 1987, Department of Water Resources Engineering (WRE), Bangladesh University of Engineering and Technology (BUET) developed a mathematical model study to assess the 1D hydrodynamics of this river [5]. In 1990, Danish Hydraulic Institute (DHI) Delft3D solves horizontal momentum, continuity and transport equation for hydrodynamic simulation. It solves Navier-Stokes equation for an incompressible fluid. The FLOW manual [6] of Delft3D extensively describes all ...
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Karnafuli is one of the most important rivers of Bangladesh which is playing a vital role in our national economy. The major sea port of Bangladesh is the Chittagong port located on the right bank of Karnafuli River Bangladesh. Karnafuli river port is considered as the lifeline of the economic activities of the country. Therefore it is always neces...
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One of the major sources of fresh water flow in south west region of Bangladesh comes from the river Gorai which takes off from its parent river, the Ganges. Due to implementation of the Farakka Barrage in 1975, the dry season flows in Ganges River started to decline subsequently. As a result, flow through the Gorai started reducing and off-take go...
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... This approach provides a more holistic understanding of the river's behavior and its response to various environmental and anthropogenic factors. The outcomes of this study will contribute to the growing body of knowledge on the Karnafuli River's dynamics, building upon and extending the work of previous researchers such as Alam and Matin (2013) and Roy et al. (2016). The novelty of this study lies in its comprehensive approach to modeling the Karnafuli River's morphodynamics. ...
... To visualize results along cross sections and some locations, five cross sections and two monitoring points were taken covering the whole reach. This comprehensive methodology allows for a detailed investigation of the Karnafuli River's complex dynamics, building upon previous studies (e.g., Alam and Matin 2013;Roy et al. 2016) while leveraging the advanced capabilities of the Delft3D FM Suite for more accurate and flexible modeling. ...
... This study's findings align with and expand upon previous research, offering valuable insights into the river's complex dynamics. The model's calibration and validation, using water level data from Khal-10, demonstrated high performance with coefficient of determination (R 2 ) and coefficient of efficiency (NSE) values close to 1, indicating robust reliability similar to that achieved by Nujhat et al. (2023) and Alam and Matin (2013) in their hydrodynamic study of the same river. The study highlights the river's complex dynamics, influenced by sediment transport and morphological changes, as seen in similar research on other rivers in Bangladesh, such as the Bishkhali River, which experiences significant morphological shifts due to sediment dynamics and tidal influences (Biswas et al. 2024;Sarkar and Rahman 2022). ...
Tidal rivers in coastal regions worldwide face increasing challenges from climate change, urbanization, and maritime development, necessitating advanced understanding of their complex dynamics for sustainable management. This study explores the hydrodynamic and morphological features of Bangladesh’s Karnafuli River using Delft3D FM Suite. A two-dimensional model was developed, calibrated, and validated with high accuracy. The analysis revealed significant tidal influences and seasonal variations in water levels. Velocities ranged from 0.4 to 1.6 m/s, with higher values during wet seasons. Bed shear stress fluctuated between 0.2 N/m² and 5.5 N/m² seasonally. Morphological simulations showed realistic erosion and deposition patterns, with maximum changes of 3 m after one year. The study also examined a jetty's impact, revealing altered velocity patterns and scouring depths of 0.5–1 m nearby. These findings provide critical engineering parameters for the Karnafuli River management. The identified velocity thresholds (1.8 m/s flood, 2.0 m/s ebb) inform safe navigation windows, the quantified bed shear stress variations (1.4–5.5 N/m²) enable prediction of erosion-prone zones. For port development, the demonstrated 25–40% tidal range damping and seasonal velocity variations of 0.2–2.0 m/s are essential for optimizing maritime operations and dredging schedules. These insights contribute to understanding tidal river dynamics and sustainable water resource management in Bangladesh and similar regions.
... Additionally, the Delft3D model has been employed to assess morphological changes and hydrodynamic characteristics, such as flow velocity, water level, and bed shear stress, in rivers like the Jamuna (Laz, 2012) and the Karnafuli (Alam & Matin, 2013), demonstrating the robustness of this tool for conducting morphological assessment studies in major water bodies. In this study images extracted from satellites such as Landsat and Sentinel, along with transect lines generated by DSAS, were used to identify areas prone to erosion and accretion within the Sundarbans. ...
The Sundarbans, a prolific mangrove wetland ecosystem part of the world's largest delta formed by the Ganges, Brahmaputra, and Meghna rivers, contribute immensely to coastal stability and protection. In deltaic mangroves such as the Sundarbans, recurrent erosion and accretion caused by the transportation of unconsolidated sediments by rivers, interact with flow velocity and bed shear to generate continuous morphological dynamics. This study analyzed the bankline migration patterns of the Shibsa and Passur rivers within the Bangladesh portion of the Sundarbans using satellite images and assessed their hydrodynamic behavior by developing a two-dimensional model using Delft3D. This study utilized Landsat and Sentinel images from 2009-2021 to identify critical erosion and deposition zones applying the DSAS tool of ArcGIS. A two-dimensional hydrodynamic model was then developed and calibrated to simulate flow velocity, bed shear stress, and water levels in these critical zones. The model was validated against limited available water level data. Six critical zones were identified, with four erosion-prone and two deposition-prone areas. The model results indicated increased velocities and bed shear stresses in the erosion zones relative to non-critical areas, while the deposition zones experienced reduced velocities and bed shear stresses. The study reveals that the high values of velocity and bed shear stresses are responsible for the morphological changes of erosion, thus emphasizing the significance of close monitoring with remotely sensed images.
... Additionally, the Delft3D model has been employed to assess morphological changes and hydrodynamic characteristics, such as flow velocity, water level, and bed shear stress, in rivers like the Jamuna (Laz, 2012) and the Karnafuli (Alam & Matin, 2013), demonstrating the robustness of this tool for conducting morphological assessment studies in major water bodies. In this study images extracted from satellites such as Landsat and Sentinel, along with transect lines generated by DSAS, were used to identify areas prone to erosion and accretion within the Sundarbans. ...
... The formation of some alluvial plains, such as Char Bakalia and Chandgaon, can be attributed to the change of the Paper ID: CE 0145 river's course from its original western and southwest paths to a new channel located on the left bank (Sarwar et al., 2010). The study area covers about 30 km stretching from Kalurghat as the upstream boundary to Khal 18 as the downstream boundary, representing the lowermost and most significant section of the river (Alam and Matin, 2013). ...
... Consequently, the incorporation of the river's dynamics and flow patterns into management strategies for navigation and flood protection is expected to improve in the future. Several research studies have been carried out on the Karnafuli River in the past (Alam and Matin, 2013;Kabir and Ali, 2017;CPA, Dept. of WRE and Institute of Flood Control and Drainage Research, BUET, 1987;Danish Hydraulic Institute, BUET, Nov. 1990). However, the use of unstructured mesh in Delft3D represents a recent development, and this study aims to enhance understanding of the hydrodynamic properties of the Karnafuli river with greater precision. ...
... In the case of a tidal river such as Karnafuli, the use of discharge data at the upstream boundary creates major challenges since discharge data is not available for tidal rivers. Consequently, a one-dimensional hydrodynamic model was developed using HEC-RAS for the Karnafuli and Halda River network to generate discharge at Kalurghat Point, considering flow coming from Kaptai Dam and the Halda River (Alam and Matin, 2013). For the Flow Flexible Mesh model setup, an unstructured grid was generated using Delft3D-RGFGRID. ...
Karnafuli River is the lifeline to the economic activities of Bangladesh since the main seaport is situated on the river. The hydrological, ecological, and hydrodynamic characteristics of the eastern hilly regions of Bangladesh are also dependent on this river. However, the river is also prone to erosion and sedimentation, which can have positive and negative impacts on the socio-ecological environment. To better understand the behavior of the river, a two-dimensional numerical model was developed using Delft3D FM suite. Delft3D FM software provides D-Flow Flexible Mesh engine for hydrodynamical simulations on unstructured grids. In this study, an approximate 30-kilometer section of the river spanning from Kalurghat to Khal 18 was selected as the model boundary. The model was calibrated and validated using available water level data collected from Chittagong Port Authority. The simulation results showed the spatial and temporal variation of water depth along the main channel, which is important for safe navigational movements of ocean-going vessels. In addition, the velocity and bed shear stress distribution were also estimated along the channel. The results could be useful to the port management authority for managing navigational draft and conservation efforts, including dredging, and future structural and non-structural developments along the river banks.
... Situated in the eastern region of Bangladesh, the Karnafuli basin is located between 91°30 ′ E -92°45 ′ E and 21°00 ′ N -23°30 ′ N. Karnafuli river is the largest river in Chittagong, which originated in the Lushai hills in Mizoram, India, and runs 270 km in the southwest before meeting the Bay of Bengal [1] . The upstream portion of the river falls in hilly areas, and a downstream portion is fairly flat towards the southwest until it reaches the Bay of Bengal. ...
This study evaluates the existing situation of the water energy and food resource interaction using an indicator-based approach and optimizes the resource use in the Karnafuli River Basin. A water allocation model based on an optimization tool, LINDO 6.1, with an objective function to maximize the economic return, is developed to allocate water to different water use sectors (domestic, agriculture, energy, industry, and environment) in the basin. It is observed that 14.58 m3 of water is required to generate 1 kWh of energy in Kaptai hydropower plant, while 4500 m3 of water is consumed to produce 1 ton of crops in the basin. Due to improper management, around 12,500 ha of land under the Karnafuli Irrigation Project remains un-irrigated, which can be cultivated with high-yield Boro crop. Results show that by prioritizing the agriculture sector, a maximum economic return of US$ 30.3 million can be obtained; however, with this only 55% of the satisfaction level is achieved for the environment sector. Systematic and integrated management of the resources is required in Karnafuli Basin for socioeconomic and sustainable development.
... Van Rijn (2016, 2012 performed an extensive study on siltation and control measures for different ports around the world, both for brackish and freshwater flow over the bed of finegrained and cohesive sediments. Among the rivers in Bangladesh, Alam and Matin (2013) studied the morphological change of the Karnafuli river due to capital dredging by numerical modeling, and Biswas et al. (2021) performed the morpho-dynamic modeling for the Madhumoti river basin. Plan form shifting of Padma-Meghna and Ganges-Jamuna confluences were studied by Gazi et al. (2020) through geospatial techniques. ...
... He found that the channels have very high siltation rates during the first year (about 1.5-2 m/year), but maintain a relevant siltation rate of 0.5 m/year in the following years. For the Karnafuli River of Bangladesh, a maximum siltation rate of 0.75 m per year with an average value of 0.26 m along the centerline of the river was reported by Alam and Matin (2013). However, in the present study, the annual siltation thickness in Pussur Channel was found to vary from 0.1 to 0.6 m in the Inner bar area, 0.3 m in the Jetty channel, 0.9 m at Jetty front, 0.2 to 0.97 m at Chalna to Digraj area and 0.1-0.5 m in the Outer bar area. ...
Mongla Port is the second gateway of Bangladesh, situated at the bank of the Pussur River some 131 km upstream from the Bay of Bengal. In this study, the available hydrographic survey charts of Pussur River were collected from Mongla Port Authority (MPA) and analyzed to assess the trends of morphological changes at the potential sites. The causes of navigation problems, previous interventions of MPA, dredging history of the river, and effectiveness of dredging was analyzed. It is found that in the upstream portion of the navigation route at the MPA jetty area and its approaches was slightly scour-prone from 2010 to 2013; however, after capital dredging in 2014, the channel was found highly siltation-prone, having a rate of 0.1 to 0.6 m/year between 2015 to 2017. Before dredging the channel, the Inner bar area (downstream of Mongla Port) did not show any significant change in the bed topography between 2010 to 2013, however, a high backfilling rate (up to 1.5 m/year) was observed after the capital dredging. The channel was sufficiently deep and quite stable from Joymonirgol to Hiron point. The current navigational channel at the outer bar (at the mouth of the river) is silted by 0.1 to 0.25 m/year. Reduction of upstream flow, numerous shipwrecks at different positions, and human disturbances were identified as the causes behind the navigational problems in the river route.
... Human activities like sand dredging in the navigation channel and harbor, building artificial islands by dredger, and lifting sediment into water in the coastal zones have great impacts on the suspended sediment concentration (SSC) in an aquatic ecosystem [8]. These processes and influences can be described with the help of the numerical model [9][10][11]. At the same time, remote sensing technology, along with in-situ observations, has been widely applied to understand the spatial distribution of suspended sediment and monitor the dredging effects on the SSC at the spatial scale [12][13][14][15][16]. Considering that the numerical model is able to simulate the water flow and sediment transport in any spatial and temporal resolution, and reveal the physical mechanism when remote sensing is applied to monitor water and sediment at a low cost and at a large-scale, it is of great significance to combine the numerical model and remote sensing to study water flow and sediment transport scientifically [17][18][19][20][21]. ...
As the largest freshwater lake in China, Poyang Lake plays an important role in the ecosystem of the Yangtze River watershed. The high suspended sediment concentration (SSC) has been an increasingly significant problem under the influence of extensive sand dredging. In this study, a hydrodynamic model integrated with the two-dimensional sediment transport model was built for Poyang Lake, considering sand dredging activities detected from satellite images. The sediment transport model was set with point sources of sand dredging, and fully calibrated and validated by observed hydrological data and remote sensing results. Simulations under different dredging intensities were implemented to investigate the impacts of the spatiotemporal variation of the SSC. The results indicated that areas significantly affected by sand dredging were located in the north of the lake and along the waterway, with a total affected area of about 730 km², and this was one of the main factors causing high turbidity in the northern part of the lake. The SSC in the northern area increased, showing a spatial pattern in which the SSC varied from high to low from south to north along the main channel, which indicated close agreement with the results captured by remote sensing. In summary, this study quantified the influence of human induced activities on sediment transport for the lake aquatic ecosystem, which could help us to better understand the water quality and manage water resources.
The Baraichari Shale Formation, which is equivalent to the Boka Bil Formation, is well exposed
within the Neogene sequence of the Sitapahar Anticline in the Chittagong-Tripura Fold Belt,
Bengal Basin, Bangladesh. Regardless of its importance in hydrocarbon accumulation, a
comprehensive facies analysis is essential to understand and explain the heterogeneity within
different depositional architectural elements. The purpose of this work is to delineate the lith-
ofacies characteristics, depositional environment heterogeneities and propose a generic deposi-
tional model for the Middle to Late Miocene shallow marine sediments of the formation. The
sedimentary facies were investigated at three outcrops along the Kaptai–Chandraghona road cut
sections of the Sitapahar anticline. The formation is composed of dark to bluish-gray shale, silty
shale, yellowish brown siltstone, and gray to yellowish brown fine-to medium-grained sandstone.
Eight distinct sedimentary facies have been identified and were categorized into three facies
associations: subtidal or estuarine, mixed flats with tidal creeks, and tidal mud flats. The subtidal
facies, predominant in the middle member, consists of fine to medium-grained ripple cross-
stratified sandstone-siltstone, herringbone cross-stratified sandstone, and trough cross-stratified
sandstone, indicating sub-tidal channel deposition. Mixed flats with tidal creeks exhibit hetero-
lithic facies, suggesting energy level changes in intertidal to sub-tidal zones influenced by tidal
currents. Tidal mud flats are predominantly laminated shale/mudstone and lenticular laminated
sandstone-siltstone, reflecting deposition during tide transitions in the intertidal zone. Fining
upward cycles within the formation indicate progressive progradation or changes in inner tidal
flats conditions during regressive periods. These depositional settings serve as analogs for
equivalent subsurface reservoirs and contribute to the construction of reservoir models with
greater accuracy.
The purpose of the research was to integrateally characterize the erosional behavior of the Ganges riverbanks and understand the geological, geotechnical, and hydrological influence on bank erosion. The current study has used multi-temporal Landsat images spanning from 1973–2020 for planform analysis using Geographic Information System (GIS), geological fieldwork data, six standard penetration test (SPT) data, laboratory analysis, and slope stability model using SLIDE to understand geological-geotechnical factors and the influence of seasonal hydrological fluctuations on the bank erosion. GIS-based planform analysis identified the erosion-accretion rate and vulnerable areas for erosion. Results suggest that the intensity of bank erosion is higher at the outer meander bend, and the right bank is more erosion-prone than the left bank. Geological and geotechnical studies suggest that bank material types and their degree of cohesion control bank erosion. In the convex outer bend of the river, the helical flow erodes the non-cohesive sandy materials at the toe of the bank, hence, the upper clayey layer loses its strength and collapses, which is the main cause of the cantilever-type bank failure in this river. Results also suggest that the Factor of Safety (FS) is proportional to the difference between river water level (RWL) and groundwater level (GWL) in the uniformly graded high permeable soil. When the water level gradient shifts from GWL toward RWL, the FS of the bank slope decreases and collapses after reaching its critical point.
River confluence has a great potential of hydrocarbon reservoirs owing to wide and thick channel-fill deposits by widening and deepening effects. The Mesozoic and Cenozoic hydrocarbon-bearing basins in China are internally drainage basins dominated and fluvial deposits are widely regarded as important hydrocarbon. The (semi-) arid regions cover 41% of the global continental areas, and river systems are widely distributed with substantial ecological resources. However, current research on river confluence is mainly focused on humid regions, and research on the channel morphology of river confluence in drylands and their controls has been rarely reported. In this study, we select the confluence (Kalakashen River and Yulongkashen River) of the Hotan River in Tarim Basin as study area. Firstly, the combination of Digital Elevation Model (DEM) and high-resolution Google Earth images were used to identify the bankfull boundaries of all river channels. Subsequently the evolution of river planform in the confluence area was analyzed using hydrological data and time-series remote sensing images. Results show that the confluence of Hotan River is a fixed and“Y”type confluence, and their junctions have different river types: Kalakashen River is meandering while Yulongkashen River is meandering-braided transitional. Cutoffs occurred along these junctions. The confluence is transformed into braided river, and its bankfull width increases by 58% (505 m wider) compared with that of junctions. Furthermore, we select 23 river confluences in typical semi-arid-arid regions (n= 10) and humid regions (n=13) around the world to investigate the changes in bankfull width from junctions to confluences. Results reveal that the increase (>50%) in bankfull widths of river confluence in drylands with (non-) sparse vegetation greatly exceeded that (17%) of river confluence in humid areas with riparian vegetation. Slopes (2%o) of these selected dryland rivers (lack of riparian vegetation) are on average one category higher than those (0.6%o) in humid regions. Therefore, lack of riparian vegetation and high slope of river profiles are the main controls for significant widening in river confluences of dryland regions. Our results not only complement the models of river confluence, but also provide a basis for the further research of sedimentary processes and their sedimentary model in dryland river confluence.
