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On the environmental controls of Bangladesh river systems

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... The Jamuna River has developed in a region of significant tectonic activity associated with Himalayan uplift and development of the Bengal foredeep (Alam et al. 1990;Barua 1994;Goodbred, Jr., et al. 2003;Singh 2007;Brammer 2012;Steckler et al. 2016), and the underlying structural control on the location of the major river systems of Bangladesh has long been debated (Morgan and McIntire 1959;Umitsu 1993;Barua 1994;Reitz et al. 2015;Grimaud et al. 2019). Steckler et al. (2016) show how subduction is still active in the region, with c. 13-17 mm yr −1 of plate convergence on an active, shallowly dipping and locked megathrust fault. ...
... The Jamuna River has developed in a region of significant tectonic activity associated with Himalayan uplift and development of the Bengal foredeep (Alam et al. 1990;Barua 1994;Goodbred, Jr., et al. 2003;Singh 2007;Brammer 2012;Steckler et al. 2016), and the underlying structural control on the location of the major river systems of Bangladesh has long been debated (Morgan and McIntire 1959;Umitsu 1993;Barua 1994;Reitz et al. 2015;Grimaud et al. 2019). Steckler et al. (2016) show how subduction is still active in the region, with c. 13-17 mm yr −1 of plate convergence on an active, shallowly dipping and locked megathrust fault. ...
... The control of uplift and subsidence is, however, clear and Allison (1998), in a review of the geologic and environmental framework of the Ganges-Brahmaputra Delta, highlights the uplifted Pleistocene terraces of the Barind and Madhupur tracts (Figure 20.1) as being first-order controls on the courses of the Jamuna and Ganga Rivers. Barua (1994) also presents a synthesis of the major environmental controls on Bangladesh's river systems and, together with the major controlling factors of regional tectonics, geology, climate, sea-level rise and vegetation, highlights the controls by the 'fluvial loading' that is dictated by water and sediment discharge and sediment calibre. Grimaud et al. (2019) contend that Late Quaternary sediment dynamics indicate subsidence and sediment infilling of c. 0.8-2 mm yr −1 in the Teesta River megafan area at the foot of the Himalayas, and uplift and erosion in the Barind Tract region at rates of c. 0.03-0.11 ...
Chapter
Bangladesh is dominated by three great rivers – the Jamuna–Brahmaputra, Ganga, and Meghna – that combine to feed sediment into one of the World's largest deltas in the Bay of Bengal. The Jamuna River has developed in a region of significant tectonic activity associated with Himalayan uplift and development of the Bengal foredeep. The bedload, although only ~10% of the total sediment load, is critical in generating a wide array of bedforms of different scale that drive channel change and migration. Within the Jamuna River, the ubiquitous occurrence of bifurcations and confluences is a key aspect of the river channel pattern and dynamics, and these features form important nodes in the braidbelt. The nature of floodplain sedimentation and inundation is vital in planning annual crop growth and may adopt great significance in the ongoing debate on the sources, causes, and accumulation of arsenic in the groundwaters of Bangladesh.
... The Jamuna River has developed in a region of signifi cant tectonic activity associated with Himalayan uplift and development of the Bengal foredeep (Alam et al., 1990;Barua, 1994;Goodbred et al., 2003), and the underlying structural control on the location of the major river systems of Bangladesh has been hypothesized by several researchers (Morgan and McIntire, 1959;Umitsu, 1993;Barua, 1994). Morgan and McIntire (1959) suggested there is a zone of 'structural weakness' along the present course of the Ganga-Jamuna-Padma Rivers due to either a subsiding trough or a fault at depth. ...
... The Jamuna River has developed in a region of signifi cant tectonic activity associated with Himalayan uplift and development of the Bengal foredeep (Alam et al., 1990;Barua, 1994;Goodbred et al., 2003), and the underlying structural control on the location of the major river systems of Bangladesh has been hypothesized by several researchers (Morgan and McIntire, 1959;Umitsu, 1993;Barua, 1994). Morgan and McIntire (1959) suggested there is a zone of 'structural weakness' along the present course of the Ganga-Jamuna-Padma Rivers due to either a subsiding trough or a fault at depth. ...
... The control of uplift and subsidence is, however, clear and Allison (1998), in a review of the geologic and environmental framework of the Ganga-Brahmaputra Delta, highlights the uplifted Pleistocene terraces of the Barind and Madhupur tracts (Figure 19.1) as being fi rst-order controls on the courses of the Jamuna and Ganga Rivers. Barua (1994) also presents a synthesis of the major environmental controls on Bangladesh's river systems and, together with the major controlling factors of regional tectonics, geology, climate, sea-level rise and vegetation, highlights the controls by the 'fl uvial loading' that is dictated by water and sediment discharge and sediment calibre. The nature of sea-level rise, together with other anthropogenic effects on Bangladesh's rivers such as fl ood control and water usage, will clearly take on great importance in the twenty-fi rst century (Begum and Fleming, 1997a,b;Choudhury et al., 1997;Mirza et al., 2001;Mirza, 2002). ...
Chapter
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Background Channel Scale Morphology and Historical Changes in the Course of the Brahmaputra-Jamuna RiverBedform Types and DynamicsBifurcations, Offtakes and ConfluencesFloodplain SedimentationSedimentology of the Jamuna RiverApplied Geomorphology and Engineering in the Jamuna RiverSummaryAcknowledgementsReferences
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Article
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River systems plays a crucial role in riverine countries like Bangladesh. We depend on rivers for various needs including agriculture, shipping, fisheries, environment and climate. The normal flow of a river change over time due to various reasons. For instance, due to siltation, the water carrying capacity and plan view of a river changes. For this reason, a clear understanding of the hydrological characteristics of a river is essential. Hydrological characteristics of a river mainly include three aspects: a) water level and discharge b) amount of sediment and c) sediment size. The present study analyzed only monthly, seasonally and annual water level and discharge at the Ganga-Jamuna River confluence at Aricha and second station at Baruria of the upstream of the Jamuna river. For this purpose, the water level and discharge data of the last 42 years (1980-2022) of two stations (Aricha and Baruria) were collected from Bangladesh Water Development Board (BWDB). Descriptive statistics have been used to analyze the data. The result reveals that the annual maximum, minimum and average water levels of Aricha station are 5.91, 4.95 and 5.45 meters respectively. On the other hand, the annual maximum, minimum and average water levels at Baruria (Jamuna) station are 5.12, 4.14 and 4.60 meters respectively. From monthly water level results, maximum water level exists in July and minimum in February at the both stations. Aricha station has an average water level of 8.09 meter during monsoon (July-September) and a minimum of 3.18 meter during dry season (December-February) i.e., the seasonal difference 4.91 meter. On the other hand, Baruria station has a maximum water level of 7.09 meter in monsoon, and a minimum of 2.42 meter in dry season i.e., the seasonal difference 4.62 meter. The water level and water discharge at both stations are seasonal which is a reflection of the basin scale water availability. The annual maximum, minimum and average of discharge at Baruria station are 60625.57, 15359.63 and 30535.52 m 3 /s respectively. Most of the water level and discharge in Aricha comes from the Jamuna. Out of 42 years of annual water level data at Aricha station, 18 years had below average levels and 24 years had above average levels. At Baruria station, 23 years were below average and 19 years were above average. Water conservation management initiatives can be taken both at the local and basin scale to reduce seasonal water level and flow variations of the rivers of Bangladesh.
... Amongst these defined four segments, the first three coastline section is a low lying, swampy, rapidly changing alluvial basin with large inputs of sediments deposited by the two vast river systems namely Ganges and Brahmaputra (Snead, 2010). The estimated annual sediment load from Brahmaputra is about 1028 t Km À 2 while the discharge from Ganges is about 502 t Km À 2 although the basin area is almost two times large compared to that of Brahmaputra (Barua, 1994). ...
Article
In a geomorphic sense, the Bangladesh located in the head Bay region comprises of numerous tidal creeks, waterway inlets, and complex coastline geometry. This region encompassing the world's largest deltaic system is thickly populated and extremely low-lying, and therefore highly susceptible to coastal flooding and sea level rise. High tidal range existent in this region primarily governs the hydrodynamic behavior and coastal processes. The present study deals on a comprehensive tidal analysis, understanding the variations in tidal behavior over spatial and temporal scales in the near-shore region off Bangladesh. The harmonic tidal analysis using SLPR2 estimates the tidal constituents using linear least squares with respective nodal correction. Tide gauge observations from five different stations viz; Hiron Point, Khepupara, Charchanga, Khal No-10, and Cox's Bazaar were used for tidal analysis. The results from SLPR2 signify considerable seasonal variations in water level attributed due to meteorological factors and excess river discharge. Tidal pattern at all these five stations are primarily mixed semi-diurnal with M 2 as the dominant constituent. The t-tide toolbox computed the equilibrium tidal amplitude for the study area. Some of the components known to be influenced by meteorological aspects such as Solar Annual component (Sa), Semi-Annual component (Ssa), and Solar Radiational component (S 1) have higher amplitudes than expected, in the study area. The shallowness of the delta cause severe deviations in the tidal behavior from equilibrium tides. Interaction of tides with river discharge also dominant in this region indicates the role of hydrological forcing. Interestingly, the study also reveals the existence of compound tidal constituent Msf in this region. Monthly analysis of Msf component, using FFT, revealed peaks corresponding to the monsoon, Kal-Baisakhi months and to the seasonal changes in atmospheric pressure, thereby unfolding the seasonal influence on Msf. The funnel shaped head Bay plays an important role in amplification of tidal constituents, wherein the form factor and maximum tide levels showed an increasing trend. This study also demonstrates how tidal dynamics can be elucidated using location specific water-level observations. Investigations on the annual variations in observed and predicted water levels clearly signify the seasonal patterns. The correlation analysis show a reasonable match with skill level exceeding 93%, and the overall prediction by SLPR2 is highly satisfactory.
... The estimated annual sediment yield of the Brahmaputra is 1028 tons km 2 , the highest among the world's largest rivers. On the other hand, the sediment yield from Ganges is only 502 tons km 2 although its basin area is twice that of the Brahmaputra (Barua, 1994). In the recent years the change in course of Ganges and Brahmaputra rivers has significant influence on the morphology of their alluvial flood plains (Rahman, 1993;Brammer, 1996). ...
Article
Abstrac The navigational aspects of marine transport and its manoeuvrability require precise knowledge on tides. Information on time varying water levels, magnitude and direction of tidal currents is quite critical in coastal waterways and estuarine environment. Real-time water levels along with other hydrodynamic parameters are used in almost all major ports for effective operations throughout the year. Also various coastal engineering projects require precise information on site-specific water level elevations. There is a rapid expansion of coastal infrastructure in the recent times, and therefore it is very essential to have reliable water level prediction system that caters the need for coastal engineers, port and harbour activities etc. The Sea Level Processing Package (SLPR2) developed by the University of Hawaii Sea Level Center in collaboration with National Oceanographic Data Center (NODC) provides reliable estimate of location specific sea level information. SLPR2 performs three primary tasks that include tidal analysis and prediction, quality control, and filtering. Harmonic tidal analysis using linear least square produces the relevant tidal constituents of a specific region. High frequency data (preferably one-hour duration) for a minimum duration of one complete year would suffice the tidal analysis phase in SLPR2. The tide prediction algorithm used in the present study uses a maximum of 68 harmonic constituents. The region of interest is the head Bay of Bengal region located along the east coast of India. Preliminary analysis of measured sea level data indicate that tide gauges located along Bangladesh has research quality data, and therefore used in this study. Station data from seven locations viz; Hiron Point, Khepupara, Charchanga, Chittagong, Khal No.10, Cox's Bazaar, and Teknaf all located in Bangladesh were used for tidal analysis, and thereafter the predictive capability of SLPR2 for one-year period was investigated. There are exceptions at two stations, Teknaf (comprising of 87% observed data) and Khal No.10 (99% of observed data), and remaining five stations are free from data gaps. In a hydrographic perspective, the Bangladesh region has complex network of waterways, and bottom topography have several detached shoals. Tides enter the Bangladesh coast through two submarine canyons, reaching Hiron Point and Cox Bazaar at almost the same time. Amongst the principal constituents, dominant modes are exhibited by M 2 and S 2 whose natural oscillation periods are 12 h 25 min, and 12 h respectively. The results from SLPR2 indicate considerable seasonal variation in water level prediction during the monsoon season, attributable to meteorological reasons and excess river discharge, at stations Cox Bazaar and Charchanga. The locations Hiron Point and Khepupara show elevated predicted tides after the onset of monsoon, indicating the presence of seasonal signature resulting from large amplitude of the annual tidal component 'Sa'. Residual time series produce the de-tidal water level variations attributed due to meteorological effects such as wind, atmospheric pressure and river discharge. Inspection of residual can help to quality control measured data such as datum level correction, and replacement of data voids. The effective shallow nature in NorthEastern Bay produces partial reflections thereby increasing the tidal range. In addition, the seasonal * Linta Rose. effects of meteorological forcing along with non-linear shallow water interaction can result in number of higher harmonics. Finally, the correlation of tidal prediction between SLPR2 and measurement show a reasonable good match.
... km, while discharge from the Ganges is about 502 tonnes/ sq. km in spite of the basin area being almost two times large compared to that of the Brahmaputra 6 . The highest tidal range in the east coast of India pertains to the head Bay region, and strong currents with reversing tides play an important role on the suspended sediment concentration and sediment transport mechanisms. ...
Article
The Hooghly estuary located in the head Bay of Ben-gal region is a part of the highly dynamic deltaic environment. Tidal variations are predominant in this estuary, and tides propagate considerable distance through a complex network of various riverine systems , inlets, bays and creeks having vital implications on water mass exchange, reworking of deltaic sediments and the mixing process. The Hooghly River houses two major ports of national importance, viz. Kolkata Dock System and Haldia Dock Complex. Tidal forcing is primarily semi-diurnal in nature and with the presence of complex riverine morphology, the tidal characteristics are substantially modified causing various tidal constituents of compound tides. The present study performs location-specific tidal analysis and prediction utilizing one-hourly tide data with SLPR2 harmonic tidal analysis tool for Gangra situated upstream of the Hooghly River. In a geomorpho-logic perspective, the water-level elevation at Gangra results from natural tidal flow, as well as refracted effects from cross-flow due to the presence of two natural island barriers, namely Sagar Island situated southward off Gangra and Nayachara in the east. The Hooghly channel comprises of complex bathymetric features and tidal analysis at Gangra reveals the presence of Msf (luni-solar synodic fortnightly) tidal constituent. Very few locations in India have reported on the existence of the Msf tides, and Gangra is one among them. This study also performs a comprehensive validation between the computed monthly tidal prediction from SLPR2 and measured water level at Gangra. The skill level of prediction exhibits a good match. This study also investigates the influence of atmospheric effects on sea-level pressure variations and the resultant water-level elevation from extreme weather events such as depressions and severe cyc-lonic storms that occurred during 2013. The study signifies the importance of tidal analysis and prediction for operational needs. Keywords: Estuary, numerical models, tide prediction and analysis, water-level elevation. THE variations in sea-level attributes arise from various factors such as astronomical tides and currents, atmospheric forcing and hydrological aspects of river discharge 1,2. These in turn govern the water-level elevation in estuaries and river channels 3. One can find increasing concerns on the sea-level rise and its variability in the recent literature. The vulnerability aspects due to sea-level rise have implications on livelihood in several coastal areas around the globe. In this context, the Sunderbans situated in the head Bay of Bengal is a low-lying deltaic environment that is highly vulnerable to threat from sea-level rise. In the recent years, one can find several studies on projections for sea-level rise due to global warming and climate change. The subject of sea-level rise and its implications has a direct bearing on socioeconomic aspects. Rapid industrialization with increased emission of greenhouse gases has increased the mean global temperature. Estimates show that global sea-level rise is in the order of about 15 cm over the past century. Several studies have been conducted based on measurements and projections from numerical models that portray increased atmospheric temperature in the near future. This indicates that coastal areas and especially the low-lying regions (such as near-shore areas in the head Bay region) have a direct risk from increased total water-level elevation (TWLE). TWLE is a combined effect due to increased storm-surge activity from high intense cyclones, wave-induced setup , and astronomical tides that happen during landfall of energetic cyclones. In other words, a paradigm shift in climate change during the recent decades has resulted in an increased probability of high-energetic events like cyclones that cause increased storm surge and flooding , as well increased wave setup along near-shore areas. This coupled with a permanent rise in sea level is a subject of major concern, especially for low-lying coastal areas. Tidal variation forms an integral component of TWLE. Therefore, tidal analysis in coastal/near-shore waters is important to understand the residual effects. The present study is confined only to tidal analysis and prediction for a specific location, Gangra, which is a part of the Hooghly riverine system adjoining the head Bay region in the Bay of Bengal (Figure 1). The study demands quality data; in addition, the measured data should be free from data gaps and spurious noise. Therefore, in the present study we develop a tide prediction system specifically for Gangra, with subsequent scope to extend such work to other regions in the head Bay of Bengal.
... e Best et al. (2007); Q is average of lower and upper estimates for bankfull discharge at Bahaduribad (Delft Hydraulics and DHI, 1996; Thorne et al., 1993); S from Delft Hydraulics and DHI (1996). f Barua (1994); Sarker and Thorne (2006). g Carson (1984); values from their Table 1, Rakaia 2. h Smith et al. (2006); Snorrason et al. (1997); estimated peak discharge from 1996 outburst flood. ...
Article
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River channels often develop channel belts—wider corridors imprinted by past channel occupation—that record past landscape dynamics and form widespread aquifers. Controls on channel belt width for braided rivers have been inferred through physical experiments that evolve an initially straight channel and yield an interpreted, quasi‐equilibrium form. Yet uncertainties remain regarding the independent effects of discharge, slope, and time on channel belt dimensions and the morphodynamic phenomena that coincide with channel belt development. To address these uncertainties, I conducted four experiments that independently varied discharge and bed slope for flow over a bed of medium sand (D50 = 0.42 mm). The laboratory basin (37 m long, 2.7 m wide) was 200 times longer and nine times wider than the width of the largest initial channel, which reduced boundary effects and provided a baseline to measure downstream variability in channel belt width. Transitions in channel belt growth rate occurred in concert with three phases captured by time‐resolved topography data: (1) meandering; (2) braiding, with logarithmic growth of the channel belt; and (3) maturity, with slowing, localized growth due to decreasing flow depth. A dimensionless framework involving discharge, slope, and sediment grain size collapses the growth trajectories of the channel belts to a common trend. In comparison, for natural cases, discharge is the dominant predictor of channel belt width (wcb ~ Q0.55). The time dependence of channel belt width in the experiments suggests that the widths of isolated, ancient channel sand bodies are wider than their formative channels.
... Amongst these defined four segments, the first three coastline section is a low lying, swampy, rapidly changing alluvial basin with large inputs of sediments deposited by the two vast river systems namely Ganges and Brahmaputra (Snead, 2010). The estimated annual sediment load from Brahmaputra is about 1028 t Km À 2 while the discharge from Ganges is about 502 t Km À 2 although the basin area is almost two times large compared to that of Brahmaputra (Barua, 1994). ...
Article
In a geomorphic sense, the Bangladesh located in the head Bay region comprises of numerous tidal creeks, waterway inlets, and complex coastline geometry. This region encompassing the world׳s largest deltaic system is thickly populated and extremely low-lying, and therefore highly susceptible to coastal flooding and sea level rise. High tidal range existent in this region primarily governs the hydrodynamic behavior and coastal processes. The present study deals on a comprehensive tidal analysis, understanding the variations in tidal behavior over spatial and temporal scales in the near-shore region off Bangladesh. The harmonic tidal analysis using SLPR2 estimates the tidal constituents using linear least squares with respective nodal correction. Tide gauge observations from five different stations viz; Hiron Point, Khepupara, Charchanga, Khal No-10, and Cox׳s Bazaar were used for tidal analysis. The results from SLPR2 signify considerable seasonal variations in water level attributed due to meteorological factors and excess river discharge. Tidal pattern at all these five stations are primarily mixed semi-diurnal with M2 as the dominant constituent. The t-tide toolbox computed the equilibrium tidal amplitude for the study area. Some of the components known to be influenced by meteorological aspects such as Solar Annual component (Sa), Semi-Annual component (Ssa), and Solar Radiational component (S1) have higher amplitudes than expected, in the study area. The shallowness of the delta cause severe deviations in the tidal behavior from equilibrium tides. Interaction of tides with river discharge also dominant in this region indicates the role of hydrological forcing. Interestingly, the study also reveals the existence of compound tidal constituent Msf in this region. Monthly analysis of Msf component, using FFT, revealed peaks corresponding to the monsoon, Kal-Baisakhi months and to the seasonal changes in atmospheric pressure, thereby unfolding the seasonal influence on Msf. The funnel shaped head Bay plays an important role in amplification of tidal constituents, wherein the form factor and maximum tide levels showed an increasing trend. This study also demonstrates how tidal dynamics can be elucidated using location specific water-level observations. Investigations on the annual variations in observed and predicted water levels clearly signify the seasonal patterns. The correlation analysis show a reasonable match with skill level exceeding 93%, and the overall prediction by SLPR2 is highly satisfactory.
... km, while discharge from the Ganges is about 502 tonnes/ sq. km in spite of the basin area being almost two times large compared to that of the Brahmaputra 6 . The highest tidal range in the east coast of India pertains to the head Bay region, and strong currents with reversing tides play an important role on the suspended sediment concentration and sediment transport mechanisms. ...
Article
The Hooghly estuary located in the head Bay of Bengal region is a part of the highly dynamic deltaic environment. Tidal variations are pre-dominant in this estuary, and tides propagate considerable distance through a complex network of various riverine systems, inlets, bays and creeks having vital implications on water mass exchange, reworking of deltaic sediments and the mixing process. The Hooghly River houses two major ports of national importance, viz. Kolkata Dock System and Haldia Dock Complex. Tidal forcing is primarily semi-diurnal in nature and with the presence of complex riverine morphology, the tidal characteristics are substantially modified causing various tidal constituents of compound tides. The present study performs location-specific tidal analysis and prediction utilizing one-hourly tide data with SLPR2 harmonic tidal analysis tool for Gangra situated upstream of the Hooghly River. In a geomorphologic perspective, the water-level elevation at Gangra results from natural tidal flow, as well as refracted effects from cross-flow due to the presence of two natural island barriers, namely Sagar Island situated southward off Gangra and Nayachara in the east. The Hooghly channel comprises of complex bathymetric features and tidal analysis at Gangra reveals the presence of Msf (luni-solar synodic fortnightly) tidal constituent. Very few locations in India have reported on the existence of the Msf tides, and Gangra is one among them. This study also performs a comprehensive validation between the computed monthly tidal prediction from SLPR2 and measured water level at Gangra. The skill level of prediction exhibits a good match. This study also investigates the influence of atmospheric effects on sea-level pressure variations and the resultant water-level elevation from extreme weather events such as depressions and severe cyclonic storms that occurred during 2013. The study signifies the importance of tidal analysis and prediction for operational needs.
... The estimated annual sediment yield of the Brahmaputra is 1028 tons km 2 , the highest among the world's largest rivers. On the other hand, the sediment yield from Ganges is only 502 tons km 2 although its basin area is twice that of the Brahmaputra (Barua, 1994). In the recent years the change in course of Ganges and Brahmaputra rivers has significant influence on the morphology of their alluvial flood plains (Rahman, 1993;Brammer, 1996). ...
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Abstrac The navigational aspects of marine transport and its manoeuvrability require precise knowledge on tides. Information on time varying water levels, magnitude and direction of tidal currents is quite critical in coastal waterways and estuarine environment. Real-time water levels along with other hydrodynamic parameters are used in almost all major ports for effective operations throughout the year. Also various coastal engineering projects require precise information on site-specific water level elevations. There is a rapid expansion of coastal infrastructure in the recent times, and therefore it is very essential to have reliable water level prediction system that caters the need for coastal engineers, port and harbour activities etc. The Sea Level Processing Package (SLPR2) developed by the University of Hawaii Sea Level Center in collaboration with National Oceanographic Data Center (NODC) provides reliable estimate of location specific sea level information. SLPR2 performs three primary tasks that include tidal analysis and prediction, quality control, and filtering. Harmonic tidal analysis using linear least square produces the relevant tidal constituents of a specific region. High frequency data (preferably one-hour duration) for a minimum duration of one complete year would suffice the tidal analysis phase in SLPR2. The tide prediction algorithm used in the present study uses a maximum of 68 harmonic constituents. The region of interest is the head Bay of Bengal region located along the east coast of India. Preliminary analysis of measured sea level data indicate that tide gauges located along Bangladesh has research quality data, and therefore used in this study. Station data from seven locations viz; Hiron Point, Khepupara, Charchanga, Chittagong, Khal No.10, Cox's Bazaar, and Teknaf all located in Bangladesh were used for tidal analysis, and thereafter the predictive capability of SLPR2 for one-year period was investigated. There are exceptions at two stations, Teknaf (comprising of 87% observed data) and Khal No.10 (99% of observed data), and remaining five stations are free from data gaps. In a hydrographic perspective, the Bangladesh region has complex network of waterways, and bottom topography have several detached shoals. Tides enter the Bangladesh coast through two submarine canyons, reaching Hiron Point and Cox Bazaar at almost the same time. Amongst the principal constituents, dominant modes are exhibited by M 2 and S 2 whose natural oscillation periods are 12 h 25 min, and 12 h respectively. The results from SLPR2 indicate considerable seasonal variation in water level prediction during the monsoon season, attributable to meteorological reasons and excess river discharge, at stations Cox Bazaar and Charchanga. The locations Hiron Point and Khepupara show elevated predicted tides after the onset of monsoon, indicating the presence of seasonal signature resulting from large amplitude of the annual tidal component 'Sa'. Residual time series produce the de-tidal water level variations attributed due to meteorological effects such as wind, atmospheric pressure and river discharge. Inspection of residual can help to quality control measured data such as datum level correction, and replacement of data voids. The effective shallow nature in NorthEastern Bay produces partial reflections thereby increasing the tidal range. In addition, the seasonal
... Mean water slope is 0.000076 over the first 130 km and 0.000065 further downstream (Flood Action Plan 24, 1996b). The grain size of the Jamuna is mainly fine sand and silt with less than 1% clay (FAP24, 1996b) and an average grain size of 220 μm (Barua, 1994;Sarker and Thorne, 2006). The fine and abundant sediment supply together with high water discharges results in the one of world's highest sediment yields that is estimated at between 590 and 792 Mt yr − 1 (FAP24, 1996a;Islam et al., 1999) with up to 10% transported as bedload . ...
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