Bar Migration Research Articles

Recognition of cross-shore dynamics of longshore bars in upper-shoreface deposits of prograding sandy coastal barriers

ABSTRACT In the past decades it has become evident that the often cyclic cross-shore migration of longshore bars is significantly influenced by wave climate. This study demonstrates that this cyclic migration, whether landward or seaward, leads to the formation of low-angle seaward-inclined stratification (SIS) spanning the beach and upper shoreface in ground-penetrating radar (GPR) data from prograding sandy coastal barriers including strandplains. Previously documented radargrams of these systems are reinterpreted using this knowledge of cross-shore dynamics of longshore bars. Five distinct wave-climate-related radar architectures are identified. A notable observation is the prevalence of SIS as the dominant upper-shoreface to beach structure in most radargrams, despite its infrequently described occurrence from outcrop observations. To address this disparity, this paper also focuses on recognizing SIS in outcrop and core data. Compelling evidence of SIS was discovered in a late Messinian coastal barrier parasequence in SE Spain, and the associated sedimentary architecture is described in detail. It is hypothesized that this example holds generic significance, illustrated using core data from Middle Jurassic strata of the Norwegian continental shelf, and suggesting that the sedimentary architectures of numerous other ancient prograding barrier deposits may exhibit variations within a similar SIS framework.

‘Short Bars Crossed’ to Remodel the Entire Chest Wall in Children and Adolescents with Pectus Excavatum

BackgroundThe cross-bar technique of minimally invasive pectus excavatum (PE) correction remains underreported, which is especially true of pediatric patients. We therefore reviewed the experience of a Turkish and an Austrian center. An additional novelty characterizing both pediatric cohorts was the use of short bars. MethodsIn a retrospective study, pediatric PE corrections involving ‘short bars crossed’ were analyzed for complications and intra-/postoperative outcomes. Cases with two or three bars were included, given that a horizontal third bar was placed whenever considered useful for upper-chest elevation. All bars were fitted with a single stabilizer near the surgical entry point. In the Austrian center, intercostal nerve cryoablation was used for pain management. Descriptive statistics are presented. ResultsSeventy-eight patients ≤18 years old were evaluable at the Turkish (n = 56) and Austrian (n = 22) centers. Total median values were 16.2 (IQR: 15.1–17.4) years for age and 4.60 (IQR: 3.50–6.11) for Haller index. Ten mild or moderate complications (12.8%) were observed, including just one revision requirement due to bar migration (1.28%). Intercostal nerve cryoablation (n = 13) was associated with longer surgical procedures at 150 (IQR: 137–171) versus 80 (IQR: 60–100) minutes but with shorter hospital stays, given an IQR of 3–4 days versus 4–5 days. Conclusion‘Short bars crossed’—with a single stabilizer in a ventral position close to the surgical entry point—ensure a wide distribution of forces, protect against bar migration, are safe and effective, and offer stability at an age characterized by growth and physical activity. Level of EvidenceIV.

Modelling flow regulation effects on vegetation recruitment and survival on alternate bars in channelized rivers

AbstractMany river reaches have transitioned to heavily vegetated systems following the regulation of their flow regime. Vegetation recruitment and survival are key to these transformations. We propose a novel predictive approach to detect how changes in the flow regime may affect conditions for successful vegetation recruitment and survival in channelized rivers with alternate bars. Our approach combines elements of existing vegetation recruitment models (Recruitment Box and Window of Opportunity) with simplified morphodynamic predictions of alternate bar migration. The approach is illustrated by applying it to a reach of the regulated Isère river, SE France, which has transitioned from migrating, unvegetated to steady, vegetated alternate bars over two decades following flow regulation associated with hydropower development. Our modelling approach identifies a strong impact of modified summer flows on vegetation recruitment since 1950 when major flow regulation began. An increase of up to 1 cm year−1 (after 1990) has occurred in the vertical extent of vegetation recruitment bands on the bars. This has been accompanied by an almost 20 m total increase (since 1950) in the horizontal extent of the recruitment bands, and a 1.5 times reduction in the frequency of high flows capable of promoting bar migration. Our modelling also suggests viable flow restoration options to limit widespread vegetation colonisation. Comparing outcomes from our modelling approach with those from the Bertagni et al. (2018) model suggests that the Isère may have been highly prone to vegetation colonisation even before flow regulation and close to some threshold for a shift from an unvegetated to a vegetated state.

Long-Term Field Observation on Sand Bar Migration near Tedori River Mouth, Japan

Long-Term Field Observation on Sand Bar Migration near Tedori River Mouth, Japan

Sedimentary Characteristics and Internal Architecture of a Sandy Braided River: Insights from a Numerical Model

Sandy braided river deposits are widely observed in ancient stratigraphic records and modern sedimentary basins. Frequent channel migration shapes intricate internal architecture, while research on its influence on fine sedimentary architecture remains limited. This study utilizes DELFT3D to simulate and analyze the sedimentary processes and architecture of the channel bar in a sandy braided river. The results show that: (1) The channel bar consists of downstream accretion (DA), lateral accretion (LA), and aggradational accretion (AA). (2) Channel bars can be divided into three types: unit bars, compound bars, and complex compound bars. Unit bars are lobate-shaped and consist of multiple accretions, including DA in the core, AA layered above, and LA deposited on the sides. Compound bars result from the migration and amalgamation of multiple unit bars, characterized by a greater number of accretions. Compound bars can further be classified as DA-dominated or LA-dominated, depending on the dominant accretion type. Complex compound bars form from the merging of multiple unit bars and compound bars. In this paper, insights from a braided river on its sedimentary processes and evolution may help to improve river management and water resources research. The in-depth understanding of sedimentary architecture on channel bars can be utilized for detailed subsurface oil and gas reservoir characterization.

A PROCESS-BASED NUMERICAL MODEL OF SHOREFACE PROFILE EVOLUTION

It remains a challenge to model numerically profile evolution across the shore-face from deep water to the shoreline with stability and accuracy. At long time scales, attempts to date typically utilise equilibrium profile shapes or bed slopes, with profile change based on the degree of disequilibrium and wave/current forcing, primarily for the surf zone in erosion events. Simulation of shoreward bar migration and beach recovery after erosion events is generally poor. Here we present an effective integrated framework and process-based dynamics in the form of a new software package that successfully models the whole shore-face zone seamlessly from relative deep water to the beach. It incorporates analytical procedures, including some simplified empirical relationships, that describe the forcing of waves and currents and the sedimentation responses that change the profile. It is shown to simulate profile evolution satisfactorily, with shoreward as well as seaward sand transport, bar development and migration and beach erosion and accretion, in a manner and at time-scales consistent with measured data, for both small scale laboratory and prototype modal and storm conditions. The model caters for water level variations due to tide, storm surge and/or sea level rise. It may be used to assess beach nourishment deposition at the beach berm, lower shore-face or across the surf zone.

Using python libraries and k-Nearest neighbors algorithms to delineate syn-sedimentary faults in sedimentary porous media

This paper introduces a methodology based on Python libraries and machine learning k-Nearest Neighbors (KNN) algorithms to create an interactive 3D HTML model (3D_Vertical_Sections_Faults_LRD.html) that combines 2D grain-size KNN-prediction vertical maps (vertical sections) from which syn-sedimentary faults and other features in sedimentary porous media can be delineated. The model can be visualized and handled with conventional web browsers. The grain-size physical parameter is measurable, constant over instrumental time, handleable mathematically, and its range can be associated to lithological classes. Grain-size input data comes from a public database of 433 boreholes in the Llobregat River Delta (LRD) in NE Spain. Four lithological classes were defined: Pre-Quaternary basement, and Quaternary gravel, sand, and clay–silt. Using a new KNN-prediction algorithm, seven NW–SE (transversal) and three SW–NE (longitudinal) vertical sections were created following the orientation of faults identified in surface and detected in reflection seismic geophysical surveys. For exploratory K values in the 1–75 range were used. K around 25 provides the general and smoothy shape of the basement top surface, whereas K = 1 is a optimal value to represent the heterogeneity of the LRD at short distance. Using a new KNN-prediction confidence algorithm inspired in the Similarity Ratio algorithm for machine-learning KNN, the vertical sections overall confidence was evaluated as satisfactory. A general decreasing confidence trend according to the decreasing data density with depth and from inland to seaward was found. The vertical sections created with K = 1 show horizontal interruptions (displacements or vertical steps) in the basement continuity and in the Quaternary coarse bodies (gravel and sand) attributable to the action of Quaternary active faults. These faults have been linked or correlated with well-known active faults in the area related in much cases with the Valencia Trough opening. Moreover, several faults detected in surface and other identified in this paper by the first time have been revealed as fault zones made of fault branches with different steps in an echelon-like arrangement. Faulting seems to be more evident in the Pleistocene Lower Detrital Complex and much less active or inactive in the Holocene Upper Detrital Complex. Syn-tectonic gravel channels faulty controlled, progradation of gravel lobes, and lateral migration of channel bars were also observed. At its current development stage, this methodology could also be applied to other geological environments, making the due minor modifications of the code, and is especially suitable to reduce the high (usually unmeasurable) uncertainty associated to the qualitative geological data used in more complex numerical tools aimed at modelling a lot of geological resources (groundwater, minerals, geothermal, petroleum) or different Earth phenomena.

Influence of the Initial Beach Profile on the Sediment Transport Processes During Post‐Storm Onshore Bar Migration

AbstractOnshore bar migration is a characteristic bar behavior during post‐storm beach recovery. The present large‐scale experiments, feature bichromatic wave groups over an initially steep (1:15), fully‐evolving beach. The same accretive wave condition is applied on two different post‐storm beach profiles featuring outer and inner bars. They are characterized by a larger (smaller) shoreline erosion and a larger (smaller) outer breaker bar located farther away from (closer to) the shoreline depending on the larger (smaller) energy of the storm condition. After a considerable post‐storm recovery time, similar equilibrium profiles are obtained, stressing the link between wave condition and equilibrium beach configuration. However, the evolution toward the equilibrium is different and depends on the initial morphological condition (post‐storm beach profile). After the larger storm, the morphological evolution is termed accretive merging (AM) and characterized by merging of the two bars (outer bar dissipation). After the smaller storm, the morphological evolution denoted as accretive non‐merging (AN) is characterized by onshore migration of the two bars with constant distance between them (bar maintenance). This study focuses on processes around the outer bar. During AN it features wave breaking, causing large suspended net offshore transport. AM, in contrast, mainly features bedload related to short wave asymmetries and low decomposed net transport rate magnitudes. High suspended net offshore transport occurs solely onshore of the outer bar trough. This causes filling of the bar trough and bar dissipation during migration. Additionally, processes around the outer bars are linked to accretion onshore of the bars and at the shoreline.

Uncertainty in Nearshore Sand Bar Migration

AbstractA coupled nearshore hydrodynamics and sediment transport model with adjoint‐based uncertainty quantification has been applied to sand bar morphodynamics in the Duck94 field experiment (Duck, NC). The model, which is based on previously established physical process formulas, is capable of producing accurate predictions of sand bar migration during the experiment. However, reasonable perturbations to the model inputs—namely initial conditions, boundary conditions, and calibration coefficients—can produce a range of model predictions. This range is taken to represent the potential for uncertainty of the model, for scenarios where one or more model inputs are poorly constrained. Experiments are presented that quantify the relative impact of different input types on uncertainty, and the results are contrasted for accretive versus erosive wave conditions. During accretive conditions (shoreward bar migration), uncertainty is dominated by the growth of errors in initial conditions, owing to positive feedbacks in the model. In contrast, during erosive conditions (seaward bar migration), there is a smaller impact of errors in initial conditions, and uncertainty is instead dominated by errors in sediment transport coefficients. The results thus point to qualitative differences in the nature of nearshore morphodynamic uncertainty under different wave conditions, with a greater role of internal error growth (positive feedbacks) during accretive conditions and errors in model physics being more important during erosive conditions.

Simulation of cross-shore breaker bar development utilizing a stabilized two-equation turbulence model

The performance of a recently developed “stabilized” turbulence (k−ω) closure model, which avoids un-physical over-production of turbulence prior to wave breaking, is investigated in the computational fluid dynamics (CFD) simulation of cross-shore sediment transport and breaker bar morphology. Comparisons are made with experiments as well as results from simulations employing (otherwise identical) “standard” turbulence closure. The stabilized turbulence model is demonstrated to result in major (qualitative and quantitative) improvements of the predicted breaker bar position and height. Conversely, the established over-production of turbulence in the standard closure, coupled with associated inaccurate undertow structure in the outer surf zone, contribute to erroneous offshore migration of the breaker bar. By correcting these shortcomings, the stabilized turbulence closure model rightly predicts initial onshore morphological migration of the breaker bar without any calibration. This work thus establishes proper turbulence modeling as a prerequisite for accurate CFD prediction of cross-shore sediment transport and profile morphology.

Near‐Bed Sediment Transport Processes During Onshore Bar Migration in Large‐Scale Experiments: Comparison With Offshore Bar Migration

AbstractDetailed information on nearshore sediment transport processes during onshore bar migration were obtained from large‐scale laboratory experiments with bichromatic wave groups on a relatively steep initial beach slope (1:15). Detailed measurements of velocity and sand concentration near the bed from shoaling up to the outer breaking zone including suspended sediment and sheet flow transport are presented. The analysis focuses on onshore migration under an accretive wave condition but comparison to an erosive condition highlights important differences. Decomposition shows that total transport mainly results from a balance of short wave‐related, bedload onshore transport and current‐related, suspended offshore transport. When comparing the accretive to the more energetic erosive condition, the balance shifts toward onshore transport, and onshore migration, because the short wave‐related transport does not decrease as much as the current‐related transport. This is related to the effects of skewness and asymmetry combined with less sediment suspension in the water column and undertow magnitude under the accretive condition. Transports from streaming in the wave boundary layer and from infragravity waves become visible but only play a subordinate role. Identified priorities for numerical model development include parametrization of wave nonlinearity effects and better description of wave breaking and its influences on sediment suspension.

Sound‐Side Inundation and Seaward Erosion of a Barrier Island During Hurricane Landfall

AbstractBarrier islands are especially vulnerable to hurricanes and other large storms, owing to their mobile composition, low elevations, and detachment from the mainland. Conceptual models of barrier‐island evolution emphasize ocean‐side processes that drive landward migration through overwash, inlet migration, and aeolian transport. In contrast, we found that the impact of Hurricane Dorian (2019) on North Core Banks, a 36‐km barrier island on the Outer Banks of North Carolina, was primarily driven by inundation of the island from Pamlico Sound, as evidenced by storm‐surge model results and observations of high‐water marks and wrack lines. Analysis of photogrammetry products from aerial imagery collected before and after the storm indicate the loss of about 18% of the subaerial volume of the island through the formation of over 80 erosional washout channels extending from the marsh and washover platform, through gaps in the foredunes, to the shoreline. The washout channels were largely co‐located with washover fans deposited by earlier events. Net seaward export of sediment resulted in the formation of deltaic bars offshore of the channels, which became part of the post‐storm berm recovery by onshore bar migration and partial filling of the washouts with washover deposits within 2 months. This event represents a volumetric setback in the overwash/rollover behavior required for barrier transgression, but the new ponds and lowland habitats may provide beneficial habit for endangered species and will likely persist for years.

Risk Factors and Techniques for Safe Pectus Bar Removal in Adults After Modified Nuss Repair

BackgroundThe Nuss repair involves implants designed for removal after 2 to 3 years. Although rare, significant complications can occur with bar removal, and the incidence of these complications may be higher in adults. This study was performed to review complications and risk factors associated with bar removal and discuss strategies to improve operative safety. MethodsA retrospective study was performed including all patients after pectus excavatum repair who underwent Nuss implant removal at Mayo Clinic Arizona (Phoenix, AZ) from 2013 to 2022. ResultsIn total, 1555 bars were removed (683 patients; 71% men; median age, 34 years[(range, 15-71 years]). Of the removals, 12.45% of patients had bars placed at outside institutions. Major complications were rare, with bleeding most common (2.05%), followed by pneumothorax (0.88%), infection (0.59%), and effusions (0.44%). Most major bleeding (85.71%) occurred from the bar track during removal and was controlled by packing the track. One patient required subsequent hematoma evacuation and transfusion. Bleeding secondary to lung injury was also successfully controlled with packing. Bar removal in 1 patient with significantly displaced bars required sternotomy and cardiopulmonary bypass as a result of aortic injury. Risk factors identified for bleeding included sternal erosion (P < .001), bar migration (P < .001), higher number of bars (P = .037), and revision of a previous pectus repair (P = 0.001). Bar migration was additionally associated with major complications (P < .001). Older age, although a risk factor for overall complications (P = 0.001), was not a risk factor for bleeding. ConclusionsBar removal can be safely performed in most patients; however, significant complications, including bleeding, may occur. Identifying potential risk factors and being prepared for rescue maneuvers are critical to prevent catastrophic outcomes.

Associated risk factors for patients undergoing a unique or double Nuss bar placement for pectus excavatum.

Pectus excavatum is the most common chest wall deformity. Surgical correction via Nuss Procedure is a common approach. Patients with long-segment sternal depression require more than one Nuss bar to be inserted. Complications of Nuss procedure include surgical site infection and bar migration which may necessitate surgical re-intervention. There has been conflicting evidence regarding the safety profile of inserting two Nuss bars. We aim to specifically review the safety profile of two Nuss bar insertion and its complications. 179 consecutive patients who had undergone Nuss procedure between November 2013 and November 2021 were identified. Data analysis was performed on patient's age at time of operation, gender, height, weight, Haller index, pre-existing medical conditions, indication for surgery, duration of operation, numbers of bars placed, length of stay, post-operative pneumothorax, bar migration, superficial and deep infections, need for surgical intervention and mortality. Patients receiving two Nuss bars were at a significantly higher risk of developing infective complications. Lower weight and Haller index increase the risk of surgical site infection and infection requiring re-operation in this group of patients. A cut-off of 50 kg has a specificity of 92.1% with a sensitivity of 68.8% in regards to surgical site infection. Patients receiving two Nuss bars as a part of their Nuss procedure are at a significantly higher risk of developing infective complications. Selecting patients more than 50 kg to receive two Nuss bars appear to be a reasonable measure to reduce surgical site infection.

Adaptation of the SANTOSS transport formula for 3D nearshore models: Application to cross-shore sandbar migration

The ability to model bar migration in the nearshore zone is critically important for predicting coastal morphology. We present a cost-effective wave-averaged 3D model (CROCO) with parameterization of wave-related bedload transport (adapted SANTOSS), and evaluate/calibrate its performance in comparison with data measured in a two-dimensional wave channel. In this model, suspended-load transport (both in and above the wave bottom boundary layer) is resolved by the flow model. We assume that if the tuning parameters are not robust to varying forcing conditions, the parameterization can be considered a failure. The present work is therefore a first step towards a numerical model capable of predicting the onshore and offshore migration of a sandbar under storm and post-storm conditions using the same set of parameters. One way to achieve this goal is to treat the effects of waves and currents in separate formulations to avoid conflicts and redundancy. We show that the implementation and adaptation of SANTOSS in CROCO can achieve this goal, provided that the hydrodynamics are accurately reproduced and the separation between the wave-related bedload and current-related suspended load formulations is respected.

Morphological evolution mechanism of Gravel-bed braided river by numerical simulation on Da-jia River

• “central bar formation” and “channel avulsion” are the main river evolution mechanism in the simulated gravel-bed reach. • As the river width expands downstream, the longitudinal profile gets stable, while the transverse oscillation becomes wild. • If the longitudinal structure (bank revetment) on the concave bank of a gravel-bed river is made by concrete with relatively smooth surface, it is very likely to cause further damage on the longitudinal structure. Due to a steep slope, rapid flow, and large amounts of sediment, rivers in Taiwan are braided rivers that are full of bars and bifurcated flows. The channel shifting behavior and bar migration within natural braided rivers results in difficult river engineering. In this study, the Nays2DH model was used to simulate the braiding processes and morphological changes downstream of Shigang Dam in the Da-jia River from 2012 to 2013. Furthermore, the characteristics of riverbed erosion, the stability of the channel in the longitudinal and transverse directions and the impact of river structures on the morphology were simulated. The numerical model can present morphological and evolutionary processes similar to an actual river, such as: central bar formation, chute cutoff, and channel avulsion. The scour pool mostly occurred at the apex of the river bend and downstream of the bar (confluence) in a braided river, which means that bar migration is the main factor that alters scour position. Under the assumption of equilibrium sediment transportation across the upstream inflow section, the width of the channel determines whether the river demonstrates longitudinal erosion or transverse changing. Results from this research can be used as a substantial reference for future research concerning river morphology evolution, river engineering, and river space planning.

A new process-based, wave-resolving, 2DH circulation model for the evolution of natural sand bars: The role of nearbed dynamics and suspended sediment transport

We study the migration of natural sand bars that evolve in the nearshore by means of a new process-based wave-resolving, 2DH circulation model. In order to perform reliable and accurate computations, the robust Nonlinear Shallow Water Equations (NSWEs) hydro-morphodynamic solver of Brocchini et al. (2001) and Postacchini et al. (2012) implements a detailed description of the Bottom Boundary Layer (BBL) dynamics and a new predictor for the Suspended Sediment Transport (SST) based on the solution of a Depth-Averaged Advection-Diffusion Equation (DAADE) for the sediment concentration. The robustness and accuracy of the enhanced model are validated against literature theoretical, experimental, and numerical results, all comparisons highlighting good performances and clarifying the role of both BBL and SST contributions, the former one having a larger positive influence than the latter one on the results. Both original and enhanced models are, then, used to predict the evolution of the sand bar system that characterizes the nearshore of Senigallia (AN). The analysis leverages the field observations collected at such a site by means of the Sena Gallica Speculator video-monitoring system. Modeling of the storm-forced sand bar migration patterns reveals that: 1) the enhanced model can adequately reproduce the seaward migration of the sand bars of the system; 2) the process of shoreline retreat in coincidence with the generation of a new-born bar is well described; 3) inclusion of the BBL improves quantitative prediction of the bar crest migration; 4) the SST, beyond improving the prediction of the bar crest location, induces some smoothing of the bar profile, in line with the literature findings of SST being a stabilizing factor for the bar emergence. • Sand bar evolution in the nearshore zone is modeled using a process-based 2DH wave resolving NSWE model. • The model includes BBL dynamics and predicts the SST based on the depth-averaged advection-diffusion equation. • The model is validated against theoretical, experimental, and numerical results. • The model is used to predict the sandbar migration in the nearshore of Senigallia (AN) during a storm. • The developed model can accurately reproduce the sandbar evolution in both field and laboratory conditions.

Data related to "Influence of the Initial Beach Profile on the Sediment Transport Processes during Post-storm Onshore Bar Migration."

Data related to "Influence of the Initial Beach Profile on the Sediment Transport Processes during Post-storm Onshore Bar Migration."

Beach profile changes induced by surrogate Posidonia Oceanica: Laboratory experiments

New flume experiments with surrogate seagrass meadows are presented. The experiments included the creation of a full-scale and realistic Posidonia Oceanica model to evaluate the effect over wave attenuation, sediment transport and shoreline erosion. A hydrodynamic and morphodynamic comparison between cases with seagrass and without seagrass for two wave energy conditions was performed. Meadow density and submergence ratio were constant for tests under irregular waves. The wave height reduction, bar crest location, total sediment transport and shoreline position were used to evaluate the coastal protection efficiency of the meadow. The measured wave heights suffered a reduction due to the presence of the seagrass. These reductions were persistent in the area located between the onshore edge of the meadow and the depth of closure, being of greater magnitude in the more energetic case. All tests showed the development of a bar and the migration of the crest offshore over time. However, the dissipation of the incoming wave energy on the meadow made the bar crest stay closer to the shoreline and consequently generated a lower freeboard. In addition, the bar migration rate was reduced by the simulated meadow effect, in particular in the lower energetic case. A sediment volume significantly smaller was transported offshore when the seagrass meadow was present in both wave conditions. Additionally, in the higher energy case, a smaller shoreline retreat was observed when the meadow was present. • Flume experiments were carried out with a realistic Posidonia Oceanica model to assess the effect on beach sediment transport. • Two wave condition were analysed comparing the test with and without seagrass meadows. • Wave heights were reduced due to the effect of the Posidonia Oceanica model in areas after the meadow. • The total volume of sediment transported in the seagrass meadows cases was considerably less than without seagrass meadows. • Bar crest morphological parameters and shoreline position were analysed to verify the meadow effect on the coastal protection.

Topography and morphodynamic study of intertidal mudflats along the eastern coast of the Gulf of Khambhat, India using remote sensing techniques

The intertidal mudflats that are exposed subaerially between the high and low tides have a complex morphology comprising ebb and flood tidal deltas, spits, shoals, and tidal sandbanks intervened with a network of meandering and branching tidal channels and inlets. The intertidal zones are highly transient and understanding their morphodynamics is critical to the ecology and economy of the region. Monitoring intertidal mudflat dynamics is imperative for sustainable development activities along coastal regions. The topography of intertidal mudflat is estimated for the eastern coast of the Gulf of Khambhat (north-western coast of India) using the waterline detection method from a series of satellite images. We have used Modified Normalized Difference Water Index and image threshold techniques to delineate waterlines from satellite images of high to low tidal conditions at different tidal heights. The waterlines are considered as elevation contours corresponding to tidal height during satellite observation, and a series of elevation contours delineated from satellite images of various tidal heights are then used to calculate the mudflat topography. The estimated topography is validated with the Differential Global Positioning System (DGPS), the Sound and navigation ranging (Sonar), and ICESat-2 ATL03 dataset observations, which results in R2 values of 0.97, 0.89, and 0.9, respectively, as well as RMSE values of 0.39 m, 0.33 m, and 0.49 m, respectively. The mudflat dynamics are studied by comparing the topographical changes estimated between the satellite images of 1998-99 and 2019. The major morphological changes are the landward shift of the low waterline, lateral migration of tidal bars, narrowing of the river mouth, as well as anthropogenic influences such as mudflat reclamation and impedance of long-shore sediment transport. The region with deposition of sediment above Mean Sea Level (MSL) has flattened the slope, making the mudflat stable and promoting mangroves expansion, while erosion has steepened the mudflats with loss of mangrove cover. These mudflats exhibit highly complex morphological changes mainly induced by sediment transport, two-way tidal currents, and fluvial fluxes. The estimated topography shall find its application in modeling coastal processes, identifying vulnerable coastal stretches, and site suitability for mangrove plantations.