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Do, A.T.K.; de Vries, S., and Stive, M.J.F., 2019. The estimation and evaluation of shoreline locations, shoreline-change rates, and coastal volume changes derived from Landsat images. Journal of Coastal Research, 35(1), 56–71. Coconut Creek (Florida), ISSN 0749-0208. Shoreline-change data are of primary importance for understanding coastal erosion and deposition as well as for studying coastal morphodynamics. Shoreline extraction from satellite images has been used as a low-cost alternative and as an addition to traditional methods. In this work, satellite-derived shorelines and corresponding shoreline-change rates and changes in volumes of coastal sediments have been estimated and evaluated for the case of the data-rich North-Holland coast. This coast is globally unique for its long in situ monitoring record and provides a perfect case to evaluate the potential of shoreline mapping techniques. A total of 13 Landsat images and 233 observed cross-shore profiles (from the JAaRlijkse KUStmeting [JARKUS] database) between 1985 and 2010 have been used in this study. Satellite-derived shorelines are found to be biased in seaward direction relative to the JARKUS-derived shorelines, with an average ranging 8 m to 9 m over 25 years. Shoreline-change rates have been estimated using time series of satellite-derived shorelines and applying linear regression. The satellite-derived shoreline-change rates show a high correlation coefficient (R2 > 0.78) when compared with the JARKUS-derived shoreline-change rates over a period of 20 and 25 years. Volume changes were calculated from the satellite-derived shoreline-change rates using assumptions defining a closure depth. Satellite-derived volume changes also show a good agreement with JARKUS-based values. Satellite-derived shorelines compare better with in situ data on beaches that have intertidal zone widths ranging from one- to two-pixel sizes (30 m–60 m). The results show that the use of Landsat images for deriving shorelines, shoreline-change rates, and volume changes have accuracies comparable to observed JARKUS-based values when considering decadal scales of measurements. This shows the potential of applying Landsat images to monitor shoreline change and coastal volume change over decades. [ABSTRACT FROM AUTHOR]

Accelerated sea level rise (SLR) in the twenty-first century will result in unprecedented coastal recession, threatening billions of dollars worth of coastal developments and infrastructure. Therefore, we cannot continue to depend on the highly uncertain coastal recession estimates obtained via the simple, deterministic method (Bruun rule) that has been widely used over the last 50 years. Furthermore, the emergence of risk management style coastal planning frameworks is now requiring probabilistic (rather than deterministic, single value) estimates of coastal recession. This paper describes the development and application of a process based model (PCR model) which provides probabilistic estimates of SLR driven coastal recession. The PCR model is proposed as a more appropriate and defensible method for determining coastal recession due to SLR for planning purposes in the twenty-first century and beyond. [ABSTRACT FROM AUTHOR]

The present paper, ‘Eb- en vloedschaarsystemen in de Nederlandse getijwateren’ (Ebb- and Flood-Channel Systems in the Dutch Tidal Waters), which was published in 1950, should be considered as Van Veen's most important publication since his thesis. It summarizes the results of 20 years of intensive study of estuarine and tidal-basin morphodynamics in The Netherlands. Unfortunately, Van Veen's paper was published in Dutch, with only a brief summary in English. Luckily, the figure captions were given in both Dutch and English, allowing international researchers coming across the paper to read it as a kind of ‘cartoon.’ Understandably though, the paper has received very limited recognition in the international literature. We have seized this occasion to publish an English version of Van Veen's paper. The paper is testimony to Van Veen's keen observational and artistic skills. His approach is nearly ‘Da Vincian,’ in the sense that he is not only a fascinated observer of nature, but a sharp one as well, and he tries to capture the essentials of the dynamic behavior of complex coastal systems in apparently simple sketches. Many of the natural systems that Van Veen studied have been regulated since; thus, this paper contains a set of irreplaceable, high-quality observations on the natural dynamics of tidal systems. It forms an excellent introduction to the study of channel dynamics in estuaries, tidal inlets, and tidal basins. [ABSTRACT FROM AUTHOR]

The coastal-tract approach to coastal morphodynamics, described in the companion paper (The Coastal-Tract Part 1), provides a framework for aggregation of process and spatial dimensions in modeling low-order coastal change (i.e., evolution of the shoreline, continental shelf and coastal plain on time scales of 10² to 10³ years). Behavior-oriented, coastal-change models encapsulate aggregate dynamics of the coastal tract. We apply these models in a coastal-tract framework to illustrate the use of the concept, and to explore low-order morphological coupling under different environmental settings. These settings are characterized by data-models that we have constructed from four contrasting continental margins (NW Europe, US Pacific, US Atlantic, and SE Australia). The gross kinematics of the coastal tract are constrained and steered by sediment-mass continuity. The rate of coastal advance or retreat is determined quantitatively by the balance between the change in sediment accommodation-space, caused by sea-level movements, and sediment availability. If the lower shoreface is shallower than required for equilibrium (negative accommodation), then sand is transferred to the upper shoreface (NW Europe, US Pacific, and SE Australian cases modelled) so that the shoreline tends to advance seaward. This tendency also occurs when relative sea level is falling (coastal emergence). Coastal retreat occurs when the lower shoreface is too deep for equilibrium (positive shoreface accommodation). This sediment-sharing between the upper and lower shoreface is an internal coupling that governs first-order coastal change. The upper shoreface and backbarrier (lagoon, estuary or mainland) also are coupled in first-order coastal change. Sediment accommodation-space is generated in the backbarrier by sea-level rise (and reduced by sea-level fall), but the amount of space is also moderated by influx of fine sediments from the coast, or sand and mud from fluvial sources. Remaining space can then be occupied by sand transferred from the upper shoreface causing a retreat of the latter (transgressive phases modelled for NW Europe, US Atlantic, and SE Australian cases). [ABSTRACT FROM AUTHOR]

Evolution of coastal morphology over centuries to millennia (low-order coastal change) is relevant to chronic problems in coastal management (e.g., systematic shoreline erosion). This type of coastal change involves parts of the coast normally ignored in predictions required for management of coastal morphology: i.e., shoreline evolution linked to behavior of the continental shelf and coastal plain. We therefore introduce a meta-morphology, the coastal tract, defined as the morphological composite comprising the lower shoreface, upper shoreface and backbarrier (where present). It is the first order-system within a cascade hierarchy that provides a framework for aggregation of processes in modeling low-order coastal change. We use this framework in defining boundary conditions and internal dynamics to separate low-order from higher-order coastal behavior for site-specific cases. This procedure involves preparation of a data-model by templating site data into a structure that complies with scale-specific properties of any given predictive model. Each level of the coastal-tract cascade is distinguished as a system that shares sediments internally. This sediment sharing constrains morphological responses of the system on a given scale. The internal dynamics of these responses involve morphological coupling of the upper shoreface to the backbarrier and to the lower shoreface. The coupling mechanisms govern systematic lateral displacements of the shoreface, and therefore determine trends in shoreline advance and retreat. These changes manifest as the most fundamental modes of coastal evolution upon which higherorder (shorter-term) changes are superimposed. We illustrate the principles in a companion paper (The Coastal Tract: Part 2). [ABSTRACT FROM AUTHOR]

A number of statistical techniques to analyze and model coastal morphological evolution over yearly and decadal (i.e., long-term) time scales based on field data are presented. After a general introduction to long-term morphological modeling, mainly linear methods are discussed, whereas nonlinear methods are treated in a companion paper (SOUTHGATE et al., 2001). The theoretical background to the methods introduced is summarized and examples of field applications are given to illustrate each method. High-quality field data sets from different sites in the world, including Germany, The Netherlands, and United States, were employed in these examples. The analysis and modeling techniques used encompassed bulk statistics (mean, standard deviation, correlation etc), random sine functions, empirical orthogonal functions, canonical correlation analysis, and principal oscillation pattern analysis. Besides an evaluation of how suitable respective technique is for analyzing and modeling long-term morphological evolution, some general observations are presented regarding scales of morphological response as derived from the field applications. Data describing the evolution of both natural and anthropogenically affected coastal systems were studied. All methods investigated proved their usefulness for extracting characteristics of long-term morphological evolution, as well as for modeling this evolution, when applied under the right circumstances. However, more sophisticated techniques rely on more data in time and space, which is typically the limiting factor in the application of statistical methods as those presented here. [ABSTRACT FROM AUTHOR]

Abstract: Spits are among the most dynamic features in the coastal zones. Their stability is, very often, the result of a fragile equilibrium between the availability of sediments and the forcing hydrodynamics. Due to the complex interactions between the processes shaping such geomorphologic features the investigation is difficult and requires separate analysis for each of the processes. A typical example of a spit is Sahalin, which emerged one century ago at the mouth of the Danube Delta''s southernmost distributary, and has continuously evolved through elongation and lateral migration. In order to investigate and quantify separately each of the main processes shaping a spit we divide our research in two stages. First, wave induced sediment transports were simulated and analyzed using a complex processes based on a numerical model for an idealised spit. This schematized spit was based on the shape of a number of spits. Secondly, the findings were used in a similar approach for a real case: the Sahalin spit. Results show convergence of the wave fields towards the spit and large transport rates for the dominant wave directions. The sediment budget, derived from the predicted transport and the historical maps of the spit, show that the evolution of the spit is the result of a continuous interaction between along- and cross-shore sediment transport. Furthermore, a good match was obtained between the volumes of sediment supplied to the spit system and those feeding the expansion of the spit. The final output is a conceptual model that includes four stages (submarine accumulation, emerging, evolution and merging with the mainland of the spit) based on the findings from the present study as well as on the findings of previous authors. Although the model was constructed to explain the evolution of Sahalin spit, it is suggested that it can be applied more generally for spits formed in wave-dominated deltas, in a microtidal environment and with a wave climate dominated by one direction. [Copyright &y& Elsevier]

Abstract: This paper attempts to highlight issues that are relevant in the application of the Parabolic Bay Shape Equation (PBSE) to a non-equilibrium bay. For this case, the bay of Imbituba in southern Brazil was chosen. The construction of a breakwater to shelter the port of Imbituba in the south of the bay was accompanied by an increase in sedimentation to the port area from an eroding downdrift beach. Superimposed plots of the coastline of the Bay of Imbituba from different years confirm a general trend of accretion of the southern part of the bay accompanied with a retreat of the coastline in the northern part. After the application of the PBSE it became clear that the breakwater caused a change in the equilibrium state of the bay. Between 1947 and 2001 the Bay of Imbituba has changed from a dynamic equilibrium to a natural beach reshaping or self-reshaping. The tendency of the sedimentation of the southern part of the bay can be explained by the SEP associated with the new updrift diffraction point (tip of the breakwater): The seaward position of the SEP predicts a need for additional sediment in order to achieve a stable plan form. [Copyright &y& Elsevier]

Abstract: This paper aims to quantify the uncertainty in the application of the Parabolic Bay Shape Equation (PBSE) for a bay in static equilibrium. By means of expert elicitation, a database was generated consisting of the position of the control points that determine the Static Equilibrium Planform (SEP). The elicitation consisted of two parts. In Part 1, 22 expert volunteers were asked to place the three control points that determine the SEP on a vertical aerial photograph of Taquaras–Taquarinhas Bay, a morphologically stable bay in the south of Brazil, approximately 1800m in width and with an indentation of 750m. The distribution of the location of the SEP along four evenly spaced (200m) profiles in the southern part of the bay was determined. The overall bias of the location of the SEP calculated over the four profiles was in the order of 41m (landward) and the average standard deviation was 116m. These parameters increased when moving alongshore toward the curved section of the bay. This means that the uncertainty in the application of the PBSE is dependent on the particular point of interest along the bay. In Part 2 of the elicitation, 30 volunteers participated. This time the consequence of the placement of the control points (the corresponding SEP) was visible. Comparing the results from Parts 1 and 2, it was observed that when volunteers were directly confronted with the result of the placement of the control points (a plotted SEP) a much smaller variation in the position of the SEP occurred. This implies that when feedback on the result is provided the PBSE is a more robust method. [Copyright &y& Elsevier]

In this study, we aim to investigate the overall morphological evolution of the Jiangsu coast after 1855, when the Yellow River shifted northward. We focus on fine sediment transport between two large-scale geomorphological units, i.e., the Abandoned Yellow River Delta (AYD) and the Radial Sand Ridges (RSRs). An existing morphodynamic model, which was established for reproducing the development of the AYD before 1855, is modified and extended. In addition to the tidal forcing, waves and human interventions (i.e., revetments) are considered in the model. The model results are compared with the existing data. Both the evolution trend of the Jiangsu coast and the spatial distribution of the offshore shoals show good agreement. The simulated fine sediment depositions in different periods are consistent with the geological measurements. The results reveal that the old Yellow River-derived sediment not only contributes to the sedimentation in the RSRs but can also be transported to the adjacent zones, especially farther south/southeast. Moreover, the spatial distribution of fine sediment deposits varies in the RSRs. The different sedimentary environments in the Dongsha and Tiaozini ridges result in significant grain size differences in these two neighboring ridges. A sensitivity analysis indicates that tides play a key role in dominating the long-term morphological evolution of the Jiangsu coast and the total erosion from the AYD. On smaller scales, the effect of revetments (built since the 1930s) on the evolution of the nearshore zone and the effect of wind waves on the erosion of offshore shoals are relatively important. The effect of a gradual coarsening process of bottom sediment along the Jiangsu coast, which may be due to continuous fine sediment removal, is identified. Fine sediment depositions in the Tiaozini ridge and in the northern offshore zone of the RSRs are relatively more sensitive to the coarsening trend of bottom sediment than other areas. [ABSTRACT FROM AUTHOR]

Abstract: The recently developed Morphological Acceleration Factor (MORFAC) approach for morphodynamic upscaling enables numerical model simulations of coastal evolution at decadal to millennial time scales. Primarily due to the massive increase in modeling time scales it affords, the MORFAC approach is now standard in state-of-the-art commercially available coastal morphodynamic modeling suites. However, the general validity of the MORFAC concept for coastal applications has not yet been comprehensively investigated. Furthermore, a robust and objective method (as opposed to the subjective and inelegant trial and error method) for the a priori determination of the highest MORFAC that is suitable for a given simulation (i.e. critical MORFAC) does not currently exist. This communication presents some initial results of an ongoing, long-term study that attempts to rigorously and methodically investigate the limitations and strengths of the MORFAC approach. Based on the results of a strategically designed numerical modeling exercise using the morphodynamic model Delft3D, two main outcomes are presented. First, the main dependencies and sensitivities of the MORFAC approach to fundamental forcing conditions and model parameters are elucidated. Second, a criterion based on the Courant–Friedrichs–Levy (CFL) condition for bed form propagation that maybe used as a guide to determine the critical MORFAC a priori is proposed. [Copyright &y& Elsevier]