Marek Szmytkiewicz

Coastal Processes in the Red River Delta Area, Vietnam

The economy and life in Vietnam is associated with the existence and development of large river deltas, i.e. the Mekong Delta and the Red River Delta. The latter is located in the northern part of Vietnam and apart from thousands of square kilometers of the area, it includes more than 165 km of coastline as well. In this area, the seashore and the adjacent densely populated, low-lying regions are often subject to intense impacts from the river (floods) and the sea (typhoons, changes in sea level, currents, etc.) and therefore undergo substantial and dynamic changes and destructions. In the current study, one of the coastal segments that are most vulnerable to destruction in Vietnam is analyzed. A synthetic analysis of the available information was carried out first and then the modeling of wave climate, currents and sediment movement patterns in the nearshore zone was done. The formulation of a phenomenological model of sediment budget, adequate for the amount of available information, allowed for assessment of the existing sediment fluxes and their relations to morphodynamic processes taking place in the studied area.

WAVE CLIMATE AND LARGE-SCALE COASTAL PROCESSES IN TERMS OF BOUNDARY CONDITIONS

The present analysis, as a kind of case study, deals with the experimental research at two different coast sites of the South Baltic. The analysis of the driving forces caused by wave fields and so on, and the responses, like current circulations, sediment transport and morphological coastal changes, gave rise to the attempt of empirical description of environmental site-specific coastal features and their large-scale interactions. In the present study, the name “large-scale” refers to the processes having the longshore scale of the order of kilometres and the cross-shore scale of hundreds of metres. Time scales lie in the range from months, seasons up to a few or dozen or so years at most. The above investigations provide an insight into the specific hydro- and morphodynamical processes occurring in coastal zones of the Baltic Sea. These processes can be regarded as representative for other small seas.

Field Observation of Edge Waves and Beach Cusps on the South Baltic Sea Coast

Abstract Within the two major theories of the generation of rhythmic shoreline features, the earlier one relates to edge waves, whereas the one developed later perceives shoreline rhythmic forms as effects of self-organized shoreline behavior. This study focused on identification of infragravity waves (edge waves) and periodic components of shoreline configuration and searched for their potential relationships in the mildly sloping, sandy south Baltic coast. The objective was not to suggest which theory better describes shoreline rhythmic features but was chosen for an empirical assessment of possible links between the generation of rhythmic morphological beach forms and specific infragravity waves motion at a dissipative shore. The investigated area features a gently sloping seabed with several bars inducing multiple breakers, which can be classified as a dissipative beach. Field measurements were taken during two periods lasting several months each. Long records of water table oscillations, nearshore currents, and measurements of shoreline configurations were analyzed using various signal processing techniques, incorporating traditional spectral analysis and the modern statistical techniques of singular spectrum analysis and discrete wavelet transform. The measurements revealed two clearly visible infragravity components with periods Tk = 30–40 seconds and Tk = 100–120 seconds at a dissipative south Baltic beach with multiple bars. They were detected by all three methods employed in the study. Additionally, less pronounced components were identified with periods Tk = 180 seconds and Tk = 10–12 seconds. The analysis of variability of the shoreline shape found periodic components with wavelengths ranging between several and several hundred meters and more. Results of this study also suggest that there are links between infragravity waves and rhythmic shoreline forms in a dissipative shore with multiple bars.

Innovative Engineering Solutions and Best Practices to Mitigate Coastal Risk

Engineering solutions are widely used for the mitigation of flood and erosion risks and have new challenges because of the expected effects induced by climate change in particular sea level rise and increase of storminess. This chapter describes both active methods of mitigation based on the reduction of the incident wave energy, such as the use of wave energy converters, floating breakwaters and artificial reefs, and passive methods, consisting of increase in overtopping resistance of dikes, improvement of resilience of breakwaters against failures, and the use of beach nourishment as well as tailored dredging operations.Existing coastal management and defense approaches are not well suited to meet the challenges of climate change and related uncertanities. Professionals in this field need a more dynamic, systematic and multidisciplinary approach. Written by an international group of experts, Coastal Risk Management in a Changing Climate provides innovative, multidisciplinary best practices for mitigating the effects of climate change on coastal structures. Based on the Theseus program, the book includes eight study sites across Europe, with specific attention to the most vulnerable coastal environments such as deltas, estuaries and wetlands, where many large cities and industrial areas are located. * Integrated risk assessment tools for considering the effects of climate change and related uncertainties* Presents latest insights on coastal engineering defenses* Provides integrated guidelines for setting up optimal mitigation measures* Provides directly applicable tools for the design of mitigation measures* Highlights socio-economic perspectives in coastal mitigation

Chapter 3 – Innovative Engineering Solutions and Best Practices to Mitigate Coastal Risk

Engineering solutions are widely used for the mitigation of flood and erosion risks and have new challenges because of the expected effects induced by climate change in particular sea level rise and increase of storminess. This chapter describes both active methods of mitigation based on the reduction of the incident wave energy, such as the use of wave energy converters, floating breakwaters and artificial reefs, and passive methods, consisting of increase in overtopping resistance of dikes, improvement of resilience of breakwaters against failures, and the use of beach nourishment as well as tailored dredging operations.Existing coastal management and defense approaches are not well suited to meet the challenges of climate change and related uncertanities. Professionals in this field need a more dynamic, systematic and multidisciplinary approach. Written by an international group of experts, Coastal Risk Management in a Changing Climate provides innovative, multidisciplinary best practices for mitigating the effects of climate change on coastal structures. Based on the Theseus program, the book includes eight study sites across Europe, with specific attention to the most vulnerable coastal environments such as deltas, estuaries and wetlands, where many large cities and industrial areas are located. * Integrated risk assessment tools for considering the effects of climate change and related uncertainties* Presents latest insights on coastal engineering defenses* Provides integrated guidelines for setting up optimal mitigation measures* Provides directly applicable tools for the design of mitigation measures* Highlights socio-economic perspectives in coastal mitigation

MODERNISATION OF THE VISTULA RIVER OUTLET – OPTIMISATION OF THE JETTIES BY MODELLING APPROACH

A vast marine alluvial fan in front of the artificial outlet of the Vistula constitutes a serious obstacle for water flow and sediment fluxes at the river-sea interface. Especially, in winter, this obstacle causes ice jams, which result in floods at adjacent, partly depressive, areas. Therefore, regulatory works need to be carried out periodically at the river mouth. Recently, to optimise the outlet modernisation, the relevant archival material has been analysed and numerical modelling has been undertaken. The optimisation comprised a number of layouts of the jetties and various flow conditions, for which the hydrodynamic, lithodynamic and morphodynamic processes were simulated theoretically using the computer software. The effectiveness of each considered solution was assessed on the basis of the results in front of the outlet, namely the flushing efficiency at the alluvial fan and the offshore distance at which the riverbome sediments were deposited.

Wave Transformation in a Multi-Bar Surf Zone: Case Study of Lubiatowo (Poland)

Abstract The paper presents results of field and theoretical investigations of wave transformation in the surf zone near the IBW PAN Coastal Research Station in Lubiatowo (Poland, the south Baltic Sea). The study site displays multi-bar cross-shore profiles that intensively dissipate wave energy, mostly induced by breaking. The main field data comprise wave heights and cross-shore bathymetric profiles.Wave transformation is modelled theoretically by two approaches, namely the IBW PAN phase-averaged wave transformation model and the approach based on the hydraulic jump model, developed by Hsu & Lai (2009) for hydrological situations encountered under the actual conditions of two field campaigns - in 1987 and 1996. Discrepancies between the measured data and the model results are discussed. In general, the model results are in good agreement with the in-situ observations. The comparison of the field data with the computational results concerns a part of the surf zone between about 5 m water depth and the first nearshore stable bar, where the depth amounts to ca. 1.2 m.

Coastal Protection and Associated Impacts - Environment Friendly Approach

The paper highlights coastal protection as a component of integrated coastal zone management (ICZM). ICZM particularly emphasizes environmental aspects of all activities in coastal areas, combining research results from natural and social sciences. In this context it particularly favors solutions avoiding undesired disturbances to coastal (eco) systems, including unnatural coastal morphology, poor water quality and impaired biodiversity. Simultaneously, it supports schemes being flexible enough to cope with the global climate change on a longer time perspective. Thus, in the ICZM view, the best measures incorporate soft coastal protection techniques, i.e. artificially initiated natural dunes and beach fills, permeable groins and submerged breakwaters, discussed extensively herein.

Groins and submerged breakwaters – new modeling and empirical experience

Abstract The relationship between the effectiveness of groins and their technical condition was studied. The supporting role of groins in artificial shore nourishment was tested using the theoretical modeling of hydrodynamic and morphodynamic processes in the nearshore zone. This modeling scheme was developed as to represent the actual coastal situation occurring on the shores of the Hel Peninsula (the Gulf of Gdańsk, the southern Baltic Sea). Based on the results of computations and the results of field observations, recommendations were prepared on the design and maintenance of groins. The second part of the paper is devoted to submerged breakwaters. The theoretical modeling of wave-current fields near the segmented submerged breakwaters led to the determination of coefficients of wave transmission and rip current velocities, which finally yielded a piece of design advice. In all numerical simulations, the Delft3D software was used.