Thesis (M.S.)--University of New Orleans, 2005. / Title from electronic submission form. "A thesis ... in partial fulfillment of the requirements for the degree of Master of Science in Dept. of Geology and Geophysics"--Thesis t.p. Vita. Includes bibliographical references.

The Nanbin-Beibin beach (South-North beach) at Haulien city on the east coast of Taiwan was probably in a dynamic state close to stable, prior to the completion of the Eastern Breakwater extension for Hualien harbor. Since 1987, this beach has begun experiencing adverse effect of the breakwater extension, with erosive trend continuing at Huazern beach and Nanbin Beach, accompanying by accretion at Beibin. Government authorities have constructed seawalls, submerged breakwaters and applied several types of precast concrete blocks to protect the eroding section of the coast. This study investigates the beach processes at Nanbin-Beibin Beach, starting from its oceanographic and climate condition, beach changes in the past four decades, to the protective countermeasures installed. With large-scale geomorphic approach, it is expected that combining headland control with nourishment could provide local residents and tourists with a harmonious semi-natural coastal space. This report contains the discussion on SBEACH¡Ðsoftware for beach changes induced by storm waves, headland control with stable bayed beach and artificial nourishment; followed by description of shoreline protection at Nanbin-Beibin Beach, and finally a proposal for improving the beach stability. The study follows some of the known principles and software available in the field of coastal engineering today. Firstly, stability of the Nanbin-Beibin Beach in relation to the total length of the Eastern Breakwater of Hualein harbor is assessed by MEPBAY software recently developed for the application of parabolic bay shape equation. Secondly, a rational beach retreat is calculated using SBEACH software, which is to be used as a minimum buffer width for a proposed bayed beach using MEPBAY. Thirdly, headland control approach is suggested using artificial headlands in a curved shape rather than the traditional straight groin and detached breakwater in narrow gaps. Finally, total volume of the fill materials and budget are estimated, in order to enhance the applicability of this study. By implementing MEPBAY, it can be found that the stability of Nanbin-Beibin Beach will transform from unstable natural re-shaping to static equilibrium, using an upcoast control point 150 m short off the tip of the Eastern Breakwater. Thus, the eroding potential to Nanbin Beach could be effectively removed, and the local erosion may then become manageable. In this way, part of the precast concrete units forming the submerged breakwaters in front of the seawalls at Nanbin Beach may be taken out for construction of new detached or submerged units or artificial headlands elsewhere at Beibin Beach. The entire detached breakwater system should then be re-designed with a widened gap between units combined with bayed beach in static equilibrium and nourishment. Sufficient buffer width should be provided to all the static bay shapes so implemented. It is envisaged that the geomorphic approach considered in this report may help devise a plan to restore the eroding beach at Hualein.

Studies have documented spatially and temporally variable rates of surface subsidence across the Mississippi River delta plain of Louisiana. Variations in patterns and rates of delta plain subsidence may reflect subsurface distribution of compactionprone lithosomes. This research investigates historical changes in the surface geomorphology of the Caillou Bay headland in relation to the distribution of subsurface lithosomes. The stratigraphic framework was developed for the headland, and lithosomes were identified to establish the distribution of different sedimentary units. The geomorphic evolution as indicated by maps was then evaluated in order to locate patterns of shoreline change and wetland loss for the headland. Land loss maps developed were overlain on lithosome contour maps to calculate amounts of land loss overlying each lithosome contour interval. Analysis of results revealed that land loss was not uniform throughout the headland and that land loss patterns for several time periods varied as a function of the thickness of compactionprone lithosomes.

Syftet med detta arbete var att undersöka om det fanns intresse för att införande av DUKC (Dynamic Under Keel Clearance) systemet i Sverige.Vi utgick ifrån en hamn i Australien, Port Hedland, som använt systemet sedan 1996, sedan tog vi reda på vad som användes i Sverige. För att få en bra grund sökte vi information om vad som krävdes för att DUKC skulle fungera tillfredställande. Vi Tog också del av en studie som man utfört i Mälaren som grundar sig på fartygs dynamiska rörelser och djupgående.Utifrån vår insamlade data ville vi fråga en sjöfartsrelaterad grupp och undersöka hur intresset för DUKC såg ut och skickade ut en enkät som även innehöll ett informationsblad.Efter sammanställning av erhållna svara framgick det att intresset för att införa just DUKC systemet inte var så stort men däremot ett system som gör det möjligt att säkerställa de krav som finns idag.

<p>Syftet med detta arbete var att undersöka om det fanns intresse för att införande av DUKC (Dynamic Under Keel Clearance) systemet i Sverige.Vi utgick ifrån en hamn i Australien, Port Hedland, som använt systemet sedan 1996, sedan tog vi reda på vad som användes i Sverige. För att få en bra grund sökte vi information om vad som krävdes för att DUKC skulle fungera tillfredställande. Vi Tog också del av en studie som man utfört i Mälaren som grundar sig på fartygs dynamiska rörelser och djupgående.Utifrån vår insamlade data ville vi fråga en sjöfartsrelaterad grupp och undersöka hur intresset för DUKC såg ut och skickade ut en enkät som även innehöll ett informationsblad.Efter sammanställning av erhållna svara framgick det att intresset för att införa just DUKC systemet inte var så stort men däremot ett system som gör det möjligt att säkerställa de krav som finns idag.</p>

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Inserido na zona costeira cearense, 85 km a oeste de Fortaleza, o municÃpio de Paracuru apresenta intensa dinÃmica geoambiental expressa na forma de variados tipos de relevo que evidenciam as trocas de matÃria e energia no sistema costeiro. Tomamos em anÃlise as influÃncias oferecidas pelo promontÃrio de Paracuru à sua dinÃmica costeira e litorÃnea. Assim, a pesquisa se baseou na anÃlise do relevo litorÃneo como instrumento à compreensÃo da dinÃmica geoambiental do referido municÃpio. Realizou-se pesquisa bibliogrÃfica em diferentes meios (livros, periÃdicos, internet), levantamento cartogrÃfico para a produÃÃo de mapas temÃticos, trabalhos de campo para reconhecimento e construÃÃo de anÃlises sobre o espaÃo costeiro, e etapas de gabinete para o tratamento de dados e escrita do trabalho final. Desenvolveu-se a caracterizaÃÃo ambiental, anÃlises sobre a dinÃmica litorÃnea e a formaÃÃo socioespacial do municÃpio considerando os principais usos do solo. Demonstra-se que o promontÃrio de Paracuru desenvolve funÃÃes determinantes na atual configuraÃÃo do litoral ao controlar a distribuiÃÃo de sedimentos transportados pela deriva litorÃnea e ainda que a variedade de usos do solo determina historicamente o acÃmulo de impactos ambientais na planÃcie costeira paracuruense. / The city of Paracuru is part of the coastal area of the state of Cearà and is located 85 km from the capital, Fortaleza. Paracuru presents intense environmental dynamics that can be seen through various types of reliefs that show the exchanges between matter and energy in the coastal system. This paper took under consideration the influence of the Paracuruâs promontory in the coastal and littoral dynamics. Thus, the research was based on the analysis of littoral relief to understand the environmental dynamics of that part of cityâs coast. To analyze these coastal areas, it was made bibliographic search, cartographic survey and fieldworks, plus some cabinet steps for the treatment of data. The environmental characterization and analysis of the coastal dynamics demonstrates that the Paracuruâs promontory develops determining functions in the current configuration of the coast because it controls the distribution of sediments transported by longshore drift. The analysis also shows that the variety of land uses determines historically the accumulation of environmental impacts on the coastal plain of Paracuru.

Confined coasts in general, and pocket beach environments in particular, are under huge development pressures worldwide, not least due to their sheltered nature and perceived shoreline stability. However, understanding of their physical functioning is poor in comparison to that of open coast beaches. This study aims to improve understanding in terms of the existing gaps in knowledge of wave processes and nearshore currents, and also to examine the importance of local wind and tide factors in generating nearshore currents, in micro-tidal pocket beaches. The boundaries of embayments are generally recognized as important controls of their beach processes and responses, yet little detailed knowledge exists of how the exact embayment dimensions and characteristics influences these processes. One key embayment feature the influence of which is poorly understood is the downcoast headland. In this thesis, field observations plus Zanuttigh and Van der Meer’s (2008) approach, and the SWAN wave model were used to evaluate the downcoast headland effects on wave processes within Okains Bay, an example pocket beach environment. The results showed that incident wave heights and directions were significantly influenced by wave reflection processes from the downcoast headland inside the bay. The intensity of reflection effects on wave characteristics inside the pocket beach varied according to approaching wave direction. Reflection effects reduced when waves approached from angles close to parallel to the headlands, increasing towards headland-perpendicular wave approaches. Field observations and the XBeach model were used to examine whether or not tides can significantly influence nearshore currents within example and model pocket beach environments. Results indicated that tides can be the primary driver of nearshore currents close to the bed inside micro-tidal pocket beaches, depending on incident wave conditions. In areas of micro-tidal pocket beaches exposed to direct approaching waves, currents were wave driven, while in areas further into the bay that experienced headland filtering of their wave environment, currents were mainly tide generated. The results of this study demonstrated how the current circulation system within micro-tidal pocket beaches is related to the incoming directions of offshore waves. If high energy waves approach oblique or normal to the shoreline (with the assumption that the shoreline is at 90° to the headlands), the current system was found to consist of longshore currents influenced by headlands, plus a rip current in the center of the shoreline or a toporip in proximity to headlands. The location of the rip current or toporip was determined by the direction of approaching incident waves. This study also examined the behavior of local winds in a pocket beach environment and their consequent effects on nearshore currents. Results for Okains Bay show that local winds tended to blow in offshore and onshore directions, as the bay is located in a valley, so orographic effects channel and shift the wind directions to angles close to offshore and onshore directions inside the bay. Results also indicated that local winds influence the hydrodynamic currents of pocket beaches that are confined by elevated topography, producing semi-cross shore influences since the winds are topographically channelled to blow in predominantly offshore and onshore directions. This research significantly refines our understanding of micro-tidal pocket beach wave and current processes, including quantification of the filtering effects of headlands on their wave environments, revealing the various and variable influences of tides and winds compared to in open coast beaches; and, significantly, highlighting the role of downcoast headland wave reflection effects. With regard to the latter, this research elucidates some key process differences between pocket and embayed beaches and clarifies reasons why the application of embayed beach models that include refraction and diffraction but exclude reflection effects to the study of pocket beaches is inappropriate for studying pocket beaches. This research also provides methodological and topic suggestions for future research on pocket beach environments, including how to use the improved hydrodynamic knowledge of this study in future studies seeking to better understand pocket beach sediment systems, a topic that was beyond the scope of the current research.

West Belle Pass Barrier is a barrier spit that formed during the last delta lobe progradation associated with the Lafourche delta complex. Located on the western flank of the Caminada-Moreau Headland, West Belle Pass Barrier and Raccoon Pass are located downdrift of the Belle Pass jetties. Morphological changes stemming from storms, jetty infrastructure, and an expanding tidal inlet are evaluated using historical shoreline data and imagery. Littoral transport around the jetties combined with inlet growth created a framework wherein sediment is transported through Raccoon Pass and sequestered as a flood-tidal delta. These events aided in the landward migration of West Belle Pass Barrier, which ultimately loaded and consolidated previously unconsolidated facies. A conceptual model illustrating the primary consolidation of backbarrier facies resulting from washover deposits during one storm is presented. The primary consolidation settlement associated with loading near-surface, water-saturated backbarrier facies is substantially larger than current subsidence rates.

A numerical study aimed at investigating the conditions under which different flow regimes appear near coastal capes is presented. The impacts of the regimes are also quantified in terms of integral quantities like mixing, current transport and form drag. Idealized and realistic numerical simulations are run both in barotropically and baroclinically-driven systems. The realistic cases model the Western Adriatic Current (WAC) in the Adriatic Sea. In both cases, the turbulent state of the flow is controlled in first approximation by the Burger number, Bu. When a steady barotropic and geostrophic current impinges on a triangular idealized cape, vertical movements are strong for Bu < 0.1 and pronounced lee waves can be found downstream of the obstacle. For 0.1 less than or equal to Bu < 1, fluid parcels flow more around the obstacle than over it. Flow separation occurs and small tip eddies start to shed. For Bu greater than or equal to 1, tip eddies merge to form larger eddies in the lee of the cape. Flow regimes are also strongly dependent on the obstacle slope alpha when Bu greater than or equal to 1. Flow regime diagrams in the Bu-alpha space are determined. A baroclinic current as the WAC becomes unstable in absence of wind as it separates from the coast for the presence of capes along its path. Downwelling favorable winds narrow and thicken the coastal buoyant current, raising Bu above a critical value and suppressing baroclinic instabilities. Upwelling favorable winds enhance instabilities via the opposite mechanism. With downwelling winds waters mix but remain relatively fresh (S less than or equal to 38), while most of the freshwater signal is lost with upwelling winds. The along-shore transport increases with downwelling winds while it decreases and can even reverse with upwelling winds. The form drag calculated across the obstacles in the different simulations is at least twice the magnitude of skin friction. In barotropic conditions it increases with increasing Bu and decreasing alpha and an empirical parametrization in the Bu-alpha space is put forth. Across the Gargano Promontory, more symmetric pressure fields are observed with downwelling winds; the form drag decreases as a result. The opposite is registered with upwelling winds.

In the last few decades, academic and institutions advanced in coastal research in Europe and America have rigorously engaged in developing numerical models for coastal wave hydrodynamic simulations. The notable products include MIKE21 from DHI in Denmark, CEDAS (with GENESIS and SBEACH) from Veri-Tech in the United States, and the SMC from University of Cantabria in Spain. Among them, the Spanish Coastal Modeling System (SMC) is the only integrated package for coastal planning and modeling. With a unique preprocess module which pre-stores the bathymetry and wave data, the SMC provides a user-friendly interface directly using the screen display for a series of coastal planning and design applications which comprise artificial nourishment with headland-bay beach, breakwater construction and extension, and dredging of navigation channel etc., as well as the usual wave-current simulation for countermeasures in coastal protection and disaster mitigation. Despite the availability of several numerical programs for wave-current simulations and beach changes that have been developed by the coastal professional in Taiwan, and the continuous effort of the Water Resources Agency, Ministry of Economic Affairs to establish a national coastal database, it is imperative to develop/setup an integrated bathymetry-hydrodynamics-protection system, such as the Spanish SMC, as the key element in the national platform for coastal planning and modeling. This dissertation first describes the coastal environment in Taiwan, major causes for shoreline evolution and then reviews the history of shore protection since 1970s, together with the current prospective for coastal environment and strategies to sustain the natural shoreline ratio. To accomplish these goals, the Water Resources Agency has endeavored to implement artificial nourishment with headland-bay beaches, in order to raise the ratio of natural shoreline, in addition to establish a national coastal planning and simulation platform. As a response to this call for eco-engineering approach, we recommend that headland-bay beach in static equilibrium be adopted for mitigating coastal erosion, beach restoration and creation of recreational beaches, which can be designed directly on the screen using the empirical bay shape equation in conjunction with the SMC. Based on the framework of the Spanish SMC, this writer has successfully attempted the preliminary pre-process module of Baco (bathymetry) and Odin (wave climate) for Taiwan, using data from digitized nautical charts, nearshore depth surveys, and long-term wave observation results around Taiwan from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS). The effort generates the first version of SMC in Taiwan. Having pre-stored the bathymetry and wave data for Dapeng bay in Pingtung County and Sizihwan Bay in Kaohsiung City, a series of coastal planning and modeling procedures for these two model sites are demonstrated in this dissertation, including a series of calculations of wave-current distribution for monsoon and storm waves, as well as planning of bay beach using artificial nourishment. Upon executing the Taiwanese version of SMC introduced in this dissertation, the modeling results can be applied to assist the planners and decision makers in comprehending the coastal environment, devising a feasible shore protection strategy, and promoting an earlier accomplishment of the so-called ¡ugeo-engineering ¡u in our country. Finally, the writer also wishes the outcome of this study could help relevant government agency to accomplish the prospective of sustainable coastal development upon implementing the strategies of establishing an appropriate coastal planning platform and promoting a systematic approach for coastal planning and design, as revealed in the "Sustainable Regeneration of Coastal Environment Project (98 ~ 103 fiscal year)".