The circular wave basin provides a means of physically modeling the nearshore without the typical problems associated with end walls. Three different coastal processes were examined to demonstrate the use of a spiral wavemaker in a circular wave basin. These were longshore currents, shear waves, and groin circulation. A beach was designed and constructed to concentrate breaking in a narrow region and minimize wave reflection. Currents in the longshore direction were generated by both the motion of the wavemaker and oblique wave approach. Two methods for measuring nearshore currents were employed. First, a 3-D acoustic current meter was positioned at various locations in the cross shore and the local radial and tangential velocities were recorded. Second, a video camera was placed approximately 8 meters above the wave basin to record the motion of a ball in the nearshore. The video tape was digitized by an image processor and the motion of the ball was determined. Measurements of nearshore circulation in the circular wave basin were used to investigate longshore currents, shear waves, and groin circulation. Average measured longshore current profiles in the cross shore were compared with numerical model predictions. An analysis of the existence of shear waves in the circular wave basin was performed by calculating longshore and cross shore current spectra. Particular attention was focused on the low frequency end of the spectra where shear waves are most energetic. Model groins were placed in the circular wave basin and measured currents were compared to predicted circulation patterns. All three applications indicated that the circular wave basin is a useful device for simulating coastal processes in a laboratory environment. / Graduation date: 1992

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)".

Although flow deflectors are routinely placed in streams to create fish pool habitat, there is dissent in the literature as to what constitutes for them an appropriate design height to ensure their success. Our objectives were to (1) examine the temporal evolution of bed topography around submerged deflectors in a laboratory flume, for different deflector heights and discharge; and (2) quantify the flow dynamics in their vicinity. Results indicate that, all else being equal, higher deflectors (characterized by less overtopping) produce a greater volume of fish pools. In contrast, over a fixed deflector design, a higher discharge (synonymous with greater overtopping) results in larger pools, because flow velocities are then faster. We also observed differences in the temporal behaviour of scour: that next to high and medium height deflectors is self-similar, but not that for the shorter model. Our results challenge the notion that low deflectors are ineffective, provide information on the development of scour next to submerged structures, and reveal key differences between the geometry of the scour holes engendered by the different deflector height models.

A three-dimensional numerical model (PHOENICS) was used to investigate the role of stream deflector angle and length on the flow field in a rectangular laboratory flume. Subsequent bed topography surveys were performed to examine the role of obstruction angle on scour hole development over time. The model was capable of predicting laboratory velocity and turbulent kinetic energy measurements, performing better for flow over a flat stable bed than over a deformed sand bed. A new method of incorporating complex bed topography into a structured Cartesian mesh was developed in the process. Flow field properties such as dynamic pressure, velocity amplification, separation zone length and width, and downwelling extent and magnitude were found to be strongly dependent on deflector geometry. Equilibrium scour hole depths and geometry are also angle-dependent. A predictive equation was produced explaining the rate at which scour holes reach equilibrium, and compared well with existing literature. Finally, a method was developed whereby characteristics of the flow field over a flat, stable bed could be used to predict equilibrium scour hole geometry.

Thesis (M.Sc. Earth and Ocean Sciences)--University of Waikato, 2008. / Title from PDF cover (viewed September 18, 2008) Includes bibliographical references (p. 121-123)

Thesis (M.S.)--University of North Carolina at Wilmington, 2004. / Includes bibliographical references (leaves : [92]-97).

Egmont Key, located at the mouth of Tampa Bay, is part of a dynamic system with many interrelated natural and anthropogenic factors influencing its morphodynamics. This study started in August 2012. During the 3-year period until August 2015, 28 beach profile transects were established and surveyed 10 times. Seventeen historical aerial images from 1942 to 2013 were geo-rectified and analyzed. Three hundred and fourteen sediment samples were procured from the navigation channel dredge area and the beach nourishment area and analyzed for grain size. A numerical wave model was established to simulate the nearshore wave field. The overall goals of this study are to understand the complex morphodynamics of Egmont Key and to evaluate the shore-protection efforts. The overall area of the Egmont Key has reduced 52% from 2.1 km2 in 1942 to 1.o km2 in 2002. The area loss was mostly caused by beach erosion along the Gulf-facing beach. The island-area reduction from 1942 to 2002 was largely linear. Two periods of accelerated area loss from 1978-1984 and 1999-2002 can be related to dredging of the Egmont Channel and the disposal of dredged materials along the channel. Concerning the relatively high mud content in the borrow area for the 2014 nourishment, a large amount of the fine sediment was lost at a temporal scale of hours to days during the dredging and beach nourishment construction processes. Some of the mud was deposited outside the surf zone at water depths of 2 m or greater. This mud became eroded naturally by energetic conditions at a temporal scale of months. Beach erosion and accretion along the Gulf-facing beach can be related qualitatively to tidal flow patterns. Numerical wave modeling shows that the transverse bars offshore Egmont Key have a moderate influence on the wave field, leading to slightly different wave heights along the shoreline. However, there is no clear relationship between the nearshore wave conditions and the erosion/accretion patterns. The severe shoreline erosion has exposed various fort structures at the shoreline and in the nearshore zone. These structures function as detached breakwaters or groins and have localized influence on the beach state.

The St Francis Bay beach has experienced chronic erosion over the past three decades. This erosion can largely be attributed to the stabilisation of a large coastal dunefield which contributed +/- 80 percent of the sand supply to St Francis Bay. Stabilisation began in 1975 initially using plant cuttings and followed by the development of the Santareme holiday suburb resulting in complete stabilisation by 1985. Effects were felt from the late 1970‟s and since then the beach has retreated at between 0.5 - 3 m.yr-1. Erosion has encroached on beachfront properties since the early 1990‟s, leading to the placement of 3-4 m high unsightly rock revetments along much of the beach. Where properly maintained these structures have proved successful in protecting the properties behind, however exacerbated erosion of areas in front and adjacent to these structures is evident. Currently no dry beach is present at high tide for most of the year, leading to a significant reduction in beach amenity value. Several technical studies to investigate remediation of this beach erosion problem have been conducted since the early 1990‟s. This study includes investigations into the processes and dynamics of the existing environment and evaluation of the effectiveness and impacts of several elements of a hybrid approach to coastal protection and amenity enhancement for St Francis Bay beach. This proposal incorporated: Multi-Purpose Reefs (MPR‟s) offshore, for coastal protection and amenity enhancement in terms of surfing; beach nourishment with sand from the Kromme Estuary and dune rehabilitation with appropriate native sand binding species. Extensive fieldwork and data collection were conducted, this included: a series of bathymetric surveys; diving surveys and a helicopter flight; sediment sampling; beach profiling and deployment of a wave/current meter. Analysis of these data provided a greater understanding of the existing environment and dynamics of St Francis Bay and provided reliable inputs for numerical modelling. Numerical and physical modelling was conducted to assess the existing processes and conduct MPR design testing. In addition calibrated hydrodynamic modelling of the Kromme Estuary was conducted in order to assess the impacts of sand extraction from the large sand banks within the mouth of the Kromme Estuary for use as beach nourishment. Comparison of bathymetric survey data collected by the author in 2005/06 with survey data collected by the South African Navy Hydrographic Office (SANHO) in 1952 suggest a major loss of sand from the bay, with a volume difference of some 8.8 X 106 m3 calculated. Greater losses were measured between 10-15 m water depths, with shallow areas of +/- 5 m water depth, remaining more stable. This can be attributed to the presence of shallow reef and rocky substrate through much of the bay at this depth range. Monthly RTK GPS survey data from September 2006 to September 2007 indicates a total loss of 40 000 m3 over this period with the greatest losses measured along the northern part of the beach. The greatest losses were measured after large long period waves from a southerly to south-easterly direction occurred in conjunction with equinox tides in mid March 2007. Sediment sampling at over 100 locations within the bay indicated a high percentage of reef (26 percent) and fairly consistent grain size in the fine to medium size class throughout much of the beach, bay and large sand bank within the estuary. While the majority of the South African Coast is exposed to the predominant south westerly winds and waves, St Francis Bay‟s orientation means that waves from a south easterly to easterly direction dominate. The results of the detailed numerical modelling of the hydrodynamics agree with previous calculations and modelling results which concluded that strong unidirectional longshore currents occur along the headland due to the oblique angle of wave incidence and the close to parallel angle of wave incidence along the beach leads to weak longshore currents of variable direction. Erosion along St Francis Bay beach is a result of cross-shore erosion due to large waves from a southerly to easterly direction. Detached breakwaters are the most effective form of coastal protection in these environments and MPR‟s offer additional benefits over traditional breakwater structures. Results of empirical calculations and numerical modelling indicate that the MPR‟s will provide effective coastal protection through the processes of wave dissipation, wave rotation, salient formation and alteration of nearshore circulation. Physical modelling results allowed the MPR design to be assessed and refined in terms of surfing amenity enhancement and construction constraints. In addition numerical modelling results indicate that impacts due to the extraction of up to 600 000 m3 of sand from the lower Kromme Estuary result in highly localised velocity reduction, mainly limited to the extraction areas. The calculated rate of sediment influx into the lower Kromme Estuary indicates that limited extraction, in the order of 20 000 – 40 000 m3 per year, should be sustainable in the long term. Sedimentation of the lower estuary over recent years has had negative recreational and ecological impacts, through reduced navigability and water exchange respectively. Therefore both the estuary and beach systems prove to benefit from this approach. Although not investigated in detail as part of this study, evidence from numerous projects worldwide indicates that foredunes help to trap wind-blown sand on the beach and form a buffer to storm erosion, therefore dune rehabilitation with native sand-binding plant species was recommended as the third element of the proposed remediation of St Francis Bay beach.

This thesis describes the processing of 3D Laser measurements from Vestpynten, Svalbard to find out the erosion pattern at the site as a basis for the design of an appropriated shore protection suggestion and also to evaluate the applicability of 3D laser measurement systems in Arctic environments. 3D laser measurements would be interesting for the analysis of areas with limited  accessibility, since 3D laser measurement allows very precise recordings of the landscape/ surfaces without the need of accessing the investigation area. Based on the processed pictures and further erosion analysis the thesis suggests an erosion protection design for Vestpynten, based on geosynthetics. This was found to be necessary, since the road connecting Bjørndalen to Longyearbyen is at Vestpynten only a few meters away from the edge of the instable, eroding cliff. The suggested geosynthetic protection design is expected to be appropriate in terms of ecological and economical requirements of the site.

Den svenska allemansrätten syftar bland annat till att stränder ska finnas tillgängliga för alla genom att ge goda förutsättningar för biologisk mångfald. För detta behövs ett strandskydd som skyddar mot exploatering men som kan tillåta ny bebyggelse, bland annat bebyggelse som leder till landsbygdsutveckling.Studien behandlar strandskyddet och landsbygdsutveckling i strandnära lägen (LIS) utmed norrlandskusten utifrån problematiken att utse nya LIS-områden. Landsbygdsutveckling i strandnära lägen är ett tillägg i den svenska strandskyddslagstiftningen och tillkom 2009 med syftet att utveckla landsbygden genom att lätta på strandskyddet och tillåta ny bebyggelse i attraktiva strandområden. LIS infördes som särskilt skäl i Miljöbalken och yrkar på att kommuner ska peka ut LIS-områden i sina översiktsplaner. LIS kan tillämpas i hela Sverige, med vissa undantag, och i LIS-områden är det sedan lättare att få beviljad dispens om åtgärden som dispensen avser bidrar till en utveckling av landsbygdenSyftet med den här studien är att underlätta utpekandet av LIS-områden rent geografiskt, men också på ett långsiktigt hållbart sätt så att landsbygdsutveckling skapas. Tidigare studier visar att det saknas tydliga kriterier som visar hur LIS-områden ska se ut för att nå LIS-tilläggets syfte med landsbygdsutveckling. Målet med studien är därför att ge förslag på kriterier som kan användas när nya LIS-områden ska utses.Studien utfördes som en fallstudie där fyra olika metoder tillämpades. I urvalet utsågs 17 kommuner efter norrlandskusten som var lämpliga kandidater för studien. Därefter genomfördes lagtolkning, enkätundersökning, intervjuer och områdesanalys.Resultatet visar ett flertal kriterier som används för att utse nya LIS-områden. En mall för LIS kriterier har tagits fram för att underlätta arbetet med LIS och för att få en samsyn om hur LIS ska pekas ut i landet. Mallen kan tillämpas i ett geografiskt informationssystem (GIS) som en multikriterieanalys (MCA).Kommuner misstolkar ofta lagstiftningen om LIS som leder till att felaktiga beslut tas om strandskydd och LIS-områden. Kommuner använder sig av kriterier för att utse LIS-områden men kriterierna ser olika ut och tillämpas på olika vis. LIS kan utvecklas så att landsbygdsutveckling nås i större utsträckning i framtiden med gemensamma mål och strategier. / Swedish public law aims to make shores accessible to everybody and provide good conditions for biodiversity. For this, a shore protection is needed that protects against exploitation, but which can allow new development, including buildings that lead to rural development.This essay is about shore protection, rural development in shore sites based on the problems in pointing out new areas for rural development in shore sites. These areas are called LIS-areas, a shortening for Landsbygdsutveckling i Strandnära lägen. Rural development in shore sites is a law from 2009 that made it possible to develop certain areas in the countryside with new buildings. LIS was added to the Environmental code with the purpose to repeal shore protection in rural areas so that municipalities could designate LIS-areas in their comprehensive plans. LIS is applicable throughout Sweden, with few exceptions, and in these certain areas it will be easier to get a dispensation approved if the dispensation will develop the rural area.The aim of this study is to facilitate the designation of LIS areas geographically, but also in a long-term sustainable way so that rural development is created. Previous studies show lack of criteria that show what LIS areas should look like and how large the areas should be in order to achieve rural development. The objective of the study is to provide suggestions on criteria that can be used when selecting new LIS areas.The study was conducted as a case study in which different methods were applied. The selection identified 17 municipalities along the coastline of northern Sweden that were suitable candidates for the study. Subsequently, reviews on LIS-areas, surveys, interviews and interpretation of the LIS-law were done.The result shows a number of criteria used to designate new LIS areas. A template for LIS criteria has been developed to facilitate the work with LIS and to obtain a consensus on how LIS should be identified in the country. The template can be applied in a geographical information system (GIS) as a multi-criteria analysis.Municipalities often misinterpret the legislation on LIS, which leads to incorrect decisions about shore protection and LIS areas. Municipalities use criteria to designate LIS areas, but the criteria look different and are applied in different ways. LIS can be developed so that rural development can be achieved to a greater extent in the future by common goals and strategies.