Shoreline sand waves are shoreline undulations with a length scale of several kilometres and a time scale of years to decades. They occur on many coasts, migrating in the direction of the dominant littoral drift and they introduce a variability into the shoreline position that can be greater than the long term coastal trend. The objective of this thesis is to provide more insight into the formation and dynamics of shoreline sand waves and, in particular, to explore the role of the so called high angle wave instability. Previous studies showed that the shoreline can be unstable under very oblique wave incidence. This high angle wave instability develops due to the feedback of shoreline changes and the associated changes in the bathymetry into the wave field. Wave propagation over this perturbed bathymetry leads to specific gradients in the alongshore transport that can cause the growth and migration of shoreline sand waves. In this thesis a quasi 2D non-linear morphodynamical model is improved and used to explore high angle wave instability and predict the formation and evolution of shoreline sand waves. The model assumes that the large scale and long term shoreline dynamics is controlled by the wave driven alongshore transport so that the details of the surfzone morphodynamics are not resolved. It overcomes some of the limitations of previous modelling studies on high angle wave instability. The wave field is computed with a simple wave module over the evolving bathymetry and an empirical formula is used to compute the alongshore transport. Cross-shore dynamics is described in a parameterized way and the model is capable of describing shoreline perturbations with a finite and dynamic cross-shore extent. The conditions under which shoreline instability can lead to the formation of shoreline sand waves are refined. Generic simulations with constant wave conditions and random initial perturbations show that the shoreline becomes unstable when the wave incidence angle at the depth of closure (i.e., the most offshore extent of the shoreline perturbations) is larger than a critical angle of about 42 degrees and shoreline sand waves develop in unison. The cross-shore dynamics plays an essential role because it determines the offshore extent of the shoreline perturbations. Using default model parameters, wave conditions and cross-shore profile, the sand waves develop with wavelengths between 2 and 5 km, the time scale for their formation is between 5 and 10 years and they migrate downdrift at about 0.5 km/yr. Simulations with a localized large scale perturbation trigger the formation of a downdrift sand wave train. Larger wave obliquity, higher waves and shorter wave periods strengthen the shoreline instability. A more realistic wave climate, with alternating high and low angle wave incidence reduces the potential for shoreline instability. A percentage of about 80% of high angle waves is required for sand wave formation. It is demonstrated that the range of low wave angles that can occur on a coast is larger than the range of high wave angles, and that the stabilizing effect produced by low angle waves (causing diffusion) is bigger than the destabilizing effect produced by high angle waves (causing growth and migration). Even if high angle waves are not dominant, the instability mechanism might still play a role in the persistence and downdrift migration of large scale shoreline perturbations. The model results are in qualitative agreement with observations of shoreline sand waves. The quasi 2D approach provides new insight into the physical mechanisms behind high angle wave instability and the occurrence of a minimal and optimal length scale for sand wave formation. Essential physical processes are wave energy dispersion due to wave refraction, wave energy focusing near the crest of a sand wave and the monotonic decrease of the gradients in alongshore transport for increasing length scales. / Les ones de sorra a la línia de costa són ondulacions de la línia de costa amb una escala espacial de kilòmetres i una escala temporal d’anys a dècades. Ocorren a moltes costes, migren en la direcció del transport litoral i introdueixen una variabilitat a la línia de costa que pot ser major que la seva tendència a llarg termini. L’objectiu d’aquesta tesi és estudiar amb més profunditat la formació i la dinàmica de les ones de sorra i, més concretament, explorar el rol de l’anomenada inestabilitat d’angle gran. Estudis previs van demostrar que la línia de costa pot ser inestable en cas d’onades obliqües que incideixen amb un angle gran. Aquesta inestabilitat d’angle gran es produeix degut a la retroalimentació entre els canvis a la línia de costa (i els que conseqüentment ocorren a la batimetria) i els canvis al camp d’onades. La propagació de les onades sobre la batimetria pertorbada crea gradients del transport de sediment longitudinal que causen el creixement i la migració de les ones de sorra. En aquesta tesi s’ha millorat un model morfodinàmic quasi 2D i no lineal per usar-lo per explorar la inestabilitat d’angle gran i predir la formació i evolució de les ones de sorra. El model assumeix que la dinàmica a gran escala i llarg termini està dominada pel transport de sediment longitudinal produït per les onades de manera que la morfodinàmica de la zona de rompents no es detalla. S’han superat algunes de les limitacions dels estudis anteriors de modelat de la inestabilitat d’angle gran. El camp d’onades es calcula amb un mòdul senzill de propagació sobre la batimetria canviant i el transport longitudinal s’estima usant una fórmula empírica. La dinàmica transversal es parametritza per descriure pertorbacions de la línia de costa amb una extensió transversal finita i dinàmica. S’han refinat les condicions sota les quals la inestabilitat d’angle gran produeix la formació d’ones de sorra. Les simulacions amb condicions constants d’onades i pertorbacions inicials aleatòries mostren que la línia de costa esdevé inestable quan l’angle d’incidència a la profunditat de tancament és major que un angle de 42 graus i les ones de sorra es desenvolupen a l’uníson. La dinàmica transversal té un rol essencial al determinar l’extensió transversal de les pertorbacions. Usant els valors per defecte dels paràmetres del model, les ones de sorra tenen espaiats d’entre 2 i 5 km i temps de creixement d’entre 5 i 10 anys, i migren en la direcció del transport a uns 0.5 km/any. Les simulacions també mostren que una pertorbació inicial localitzada desencadena la formació d’un tren d’ones de sorra. Com més obliqües i grans són les onades i com menor és el seu període major és la inestabilitat. Un clima d’onatge més realista, alternant onades d’angle d’incidència gran i petit, redueix el potencial de la inestabilitat d’angle gran. Calen almenys un 80% d’onades d’angle gran perquè es formin ones de sorra. El rang d’onades d’angle petit que poden succeir en una costa és major que el d’onades d’angle gran, i l’efecte estabilitzador de les onades d’angle petit (que produeix difusió) és més important que l’efecte desestabilitzador de les onades d’angle gran (que produeix creixement i migració). Fins i tot si les onades d’angle gran no dominen, el mecanisme d’inestabilitat pot tenir un paper important en la persistència i migració de pertorbacions de la línia de costa a gran escala. Els resultats s’assemblen qualitativament a les observacions d’ones de sorra. L’enfocament quasi 2D permet estudiar més detalls del mecanisme físic que hi ha darrere de la inestabilitat d’angle gran i del fet que existeixin longituds d’ona mínima i òptima per la formació d’ones de sorra. Els processos físics essencials són la dispersió de l’energia de l’onatge degut a la refracció, la concentració d’energia de les onades a les crestes de les ones de sorra i el decreixement monòton del transport litoral quan augmenta l’escala espacial.

Eastern Sand Darter (Ammocrypta pellucida) is listed as Threatened under the Canadian Species at Risk Act. Canadian populations are declining primarily due to the siltation of sandy depositional areas, the preferred habitat of the species. Little other relevant biological information is available for most Canadian populations and only limited information is available for populations in the United States. To supplement the paucity of information, this study collected biological information on A. pellucida during field surveys in 2006- 2007 from 10 sites located around the Big Bend Conservation Area in the lower Thames River, Ontario, Canada. Collected data were used to estimate critical life history traits including: longevity, fecundity, clutch size and number, growth, survival, age-at-first-maturity and cohort age structure. Longevity was 3+ years, with age-at-first-maturity being 1+ for both sexes. A minimum of 2 clutches, were laid per year with an average clutch size of 71 eggs. Average density within in the study area was 0.36 ± 0.11 A. pellucida/m². Quantitative comparison of lower Thames River biological information with a more southerly A. pellucida population in the Little Muskingum River, Ohio, demonstrated little latitudinal variation between the populations. Data comparison suggests that localized environmental factors are affecting biological characteristics, in particular water temperature that may be controlled by differences in riparian cover and/or groundwater input. Field derived life history information was used to create a Leslie matrix model which was used for population viability analysis. Perturbation analyses of reproductive scenarios involving changes in clutch numbers and size and age-at-first maturity found large variations in the finite rate of population growth. Elasticity analyses further indicated that 0+ survival and 1+ fertility were the limiting life history parameters. Thus allowing fish to survive until first reproduction would have the largest overall impact on improving population viability. Inclusion of environmental stochasticity in the model facilitated estimation of extinction probabilities in the range of 0.13 to 0.21 within 100 years. Based on the above, it is recommended that management activities for protection and restoration of A. pellucida focus on habitat protection of nursery and spawning areas.

Eastern Sand Darter (Ammocrypta pellucida) is listed as Threatened under the Canadian Species at Risk Act. Canadian populations are declining primarily due to the siltation of sandy depositional areas, the preferred habitat of the species. Little other relevant biological information is available for most Canadian populations and only limited information is available for populations in the United States. To supplement the paucity of information, this study collected biological information on A. pellucida during field surveys in 2006- 2007 from 10 sites located around the Big Bend Conservation Area in the lower Thames River, Ontario, Canada. Collected data were used to estimate critical life history traits including: longevity, fecundity, clutch size and number, growth, survival, age-at-first-maturity and cohort age structure. Longevity was 3+ years, with age-at-first-maturity being 1+ for both sexes. A minimum of 2 clutches, were laid per year with an average clutch size of 71 eggs. Average density within in the study area was 0.36 ± 0.11 A. pellucida/m². Quantitative comparison of lower Thames River biological information with a more southerly A. pellucida population in the Little Muskingum River, Ohio, demonstrated little latitudinal variation between the populations. Data comparison suggests that localized environmental factors are affecting biological characteristics, in particular water temperature that may be controlled by differences in riparian cover and/or groundwater input. Field derived life history information was used to create a Leslie matrix model which was used for population viability analysis. Perturbation analyses of reproductive scenarios involving changes in clutch numbers and size and age-at-first maturity found large variations in the finite rate of population growth. Elasticity analyses further indicated that 0+ survival and 1+ fertility were the limiting life history parameters. Thus allowing fish to survive until first reproduction would have the largest overall impact on improving population viability. Inclusion of environmental stochasticity in the model facilitated estimation of extinction probabilities in the range of 0.13 to 0.21 within 100 years. Based on the above, it is recommended that management activities for protection and restoration of A. pellucida focus on habitat protection of nursery and spawning areas.

Under loading conditions found in many geotechnical structures, it is common to observe failure in zones of high localized strain called shear bands. Existing models predict these localizations, but provide little insight into the micromechanics within the shear bands. This research captures the variation in microstructure inside and outside of shear bands that were formed in laboratory plane strain and two-dimensional discrete element method (DEM) biaxial compression experiments. Plane strain compression tests were conducted on dry specimens of Ottawa 20-30 sand to calibrate the device, assess global response repeatability, and develop a procedure to quantitatively define the onset of localization. A new methodology was employed to quantify and correct for the additional stresses imparted by the confining membrane in the vicinity of the shear band. Unsheared and sheared specimens of varying dilatancy were solidified using a two-stage resin impregnation procedure. DEM tests were performed using an innovative servo-controlled flexible lateral confinement algorithm to provide additional insights into laboratory results. The solidified specimens were sectioned and the resulting surfaces prepared for microstructure observation using bright field microscopy and morphological analysis. Local void ratio distributions and their statistical properties were determined and compared. Microstructural parameters for subregions in a grid pattern and along predefined inclined zones were also calculated. Virtual surfaces parallel to the shear band were identified and their roughnesses assessed. Similar calculations were performed on the DEM simulations at varying strain levels to characterize the evolution of microstructure with increasing strain. The various observations showed that the mean, standard deviation, and entropy of the local void ratio distributions all increased with increasing strain levels, particularly within regions of high local strains. These results indicate that disorder increases within a shear band and that the soil within the shear band does not adhere to the classical concept of critical state, but reaches a terminal void ratio that is largely a function of initial void ratio. Furthermore, there appears to be a transition zone between the far field and the fully formed shear block, as opposed to an abrupt delineation as traditionally inferred.

The health of Florida's beaches are vital to the survival of loggerhead sea turtles (Caretta caretta), as nearly half of the world's loggerheads nest on the states beaches. Many of the beaches utilized by the turtles have undergone nourishment projects in hopes of combating erosion of the shoreline, protecting beachfront property, and creating more suitable beaches for tourism. Although it is argued that beach nourishment benefits sea turtles by providing more nesting habitat, the effects of the Pinellas County nourishment projects on loggerhead nesting are unknown. Beach nourishment can alter the compaction, moisture content, and temperature of the sand, all of which are variables that can affect nest site selection and the proper development of eggs. This research has four objectives: (1) to create a GIS dataset using historic loggerhead sea turtle data collected at the individual nest level along the West coast of Florida, (2) to examine the densities of loggerhead nests, the densities of false crawls (i.e. unsuccessful nesting attempts), and the nest-to-false crawl ratio on natural and nourished beaches for the 2006-2010 nesting seasons; (3) to determine the effects of beach nourishment projects on the hatchling success rates and emergence success rates; and (4) to determine areas preferred or avoided by turtles for nesting. The study found that nesting and false crawl densities significantly differed between natural and nourished beaches during three of the five nesting seasons. Nesting densities increased directly following nourishment and false crawl densities were higher in nourishment areas during every nesting season. False crawl densities were higher than statistically expected on nourished beaches and lower than expected on natural beaches. No significant differences were found between hatchling and emergence success rates between natural and nourished beaches. However, when the rates were analyzed by nesting season, the average hatching and emergence success rates were always lower on nourished beaches than on natural beaches. A hotspot analysis on nests and false crawls revealed that turtles preferred natural beaches that border nourished areas for nesting while false crawls were more evenly distributed through the study area. Although this study documents the negative effects of beach nourishment on loggerhead sea turtle nesting, nourishment projects are likely to continue because of their benefits to human populations. Further examining of the impacts that humans have on nesting and developing loggerheads will ultimately aid policy formation as we continue to manage and protect the future of the species.

The following study investigates how a sand dune system in the central part of Laholm Bay (Laholmsbukten) in Halland County, Sweden, has evolved over the time period 1947 to 2014. Effort was made to contribute to improved knowledge of how geomorphological variations and anthropogenic activity in the area have been influenced by each other over time. The study is aiming to provide an improved science basis for further development of coastal management in the area. Initial focus points were to investigate the correlation over time between changes in dune system morphology, vegetation distribution and anthropogenic influence. Furthermore connections were made as to how climate has influenced the development and how climate change during the 21st century might affect the area. Methods used during the course of this study entailed fieldwork and remote sensing of aerial photographs. Changes in dune system dynamics, land cover and human impact on the area over time were analyzed. The result demonstrates that the area has undergone dynamic changes, affected by climatological aspects, human activities as well as vegetation changes. Decreasing topographic variations in the southern part of the dune system compared to the north is identified to be dependent on variations in soil fractions. This combined with the identified changes in vegetation distribution over time has an affect on erosion and deposition processes within the area. Future climate change during this century may further increase the dynamic behavior of the dune system, an important aspect to consider within local coastal management. / Följande studie utreder hur ett sanddynsområde i de centrala delarna av Laholmsbukten i Hallands län utvecklats under tidsperioden 1947-2014. Syftet var att skapa en uppdaterad kunskapsbild av områdets geomorfologiska utveckling och hur den antropogena aktiviteten i området har påverkat denna, för att, om möjligt bidra med underlag till en utveckling av förvaltningsarbetet i kustområdet. Fokus låg på att utreda sambanden mellan förändringar av landskapets morfologi, vegetationens utbredning och antropogen påverkan. Vidare undersöks hur klimatet under tidsperioden kan ha bidragit till den geomorfologiska utvecklingen och hur området kan komma att förändras fram till sekelskiftet år 2100. Arbetet innefattade fältarbete och fjärranalys av flygbilder. Faktorer såsom dynsystemets dynamik, areella förändringar i marktäcke och mänsklig påverkan på området analyserades. Resultatet påvisar att sanddynsområdet genomgått dynamiska förändringar över tid som kan antas bero på klimatologiska aspekter i kombination med mänsklig aktivitet och vegetationsförändringar. Dynområdets minskande relief i nord-sydlig riktning och variationer i dynkantens förskjutning över tid är beroende av det dynbildande materialets sammansättning. I kombination med identifierade variationer i vegetationens utbredning påverkar detta erosions- och ackumulationsförutsättningarna i området. Klimatförändringar under detta sekel kan komma att påverka de faktorer som reglerar dynsystemets uppbyggnad vilket kan öka dynamiken i systemet ytterligare. En aspekt som är viktig att ta hänsyn till i förvaltningen av dynområdet.

The principle source of heterogeneity affecting flow behavior in conventional clastic reservoirs is discontinuous, low-permeability mudstone beds and laminae (shales). Simple ‘streamline’ models have been developed which relate permeability anisotropy (kv/kh ) at the reservoir scale to shale geometry, fraction, and vertical frequency. A limitation of these models, especially for tidally-influenced reservoirs, is the lack of quantitative geologic inputs. While qualitative models exist that predict shale character in tidally-influenced environments (with the largest shales being deposited near the turbidity maximum in estuaries, and in the prodelta-delta front), little quantitative shale character data is available. The purpose of this dissertation is to collect quantitative data to test hypothetical relationships between depositional environment and shale character and to use this data to make geologically-based estimates of for different reservoir elements. For this study, high-resolution, lidar point-clouds were used to measure shale length, thickness, and frequency. This dissertation reports a novel method for using distance-corrected lidar intensity returns to distinguish sandstone and mudstone lithology. Lidar spectral and spatial data, photo panels, and outcrop measurements were used to map and quantify shale character. Detailed shale characteristics were measured from four different tidally-influenced reservoir analogs: estuarine point bar (McMurray Formation, Alberta, Canada), tidal sand ridge (Tocito Sandstone, New Mexico), and unconfined and confined tidal bars (Sego Sandstone, Utah). Estuarine point bars have long (l=67.8 m) shales that are thick and frequent relative to the other units. Tidal sand ridges have short (l=8.6 m dip orientation) shales that are thin and frequent. Confined tidal bars contain shales that are thin, infrequent, and anisotropic, averaging 16.3 m in length (dip orientation). Unconfined tidal bars contain nearly equidimensional (l=18.6 m dip orientation) shales with moderate thicknesses and vertical frequency. The observed shale geometries agree well with conceptual models for tidal environments. The unique shale character of each unit results in a different distribution of estimated . The average estimated kv/kh values for each reservoir element are: 8.2*10^4 for estuarine point bars, 0.038 for confined tidal bars, 0.004 for unconfined tidal bars, and 0.011 for tidal sand ridges. / text

This work explains the effect of failure on permeability anisotropy and dilation in sands. Shear failure is widely observed in field operations. There is incomplete understanding of the influence of shear failure in sand formations. Shear plane orientations are dependent on the stress anisotropy and that view is confirmed in this research. The effect of shear failure on the permeability is confirmed and calculated. Description of permeability anisotropy due to shear failure has also been discussed. In this work, three-dimensional discrete element modeling is used to model the behavior of uncemented and weakly cemented sand samples. Mechanical deformation data from experiments conducted on sand samples is used to calibrate the properties of the spherical particles in the simulations. Orientation of the failure planes (due to mechanical deformation) is analyzed both in an axi-symmetric stress regime (cylindrical specimen) and a non-axi-symmetric stress regime (right cuboidal specimen). Pore network fluid flow simulations are conducted before and after mechanical deformation to observe the effect of failure and stress anisotropy on the permeability and dilation of the granular specimen. A rolling resistance strategy is applied in the simulations, incorporating the stiffness of the specimens due to particle angularity, aiding in the calibration of the simulated samples against experimental data to derive optimum granular scale elastic and friction properties. A flexible membrane algorithm is applied on the lateral boundary of the simulation samples to implement the effect of a rubber/latex jacket. The effect of particle size distribution, stress anisotropy, and confining pressure on failure, permeability and dilation is studied. Using the calibrated micro-properties, simulations are extended to non-cylindrical specimen geometries to simulate field-like anisotropic stress regimes. The shear failure plane alignment is observed to be parallel to the maximum horizontal stress plane. Pore network fluid flow simulations confirm the increase in permeability due to shear failure and show a significantly greater permeability increase in the maximum horizontal stress direction. Using the flow simulations, anisotropy in the permeability field is observed by plotting the permeability ellipsoid. Samples with a small value of inter-granular cohesion depict greater shear failure, larger permeability increase and a greater permeability anisotropy than samples with a larger value of inter-granular cohesion. This is estimated by the number of micro-cracks observed. / text

Σκοπός της διατριβής είναι η διερεύνηση των τεχνικογεωλογικών συνθηκών στο Νομό Αχαΐας σχετικά με την αναζήτηση αδρανών υλικών για διάφορες χρήσεις. Εξετάζονται οι γενικές, γεωμετρικές, φυσικές και μηχανικές ιδιότητες των χαλαρών αποθέσεων του Νομού οι οποίες βρίσκονται σε αφθονία στην περιοχή και μπορούν να αποτελέσουν φυσικά κοιτάσματα απόληψης αδρανών υλικών χαμηλής ποιότητας και των ασβεστολιθικών σχηματισμών που χρησιμοποιούνται κατά βάση για την παραγωγή θραυστών αδρανών. Δημιουργήθηκε βάση δεδομένων με τη βοήθεια των Γεωγραφικών Συστημάτων Πληροφοριών όπου αποτυπώνονται σε χάρτες οι περιοχές που πληρούν τα κριτήρια για να χρησιμοποιηθούν ως πηγές λήψης αδρανών υλικών με στόχο την ορθολογική διαχείριση. Τα κυριότερα προβλήματα που παρουσιάζουν οι χαλαρές αδρομερείς αποθέσεις που εξετάστηκαν είναι το μεγάλο ποσοστό παιπάλης σε πολλές περιοχές καθώς και η παρουσία κερατολιθικού υλικού που φτάνει σε ποσοστό μέχρι και 23%. / In this thesis the engineering geological conditions in Achaia prefecture are examined, in order to find materials suitable for aggregates. The general, geometrical, physical and mechanical parameters of the sand and gravel deposits examined as they are in abundance in the wider area in order to locate areas suitable for the quarrying of low quality aggregates. Moreover limestone representative samples were examined as crushed stone aggregates. Issues such as location, abundance, type and quality and general characteristics of aggregate addressed using GIS technology, while because statutory regulations, technological capabilities and available funding change with time, the maps are designed to provide a resource data base that will be useful over the years. The main problems of the examined deposits are the localy high percentage of filler which deminish the results of the sand equivalent and the quite high percentage of chert content which deminish their density and increase their soundness.

In the late spring of 2008, the Chevron-led Gulf of Mexico Gas Hydrate Joint Industry Project (JIP) expects to conduct an exploratory drilling and logging campaign to better understand gas hydrate-bearing sands in the deepwater Gulf of Mexico. The JIP Site Selection team selected three areas to test alternative geological models and geophysical interpretations supporting the existence of potential high gas hydrate saturations in reservoir-quality sands. The three sites are near existing drill holes which provide geological and geophysical constraints in Alaminos Canyon (AC) lease block 818, Green Canyon (GC) 955, and Walker Ridge (WR) 313. At the AC818 site, gas hydrate is interpreted to occur within the Oligocene Frio volcaniclastic sand at the crest of a fold that is shallow enough to be in the hydrate stability zone. Drilling at GC955 will sample a faulted, buried Pleistocene channel-levee system in an area characterized by seafloor fluid expulsion features, structural closure associated with uplifted salt, and abundant seismic evidence for upward migration of fluids and gas into the sand-rich parts of the sedimentary section. Drilling at WR313 targets ponded sheet sands and associated channel/levee deposits within a minibasin, making this a non-structural play. The potential for gas hydrate occurrence at WR313 is supported by shingled phase reversals consistent with the transition from gas-charged sand to overlying gas-hydrate saturated sand. Drilling locations have been selected at each site to 1) test geological methods and models used to infer the occurrence of gas hydrate in sand reservoirs in different settings in the northern Gulf of Mexico; 2) calibrate geophysical models used to detect gas hydrate sands, map reservoir thicknesses, and estimate the degree of gas hydrate saturation; and 3) delineate potential locations for subsequent JIP drilling and coring operations that will collect samples for comprehensive physical property, geochemical and other analyses