Ailbhe Travers

Bio: Ailbhe Travers is an academic researcher from University of Western Australia. The author has contributed to research in topics: Shore & Beach morphodynamics. The author has an hindex of 4, co-authored 4 publications receiving 179 citations.

Sheltered sandy beaches of southwestern Australia

Abstract: Morphodynamic classifications of sandy beaches have been established for open-ocean, wave-dominated environments. However, many natural sandy beaches exist in embayments, or are landward of protective reefs, where they are sheltered from the full effects of ocean waves. It is therefore appropriate to question whether such low-energy beaches can be related to conceptual models of beach hierarchies, and to examine whether they have identifiable morphodynamic signatures. Surveys were conducted of the nearshore morphology and dynamics on over fifty beaches on the microtidal coast of Southwestern Australia, between Cape Arid on the South and Geraldton on the West Coast. In most instances, surveys were conducted on beaches that were sheltered by their aspect and/or the presence of offshore reefs. The remaining surveys were conducted on wave-dominated beaches in order to provide a link to the existing morphodynamic models. Descriptions of beach morphology, determined from the surveys, were subjected to a cluster analysis to establish groupings of similar morphologic types. This analysis provided a six-fold classification of beach morphologies and indicated a clear separation between the low- and high-energy beach morphologies on the basis of the overall scalp of the nearshore profiles. Four low-energy morphotypes were distinguished. These are essentially planar and characterized by the absence of either nearshore bars or other rhythmic features. However, the low-energy morphotypes may be discriminated by variations in beach slope and curvature. Canonical variate analysis was conducted to examine the discrimination of the six morphotypes on the basis of their sedimentary and dynamic characteristics. This analysis indicated consistent sedimentologic differences between the morphotypes, despite moderate overlapping between several of the beach forms. The variation accords with expectations that flatter beaches tend to have finer sediments. Discrimination between the morphotypes on the basis of their dynamic variables was less revealing. This raises questions of misfitting between form and process during the surveys and may indicate the importance of storm events in the formation of these low-energy morphotypes.

Morphology of a Low-Energy Beach, Como Beach, Western Australia

Abstract: The morphology of Como Beach in the Swan River Estuary, Western Australia, is described. Como Beach is in a microtidal estuarine environment in which modal wave conditions are extremely low and nontidal fluctuations in water level are principally determined by storm surges and low-frequency changes in ocean water levels. Detailed descriptions of sandy beaches in very sheltered locations, such as Como, are uncommon in the literature, although these beaches are a common feature of coastal environments. In contrast to beaches in wave-dominated environments, those in very sheltered, low-energy locations may support subtidal terraces and beach profiles that differ in form and scale from the bars and intertidal flats in wave- and tide-dominated environments. At Como, beach profiles are superimposed on a subtidal terrace rising steeply from waters several metres deep to −1.5 m (Australian Height Datum; AHD), then with a low gradient to approximately −0.3 m (AHD) at the shore. The profiles range from pla...

Low-Energy Beach Morphology with Respect to Physical Setting: A Case Study from Cockburn Sound, Southwestern Australia

Abstract: Low-energy beaches are omnipresent coastal features. In total, their overall length greatly exceeds that of ocean shorelines throughout the world. However, a comprehensive understanding of low-energy beaches is lacking, with their dynamics generally considered under existing principles governing open ocean beaches. This study investigates the morphodynamic characteristics of very low energy beaches on which wave heights can be less than 0.15 m under nonstorm conditions, as distinguished from the characteristic of high-energy environments in which low energy states commonly have modal wave heights of 0.5–1 m. This investigation is achieved through an analysis of a 30-year profile data set for Cockburn Sound, a fetch-limited, low-energy basin in southwestern Australia. The Sound experiences the full ranging of microtides and surges of the region, together with locally generated wind waves. Recurring patterns in cross-shore geometries and their distribution were identified through regression analysi...

Dynamics of Scarborough Beach, city of Stirling, Western Australia

Abstract: Investigation of historic beach and dune field evolution was undertaken, to develop a probabilistic model of future shoreline change, to be used for coastal vulnerability assessment of foreshore infrastructure at Scarborough Beach. The analysis compared long-term records with previous studies of beach width, to describe relationships with key climate variables. A major finding of the investigations was the significant role of annual alongshore wind anomalies in beach growth or recession.

Sandy shore ecosystems and the threats facing them: some predictions for the year 2025

Abstract: Pollution, mining, disruption of sand transport and tourism development widely affect sandy shores, and these systems may be subject to increased erosion in future, yet there have been few attempts to review them. The present review focuses largely on ocean sandy beaches, providing an introduction to much of the relevant literature, and predicting possible states of the system by 2025. Sandy shores are dynamic harsh environments, the action of waves and tides largely determining species diversity, biomass and community structure. There is an interchange of sand, biological matter and other materials between dunes, intertidal beaches and surf zones. Storms and associated erosion present the most substantial universal hazard to the fauna. Human-related perturbations vary from beach to beach; however, structures or activities that impede natural sand transport or alter the sand budget commonly lead to severe erosion, often of a permanent nature. Many beaches also suffer intermittent or chronic pollution, and direct human interference includes off-road vehicles, mining, trampling, bait collecting, beach cleaning and ecotourism. These interferences typically have a negative impact on the system. Identified long-term trends include chronic beach erosion, often largely due to natural causes, as well as increased ultraviolet (UV) radiation and changes related to global warming. It is not expected that predicted temperature changes will have dramatic effects on the world's beaches by 2025, but the expected rise in sea level, if coupled with an increase in the frequency and/or intensity of storms, as predicted for some regions, is likely to lead to escalating erosion and consequent loss of habitat. It is suggested that increased UV radiation is unlikely to have significant effects. Increases in coastal human populations and tourism, thus increasing pressure on the shore, while serious, may be largely offset in developed and developing countries by better management resulting from greater understanding of the factors governing sandy-shore systems and better communication with beach managers and developers. Beach nourishment is likely to become more widely practised. However, the continuing hardening of surfaces in and above the dunes is bound to be damaging. Human pressures in many underdeveloped countries show no signs of being mitigated by conservation measures; it is likely that their sandy shores will continue to deteriorate during the first quarter of this century. A long-term trend that cannot be ignored is the excessive amount of nitrogen entering the sea, particularly affecting beaches in estuaries and sheltered lagoons. The data presently available and the uncertainty of a number of predictions do not permit of quantitative assessment or modelling of the state of the world's sandy shores by the year 2025, but some tentative, qualitative predictions are offered.

Australian Beach Systems—Nature and Distribution

Abstract: The Australian coast contains 10,685 beach systems, which occupy half the coast and can be classified into 15 beach types. These include six wave-dominated, three tide-modified, and four tide-dominated types which are a product of wave-tide and sediment conditions and two types which are influenced by intertidal rocks and fringing reefs. Wave-dominated beaches occupy the higher energy, microtidal southern coast exposed to persistent Southern Ocean swell. Tide-modified and tide-dominated beaches are most prevalent around the more tropical northern coast, which experiences meso-, macro-, and mega-tides and receives lower seas, as well as some sheltered and mesotidal southern locations. This article assesses the roles of waves, sediment, and tide range in contributing to beach type, particularly through the dimensionless fall velocity and relative tide range. It also describes their regional distribution, together with the occurrence of rip currents, multibar beach systems, and the influence of geol...

Tourist Perceptions of Degradation Caused by Coastal Nature-Based Recreation

Abstract: Tourist perceptions of environmental degradation caused by nature-based tourism activities in a coastal environment were determined in the Central Coast Region of Western Australia. Structured surveys were administered to 702 visitors over two peak seasons. Visitors were required to indicate their perceptions on a Likert-type scale. Activities assessed were swimming, boating, fishing, diving and snorkelling, (wind)surfing, sandboarding, four-wheel driving, (bush)walking, camping, horseriding and sightseeing. Tourists had significantly variable demographic characteristics over two seasons and participated in different activities. However, perception of environmental degradation of individual activities did not vary significantly between seasons, except for fishing, four-wheel driving and sandboarding. The age, origin and level of education of visitors had more effect on perceptions than gender or income group. Participation in an activity affected perceptions only for those who went fishing, sandboarding, four-wheel driving and sightseeing. Visitor perceptions were comparable to ‘real’ impacts documented in the recreation ecology literature. The results of this research indicate a need for improved visitor education and interpretation facilities.