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The 550 km-long KwaZulu-Natal coast broadly divides into a bedrock-framed southern section and northern coastal plain section, each of approximately equal length. Seven types of coastal dune are identified on this coast: estuary barrier dunes; mainland beach foredunes; prograded beachridge dunes; headland bypass dunes; transverse dune fields; parabolic/migrating dunefield; and climbing dunes. The development and distribution of the various dune forms is more strongly controlled by the geological setting, than the aerodynamic regime. [ABSTRACT FROM AUTHOR]

Barrier islands commonly occur in coastal plain and deltaic settings, and a variety of behavioral and stratigraphic models exist. In this paper, a 90 km long barrier island system in the Outer Hebrides of Scotland is identified for the first time. Uniquely among barrier islands, the system rests directly on a planar bedrock (gneiss) surface (a strandflat). This bedrock surface has a profound influence on the morphology of the barrier island chain, and exerts the dominant influence on barrier island form and evolution during transgression. Topographical irregularities on the bedrock surface control both plan and profile morphology of the barrier islands. Under sea-level rise, by barrier migration, sediment is redistributed onshore and alongshore in a strongly three-dimensional manner, determined by topographic variability in the bedrock. The barrier islands represent an endpoint in transgressive barrier island geomorphology that is controlled by the bedrock surface: they are at the upper end of the recognized tidal amplitude for barrier islands; the offshore wave regime is very high-energy; they lack a shoreface; and neither ravinement surface nor transgressive sand sheet are developed. Sediment supply is dominated by offshore-derived skeletal carbonate. [ABSTRACT FROM AUTHOR]

The calculation of the degree of sediment disturbance through wave action in the surf and swash zone has been examined at various levels in recent years using a number of empirical techniques. Quantifying 'depth of disturbance'(also know as sediment mixing depth) enables a better understanding of nearshore processes, where interaction between sediment and surf zone wave action is complex. Better understanding of how sediment responds to given surf and swash zone parameters is paramount in examining a number of phenomena such as natural beach evolution, sediment movement around engineering structures, the design and planning of beach renourishment schemes, and the monitoring of pollution behaviour. Previous empirical studies have concentrated their efforts in various methodologies such as the use of sediment tracers to mark the sediment, depth of disturbance rods deployed over a tidal cycle and the use of plug-holes filled with marked sediment. All efforts at estimating sediment disturbance in the field to date have resolved their measurements only after a complete tidal cycle and have been unable to measure processes during the actual perturbations caused by wave action within the tidal event, an essential period of activity to understand bed elevation patterns. This paper seeks to address the present shortfall in methodology with the design and construction of a new, high resolution, vertical measurement system. The new instrument, a Sediment Activity Meter (SAM), characterises surface elevation changes in the sediment bed of the surf zone at a given deployment location at approximately 2 minute sampling intervals. This technique will, for the first time, enable realistic comparisons to be made between bed change and the main forcing variables of the system during a tidal cycle. The paper mainly outlines the basic design of the new field instrument and describes, for the first time, surf zone seabed elevation changes (at a single point) measured at approximately 2-minute intervals alongside corresponding wave parameters and water depths within the surf zone. The field trials took place on a high-energy beach system in Northern Ireland. [ABSTRACT FROM AUTHOR]

Intertidal flats are very sensitive coastal environments. They support large communities of highly specialised fauna and flora and are subject to physical processes that combine hydrodynamic and sedimentary processes that are highly sensitive to change. An added factor to the difficulty of studying and monitoring intertidal flats and their environment is that they may be situated near a human settlement that requires protection from flooding or inundation. Monitoring sensitive intertidal flat ecosystems to obtain precise and updated information on its geomorphological and biological state is a challenging task for coastal scientists, managers and engineers, who have to deal with both, the conservation of the environment and human demands. This paper describes a monitoring programme designed to establish, for a sensitive intertidal flat, the state of a comprehensive number of environmental factors prior, during and after the construction of sea defences. The rigorous assessment of environmental impact has been the backbone of the design and implementation of this monitoring programme based in Newtownards, at the Northern end of Strangford Lough in Northern Ireland. The Lough is a major wildlife and scientific resource that is subject to several domestic conservation designations as well as being considered, under European Community Directives, as a site of importance for nature conservation. The individual components of the intervening forces and responses have been identified and studied on a highresolution spatial basis whilst not interfering with the fragile ecosystem. Biological and geomorphological parameters were identified for monitoring. Surveys comprised plant ecology, spatial distribution of density and type of vertebrates and invertebrates, sedimentological analysis (both historical and contemporary), hydrodynamic controls and topographic evolution as well as salt marsh shoreline monitoring. A wide range of technologies have been implemented to achieve a monitoring programme that that can be fully integrated in a Geographic Information System minimising post-processing times for interpretation and data-base access. Some of the techniques include the use of an ATV mounted DGPS with sub-centimetre accuracy for topographical and biological surveys, colour infrared digital airborne image acquisition using the Kodak DCS460 and image analysis, as well as numerical wave modelling of wave propagation. A virtual monitoring centre is being created as the main outcome of this project. The participating institutions (research, management and the public) will be able to access the electronic libraries and maps via an integrated web-based database. This project has been approached as a research and development programme that serves as a model for integrated coastal zone management in sensitive tidal flat ecosystems. [ABSTRACT FROM AUTHOR]

O' Connor, M., Cooper, J. A. G., and Jackson, D. W. T., 2007. Morphological behaviour of headland-embayment and inlet-associated beaches, northwest Ireland. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 626 – 630. Gold Coast, Australia, ISSN 0749.0208 Both static and dynamic environmental conditions contribute to the behaviour of coastal sedimentary systems. Sand beaches on the bedrock-framed northwest coast of Ireland exist in two distinct planform settings that offer the opportunity to examine their varying behaviour. Beaches in this region are either located in coastal re-entrants between rocky headlands and backed by vegetated sand dunes or adjacent to the inlets of large sandy estuaries that are themselves located in bedrock valleys. They all have a finite sediment volume due to the deeply embayed coastal morphology and lack of contemporary sediment input. The behaviour of these types of systems over the past 170 years is recorded in historical maps, air photographs and morphological measurements. Preliminary results show that the beaches of inlet-associated systems involve complex exchanges between beach, dunes and tidal delta while headland-embayment beaches cycle sediment between beach and dunes. The inlet-associated beaches are typically more dynamic than the headland-associated beaches, although both are subject to the same range of wave forcing. Inlet-associated beaches appear to show cyclicity in their behaviour that alternates between rapid erosion and accretion at horizontal scales of decametres and timescales of decades. Headland-embayment beaches show relative stability or slow progressive erosion. High magnitude storms, long term patterns of 'storminess' and morphological feedback all offer potential explanations for the behaviour identified. [ABSTRACT FROM AUTHOR]

High-energy events (extratropical storms, tsunamis, and hurricanes), sediment supply variability, and sea-level rise are regarded as major drivers of coastal geomorphic behavior. In this paper we document a 170 yr record of cyclic coastal changes that occur independently of such external drivers. In a geologically constrained situation with no external sediment input, two end-member morphological configurations (attractors) are identified between which the system alternates. Although neither configuration is stable, the system as a whole exhibits century-scale equilibrium. Our findings present a hitherto unreported form of decadal scale self-adjustment in a coastal system that has occurred under a stable sea level with a consistent wave and tidal regime. [ABSTRACT FROM AUTHOR]