Beach nourishment provides an excellent opportunity for the study of intensified sediment transport gradients and associated morphological changes in a natural setting. The objectives of this study are to quantify and predict longshore and cross-shore transport gradients induced by 1) beach nourishment, 2) different storm wave conditions, and 3) the annual wave climate and long-term sediment supply. The details of sediment transport rates and gradients induced by gradual processes and high-energy events are analyzed on a macro-scale. Well-planned monitoring of the 2004 Upham Beach nourishment project in west-central Florida collected high-spatial and -temporal resolution field data. Three hurricanes passed by the project soon after nourishment was complete.Post-nourishment planform adjustment occurs immediately after nourishment via diffusion spit development at the end transitions. Thus, the initiation of planform adjustment may be abrupt, rather than gradual as pred icted by the typical diffusion models. Diffusion spit formation is dominant during relatively calm wave conditions on coasts with low wave heights and tidal ranges.Profile equilibration also may be an event-driven, rather than a gradual, process. Rapid profile equilibration following nourishment occurred not only due to hurricane passage, but also during a winter season. The duration between nourishment and the passage of the first high-energy event is an important factor controlling the time scale of profile equilibration.The passage of three hurricanes generated different wave conditions and induced different sediment transport directions, rates, and gradients due to their variable proximities to the project area. The direction of cross-shore transport was governed by wave steepness. Onshore sediment transport occurred during a storm event, in contrast with the concepts of gradual onshore transport during mild wave conditions and abrupt offshore transport during storm events, as cited in the literature.By formulating sediment budgets on various temporal and spatial scales, both event-driven and average transport rates and gradients can be resolved. Annual average transport rates for a region should not be arbitrarily applied to nourished beaches; rather, sediment budgets formulated with high-spatial and -temporal resolution field data should be formulated during the design phase of future nourishment projects.

Magister Philosophiae (Integrated Water Resource Management) / Rare-infrequent magnitude floods of shorter duration events are significant natural hazards and play a key role in shaping river channel and island geomorphology. For a given river or channel, there is a relationship between the magnitude of a flood, frequency of a flood and duration of a flood, once a flood exceeds a reach-averaged erosional threshold geomorphic change can begin to occur. Expansion of conceptual models for the response of mixed bedrock alluvial influenced dryland rivers to such floods is of increasing scientific importance. The Vaal River near Parys in the Free State Province is characterised by a variable degree of mixed bedrock-alluvial anabranching channels which divide and re-join around the islands. In this study the historical aerial images and flow data from 1938 to 2016 were used to determine the effects of flood dynamics on island geomorphology in a large mixed bedrock-alluvial anabranching river: Vaal River near Parys. The historical aerial images and flow data reveals some minor island geomorphological changes during flood of rare magnitude, infrequent and shorter duration. The highest flood in the record was the one which was found having a recurrence interval of 20-50 years. The changes observed in the mixed bedrock-alluvial anabranching river in the Vaal River near Parys, indicate some minor decrease in the island bar area during flood of rare magnitudes, infrequent and shorter duration with recurrence interval of 20-50 years. The findings in this study area also reveals that the island bars in the area of study shows some degree of stability, however for the past 78 years the islands bar have not change the position. The impact of flood dynamics on island geomorphology in a large, mixed bedrock-alluvial anabranching river is not yet researched in the area of study (Vaal River), these findings will contribute to enhanced analysis of the Vaal River, relatively the impacts of extreme floods in island and channel geomorphology.