12 research outputs found

    The need for data integration to address the challenges of climate change on the Guyana coast

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    Guyana's capacity to address the impacts of climate change on its coastal environment requires the ability to monitor, quantify and understand coastal change over short-, medium- and long- term. Understanding the drivers of change in coastal and marine environment can be achieved through the accurate measurement and critical analyses of morphologies, flows, processes and responses. This manuscript presents a strategy developed to create a central resource, database and web-based platform to integrate data and information on the drivers and the changes within Guyana coastal and marine environment. The strategy involves four complimentary work packages including data collection, development of a platform for data integration, application of the data for coastal change analyses and consultation with stakeholders. The last aims to assess the role of the integrated data systems to support strategic governance and sustainable decision-making. It is hoped that the output of this strategy would support the country's climate-focused agencies, organisations, decision-makers, and researchers in their tasks and endeavours

    Estuary – coast interaction and morphodynamic evolution: a comparative analysis of three estuaries in southwest England

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    Investigations of geomorphology and morphodynamics within the coastal zone have tended to treat the open coast as an independent system to that of any neighbouring estuaries. This separation is also evident within shoreline management, which has traditionally been undertaken within the context of coastal cells or estuarine valleys. The focus of this research is a comparative analysis of morphodynamic behaviour and sedimentary characteristics of connected open-coast – estuary systems. The north coast of Cornwall, southwest England, is notably indented and dominated by bedrock cliff and shore platforms. However, it also comprises some broad embayments that accommodate estuarine valleys and open coast, typically sandy beaches. The region provides an ideal environment within which to assess broad-scale coastal change and the association between estuarine and open-coast morphodynamics. Furthermore, it provides an opportunity to consider regional coherence in coastal behaviour and to evaluate the relative importance of local physical context vs. regional climate forcing. The Hayle, the Gannel and the Camel estuaries that are located within St Ives, Crantock and Padstow bays respectively, have received considerable attention in terms of the impacts of mining on estuarine sedimentation. The impacts on sediment supply, sedimentology and mineraology have been explored extensively in these past studies, however, very little consideration has been given to the nature of coastal geomorphology and coastal system dynamics. This PhD research explores mesoscale coastal dynamics, and evaluates coastal behaviour over decades to centuries in the context of climate and sea-level change. Historical geomorphological evolution of these estuaries and their adjacent shorelines are examined to evaluate morphodynamic connectivity through the application of shoreline analysis tools (such as Digital Shoreline Analysis System (DSAS) and Location Probability Analysis). This study showed that low shoreline recession along the north Cornwall coast, where sediments are present, has attributed most to the significant sea-level rise in this region (no significant change was observed on rocky low water shorelines). The high water shoreline imposes a different pattern of change in response to constraining factors which are triggered by both environmental factors and historical human activities. Changes over contemporary time scales are focused on bedform movement into, within and landward of inlets and are primarily driven both by waves in the outer estuary/ebb delta region and by tides in the channels/flood delta region. The inlets, however, are largely fixed in position by the bedrock valley, and channel dynamics within the estuary are dependent on the accommodation space provided by the valley. Sedimentary linkages are also explored through the sedimentological and geochemical analysis of sediments sampled from the intertidal zone of these systems. Based on grain-size parameters, there is considerable homogeneity in the sediment populations specific to the sub-environments sampled and analysed. There is evidence of sediment mixing between estuarine and beach environments. Geochemical (XRF) and mineraological composition of sediment indicate contamination by mine waste tailings in the estuaries resulting from major historical mining activities in the region with Sn, Cu, As and Zn as predominant in the Hayle, Pb and Zn in the Gannel and Sn, W, and Zr in the Camel estuaries. This research presents a multidisciplinary approach that employs a range of computer and lab-based analyses to integrate geospatial resources (including published maps, chart archives, etc) and sedimentological characteristics (including grain size and XRF analyses). The thesis is the first comprehensive comparative investigation of the morphodynamic behaviour and sedimentology of these north Cornwall estuaries

    Comparable short-term morphodynamics of three estuarine–coastal systems in the southwest coastal region of England, UK

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    Here, we describe and compare the changes in low tide channel position and the morphology of the three estuaries in southwest England from an analysis of contemporary (2008–2016) topographic surveys. The Hayle, Gannel, and Camel estuaries and their adjacent open-coast shorelines were subject of various studies in the past principally in terms of mining impacts on estuarine sediments and sedimentation, but no regional synthesis of the contemporary behaviour has yet been attempted. Light Detection and Ranging (LiDAR) data for the north coast of Cornwall are analysed for planform morphological changes of the systems. At the annual scale, intertidal bars and sandwaves migrate across the foreshore and into the inlet region, where flood-oriented and wave-forced movement is evident. This is evidenced at all the estuarine systems considered here. However, the steep upstream slope of the Hayle is almost devoid of bedforms, while the shallower upstream slope of the Gannel comprises similar scaled bedforms to the whole flood delta, and the megaripples of Camel flood delta are smaller on the backslope. Over the short-term covered by the LiDAR data considered here, there was no significant storm surges, and a relatively consistent wave climate. The occurrence of strong onshore wave conditions are possibly the drivers of contemporary behaviour, and with the inner estuary intertidal currents, for the movements of sediments within the estuarine environment, thereby causing the re-organisation of sediments and the shifting of channel position
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