A national coastal erosion susceptibility model for Scotland

The upland nature of the Scottish landscape means that much of the social and economic activity has a coastal bias. The importance of the coast is further highlighted by the wide range of ecosystem services that coastal habitats provide. It follows that the threat posed by coastal erosion and flooding has the potential to have a substantial effect on the socioeconomic activity of the whole country. Currently, the knowledge base of coastal erosion is poor and this serves to hinder the current and future management of the coast. To address this knowledge gap, two interrelated models have been developed and are presented here: the Underlying Physical Susceptibility Model (UPSM) and the Coastal Erosion Susceptibility Model (CESM). The UPSM is generated within a GIS at a 50 m2 raster of national coverage, using data relating to ground elevation, rockhead elevation, wave exposure and proximity to the open coast. The CESM moderates the outputs of the UPSM to include the effects of sediment supply and coastal defence data. When validated against locations in Scotland that are currently experiencing coastal erosion, the CESM successfully identifies these areas as having high susceptibility. This allows the UPSM and CESM to be used as tools to identify assets inherently exposed to coastal erosion, areas where coastal erosion may exacerbate coastal flooding, and areas are inherently resilient to erosion, thus allow more efficient and effective management of the Scottish coast

A method for modelling coastal erosion risk: the example of Scotland

It is thought that 70% of beaches worldwide are experiencing erosion (Bird in Coastline changes: a global review, Wiley, Hoboken, 1985), and as global sea levels are rising and expected to accelerate, the management of coastal erosion is now a shared global issue. This paper aims to demonstrate a method to robustly model both the incidence of the coastal erosion hazard, the vulnerability of the population, and the exposure of coastal assets to determine coastal erosion risk, using Scotland as a case study. In Scotland, the 2017 Climate Change Risk Assessment for Scotland highlights the threat posed by coastal erosion to coastal assets and the Climate Change (Scotland) Act 2009 requires an Adaptation Programme to address the risks posed by climate change. Internationally, an understanding and adaption to coastal hazards is imperative to people, infrastructure and economies, with Scotland being no exception. This paper uses a Coastal Erosion Susceptibility Model (CESM) (Fitton et al. in Ocean Coast Manag 132:80–89. https://doi.org/10.1016/j.ocecoaman.2016.08.018 , 2016) to establish the exposure to coastal erosion of residential dwellings, roads, and rail track in Scotland. In parallel, the vulnerability of the population to coastal erosion, using a suite of indicators and Experian Mosaic Scotland geodemographic classification, is also presented. The combined exposure and vulnerability data are then used to determine coastal erosion risk in Scotland. This paper identifies that 3310 dwellings (a value of £524 m) are exposed to erosion, and the Coastal Erosion Vulnerability Index (CEVI) identifies 1273 of these are also considered to be highly vulnerable to coastal erosion, i.e. at high risk. Additionally, the CESM classified 179 km (£1.2 bn worth) of road and 13 km of rail track (£93 m to £2 bn worth) to be exposed. Identifying locations and assets that are exposed and at risk from coastal erosion is crucial for effective management and enables proactive, rather that reactive, decisions to be made at the coast. Natural hazards and climate change are set to impact most on the vulnerable in society. It is therefore imperative that we begin to plan, manage, and support both people and the environment in a manner which is socially just and sustainable. We encourage a detailed vulnerability analysis, such as the CEVI demonstrated here for Scotland, to be included within future coastal erosion risk research. This approach would support a more sustainable and long-term approach to coastal management decisions

Ice-formed intertidal boulder pavements in the sub-Antarctic

No abstract available

Shore-platform development in the South Shetland Islands, Antarctica

Shore platforms in the South Shetland Islands, Antarctica, display morphological differences from mid-latitude platforms that are explicable in terms of the morphogenetic environment. These differences include marked horizontality of the platform surface terminated abruptly by low-tide and high-tide gradient changes. Since the processes of ice freezing-on, quarrying by impact and abrasion are responsible for such horizontality the platforms are widest in areas of restricted fetch where ice persists longest. In exposed locations, wave quarrying and abrasion limit the development of horizontality. Stratigraphic evidence suggests that the shore platforms of the South Shetland Islands are inherited features that have been rapidly retrimmed by polar shore processes. Some suggestions for future research are made

Archaeological survivability and past coastal processes

No abstract available

Intertidal forms produced by floating ice in Vestfirdir, Iceland

Forms produced by the action of intertidal ice in the fjord of Kaldalon, Vestfirdir, Iceland, are described and interpreted in terms of their morphogenetic environment. Isolated boulders resting on top of undisturbed fine sediments are interpreted as dropstones from floating intertidal ice following rockfall events. Boulder pavements and ridges which occur in the upper intertidal zone are related to the onshore movement of ice packing and bulldozing boulders together. The occurrence of such ice-formed features in Kaldalon is attributed to their preservation within a low-energy environment in spite of a limited ice-climate. The paucity of such forms preserved in the sedimentary record suggests that opportunities for burial and preservation are limited except where local infill is rapid

Tir a’ Mhachair, Tir nan Loch? Climate change scenarios for Scottish Machair systems: a wetter future

Climate change scenarios for NW Scotland and the Western Isles envisage a combination of rising sea level, increased winter precipitation, and increased frequency and severity of winter storms. The flat, low-lying machair lands of the Uists are thus particularly vulnerable, not only from marine overtopping of coastal dune ridges, but also from inland flooding and restricted drainage, which may enhance the duration and area of seasonal standing waters within the machair lands. The drainage network of the Uist machairs is a legacy of historic drainage of a more extensive loch network, which now forms an intricately balanced complex of linked water bodies exhibiting a wide range of pH and salinity. Any future change in water levels would impose significant environmental shifts. The conservation importance of machair is significantly augmented by a pattern of rotational cultivation that largely employs traditional methods and provides species-rich fallows. This tradition is already under economic threat, and increased flooding could have far-reaching consequences for both agriculture and wildlife. The Uist machair systems have a range of inter-dependent, multiple-interest international conservation designations and the vulnerability of these is examined in a context that incorporates the vital human dimension

Managing lakeshore erosion: impacts of bank protection on Loch Lomond, Scotland

The shoreline of Loch Lomond is currently undergoing erosion not only because of passive natural changes but also because of active changes produced by the interaction of shoreline protection structures and natural processes. In order to assess the influence of protection structures on different types of loch shore, the shores were classified and their total extent, including the extent of artificial shore, was quantified. The effect of structures is often felt on adjacent shores as well as on those that the structure is designed to protect. In order to assess the extent of impact of structures, sediment cells were identified along the loch shore within which the effects of a structure may produce compensatory effects but beyond which they will not. A management strategy is presented that is aimed at minimising the detrimental effects of any future intervention in the shore system

A Markov model for beach changes on the holderness coast of England

Markov models offer an objective and quantitative method of assessing beach changes. For a stretch of the Holderness coast a beach classification scheme was devised and a probabilistic first order matrix model based on surveyed profile data was produced. This could describe and predict transitions between beach types and between different time periods. Different profile types dominated different coastal locations and seasonal variations were seen. In order to improve the accuracy of prediction throughout the year a second, ‘winter’, model was added to the original ‘summer’ one. Although the models had been prepared independently of wave conditions, a comparison of the wave record and beach transitions revealed that waves under 0·3–0·5 m high produced fairly static beaches; when waves were between 0·5 and 1·0 m the beach was more dynamic and variable, while waves over 1·0 m led to the depletion of the upper beach. This was broadly in accordance with published theory. Markov models have the advantage that they can be adjusted periodically if conditions change, and are thus useful for prediction on coasts for which no wave records exist