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Globally, due to climate change and increased rates of coastal erosion, along with the need to protect sensitive habitats, there is an increasing requirement for a sustainable approach which considers both the effect of the marine environment on critical infrastructure and the impact of that infrastructure on the local environment. This paper presents a methodology for assessing the impact of a marine structure on longshore dynamics and shoreline evolution by using an external coupling of the phase-resolving ARTEMIS wave model and the shoreline evolution model, UNIBEST. The methodology can be applied at any coastal location, but for this study, it was applied to Sizewell Bay on the east coast of England to assess the impact of a shore-normal jetty on a gently curving stretch of shoreline with relatively complex offshore geomorphology. Results from simulating 22 years of shoreline evolution have shown that, at the jetty location, the shoreline at Sizewell will migrate seaward up to 45 m compared with the no-jetty case. Immediately south of the jetty, the shoreline was predicted to retreat landward by about 15 m. This behaviour is similar to observed changes at other locations, and the predicted longshore transport rates are in agreement with findings from previous studies, validating the methodology. [ABSTRACT FROM AUTHOR]

Sea defence policy in England has proven contentious in the early twenty-first century, with government willing to defend the coast only where it is considered cost effective and not minded to compensate people for any resulting abandonment of homes. Additional focus is brought to this position by the 2015 United Nations Sustainable Development Goals (SDGs) which reflect a growing emphasis on climate change effects and other environmental hazards, and the wellbeing of the current generation and those to come. This requires policy makers to seek to balance economic, social and environmental dimensions, and to tackle inequalities; with a central commitment of the goals to "leave no one behind". Subsequent to publication of the SDGs, England was promised a revolution in the government's approach to Flood and Coastal Erosion Risk Management (FCERM). This paper seeks to understand the nature of this revolution with particular regard to extant issues around just governance. It finds that policy fails to deal with issues over the local acceptability of proposals for change and the bearing of risk, and instead lies principally in the elevation of the problematic concept of resilience and an accompanying ambivalence towards ideas of sustainability and sustainable development. International agreement that compensation should be paid to those countries suffering the worst effects of climate change, including sea level rise, suggests that adoption of a similar approach to vulnerable homeowners might be the more appropriate revolution and bring policy more into line with the aspirations of the SDGs. [ABSTRACT FROM AUTHOR]

Coastal sediment grain size is an important factor in determining coastal morphodynamics. In this study, we explore a novel approach for retrieving the median sediment grain size (D50) of gravel-dominated beaches using Synthetic Aperture Radar (SAR) spaceborne imagery. We assessed this by using thirty-six Sentinel-1 (C-band SAR) satellite images acquired in May and June 2022 and 2023, and three NovaSAR (S-band SAR) satellite images acquired in May and June 2022, for three different training sites and one test site across England (the UK). The results from the Sentinel-1 C-band data show strong positive correlations (R2 ≥ 0.75 ) between the D50 and the backscatter coefficients for 15/18 of the resultant models. The models were subsequently used to derive predictions of D50 for the test site, with the models which exhibited the strongest correlations resulting in Mean Absolute Errors (MAEs) in the range 2.26–5.47 mm. No correlation (R2 = 0.04) was found between the backscatter coefficients from the S-band NovaSAR data and D50. These results highlight the potential to derive near-real time estimates of coastal sediment grain size for gravel beaches to better inform coastal erosion and monitoring programs. [ABSTRACT FROM AUTHOR]