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The paper integrates well-established methods from other spheres of flood risk assessment in a novel way to explore the currently poorly understood Safe Development Paradox (SDP) phenomenon in coastal settings. The study contributes to addressing this knowledge gap based on insights from contrasting UK case studies: Portsmouth, Weston-super-Mare, and Southport. Differential analysis of historic LiDAR Digital Surface Models (DSMs) was used to identify temporal changes in the urban landscape to create a DSM of Difference (DoD), representing elevation change between two locations over time. Geostatistical testing, specifically t-tests, were then used to infer statistical significance of changes in urban development. The findings reveal a consistent pattern: following completion or improvement of large-scale structural coastal flood defences, there is subsequent, and statistically significant, increases in urban development within/near flood-exposed areas across all three case studies, contrary to the limited flood-exposed development in neighbouring settlements, with no comparable defences constructed during the same period. On average, new urban development occurs approximately 2 years after the completion of coastal flood defence projects. The study emphasises the importance of context-specific and neighbourhood analyses, considering settlement size, economy, and extraneous factors influencing the nature of development to better understand the SDP’s long-term implications.

Climate change and continued urban development in flood-prone areas exacerbate flood risks. Flood Risk Management authorities often turn to structural protection measures to minimise losses. However, these measures often lead to infrastructural lock-ins with potential unintended consequences as increased safety can induce increased development, ultimately leading to higher losses in the event of failures of the structural safe-guards in place. This process has been referred to as the Safe Development Paradox: a cross-cutting science-policy-practice challenge that requires a systematic understanding in the context of climate change and the United Nations Sustainable Development Goals. Yet, there are no comprehensive review studies, to date, that summarize the state of knowledge of the Safe Development Paradox. This paper provides the first evidence base through a critical review of the state-of-the-art and quantitative analysis of the peer-reviewed English-language literature since 2000, highlighting key knowledge gaps and issues hindering progress in addressing the Safe Development Paradox. It was identified that current research is compounded by a lack of consistent terminology, limited geographic distribution of case studies, and skewed emphasis on fluvial flooding. The review ends with potential directions across the science, policy, and practice domains for increasing knowledge and tackling the Safe Development Paradox. [ABSTRACT FROM AUTHOR]

Increasing coastal flood risk has prompted a proliferation of cities that are adopting risk reduction and adaptation tools. This article inquires into what types of tools local governments tend to adopt for managing coastal flood risk and the factors that may be influencing these choices; in particular, factors related to hazard vulnerability and institutional capacity. Focusing on 40 diverse coastal communities in a study region in Canada, the study utilised data from the communities' Official Community Plans to characterise their approaches to managing coastal flood risk in terms of land use regulations, construction specifications, and/or structural flood protection tools. The data revealed considerable diversity in the portfolio of tools that the communities have adopted. Tool adoption was found to correlate strongly with hazard vulnerability; that is, communities with similar physical and socio‐economic vulnerability conditions tended to take similar adaptation actions. For example, established communities with highly urbanised coastlines tended to rely on structural flood protection while suburban communities with semi‐developed coastlines predominantly utilised land use regulations. Institutional factors such as resource availability and local leadership, which were operationalised using survey data, exhibited surprisingly little correlation with the types of tools that communities adopted. [ABSTRACT FROM AUTHOR]