Application of flood risk modelling in a web-based geospatial decision support tool for coastal adaptation to climate change

Abstract

Abstract.A pressing problem facing coastal decision makers is the conversion of "high-level" but plausible climate change assessments into an effective basis for climate change adaptation at the local scale. Here, we describe a web-based, geospatial decision support tool (DST) that provides an assessment of the potential flood risk for populated coastal lowlands arising from future sea-level rise, coastal storms, and high river flows. This DST has been developed to support operational and strategic decision making by enabling the user to explore the flood hazard from extreme events, changes in the extent of the flood-prone areas with sea-level rise, and thresholds of sea-level rise where current policy and resource options are no longer viable. The DST is built in an open-source GIS that uses freely available geospatial data. Flood risk assessments from a combination of LISFLOOD-FP and SWAB (Shallow Water And Boussinesq) models are embedded within the tool; the user interface enables interrogation of different combinations of coastal and river events under rising-sea-level scenarios. Users can readily vary the input parameters (sea level, storms, wave height and river flow) relative to the present-day topography and infrastructure to identify combinations where significant regime shifts or "tipping points" occur. Two case studies demonstrate the attributes of the DST with respect to the wider coastal community and the UK energy sector. Examples report on the assets at risk and illustrate the extent of flooding in relation to infrastructure access. This informs an economic assessment of potential losses due to climate change and thus provides local authorities and energy operators with essential information on the feasibility of investment for building resilience into vulnerable components of their area of responsibility.

Preface: Monitoring and modelling to guide coastal adaptation to extreme storm events in a changing climate

“…The development of risk maps based on cost-distance analysis can be used to identify the cost-benefit ratio of different coastal defence systems . Incorporating such maps into decision-support tools (see Knight et al, 2015) enables assessment of the time variation of the flood hazard during storms, and in response to climate change, sea-level rise and future management intervention. Improved knowledge of pathways for flood water also improves evacuation planning Lapidez et al, 2015) in preparation for early warning.…”

“…The accuracy of the mapping is not only important for knowledge of flood depths and velocities to identify the hazard rating of events, but also to enable managers to consider cost-benefit analysis of varied solutions to coastal flood and erosion risk. To support managers in planning more strategically, the development of decision-support tools, which incorporate a range of flood maps to cover plausible hazard scenarios, is becoming more common (Knight et al, 2015). Such tools are designed to meet the needs of the end-user, but incorporate the latest advances in scientific models to provide evidence to underpin management decisions.…”

“…Such tools are designed to meet the needs of the end-user, but incorporate the latest advances in scientific models to provide evidence to underpin management decisions. One difficulty in generating such tools beyond the scale of a local region is the lack of standardized monitoring to enable identical model applications to populate the tool in a uniform way at the national level (Knight et al, 2015).…”

“…This enables better understanding of the critical conditions that trigger a change in a system's resilience. In the most extreme cases this change may be permanent, requiring a change in management policy (Knight et al, 2015). Early warning of when a system may reach a tipping point is thus required to plan long-term management strategies.…”

“…This is particularly important at sites of coastal industry that have long life expectancies, e.g. the nuclear energy sector (see also Knight et al, 2015). Conflicting coastal interests often complicate coastal management, preventing a uniform approach across a region, although numerous interactions and feedbacks exist (Armstrong et al, 2015).…”