iCOASST – integrating coastal sediment systems

UK coasts are subject to widespread erosion in part due to the cumulative effect of human intervention on soft coastlines, and further threatened due to more rapid change due to climate change, especially sea-level rise. At the same time, Shoreline Management now requires predictions of coastal evolution up to 100 years in the future. This leads to the challenge of predicting coastal geomorphic behaviour at the mesoscale (10 to 100 km and 10 to 100 years). Currently, this is often based on expert judgement. However, relevant components for mesoscale coastal simulation are emerging, including: (1) new methods for system-level analysis of coast, estuary and offshore landform behaviour, which include engineering and management interventions in a consistent manner to natural drivers; (2) well validated ‘bottom-up’ hydrodynamic and sediment transport models such as POLCOMS and TELEMAC; (3) operational ‘reduced complexity models’ of selected coastal landforms (e.g., cliffs (SCAPE), estuaries (ASMITA), saltmarsh (SLAMM)); and (4) growing observational datasets that allow data-driven approaches to coastal analysis and prediction. The iCOASST Project will use these components to develop and apply an integrated systems modelling framework for mesoscale coastal simulation as explained in this paper

Improving decadal coastal geomorphic predictions: An overview of the iCOASST project

Coastal areas are already at high risk from a range of geohazards. The cumulative effect of human intervention on soft coastlines has frequently left them far from equilibrium under today’s conditions, especially in densely populated areas. Future changes in marine forcing due to climate change reinforce the need to understand and predict processes of change in shoreline position and configuration at management (decadal) scales. The UK-based iCOASST project is developing new and improved methods to predict decadal geomorphic evolution, linked to coastal erosion and flood risk management. This is based on a framework that links several components to develop a system-level understanding of this change. The framework includes: (1) new methods for system-level analysis and mapping of coast, estuary and inner shelf landform behaviour; (2) well validated ‘bottom-up’ hydrodynamic and sediment transport shelf models which can be applied at shelf scales to investigate inner shelf-coastal interactions; and (3) model compositions formed of existing or new ‘reduced complexity models’ of selected coastal landforms and processes that are suitable for multiple decadal length simulations. This will ultimately allow multiple simulations of coastal evolution which can explore uncertainties in future decadal-scale coastal response, including the effects of climate change and management choices. This paper outlines the current state of progress in the iCOASST Project