Towards an integrated coastal sediment dynamics and shoreline response simulator

This report describes a regional scale assessment of coastal erosion undertaken during the period2000-2100 for a 30-km length of soft-rock coast between Weybourne and Happisburgh, northeastNorfolk. This coastline comprises large lengths of soft, erodible, cliffs, which will be vulnerable toincreases in sea level and storminess under future changes in climate. The magnitude of erosionduring the next century is of concern to scientists, policymakers and the general public, especiallywith the expectation of acceleration in sea-level rise. The regional-scale assessment considerscombined scenarios of sea-level rise, changing wave climate and coastal management, bysuccessfully integrating a number of modelled elements for the first time:1. Broad scale modelling of shoreline erosion and profile evolution using the process-basedSCAPE (Soft Cliff and Platform Erosion) model;2. A probabilistic model of cliff-top position derived from SCAPE outputs;3. Nearshore wave climate modelling.SCAPE describes the functioning and emergent behaviour of the coastal system at a regional scale,and provides a detailed dataset for analysis of risk and responses to future coastal erosion. TheSCAPE model outputs have been linked with a flexible GIS tool (SCAPEGIS), developed toprovide visualisation and interpretation of the model results. Outputs are available in the form ofmaps, dynamic visualisation, and descriptive statistics of key parameters such as cliff toe and clifftop position. It also allows analysis with other datasets such as land use and building location forimpact evaluation, and hence could be used in shoreline management and cliff-top land useplanning.This research seeks to address a shortfall in coastal erosion research in the UK, whereby analysis ofrisks and responses to erosion at the coast is hindered by limited knowledge of the size and locationof erosion hazard zones. Through the process of considering potential impacts of sea level rise andchanging wave climates on rates of soft shore recession a number of questions have been raisedconcerning the relative importance of shore platform lowering; the extent to which relative sea levelrise is controlling continuous cliff retreat; and the nature of the relationship between offshoreseabed morphology and coastal evolution. The modelling philosophy adopted by SCAPE offersconsiderable scope for addressing questions such as these, and thereby provides an important step inimproving our understanding of coastal risk from climatic change. Using the approach developedhere, planners are provided with a method for examining broad-level system response withcombined management and climate-change scenarios