Predicting long term estuary evolution using regime theory

There is ever increasing pressure to better predict the possible future morphological evolution of estuaries over long time periods (decades to centuries), owing to a variety of commercial, social and environmental reasons and to inform the development of sustainable management policies. Due to the highly complex nature of estuaries, conventional 2 and 3 dimensional numerical models struggle to describe the large number of parameters needed to fully predict the morphological response to changing environmental conditions.
In order to address this requirement a hybrid modelling approach is proposed comprising of a 1-dimensional process based model to describe the detailed hydrodynamic conditions combined with a system goal ‘Regime’ morphological relationship. This hybrid modelling approach uses the tools developed under the current UK Estuaries Research Program Phase 2. To provide a flexible interface between hydrodynamics and such regime relationships, a program has been developed, referred to as the ‘Shell’ interface. This tool is then applied to the English Severn Estuary, predicting the 100year evolution following the addition of potential realignment sites and accounting for sea level rise.