FD2107 Development of Estuary Morphological Models ERP Home | FD2107 Documents Summary objective The primary objective is the development of models capable of indicating likely estuarine morphologies 50y hence, thereby providing estimates of the associated changes in flood risks. This involves development of: (i) a Framework for application of B-U models in relation to morphological changes; (ii) new HYBRID models via integration of B-U and T-D models. background Whilst bottom-up (B-U) numerical models can accurately reproduce water levels and currents in estuaries, the simulation of sediment transports is more problematic. Moreover, since errors in the associated evolving morphology accumulate, the validity of longer-term (decadal) simulations is uncertain. To address this problem, conclusions from Phase 1 (1998-2000) of the Estuaries Research Programme (ERP) recommended integration of B-U models with top-down (T-D) models to develop HYBRID models to combine the advantages of both approaches. approach Here we seek to improve confidence in morphological predictions by inter-relating results from application, to a variety of UK estuaries, of existing and new B-U, T-D and HYBRID models in an ensemble approach with attendant sensitivity an Effective future planning and management of the UK's estuaries is reliant on such improvements in our forecasting capabilities. The project will incorporate new developments from ESTPROC (FD1905) and utilise revised morphological concepts from (FD2116). deliverables The primary deliverable will be a quantitative appreciation of the capabilities for predicting the evolution of morphology in UK estuaries based on bottom-up, top-down and hybrid models. This appreciation will include effects of generalised sources of uncertainty and the specific sensitivities of selected estuaries to possible global climate change (GCC) and interventions. The project will provide inputs to concurrent projects, namely the production of Estuarine Simulators (FD2117) and Ecological Modelling (FD2108), whilst extending dissemination activities initiated in FD2110. Subsequently, the project will provide the basis for the sedimentary and dynamical module of an EMS to be delivered in Phase 3 of the ERP. Background The Estuaries Research Programme (ERP) The UK's economy is significantly impacted by the effective functioning of its estuaries - for navigation, leisure, property development, flood defence and industry. The DEFRA has responsibilities both for proposed estuarine 'interventions' (engineering works, dredging, discharges, etc.) and long-term planning to accommodate climate change. To inform shorter-term management and longer-term strategic policy planning, improvements in our related forecasting capabilities are essential. THE UK ERP EXTENDS OVER 10 YEARS in three phases Phase 1 (1998-2000) included a critical analysis of the limitations of B-U models alongside a review of top-down (T-D) models. Recognising the necessity of exploiting both approaches, a priority in Phase 2 of the ERP is the development of HYBRID models which seek to combine elements from both the B-U and T-D approaches.Phase 3 will incorporate the scientific and technical developments into an Estuarine Management System. To develop models capable of indicating 50y changes in morphology, we examine (1) methodologies for applying B-U models ,(2) development of T-D models (in conjunction with FD2116) and their integration in B-U models to produce new HYBRID models and (3) the influences of GCC and interventions on flood forecasting habitats. Workpackages (1) A Framework for application of B-U models in relation to morphological changes Given specified bathymetry and surficial sediment distribution, deterministic bottom-up (B-U) numerical models can accurately reproduce water levels and currents. However, the corresponding simulation of sediment transports is more problematic (involving much wider spectral scales with net fluxes generally determined by non-linear coupling and subject to biological and chemical mediation). Moreover associated 'errors' in evolving morphology accumulate - further amplifying 'errors' in transports. Thus longer-term (decadal) simulations with B-U models (involving bathymetry and surficial sediments significantly different from initial specifications) must encapsulate the wide-range of possible outcomes, i.e., provide an ensemble of predictions. WP1 provides a new framework for the application of B-U models to estuarine management issues involving morphological change. (2) Development of new HYBRID models via integration of B-U and T-D models and characterisation of likely changes in estuarine morphology by 2050 WP2, utilising new results from FD2116, involves the development and application of T-D models and provides a SHELL to couple these with B-U models to produce new HYBRID models. WP2 also involves the application of these new and existing HYBRID models to predict characteristic 2050 morphologies. (3) Estimates of impacts of morphological changes on potential for flooding WP3 estimates the impacts of these characteristic morphologies on flood forecasts and habitats. This study assesses model performance in applications involving 8 estuaries (table 1). By quantifying related uncertainties in underlying processes, we will provide a platform for determining the format for the EIAS (Environmental Impact Assessment System) to underpin the EMS (Estuarine Management System) to be completed in ERP Phase III. Specific Deliverables 1) A framework for application of B-U models for impacts of GCC on flooding. 2) Refined estuarine models,including HYBRID models capable of 50y morphological predictions. 3) An applications framework SHELL for coupling B-U to T-D models, providing new HYBRID models with suitable assessment and visualisation capabilities. 4) An estuarine morphological emulator for incorporation into a system-based estuarine simulator (FD2117). 5) Enhanced models of estuarine sub-systems and mixed sediments. PARTNERS Proudman Oceanographic Laboratory Joseph Proudman Building 6 Brownlow Street Liverpool L3 5DA HR Wallingford Ltd. Howberry Park Wallingford Oxfordshire OX10 8BA ABP Marine Environmental Research Ltd. Pathfinder House Maritime Way Southampton SO14 3AE WL|Delft Hydraulics Rotterdamseveg 185 PO Box 177 2100 MH Delft The Netherlands School of Engineering Reynolds Building University of Plymouth Drake Circus Plymouth PL4 8AA ERP Home | FD2107 Documents | Top of page