In recent years there has been growing concern about the impact of diffuse source pollution on river, estuarine and coastal water quality and particularly with regard to non-compliance of bathing waters. Climate change, and particularly more intense storms in the bathing season, has led to increased compliance failure of bathing waters, e.g. last summer saw widely publicised beach failure occurrences at Amroth and Rhyl. Hydro-environmental impact assessment modelling studies, regularly undertaken by specialist consulting environmental companies, are generally regarded as having two fundamental shortcomings in model simulations, which can lead to erromneous environmental impact assessment outcomes. These shortcomings will be addressed in this project and include: (i) improving the computational linking of catchment, river and estuarine-coastal models to ensure momentum and mass conservation across the link boundary, and (ii) improving the kinetic decay process representation in deterministic models, to include the impact of salinity, irradiance, turbidity and suspended sediment levels. The main aim of this research project will therefore be to develop and validate linked hydro-environmental deterministic models to predict improved fluxes and concentration levels of faecal bacterial from catchment to coast, using dynamic decay rates related to a range of primary variables. This main objective will be achieved by: (i) setting up linked catchment, river and estuary-coastal models to predict flow and solute transport processes from Cloud to Coast; (ii) linking these models through an Open MI system and refining the link to include momentum conservation; (iii) extending the Cardiff Research Centre's Severn and Ribble river basin models to include catchments, (iv) developing and testing the Severn model against scaled laboratory model data for conservative tracer measurements, obtained using an idealised catchment-river-estuary physical model at Cardiff University, (v) undertaking a detailed analysis of earlier field studies (undertaken by the main supervisor and Professor David Kay, Aberystwyth) on the impact of turbidity and sediment adsorption on bacterial levels in the Severn estuary, with the aim of developing new formulations linking bacterial concentration levels with: salinity, irradiance, turbidity and suspended sediment), (vi) including the new formulations for bacterial decay (in the form of T90 values) in the linked models for river and estuary-coastal systems and to investigate the sensitivity of the receiving water concentration levels to these parameters, and (vii) studying briefly the effects of various renewable energy structures in the Severn estuary (including the Severn Barrage) on the receiving water faecal bacterial levels, particularly in terms of establishing the impact of the new linking methodology and the dynamic decay rates on the predicted concentration levels. The outcomes from this study will be published in journal and conference papers and presented in talks and lectures on the Centre's activities relating to marine renewable energy and particularly for the Severn estuary.

Sea level rise is now acknowledged as a real threat to our coastal towns and cities. In addition, global climate changes may lead to increasing frequency and severity of storms. As a result the value of the UK's assets at risk from flooding by the sea have significantly increased. The current UK coastal flood defences, which have typically been designed to withstand storm events with a return period of 50-100 years, may now be inadequate to protect the coastal areas under threat. To improve the design of future coastal defences requires a better understanding of the linkages between atmosphere, ocean and seabed; as well as improved quantification of the inherent uncertainties in the predictions. This joint research proposal between the Universities of Plymouth, Bristol and Liverpool, aims to develop a robust and integrated 'Cloud-to-Coast' modelling framework which will include the complex interactions between atmosphere, ocean and coastal flood and erosion, so that the flood risk in the coastal areas from the extreme events, such as severe storms, can be accurately predicted and assessed. The project will use various existing proven computer programmes together with necessary further developments to provide information on meteorological conditions under severe storms, the associated surge and wave conditions, as well as detailed transformation of wind and waves from the offshore to areas close to shoreline in order to predict coastal flood and erosion due to wave overtopping and scour. The main work of the project includes: 1) integration of the large-scale high-resolution weather models for predicting the atmospheric pressure and wind field, the regional and local scale process models for wave transformation from offshore to nearshore, and the local coastal models for predicting wave overtopping and scour near the coastal defence structures; 2) validation of the integrated modelling system with extensive field datasets; and 3) application of the modelling system to investigate uncertainties by creating ensembles of possible future storm events. The major output of the project will be a well-developed and validated modelling system which can be used as a useful tool for coastal engineers and coastal zone managers to assess the possible flood risk in coastal areas.

The problem of hydraulic resistance in wall-bounded flows remains among the hottest research topics in theoretical and applied fluid mechanics in spite of also being one of the most long-standing hydraulic problems. Researchers continue exploring a wide variety of empirical and conceptual approaches to resolve this problem, particularly focusing on the parameterisation of the bed friction that controls water levels, flood inundation extent, flow rates, depths, and water velocities. The approach currently used for quantifying bed friction is mostly empirical and thus should be considered the weakest component of otherwise quite sophisticated design and modelling methodologies. Despite world-wide efforts to advance capabilities for prediction and control of water levels in free surface flows, especially during flood events, hydraulic engineers still use empirical or semi-empirical relationships for 'roughness' or 'friction' factors. These resistance coefficients subsume the combined effects of complex hydrodynamic processes in simple forms making them convenient for practical applications. There is a general agreement that these resistance coefficients depend on parameters of the flow, bed material, bed and channel forms, and in-stream and bank vegetation. Although the quantitative form of this dependence has been targeted by several generations of hydraulicians, available relationships linking the resistance coefficients to flow and roughness parameters are still largely empirical rather than theoretically justified. As a result, the level of uncertainties of hydraulic models of overland flows, canals, waterways, rivers, and estuaries remains high, often exceeding 20-40%. The central goal of the project is therefore to develop advanced predictive capabilities for quantification of hydraulic resistance in rough-bed open-channel flows and propose a methodology for incorporation of the theoretical and physical insights from this study into applied hydraulic models that are most relevant to the end-users. To achieve this goal, the project team will build a rigorous theoretical framework to explicitly reveal contributions to the total bed friction from viscous, turbulent, and form-induced stresses, secondary currents, non-uniformity, and unsteadiness, and link these contributions to the physics of the flow. This theoretical analysis will underpin sophisticated laboratory experiments in Aberdeen and Large Eddy Simulation numerical studies in Cardiff to clarify the nature of bed friction in open-channel flows, refine the definitions of the roughness regimes, and identify and quantify the contributions to the overall friction from the dominant friction-generated mechanisms. The combination of the theoretical analysis with laboratory and numerical studies will lead to the generalised relationships for the friction coefficients suitable for applied hydraulic models. The examples of benefits that the proposed research will bring include significantly reduced uncertainties in predictions of water levels and flood inundation extent; better urban planning and new design philosophies based on friction control/reduction aptitudes that this research intends to develop (e.g., 'friction-reduced' urban planning as part of 'green cities' concept and more efficient drainage systems); and improved stream restoration design and implementation, among many others. The theoretical and methodological developments of the project will be also applicable, in addition to water engineering, to other areas such as aerospace and mechanical engineering, where drag control studies are particularly important and continue to grow. The interdisciplinary fields of overland flow and soil erosion, biomimetics, and ecosystems (both terrestrial and aquatic), represent other examples where the outcomes of this project can be directly employed.

Our current infrastructure cannot deliver the adaptable, low-carbon future planned by the Government. Existing stock does not make best use of resources and materials; flows of material in and out of the system are poorly understood; and greater vulnerability caused by increased reliance on scarce materials (e.g. rare metals) is ignored. Low carbon infrastructure is being planned without taking into account the availability of materials required to support it. Measures taken to change the properties (embodied carbon/energy, strength etc) of materials, taken in good faith, can have unpredictable effects on input, stock and output of scarce resources in infrastructure. Unfortunate policy decisions are already being taken that will lock us into costly solutions. Left untreated, this will throw up huge obstacles to developing a sustainable infrastructure. We need to fully understand the material barriers to achieving adaptable low carbon infrastructure and propose approaches and systems to overcome these barriers. We will enhance the established stocks and flows (S&F) methodology used in industrial ecology by adding layers of extra information on material properties and vulnerability. We will extend S&F to include measures of quality (in terms of material properties and age) and vulnerability (in terms of scarcity, geo-politics and substitutability). This will transform S&F from being concerned only with quantities of materials, to capturing quality and availability as well. This will in turn allow us to analyse how changes in the properties of the materials used in a system may introduce vulnerabilities, associated with materials supply, waste management or stock changes. More excitingly, it will allow us to design more resilient solutions 'designing out' pinch-points in materials supply; it will inform CO2 policy making to encourage best value for money emission reduction; and it will provide a robust new framework for analysis of complex interconnected infrastructure systems. This methodology will be tested on three case studies to refine the initial approach and demonstrate its applicability to the challenge described in this proposal. The case studies will include: - Some simple, proof-of-concept physical infrastructure systems (such as a bridge) - More detailed of a system; for example a power station; and - a system of systems; a place that interacts with a number of different infrastructure systems (for example a neighbourhood or city). The case studies will be analysed to identify existing stocks, assess the vulnerability of 'replacement' infrastructures and identify new proposals and solutions for alternative approaches. We recognise that the boundaries of the systems and flows may be difficult to define in this project. However, we consider that it would be more important to demonstrate the approach than to define the boundaries absolutely. This demonstration will help us to understand how this approach could be used by policy makers and decision makers and inform more detailed studies in the future. Some single sector stocks and flows studies have been performed, and the apparent vulnerability of particular material supplies has been established (e.g. DEFRA A review of resource risks to business) but these have not been 'joined together' to produce a full picture of the vulnerability and adaptability of infrastructure. The proposal is adventurous in that the development of the complex methodology required, while based on a combination of well-understood approaches (S&F, LCA etc), will be challenging and require intellectual clarity from three contrasting disciplines: materials science, industrial ecology and environmental engineering. Our aim is to produce a new, low carbon, adaptive design paradigm for hyper-efficient use of valuable materials. This will lead to a step change in resource use, reduce the vulnerability of future infrastructure, reduce CO2 emissions and enable adaptability.