Modelling Mixing Mechanisms in 1D Water Network Models

The management of water quality in rivers, urban drainage and water supply networks is essential for ecological and human well-being. Predicting the effects of management strategies requires knowledge of the hydrodynamic processes covering spatial scales of a few millimetres (turbulence) to several hundred kilometres (catchments), with a similarly large range of timescales from milliseconds to weeks. Predicting underlying water quality processes and their human and ecological impact is complicated as they are dependent on contaminant concentration. Current water quality modelling methods range from complex three dimensional computational fluid dynamics (3D CFD) models, for short time and small spatial scales, to one-dimensional (1D) time dependent models, critical for economic, fast, easy-to-use applications within highly complex situations in river catchments, water supply and urban drainage systems. Mixing effects in channels and pipes of uniform geometry can be represented with some confidence in highly turbulent, steady flows. However, in the majority of water networks, the standard 1D model predictions fall short because of knowledge gaps due to low turbulence, 3D shapes and unsteady flows. This Fellowship will work to address the knowledge gaps, delivering a step change in the predictive capability of 1D water quality network models. It will achieve this via the strategic leadership of a programme of laboratory and full-scale field measurements, the implementation of system identification techniques and active engagement with primary users. The proposal covers aspects from fundamental research, through applications, to end-user delivery, by providing a new modelling methodology to inform design, appraisal and management decisions made by environmental regulators, engineering consultants and water utilities.

1D water quality network models are used in water supply, urban drainage and river catchment management. Regulators, operators, consultants, service suppliers and software developers have acknowledged the inadequacy of current knowledge and have welcomed this initiative to generate improved integrated understanding and more robust management tools. Evidence of this is provided in the strong Statements of Support from the key relevant regulators, Environment Agency and Drinking Water Inspectorate; through active, industry-leading consultants (Clear/RPS, Mouchel, JBA, WRc) who provide engineering guidance across the range of water network systems, to a major UK water utility (Severn Trent Water Ltd, who are required under the Water Framework Directive to implement cost-effective measures and to supply drinking water to achieve specific standards); and major international software developers (DHI). Additionally, Unilever, a major multi-national consumer products company, with expertise in environmental assessment, is providing guidance on wider catchment-scale applications. In the longer term, society will benefit significantly from the implementation of more accurate 1D water quality models as rural and urban environments will become better places to live, with improved water quality, and added biodiversity and amenity values.
Improved knowledge, application and impact from this proposal will contribute to the UK establishing itself as an innovation powerhouse in the global water technology sector, which the recent UKWRIP report estimates, in the period up to 2020, to amount to over $50 billion.
How will they benefit from this research?
- Regulators, utilities, and consultants will benefit directly from the new descriptions of mixing within network components and improved, validated modelling methodologies that will lead to better-informed network design, maintenance and management decisions.
- Academics and practitioners will benefit from rigorous methodologies for experimental and numerical mixing and residence time characterisation that will have generic value for future research and development activities relating to all types of mixing and water quality processes.
- Benefit to research staff - Staff engaged on the project will work within a high calibre research environment, with strong international links, undertaking fundamental research through to applied field studies and state-of-the-art model development, whilst interacting with regulators, utilities and a range of consultants. This represents a unique and highly valued skill set that will equip them to progress authoritatively into academic or practitioner roles within the global water technology sector.