Experimental and numerical investigation of pluvial flood flows and pollutant transport at and between system interface points

Lead Research Organisation: University of Exeter
Department Name: Engineering Computer Science and Maths

Abstract

The 2007 flood events in the UK were estimated to have had an economic cost of £3.2billion and resulted in 13 deaths. The frequency and magnitude of flood events has been forecast to increase due to the impacts of climate change, urbanisation and the deterioration of wastewater infrastructure. In the last summer period alone Newcastle, Manchester, Belfast and many other UK towns and cities have experienced significant pluvial flooding events. To mitigate these effects urban flooding hydraulic models have been developed which characterise the flow in the sewer system, overland flow in the urban catchment, and the exchange of flow between these systems so as to identify those areas which are most at risk of flooding. Such models are used by local authorities and water companies to identify areas for flood mitigation work, such as prioritising investment to improve drainage infrastructure, taking measures to reduce storm water runoff and raising the awareness of residents.
However the accuracy such models is inherently difficult to verify due to the difficultly of acquiring reliable data during flood events, e.g. it is not feasible to be sure that the modelled flow paths and velocities are accurately predicted at the time of the flood event. Similarly, but more complexly, it is not currently possible to quantify the transport of potentially dangerous faecal contaminants from the sewer networks to residential areas in flood events, and hence to assess the risk to health of flood waters. Previous sampling of flood waters has shown that this health risk may be significant. The behaviour of interaction points (e.g. manholes) is critical to the transfer of such flow and pollution between sewer and surface, but the hydraulic behaviour at such interfaces is especially difficult to quantify due to the complex nature of the flow.
This proposal seeks to better understand these interactive processes within a unique scale model facility at the University of Sheffield that combnes the flow in a below ground sewer system with the shallow water surface flows over the catchment, linked by a number of manholes. The overall aim of the research is to improve the verification process of urban flood models, to provide detailed measurements and a more accurate understanding of the hydraulic characteristics of interaction points, to quantify surface flow paths and to advance the modelling capability to the spread of pollutants from sewer systems within the surface flow. The outcome will be a significantly enhanced modelling capability for urban flood flows and a much improved understanding of flood risk in urban areas. This will be achieved by a detailed programme of experimental testing using the facility at Sheffield, coupled with state of the art modelling work to calibrate, improve and verify urban flood models. The proposal enjoys the support and engagement of leading developers of urban flood models in the UK (Innovyze, Microdrainage), as well as consultants, water companies and a local authority. This partnership will ensure that the research findings are incorporated into the latest modelling approaches and are utilised to improve flood risk evaluation in the UK.
As well as advancing existing models that predict flood extent and depth, it is seen as important and ambitious to extend models to predict of mass transport, which will enable quality and potential health implications of flooding to be better established. In addition, to develop these aspects further, there is also significant value in extending the work proposed to include characterising the transport of sediments from sewers to surface flow in flood conditions. This would be of scientific and practical value as contaminants that pose a significant health risk are often attached to sewer sediments. The department has therefore agreed to provide scholarship which will use the facility to study the transport of sediments, further expanding the value of the proposed work.
 
Description Key findings from this project are: (i) unique and comprehensive data sets (ii) range of original computational models. All these signifcantly improve understanding of studied problems.
Exploitation Route By incorporation in urban flood models.
Sectors Environment

URL https://www.sheffield.ac.uk/floodinteract/outputs
 
Description Several software companies are carefully considering the outcomes of this project and how these can be incorporated in their products.
First Year Of Impact 2018
Sector Environment
Impact Types Economic

 
Description H2020
Amount € 499,276 (EUR)
Organisation EU-T0 
Sector Public
Country European Union (EU)
Start 05/2016 
End 04/2020
 
Title Experimental data on sewer pipe flow - surface flow interaction 
Description Experimental data on sewer pipe flow - surface flow interaction 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact Use for improvement of urban flood models 
URL https://www.sheffield.ac.uk/floodinteract/outputs
 
Description Keynote lecture entitled: "Examples of applications of modern methods in computational hydraulics" at the 18th Conference of Serbian Association for Hydraulic Research (SDHI) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Keynote lecture attracted interest from:
professionals/practitioners, which may lead to practical further practical applications of the tools developed in our projects, and
post-graduate students, which may develop our methodologies further
Year(s) Of Engagement Activity 2018
URL http://hikom.grf.bg.ac.rs/SDHI18/
 
Description Talk entitled: "Simulation and visualisation of impacts of flooding and the selected other research at the Exeter Centre for Water Systems" at Eawag/ETH Zurich 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact The research group at Eawag (about 15 people) attended this presentation. The outcome - in addition to parallel activities during Prof Djordjevic visit to Zurich - was the submission of a major £1.5m proposal to EPSRC International Centre-to-Centre scheme between the Exeter Centre for Water Systems and Eawag at ETH Cluster Zurich. The proposal is shortlisted, received very good reviews, and funding decision will be made on the EPSRC panel to be held in April 2019.
Year(s) Of Engagement Activity 2018
URL https://epsrc.ukri.org/funding/calls/intlcentretocentrerescollabsfull/