Decision support framework to incorporate river bank stability in pipeline crossing risk assessment

Lead Research Organisation: University of Glasgow
Department Name: School of Geographical & Earth Sciences

Abstract

Scottish Water has identified the need to develop their approach to dealing with uncertainty when assessing the risk of river erosion at pipeline crossings. In particular, there is a need to develop and pilot methods that can use data from initial asset inspections to quantify risks and uncertainties in making decisions on where to invest additional resources in more detailed inspections, for assets deemed to be at greater risk from river bank erosion or scour around bridge abutments. This challenge arises from the reality that, over the past 10-15 years, pipeline crossing inspections have been undertaken in an ad-hoc manner. The aim of this proposal is, therefore, to develop a decision support framework to incorporate river bank stability in pipeline crossing risk assessment. This will be used immediately during 2016 in Scottish Water's first, national-scale pipeline bridge asset inspection programme. The specific objectives are to: (i) evaluate uncertainty in the existing low-cost app-based inspection database that is used to screening risk; (ii) assess the uncertainty that arises from the initial desk-based phase of river bank stability assessment; (iii) develop a pipeline crossing scour assessment framework for analysing river bank stability at the screening phase and determining appropriate analysis for the initial assessment phase; and (iv) recursively test the risk assessment framework. To address these objectives there will be three methodological phases, results from which will be progressively reported. First, a sample of the pipeline crossings will be re-surveyed using a replicate inspection app. Results will enable evaluation of uncertainties in data capture and their consequences for river stability decision making at the screening stage of risk management. Second, uncertainty in assessing bank erosion will be assessed considering data from the asset inspection app, Google Earth imagery, high-resolution aerial images commissioned by Scottish Water, and legacy LiDAR acquired by the Scottish Government. Evidence of river instability will be mapped from imagery. Change will be quantified using appropriate techniques to represent errors in digitising and topographic change analysis. Finally, results will be used to produce a framework to: (i) characterise risk during screening; and (ii) determine the most appropriate forms of desk based analysis for initial risk assessment. The framework will include a multi-criteria process for calculating risk after the initial assessment phase to determine whether a more detailed assessment phase is necessary and, if so, necessary actions. This framework will be tested at a further set of 20 sites. Project outputs will be operationalised and used to improve decision making. App-based data capture will be improved with enhanced data fields and training material for asset inspectors. Results from evaluating uncertainty in data and analysis will be input to a multi-criteria scoring framework that will improve decision making at the screening and initial assessment stages and will thus enable scarce resources to be prioritised for desk-based river bank stability analyses. The framework will be used in the current drinking water pipeline crossing inspection programme and will also be of value for a future waste water pipeline crossing inspection programme. The project will last 12 months which will enable evaluation of uncertainty in a sufficiently large sample of data, analysis approaches and sites. The total cost (80% FEC) of the project is £89,707. This includes staff costs for Williams and Hoey, 9 months research assistant time, computer hardware, and travel.

Planned Impact

This project aims to develop a decision support framework to incorporate river bank stability in pipeline crossing risk assessment. The project will focus upon evaluating the uncertainty associated with using different data sources, and different analytical approaches, to measure river stability. It will also develop a multi-criteria scoring system that can be used to calculate risk at each pipeline crossing, based on uncertainties in associated data and analysis. Quantifying how different uncertainties propagate through decision making to determine whether an asset is classified as being at sufficient risk to warrant further investment in scour risk management will contribute to an improved asset inspection workflow at Scottish Water. Kirby et al. (2015) estimate that stages in scour risk assessment take the following amounts of time per asset: initial screening (3-5 hours); initial assessment (10-15 hours); and detailed assessment (25-40 hours). Scottish Water estimate that initial screening costs £500 per asset. Making appropriate decisions about whether to pursue further assessment following this screening is thus critical to focus scarce resources, provide value for customers, and support statutory and regulatory compliance. The framework that will be developed by this project will also provide guidance on future frequency of screening and assessment, explicitly accounting for uncertainty in data analysis. This framework will guide the review and development of pipeline management plans, informing Scottish Water's future business and investment planning from 2021.

The main expected benefits and outcomes for Scottish Water are as follows:
(1) Improved forms to capture river stability information using the asset inspection app;
(2) Improved technical capability of asset inspectors through river stability training;
(3) Enhanced ability to use a range of Geographic Information System (GIS) data layers to make decisions about river stability, with tools that exlicitly measure how uncertainty contributes to what conclusions should be made;
(4) A support framework to make decisions after screening. This will focus upon aiding decision making about which desk-based approaches to adopt, which high-resolution survey technologies to commission if further information is needed, and when to scope different erosion or scour prevention measures;
(5) A support framework to determine the frequency and method (site visits or remote sensing) of future river stability screening activities. This will be based on the comparison between uncertainty in river stability measured from the low-cost app versus a range of desk-based assessment methods, to guide future inspections to assess changes in river stability; and
(6) Quantification of the uncertainty associated with data capture on river stability from the low-cost asset inspection app will enable Scottish Water to demonstrate that its asset management programme meets statutory and regulatory compliance.

Overall, the project will impact decision making in the asset management of pipe bridges by influencing the ongoing site-visit based asset inspection programme (from month 3 of the project) and the framework for desk based assessment. The project will also impact longer term planning beyond the current asset inspection programme.

Reference: Kirby et al., 2015, Manual on scour at bridges and other structures.

Publications

10 25 50
 
Description This project was a partnership between the University of Glasgow (UofG) and Scottish Water (SW). The outcomes of this project are categorised into: (i) provision of a geomorphological context for an existing asset inspection protocol for pipeline crossings over rivers; and (ii) development and verification of new Erosion Risk Index (ERI) for the classification of pipe crossings according to their exposure to river bank erosion. For (i) UofG wrote two reports with summaries of basic geomorphological concepts and river bank protection techniques. Forms in SW's asset inspection app were then updated so that asset inspectors could record relevant information when on site visits. For (ii) UofG designed an iterative ERI development and testing methodology. UofG and SW worked in partnership to collect test data. UofG wrote two intermediate reports for SW, explaining the theoretical background and the methodology that comprised the new ERI classification.
Exploitation Route We are in discussion with CIRIA to disseminate findings to the water industry through a webinar and publication in industry magazines.
Sectors Aerospace, Defence and Marine,Environment

 
Description Findings from this project have been used to update Scottish Water's asset inspection app, and associated protocol, for pipeline crossings over rivers. The revised app and protocol makes use of a new Erosion Risk Index (ERI) that was developed as part of this project to classify pipe crossings according to their exposure to river bank erosion.
First Year Of Impact 2017
Sector Environment
Impact Types Societal,Economic

 
Description Scottish Water pipeline inspection protocol and app
Geographic Reach Local/Municipal/Regional 
Policy Influence Type Influenced training of practitioners or researchers
Impact The project delivered an improved app and inspection protocol to collect information on river erosion during site inspections of pipeline crossings. Information that was collected using the app was used to develop an Erosion Risk Index (ERI) which was extensively tested using from 163 sites. Scottish Water plan to embed the app and protocol into their inspection of approximately 1500 pipeline crossings. This will contribute to more effective asset management and thus reduce the risk of asset failure and either (i) interruption of clean water supply to communities or (ii) leakage of sewage water into rivers.
 
Description GCRF Small Grants
Amount £32,830 (GBP)
Organisation Government of Scotland 
Department Scottish Funding Council
Sector Public
Country United Kingdom
Start 09/2017 
End 03/2018
 
Description Edit Infrastructure and River Stability Workshop: Collaborations with Indonesia and Philippines 
Organisation Mott Macdonald UK Ltd
Country United Kingdom 
Sector Private 
PI Contribution A workshop was organised by our research team to identify infrastructure and river stability challenges in Indonesia and the Philippines. Delegates included: Mott MacDonald: Tom Beskeen, Citra Sumarmi, Richard Brice.
Collaborator Contribution Partners contributed time to a 2 day workshop that mapped management and research challenges.
Impact Multi-disciplinary includes engineering, environmental science, geomorphology, flood modelling, hydrology. Outputs have included a funded Scottish Funding Council Grant, and two NERC hydrometeorological hazards in SE Asia proposals.
Start Year 2017
 
Description Infrastructure and River Stability Workshop: Collaborations with Indonesia and Philippines 
Organisation Glendale Partners LLC
PI Contribution A workshop was organised by our research team to identify infrastructure and river stability challenges in Indonesia and the Philippines. Delegates included: Glendale Partners: Professor J Scott Younger, Dr David Parry, Mr Mark Murray.
Collaborator Contribution Partners contributed time to a 2 day workshop that mapped management and research challenges.
Impact Multi-disciplinary includes engineering, environmental science, geomorphology, flood modelling, hydrology. Outputs have included a funded Scottish Funding Council Grant, and two NERC hydrometeorological hazards in SE Asia proposals.
Start Year 2017
 
Description Infrastructure and River Stability Workshop: Collaborations with Philippines and Indonesia 
Organisation University of the Philippines
Country Philippines 
Sector Academic/University 
PI Contribution A workshop was organised by our research team to identify infrastructure and river stability challenges in Indonesia and the Philippines. Delegates included: University of the Philippines: Dr Eric Paringit, Dr Eugene Herrera, Dr Rhodora Gonzalez, Pamela Tolentino, *Dr CP David, Dr Ariel Blanco.
Collaborator Contribution Partners contributed time to a 2 day workshop that mapped management and research challenges.
Impact Multi-disciplinary includes engineering, environmental science, geomorphology, flood modelling, hydrology. Outputs have included a funded Scottish Funding Council Grant, and a NERC hydrometeorological hazards in SE Asia proposal.
Start Year 2017