This article focuses on the research and development of a robust model for the quantitative risk assessment of water and wastewater pipelines by taking into account the likelihood and consequence of pipeline failure.

Extensive global parameters are taken into consideration to determine the likelihood and consequence of pipeline failure, and these parameters are evaluated by water and wastewater utilities in the US, and derived by geographic information system (GIS) using advanced geospatial tools.

A web GIS-based Pipeline Infrastructure Database (PID) will be developed as a tool for utilities to access and tweak the risk assessment model for each type of pipe. An exclusive working environment will be provided for each utility with access to their respective data to access the global risk assessment model and export the results in customised formats as reports, shape files and databases, and thus this serves as a comprehensive tool for sustainable utility risk management. Also, this is a global risk model for strategic infrastructure asset management and thus for asset allocation, financial planning, and determining condition assessment methods.


Background

Based on the feedback from major water and wastewater utilities across the US, it has been stressed that there is no GIS-integrated robust risk model available for use by the utilities. Thus, this research involves developing a web GIS-based risk model with intuitive applications, making it highly useful for utility managers to access risk models, assess their pipeline infrastructure, and plan for strategic asset management.

The risk models used by major utilities in the US, Australia, and also those used in the oil and gas pipeline industry have been extensively reviewed. Most of these models currently used in the industry included limitations, and many are not GIS-integrated. Some of the limitations of the major risk models are listed below:

  • Limited parameters for both likelihood of failure and consequence of failure.
  • Models are not trusted by utility managers as they are not validated or pilot-studied in other similar utilities.
  • A GIS-based approach to query and visualise other supplementary data along with the robust model results such as soil, roads, weather is not yet available.
  • Factors and weights used in the model are not evaluated and weighed by experts.


Research methodology

A sophisticated web GIS application has been developed using ArcGIS API for Flex. The GIS data received from utilities is processed at Virginia Tech and, using an ArcSDE connection, the data is hosted on an Oracle instance at Virginia Tech managed by Center of Geospatial Information Technology. Using ArcGIS Server Manager, REST and SOAP services are published from the data hosted on the Oracle Instance through ArcSDE.

Using Adobe Flash Builder, web-application and widgets are developed using ArcGIS API for Flex and MXML programming language to query and visualise the geospatial data. This web GIS application is then hosted using VT Hosting, and protected with access codes using JavaScript, enabling utilities to login and work with their respective data.

Risk is defined as likelihood of failure of pipe and the associated consequences due to the failure of the pipe. By extensive literature review and feedback from major utilities, parameters that determine the likelihood and consequence of failure of water and wastewater pipelines were identified. The risk model will be developed using Analytical Hierarchy Process. A document was prepared which listed the parameters and tables to mark the significance of each parameter. This document was sent out to utility managers, and the significance of each parameter was received. The significance of each parameter represents the relative importance of this parameter among the others. The risk model results would have a range from 1–5 (low risk to high risk), which would be colour coded on pipes from yellow to red.


Expected outcome

The key contributions of this research will be:

  • An advanced GIS-based web application for pipeline data visualisation and querying using state-of-the-art technology – Adobe Flex-based environment.
  • Access to a robust global likelihood and consequence of failure model for water and wastewater pipelines integrated into the web GIS application.
  • The ability to tweak and simulate model results on the web application, and export results in desired formats for effective strategic infrastructure asset management.


Conclusion

This research has developed an advanced web GIS-based global risk model for water and wastewater pipelines, thus aiding strategic infrastructure asset management. Currently, there is no advanced software or application that integrate data visualisation, querying and web-based risk models. This web application is highly received by the water and wastewater utilities as the models and tools are developed based on the feedback from major utilities and validated by them.