Risk Prioritisation Tool

Risk Prioritisation Tool for Drainage Services Department, Hong Kong SAR
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The underground assets of the Drainage Services Department (DSD) expanded rapidly with the continuous development and urbanisation of Hong Kong in the past few decades. Part of the systems becomes aging and increasingly difficult and costly to maintain. It was proposed to carry out a study (i) to collect and assess the structural condition of the underground assets and (ii) to develop a systematic and cost-effective inspection, replacement and rehabilitation strategy to the underground assets.


Need: Several road subsidence incidents caused by the collapse of aged and dilapidated sewers and drains occurred in 2011. A systematic and well-organised inspection, replacement and rehabilitation (R&R) strategy was necessary for the enhanced management of the sewers and drains.

Challenge: B&V Information Management & Analytics (IMA) department were asked to provide their expertise in developing a solution that would allow the implementation of the Risk Methodology into a auditable decision support tool. This tool would use various disparate datasets that would need pulling together into a central location where the client could change parameters depending on their requirements.

Solution: The RPT was created as a auditable decision support tool (ADST) that allows parameter values to be set in order to calculate the relative risk of an asset against the whole asset type base. The RPT also contains a GIS element that was used to calculate the relative consequence if an asset were to fail. This consequence modelling was undertaken in ArcGIS to spatially analyse the assets against agreed receptors. The results of the consequence modelling and the probability of failure were then loaded in the RPT to enable the client to repeat the analysis with new data. The RPT then brought the probability of failure and consequence together through a series of calculations to output a Risk score and rank against each asset. These assets could then be ranked accordingly and actioned as appropriate.

Benefits: The RPT was developed to as flexible as possible based on the very high level requirements specified at the start of the project. As such, having the ability to run the model, change some parameters and re-run and compare against previous model runs allows you to fine tune your outputs. A decision was made to design and create the database in MS Access allowing DSD full control and access to the data and outputs from a single source. MS Access has the benefit of stringing a number of queries together which helps build the decision making process into a tangible output.

Key benefits
  • DSD have a repeatable and auditable tool that provides a rank of assets to target
  • Designed so the client can update and change parameters easily
  • Provides a ‘one stop shop’ for risk and consequence on the network.


Key features:
  • A relational database allowing the ranking of assets according to Risk and Consequence
  • Provides an auditable tool to support network planning and maintenance
  • Provides links to GIS to enable the client to visualise the outputs
  • A cost-effective solution developed in a rapid programme

Risk Model, Consequence,  Sewers, Rising Mains, DSD