5 minute read
Aging infrastructure combined with increasing customer expectations and demand growth are causing a real threat to our networks. Some assets in our networks could be considered critical: because of number of customers they serve, because of the type of customers (schools, hospitals, etc.), because of their age or because they affect resilience. The path towards water resilience starts from understanding which are the critical assets and by making decisions on acceptable levels of risk. When you think about resilience, it is crazy to try to plan for every possible thing that can go wrong. It is far better to look at the impact if an asset fails. The worse the impact, the more critical that asset is. That is where you should focus your efforts: protecting key infrastructure assets.
InfoWorks WS Pro can assess full holistic network assessments on all network assets. The ability to run simulations in parallel ensures that this analysis can be done quickly. The risk and resilience assessments that InfoWorks WS Pro can undertake include:
- Available hydrant fire flow assessment and a pass and fail of requirement.
- Assess the critical mains in the network based on customers affected by isolation.
- Transient impact from all network pumps tripping out because of an electrical failure, or the transient affect from isolation and boundary valves being shut/closed.
- Customers affected by hydrant opening and levels of service they achieve.
- The water quality changes experienced when there are network rezones by assessing turbidity, flow reversals, changes of concertation and age of water.
In the example below we can see the results of assessing the available fire flow at peak demand (minimum pressure) to assess the worst-case scenario. Minimum pressure will occur at different points in time throughout the network, this analysis will see when that is and the corresponding fire flow results. From this the lowest available fire flow can be seen and works can be put in place if necessary, to reduce this risk to ensure compliant pressure and supply.
Case Study: Bristol Water (UK)
Identification of critical assets
Bristol Water used the critical link analysis tools within InfoWorks WS Pro for their business plan submission to OFWAT for PR19.
Challenge: Minimize disruption to water supply
- Which main would affect the highest number of customers if it burst?
- Where to divert the water from an isolated main while it is being repaired or replaced?
- How to assess what happens at the reservoir when a main is replaced?
Solution: Automated workflows to assess pipe criticality
Critical Link Analysis is not just about reducing leaks. It is about understanding what is at risk when an asset fails – preferably before it happens – and taking decisive action to protect communities.
Result: Bristol Water was able to put together a robust business case for its resilience plans with greater confidence than previous AMP
Bristol Water was able to make a direct comparison of the impact of using Critical Link Analysis in InfoWorks WS Pro. For the previous price review, PR14, Bristol Water had joined a simplified model together to run a critical link analysis. It was limited by the available computing power and there was little confidence in the results. “We saw massive improvements in performance for PR19,” said Kevin Henderson, Network Asset Modelling Manager for Bristol water. “InfoWorks WS Pro made our analysis overwhelmingly better.”
The project identified spending £22 million on mains and control valves over the next two AMP periods 2020 – 2030, to reduce criticality to acceptable levels.