Key Takeaways:
- The council is still at risk of a major flood event due to trees and other obstacles near the water supply pipeline.
- The council has identified high-risk trees and is working to remove them, but the process is challenging and time-consuming.
- The council has mitigations in place, including a spare pipe and a backup water treatment plant, but the risk of an event is still considered high.
- The council is working to reduce the overall risk, but the magnitude of the issue is still a concern.
- The council is considering a system-wide approach to risk management appetite, but the impact of the issue is still being assessed.
Introduction to the Issue
The council is facing a significant risk of a major flood event due to trees and other obstacles near the water supply pipeline. Alder, a council member, expressed his concern about the issue, stating that it keeps him awake at night. He believes that it is premature to shift the residual risk rating from serious to moderate until the problem is addressed. The council report provided a quarterly update on the council’s strategic and enterprise risk management activities, but Alder is not satisfied with the progress made so far.
The Risk of Flooding
The council’s community lifelines director, Tim Barry, explained that the council has put the resilience of the Te Arai water supply at the highest possible level. However, he acknowledged that it is an outlier across general infrastructure. The council is advancing consents for forestry companies to remove trees in sensitive areas, which the council knows will pose a risk to the water supply pipeline. The council is looking to "surgically move into that area in the new year" to address the issue. Barry explained that some of the challenges are typographical in nature, with extremely steep slopes right by water bodies, and that bridges and trees do not work well together in events.
Challenges in Addressing the Issue
The council has identified high-risk trees, some of which are very large masses of timber that sit above the council’s assets. However, removing these trees is a delicate and challenging process, and the council is trying to do so in the 2025-26 timeframe. Even if the council is able to remove the trees, the risk will still be ongoing due to difficult areas to access. Barry acknowledged that this is the council’s biggest utility known risk, with a high chance of an event happening over a long timeframe, although the chances are not high in any one year.
Mitigations in Place
The council has mitigations in place to address the risk, including a spare pipe sitting at Waingake, available to pull into action. The council also has the Waipaoa Water Treatment Plant, which can take water out of the Waipaoa to run the city in "limp mode" for a period of time. The council’s chief financial officer, Pauline Foreman, stated that the council has mitigations in place and is working towards reducing the overall risks. However, the council does not have the money for a duplication pipe, which would provide an additional layer of protection.
Next Steps
The council’s chief executive, Nedine Thatcher Swann, stated that she is unsure whether the magnitude of the issue is significant enough to impact on a whole system-wide approach to risk management appetite. The consents for tree removal are for three private companies, and councillors can be taken to have a look at the area and have a briefing if they are interested. The independent chairman of the meeting, Bruce Robertson, asked Barry to update the committee on the situation at the next quarterly meeting, following the work the council planned to do in the new year.
Conclusion
In conclusion, the council is facing a significant risk of a major flood event due to trees and other obstacles near the water supply pipeline. While the council has mitigations in place, the risk is still considered high, and the magnitude of the issue is still being assessed. The council is working to reduce the overall risk, but the process is challenging and time-consuming. The council will continue to monitor the situation and provide updates on the progress made in addressing the issue.