Dr WOODRUFF - Mr Bolt, are you aware of the recent research by the University of New South Wales and the University of Melbourne. It was published in Water Resources Research and that was called the Impact of Climate Change on Operational Probable Maximum Precipitation Estimates? You might not be. That research found that current models for probable maximum precipitation that engineers use for designing large dams and other infrastructure haven't been updated for 20 years and found that those models are in urgent need of review given the extreme precipitation and increased precipitation that we will experience.
As we understand it, the PMP calculation is currently based only on the historical data and modelling in this research found that for the 546 large dams across Australia, their probable maximum precipitation is expected to increase by 14 and 38 per cent on average. We understand Hydro provided some support for that research work. Is the company doing any further work regarding those models? What's the exposure and risk and response management of the research findings?
Mr BOLT - Because our contribution to the state's energy security is fundamentally bound up with rainfall and therefore with climate, we are well aware of that being a significant risk and opportunity, depending on how the trends go. I have been involved in discussions to explore how we are monitoring that risk. We are confident that it’s a very active process of inquiry and monitoring, bearing in mind that there is this great uncertainty even with studies such as you have just mentioned, of which I am not personally familiar. It is difficult to be very precise about what is going to happen over the next 12 months of rainfall, let alone over the coming years an decades. As a general statement, we are very well aware of the risk and are monitoring it. As to the specifics of that research and what it might mean for our operations, I can't answer the question personally but the organisation can.
Mr BROOKSBANK - Obviously this would go to the safety of our dams. The dams we have are underpinned by our asset management policies. The work we do on them is planned ahead in our strategic asset management plan. Supporting that policy is the dam safety management risk standard. This is a high level document which defines the context, framework, and boundaries for management of dam safety risk within the Hydro Tasmania portfolio. As you have clearly outlined, climate change and the level of precipitation, particularly if it increases dramatically or indeed decreases -
Dr WOODRUFF - When it does we know that it will. For every degree increase there is something in the order of a 10 per cent increase in the amount of water vapour that the air can hold, so it all comes down.
Mr BROOKSBANK - The dam safety management risk standard adheres to all the requirements under the Tasmanian Water Management Act 1999 and the associated Water Management (Safety of Dams) Regulation 2015. The act states that there is a requirement that dam owners must, so far as reasonably practicable, maintain and operate the dam so as not to cause or be likely to cause material environmental harm or social environmental harm, or danger.
Clearly we participate in studies such as the one you mentioned to ensure that we have a clear handle as best you can forecasting ahead what climate change impacts will be to our system. Within the dam safety regulations, the Australian National Committee on Large Dams (ANCOLD) is a suite of guidelines that we reference. In Tasmania these guidelines are used to standards. ANCOLD was formed in 1937 as an Australian-based apolitical industry body that focuses on disseminating knowledge, developing capability, and providing guidance in achieving excellence for all aspects of dam engineering, management, and associated issues.
Among other things, ANCOLD prepares and issues guidelines which represent current engineering practice. That's important because as you have highlighted, climate change is occurring and engineering standards and dam management must keep pace with what we are seeing in the environment. On a bi-annual basis, the dam safety management program is independently reviewed by dam safety specialists during Hydro Tasmania's civil assets performance review group. Following the review, the findings and recommendations are incorporated into our dam safety program. We look at dam safety over the long term.
We are an organisation that has been around for over a 100 years. While our asset management plan informs the current year's budget, it also encompasses a great many years into the future of Hydro Tasmania and assets. To manage the safety and identify dam safety changes, our dam safety management program includes various assessments, including maintenance assessments, engineering assessments and changes.
