Delivering water in a changing climate

Victoria’s water grid works much like our road network, connecting sources such as dams, reservoirs, irrigation districts and the desalination plant via infrastructure including pipes and pumps, and natural elements like rivers. To identify the resilience of our water systems to cope with climate change, a ‘stress test’ of the central south region (including Melbourne’s Water network) of the grid was undertaken.

With water sector stakeholders we tested how the grid could function under different severe, but plausible, scenarios which may occur as Victoria’s climate continues to change. The implementation report prepared for the water sector provides detailed insights as to how our water system may operate under such scenarios – giving the sector vital information to improve the resilience of the grid in the future.

While an increase in extreme rainfall may increase the likelihood of flash flooding, it is possible that overall drier conditions in Victoria will allow catchments to absorb more rainfall, offsetting projected increases in rainfall intensity.

Improving our understanding of how projected increases in rainfall intensity may interact with drier conditions is vital to understand how flood risk may change across Victoria. A scientific research report analyzing this question was prepared for water sector organisations, and key findings presented at the Victorian floodplain managers forum.

Integrated Water Management (IWM) is a collaborative process. By thinking about water in an integrated way, we can achieve multiple outcomes which address population growth, land use change, community needs, and climate change in a sustainable way. IWM Forums have been established across Victoria to identify, prioritise, and oversee the implementation of critical collaborative water opportunities and projects, with Strategic Direction Statements developed for each forum region to prioritise different IWM opportunities and projects.

To meet the challenge of climate change and prepare Victoria’s water system for a range of possible climate futures, climate change mitigation and adaptation actions will be embedded in all IWM Forum decisions. A 2020 desktop analysis of Strategic Directions Statements highlighted climate change as a core consideration in IWM thinking across Victoria.

Australian Rainfall and Runoff (ARR) is a national guideline document, as well as a data and software suite that can be used for the estimation of design flood characteristics in Australia. First developed in 1987 the suite has been continually updated and improved over time.

In collaboration with Stormwater Victoria, DELWP delivered a series of in-person training workshops attended by over 100 key water sector stakeholders to build capability and capacity in the use of ARR 2016, the most recent ARR major suite update at the time of training. This suite includes the latest methods to model more intense rainfall under climate change.

Aboriginal water-related values are vulnerable to climate change. For example, reduced rainfall may see significant ecological or cultural sites along waterways not receiving the levels of water they have in the past. DELWP is working with Traditional Owners to better understand what the expected impacts of climate change will be on Aboriginal cultural values associated with water, what can be done to adapt to the changes, and what we can learn from Traditional Owners and Aboriginal groups about how to adapt to water-related changes.

DELWP is partnering with the Dja Dja Wurrung Clans Aboriginal Corporation to undertake this ongoing work.

A core service delivery requirement for many of Victoria’s water corporations is the removal and treatment of sewage. Previously there was no readily-available compilation of best practice engineering and science for sewerage planners, managers and operators, to assist in making business decisions in Victoria.

To address this need, a series of five technical reports were prepared for the water sector assessing the processes involved in planning, designing and operating sewerage systems and how these may be affected by climate change. These reports also support the development of climate change sewerage guidelines (Action 20).

As part of stakeholder consultation to develop adaptation actions for the Pilot WSAAP, staff from different water sector organisations identified a desire to learn more from one another, by sharing case studies and other information about climate change adaptation.

To start to address this need, the Victorian Government’s water sector climate change webpages have been updated to include a series of adaptation and emissions reduction case studies. A collaboration site has also been developed and launched in 2021 for water sector entities to share adaptation information and successful case studies amongst each other on a single platform.

Assessing the Impact of Climate Change on Water Availability in Victoria present a consistent approach for applying climate change scenarios for temperature, potential evapotranspiration, rainfall, runoff and groundwater recharge to be used across Victoria for assessing the impact of climate change on water availability. These guidelines have now been reviewed and an updated set of guidance was released to the water sector in December 2020.

The latest update ensures the guidelines continue to incorporate the most recent knowledge of climate change impacts on water availability in Victoria. More information can be found here.

Climate change affects nearly all business decisions in the water sector, not just those associated with our water supplies. To successfully adapt to climate change, climate change impacts should be considered in all relevant business decisions – including those related to waterway health, risk management, emergency management, infrastructure, and more.

Development of a stand-alone framework is now underway and will incorporate these principles.

An implementation plan was developed to guide the delivery of all WSAAP adaptation actions and capture lessons to improve future projects. DELWP undertook a mid-term and end of pilot review to inform the development and implementation of the Water Cycle System Adaptation Action Plan 2022-26.

Scenario planning allows water corporations to consider how possible futures under climate change may impact a water sector organisation’s ability to deliver and treat water. Improper representation of climate futures in scenario planning in the water sector may result in a sector not adequately prepared for the future.

A final report has been prepared and circulated to the water sector. It includes a series of best practice principles for using scenarios in water sector adaptation planning, and a series of principles for embedding climate change into decision making across a water sector organisation.

The Eastern Victorian Fires in 2019/20 were unprecedented in that they were large scale, prolonged over many months and occurred alongside bushfires across the eastern seaboard and other parts of Australia. The 2020 Royal Commission into National Natural Disaster Arrangements heard that climate-driven hazards are expected to continue to become more frequent and intense.

DELWP has updated water sector emergency response plans for dam safety, algal blooms, non-hazardous pollutants of inland waterways, and water and wastewater service disruption to better incorporate climate change. Two guidance notes have also been prepared for Victorian water corporations and catchment management authorities to better incorporate climate change risk into emergency management planning.

Victoria is already experiencing the impacts of climate change, and it is expected that climate change will continue to amplify the risks that the Victorian water sector faces from more likely, more intense, more frequent, and overlapping emergency events.

An assessment of the Victorian water sector’s emergency capacity was undertaken in 2020. As part of this assessment, future capability to respond to emergencies under climate change was considered. Results from this assessment will inform future training and capability priorities and initiatives in the water sector going forward.

The water sector provides critical services upon which the Victorian community rely. The complex, interconnected, and often interdependent nature of water sector infrastructure with other critical infrastructure, such as communications, transport, food supply and energy increase the risk of a disastrous systemic failure – leaving the water sector, and other sectors, incapable of providing services.

A methodology was developed in 2019 to identify critical interdependencies between the water sector and other service sectors, determine how important the interdependency is, and prioritise actions to reduce risk. This methodology was supplemented by a water sector case study to highlight how the methodology can be used. These documents were presented to Victoria’s Water Sector Resilience Network in 2020 for application within individual water corporations.

Adaptation business cases can be difficult to prepare because of the high levels of risk and uncertainty, the difficulty in quantifying benefits and costs, and the long, and often uncertain, payback period for investment in more climate resilient infrastructure.

A guidance note was prepared in 2020 and distributed to the water sector to address these challenges. The guidance note provides simple guidance to assist water sector stakeholders to develop a successful adaptation business case. The document also provides guidance on six specific economic assessment techniques that can be used to undertake an economic analysis of adaptation investments.

Water sector organisations in Victoria must manage the risks to their ability to deliver key water services, such as the supply of water and treatment of wastewater. Climate change is one such risk.

A guidance note was prepared in 2019 and distributed to the Victorian water sector to assist board members and executives of water sector organisations in understanding the scope of their responsibilities in relation to climate change.

It is important that water sector organisations understand the potential costs of climate change impacts to enable prudent and efficient investment decisions. Importantly, by assessing the costs of climate change, water corporations will also be better placed to engage with customers and the broader community on the issue,  and prepare more informed project business cases to address those climate impacts.

A guidance note has been prepared in 2020 and distributed to the Victorian water sector including an overview of the broad framework though which the costs of climate change will often be assessed; and step by step guidelines on how to go about assessing the costs of climate change.

An algal bloom is an increase in algae concentrations to such an extent that it may discolour the water, impart taste, musty odours, toxins, and/or other compounds into the water. These algal blooms can be toxic, impacting on water quality for communities and our environment. As our climate continues to change, some of the conditions favourable to the development of blooms, such as warmer temperatures, are becoming more likely.

A report was completed in 2020 outlining the latest science on blue green algae, how blue green algae responds to non-climate and climate stressors, and best practice prevention, control, and mitigation options to minimise the impact of blooms.