Paul Wyrwoll and Quentin Grafton, The Australian National University, Australia

Catastrophic floods and droughts are currently being experienced across the world. Paul Wyrwoll and Quentin Grafton argue that our existing approaches to managing water are not working. We need a new paradigm for how we manage water, a rethinking where human societies work with and nurture the hydrological cycle, instead of trying to master it. At the heart of this approach is the understanding that water infrastructure is not just concrete and steel. Instead, it is the interplay between ‘grey’ (built), ‘green’ (natural), and ‘soft’ (governance) infrastructures that will determine the benefits, costs, and risks of water uses. Here, on World Rivers Day 2022, they explain this approach and use the Murrumbidgee River, one of Australia’s most important river systems, as a case study of how it might be applied.

The control of water has been central to the extraordinary economic development of human societies since the Industrial Revolution. The storage and diversion of large volumes of water has transformed deserts into food bowls, rural areas into industrial zones, and floodplains into mega-cities. From improved electricity access to maternal health and beyond, the delivery of water when and where it is needed has contributed enormously to raising humanity’s standard of living.

For most of the 20th century, policy-makers and businesses focused on building new dams, canals, pipelines, and other so-called grey infrastructures to generate the economic and social benefits of water use. It worked, but at a big cost. In this approach, the negative impacts on ecosystems were viewed as an unfortunate but necessary by-product of technological and economic progress.

Today, on World Rivers Day 2022 we need to reimagine the world of water.

Capturing many values

The ecosystem services provided by rivers, wetlands, and aquifers need to be measured, valued, and incorporated into decision-making. Rather than being treated as a constraint on economic progress, healthy waterways must be considered fundamental to inclusive development that promotes water justice and increases societal resilience to floods, droughts, and other climate change risks. In this reimagining, we must explicitly account for where water is and what it is doing, including in the environment.

Reshaping water infrastructure is about prioritising what water services we need while evaluating all options, all benefits, and all costs. It means placing green infrastructure, such as watersheds, at the centre of investments in our water future. And this is not just an environmental concern. Increasingly, the private and public sectors are recognising the pay-offs from conserving where our freshwater comes from and carefully managing where it goes.  

Slowly, and only in some places, the cultural, social, and economic values that Indigenous Peoples hold for rivers and water are being acknowledged in government policies. But shared decision-making requires more. It needs true and equal partnerships, not superficial consultations that maintain business as usual with minimal change.

The three water infrastructures

Effective water governance can no longer be on a ‘To Do’ list, something we’ll get to down the line. It is key to protecting people and the world we live in; a world currently facing multiple crises including collapsing biodiversity and climate disruption (droughts, floods, extreme weather and wildfires). Policies, regulations, and other forms of ‘soft infrastructure’ need to manage increasingly acute trade-offs between competing water uses and users. Food-energy-water systems are becoming a source of global systemic risks as key components, such as power plants and supply chains, are operating in water and climate conditions outside their design specifications.

The catastrophic floods and droughts being experienced across the world in 2022 are highlighting the need for a new paradigm. This rethinking is one where human societies work with and nurture the hydrological cycle, instead of trying to master it. At the heart of this prosocial approach is the understanding that water infrastructure is not just concrete and steel. Instead, it’s the interplay between ‘grey’ (hard), ‘green’ (natural), and ‘soft’ (governance) infrastructures that will determine the benefits, costs, and risks of water uses (see Figure 1).

Figure 1. The Three Water Infrastructures. (Source: the authors.)

A growing and mainstream acceptance of the three infrastructures will reshape how water infrastructure projects and programs are conceived, assessed, developed, and operated in the 21st century and beyond.

The three infrastructures in our own backyard

Working with the three infrastructures includes connecting the global to the local and the local to the global. We live and work on Ngunnawal Country in Australia’s capital city of Canberra. The Murrumbidgee River forms the western boundary of Canberra’s suburbs and is the third longest river on the Australian continent running for almost 1,500 km. For tens of thousands of years, Traditional Custodians living along its length have cared for the river and Country. Waterways are pathways, meeting places, and natural resources that support many cultural, economic, and social values.

In 1960, Tantangara Dam was built across the Murrumbidgee River 242 km kilometres upstream of Canberra in the state of New South Wales (NSW). This 45-metre high and 216 metre long dam diverts more than 90% of annual flows from the Upper Murrumbidgee via a network of tunnels and reservoirs to a cascade of five hydroelectricity power stations on the other side of the Snowy Mountains range (total capacity 2.2GW). The diverted water then re-enters the Murrumbidgee 212 km downstream from Canberra (see Figure 2 for an overview of the diversion and impacts. This map and tables illustrate the hydropower scheme).

Figure 2. The Upper Murrumbidgee River: negative impacts of flow diversion. Source: Upper Murrumbidgee Catchment Network.

This grey infrastructure system was not built to support the ecosystems and other green infrastructure of the Upper Murrumbidgee. Its governance was not configured to manage the impact of large diversions by partnering and working with Indigenous Peoples around the how, what, where, and when of water in their Country. Instead, the Snowy Hydro Scheme, of which Tantangara Dam is a key component, was a ‘nation-building’ project of colonial Australian governments to expand irrigation by settler communities and provide electricity for cities and industry.

The consequences of a narrow view of water infrastructure

Reimagining the narrow, colonial view of water infrastructure that prevailed 60 years ago is urgent. The 27 km river reach beneath the dam has become an intermittently flowing creek choked with vegetation. Lack of stream flows are compounding the impacts of rural land clearing further downstream, with excess sediment smothering the habitat of at least seven vulnerable or endangered fish and crayfish species. The loss of major flushes from snowmelt and low flows in dry periods is also causing environmental and human health risks (see ACT CMCG n.d. and ACT Government 2010, 2021 for an overview of impacts).

These negative impacts affect downstream communities and towns, including Canberra where the Murrumbidgee is an important secondary source of urban water for a population of 450,000 projected to grow by over 70% in the next 30 years. In 2019, the river ceased flowing at the village of Tharwa on the border of the Australian Capital Territory (ACT) (in which Canberra is located) despite inflows of 40ML/day into Lake Tantangara at that time (ACT CMCG n.d.). The degradation of the river is undermining both ecological and cultural values, and is impacting the health and well-being of Ngunnawal people (Bell 2021). Recreational sites along the river in Canberra are regularly closed due to elevated bacterial levels (Vincent et al, 2022). Upstream regulation is increasing the vulnerability of aquatic ecosystems to climate change (Dyer et al, 2014).

Importantly, the declining health of the Upper Murrumbidgee is due to both the existence of the dam and how it is regulated. The Snowy Hydro Scheme is not fully integrated into the national framework for sustainably managing the transboundary Murray-Darling Basin. The limited downstream flows provided through the Snowy Water License are insufficient to restore river health, follow a daily schedule determined one year in advance that prevents adaptive management, and, perversely, decline as the availability of regional water declines. During a severe drought in 2018-19, there were no flows released from Tantangara for 305 days (Doyle 2022, see p.6 of Snowy Hydro 2019). Under the New South Wales planning framework, the Upper Murrumbidgee is considered ‘unregulated’ by the dam, meaning that environmental flows are not protected from irrigation extractions upstream of Canberra.

Grey, green, and soft infrastructure on the Murrumbidgee

The Forgotten River campaign was launched in 2022 to advocate for governance reforms that improve the health of the Upper Murrumbidgee (see an overview presentation here). Also in 2022, the Upper Murrumbidgee Catchment Network held a multi-stakeholder forum identifying key challenges and pathways toward better outcomes under climate change (the presentations can be viewed here).

Increasing the volume of flows from the existing Tantangara dam infrastructure is only part of the long-term solution; the capacity of the outlet (see Figure 3) is insufficient to recreate large spring rainfall and snowmelt pulses without new engineering works. Potential pathways forward encompass grey, green, and soft infrastructure approaches (see Figure 4 for a summary from above sources). All levels of government have an opportunity to work with Traditional Custodians of the Upper Murrumbidgee to develop, evaluate, and implement water and land management reforms.

Figure 3. Tantangara dam and downstream area with outlet discharging at full capacity. Source: Paul Wyrwoll.

From a public policy perspective, an important step will be to conduct a comprehensive assessment of potential reforms. For example, the $AU5 billion Snowy 2.0 pumped hydropower project (for which Lake Tantangara is the upper reservoir) and the broader renewable energy transition will alter the opportunity cost to Snowy Hydro of Upper Murrumbidgee releases. Greater water availability in the Murrumbidgee could delay capital investments in urban water supply, and the associated costs, as Canberra grows. Riparian land rehabilitation could generate increasingly valuable carbon credits. A larger outlet or bypass structure at Tantangara Dam could also include a mini-hydropower plant. From base flow restoration to ‘run-of-river’ dam reoperation, there will be spectrums of economic costs and benefits to examine. And they will all vary under climate change.

Figure 4. Pathways toward improving the health of the Upper Murrumbidgee River. Sources: Forgotten River campaign and Upper Murrumbidgee Catchment Network Water Quality and Security Forum.

The Upper Murrumbidgee River and Tantangara Dam are not an isolated example. There is a growing body of research and practice on the benefits of reoperating existing dams across the world (e.g. Opperman et al. 2019, Ruhi et al. 2022, Brown et al. 2019, Turley et al. 2022, Owusu et al. 2021, Kondolf et al. 2022). This ‘system view’ of water infrastructure and the opportunities for grey-green approaches include nature-based methods for flood management and sea-level rise.

A sound investment

In a recent report on the global gap in water infrastructure finance, the Organisation of Economic Cooperation and Development (OECD) emphasised the need to make better use of existing infrastructure assets. A 2021 report by the World Economic Forum (WEF) with partners highlighted that investments in nature-based approaches will need to “at least triple by 2030 to meet global climate change, biodiversity, and land degradation targets”. Meanwhile, in a 2019 study the World Bank stressed that “strategically combining green and grey infrastructure to lower costs and improve resiliency can help tackle the looming financial and environmental crisis facing global infrastructure systems”.

These calls for action highlight the unrealised economic, social, and cultural benefits from reimagining what existing water infrastructure is, and the benefits it can provide to human societies. It’s time everyone realised that environmental sustainability and good governance are not costs, they are investments in water security and, ultimately, inclusive and sustainable development.

More information:


Australian Capital Territory (ACT) Government (2010). Upper Murrumbidgee Demonstration Reach Implementation Plan.

ACT Government (2021). Case study – Maximising benefits in the upper Murrumbidgee River. MDBP Schedule 12 Annual Reporting – Matter 10 Indicator 10.4. Opportunities to improve the Basin Plan and/or Environmental Watering Plan.

Bell B (2021). Murabidji Letter to the minister 2021 re: Water Resource Plan.

Brown C, V Zakaria, A Joubert, M Rafique, J Murad, J King, … & L Alonzo (2019). Achieving an environmentally sustainable outcome for the Gulpur hydropower project in the Poonch River Mahaseer National Park, Pakistan. Sustainable Water Resources Management, 5: 611-628.

Doyle P (2022). Tantangara Dam: 2022-23 Release Planes, and Longer Term Issues. Presentation to the Upper Murrumbidgee Catchment Network Water Quality and Security Forum. Office of Environment and Heritage, New South Wales Government.

Dyer F, S ElSawah, B Croke, R Griffiths, E Harrison, P Lucena-Moya & A Jakeman (2014). The effects of climate change on ecologically-relevant flow regime and water quality attributes. Stochastic Environmental Research and Risk Assessment 28: 67-82.

Kondolf M & J Yi (2022). Dam Renovation to Prolong Reservoir Life and Mitigate Dam Impacts. Water 14: 1464.

Opperman JJ, E Kendy & E Barrios (2019). Securing environmental flows through system reoperation and management: Lessons from case studies of implementation. Frontiers in Environmental Science 7, 104.

Owusu AG, M Mul, P van der Zaag & J Slinger (2021). Re‐operating dams for environmental flows: From recommendation to practice. River Research and Applications 37: 176-186.

Ruhi A, J Hwang, N Devineni, S Mukhopadhyay, H Kumar, L Comte, … & A Sankarasubramanian (2022). How does flow alteration propagate across a large, highly regulated basin? Dam attributes, network context, and implications for biodiversity. Earth’s Future 10(6), e2021EF002490.

Turley L, C Bréthaut & G Pflieger (2022). Institutions for reoperating reservoirs in semi-arid regions facing climate change and competing societal water demands: insights from Colorado. Water International 47: 30-54.

Upper Murrumbidgee Catchment Network (UMCN) (2022). Submission from UMCN to the Draft Murrumbidgee Regional Water Strategy.

Upper Murrumbidgee Demonstration Reach (UMDR) (2022). Re: Submission of comment on the Murrumbidgee Regional Water Strategy.

Snowy Hydro (2020). Water Compliance Report. 2018-2019 Water Year.

Vincent K, D Starrs, V Wansink, N Waters & A Lal (2022). Relationships between extreme flows and microbial contamination in inland recreational swimming areas. Journal of Water and Health 20: 781-793.

Paul Wyrwoll is a Research Fellow at the Australian National University’s (ANU) Crawford School of Public Policy and a Fellow at the ANU Institute of Water Futures. He is the Lead Author on the technical report on Water Infrastructure for the Global Commission on the Economics of Water.

Quentin Grafton is Professor of Economics at the ANU, Convenor of the Water Justice Hub, and Lead Expert and Commissioner of the Global Commission on the Economics of Water. He is also the Executive Editor of the Global Water Forum.

The views expressed in this article belong to the individual authors and do not represent the views of the Global Water Forum, the UNESCO Chair in Water Economics and Transboundary Water Governance, UNESCO, the Australian National University, Oxford University, or any of the institutions to which the authors are associated. Please see the Global Water Forum terms and conditions here.

Banner image: The Murrumbidgee River as it flows through north Canberra. A narrow focus on grey infrastructure along the Murrumbidgee has created a raft of problems and challenges for people dependent on the river. (Image by David Salt)