Dams are crucial to climate change response and the energy transition

At the recent ICOLD meeting in Gothenburg, Sweden, dam engineering experts from across the globe came together to share knowledge, discuss trends and issues, and engage with each other. One important topic of discussion was the role of dams in the international response to climate change and what that will mean for the dams industry. Richard Herweynen, Entura’s Technical Director, Water, shares his thoughts on this topic here …

Why will dams play a critical role?

Three major reasons why dams will be crucial in the climate change response and energy transition are water security, dispatchability of electricity, and tailings storage.

  1. Water storages will be vital to provide the same level of water security

Water security is essential for humanity. With greater hydrological variability due to climate change, more storage will be needed to provide the same level of security of water, food and energy. Water storage is a fundamental protection from the impacts of a changing climate, safeguarding the supply of water, and the water–food–energy nexus, even during extended drought.

The effects of climate change are predicted to increase and to result in greater magnitude and frequency of hydrological extremes, such as prolonged droughts and significant floods. With prolonged drought, inflows to storages will reduce. If demand remains the same, stress on existing water storages will increase.

Water storages are used to regulate flows and manage this variability: storing water when there are high inflows (or floods) and then using this stored water during low inflows (or droughts). Dams are used to create these vital water storages.

  1. Hydropower and pumped hydro energy storage (PHES) are critical for the energy transition

A key response to climate change is the decarbonisation of the electricity sector through renewable energy. Wind and solar power now offer the lowest cost of energy, have low ongoing operational costs, and emit the least greenhouse gases across their lifecycle – and therefore hold the greatest potential for rapid decarbonisation of the energy sector. Of course, wind and solar PV output vary according to the weather and the time of day – but the electricity market needs the supply of electricity to match demand, or for these renewables to be dispatchable.

Energy storage is the key to smoothing out the variability of renewable energy generated by solar and wind. The power and duration of the storage are the two key variables in determining the most suitable solution. Low-power, short-term storage is currently more cost-effective using batteries, but longer periods and larger power requirements are likely to rely on bigger storage options, such as pumped hydro energy storage (PHES) and traditional hydropower. Smoothing out the daily variability in renewables can be achieved effectively through pumped hydro. Dams are used to create the water storages used in both traditional hydropower and PHES.

  1. The transition to renewables will demand more minerals and metals

The global energy transition will demand a major increase in renewable energy technologies – which in turn will require more of the ‘critical energy minerals’ and metals. The rising need for minerals such as copper, aluminium, graphite, lithium and cobalt will not be able to be met by recycling and reuse alone. Therefore, extraction and storage of minerals from mining operations will be essential to sustain the renewable energy transition.

According to a report by the World Bank Group, the production of minerals such as graphite, lithium, and cobalt could increase by nearly 500% by 2050 to meet the escalating demand for clean energy technologies. It is estimated that over 3 billion tonnes of minerals and metals will be necessary for the deployment of wind, solar, geothermal power and energy storage, all of which are vital for achieving a sustainable future with temperatures below 2°C.

However, this need for mining activity comes with a special responsibility for sustainable practices, including the proper management and storage of mining waste. Rock, soil and other by-products are left behind after the desired minerals have been extracted from the ore. Tailings facilities store this waste, playing a crucial role in mitigating the environmental impact of mining operations. Dams, in particular, are commonly used to create these facilities, as they provide an effective means of containing the waste.

Dams used in tailings facilities are designed to withstand the weight and pressure of the waste materials, prevent seepage of contaminants into the surrounding environment, and take into account factors such as stability, erosion control and water management. Dams that are well designed, constructed and monitored, adhering to stringent environmental and safety regulations, can help prevent the spread of mining waste into nearby water bodies, reducing the risk of water contamination and protecting aquatic ecosystems.

Working towards ‘good dams’

While there have certainly been some examples around the world of dams that have had adverse impacts, it is clear that dams will play a critical role in the international response to climate change and the decarbonisation of the energy sector. It’s therefore vital that dams are planned, constructed and managed appropriately and safely. With increasing understanding of impacts and far greater sophistication of internationally accepted sustainability protocols, it is now up to developers and planners to heed the lessons of the past and find the right dam sites for nature and communities.

It is important that we ensure the safety of existing dams as well as the safety of any new dams. Examples from around the world demonstrate the devastating consequences of dam failures. Safety must be every dam owner’s key concern, and should be managed through an active dam safety program.

Of course, the larger the portfolio of dams an owner is managing, the greater the demand on their resources; however, it is critical that dam safety risks for water storages and tailings facilities are managed appropriately across dam portfolios to protect downstream communities. The Portfolio Risk Assessment process increases the focus on potential failure modes and risk as drivers of the dam safety program and as the basis for deciding priorities for allocating operational and capital resources.

It will also be vital that dams engineers, owners and operators keep up to date with the latest developments in the dams industry worldwide through continuous learning and important global forums such as ICOLD.

If you’d like to talk with Entura about your water or dam project, contact Richard Herweynen.

About the author

Richard Herweynen is Entura’s Technical Director, Water. Richard has three decades of experience in dam and hydropower engineering, and has worked throughout the Indo-Pacific region on both dam and hydropower projects, covering all aspects including investigations, feasibility studies, detailed design, construction liaison, operation and maintenance and risk assessment for both new and existing projects. Richard has been part of a number of recent expert review panels for major water projects. He participated in the ANCOLD working group for concrete gravity dams and is the Chairman of the ICOLD technical committee on engineering activities in the planning process for water resources projects. Richard has won many engineering excellence and innovation awards (including Engineers Australia’s Professional Engineer of the Year 2012 – Tasmanian Division), and has published more than 30 technical papers on dam engineering.


When is the best time to invest in deeper understanding? An example from hydraulic modelling

With projects and operations, like life, knowledge is power – the power to make informed decisions and manage risk. That knowledge can be gained in different ways, at different costs, and at different stages of a project. In an era of ever-more-sophisticated digital tools, how do we decide what’s best for the project?

The understanding of when to invest in more accurate assessments is changing. Traditionally, more accurate assessments were time-consuming and costly, and left to later in a project’s life. Now, however, improved techniques and computing power make greater accuracy both possible and affordable earlier.

Here we look at the issue of when to invest in more accurate assessment tools using the example of where hydraulic modelling is a key part of projects, often in the development of water infrastructure.

As a project evolves or a system is operated, different levels of knowledge will be needed to make informed, defensible decisions. This knowledge comes from experience and from assessments specific to the project. With water modelling, these assessments vary in complexity and data requirements. They also need to be integrated into the design and approval for the development.

Investing too early in a detailed assessment can be wasteful, as there usually isn’t the data to support the approach. Even if the data is available, a high-cost investment too early in the project can be wasteful if the project is stopped or changes direction. However, investing too late in gaining a better understanding of the system and risks can lead to poor decisions and rework later, as the design may have advanced on poor assumptions for critical elements.

There is, therefore, always a balance to be found in the timing and the approach to take. If there are too many options for solutions late in the project life, there’s a danger of analysis paralysis. Knowledge gaps, too, can paralyse a project.

Increasingly sophisticated modelling is becoming more widespread and available

Understanding the behaviour of water as it moves around us, our environment and our structures is based on physics and statistics. Hydraulic modelling of water systems can range from a single line equation that takes only seconds to calculate, to complex numerical models that take months to work through.

In the past, with limited or no computing power, modelling required hand calculations. As techniques improved and computing power increased, it became possible to conduct numerical modelling with a simplified set of physics. For surface and pressurised water systems, these were called one-dimensional models. Over time, it became practical to use two-dimensional models, then limited three-dimensional models, and then full three-dimensional ‘CFD’ models. Computational fluid dynamic (CFD) models are the current state-of-the-art tools for hydraulic modelling.

CFD and physical modelling can provide such competitive advantage that there are now rules to limit the use of these tools in the racing car industry. This is because the tools are costly, so less affluent teams are disadvantaged by not having access to them. To level the playing field, the top teams are required to use less than the bottom teams.

In the world beyond racing cars, there are also limits on using state-of-the-art tools. Limits can be financial, skills, suitable input data and time. But as they become easier to use, CFD tools are finding their way into the early stages of projects.

In hydraulic modelling, not every engineer has access to a hydraulics laboratory in their office, although we all wish we did! So when there are uncertainties about how a system may work, it’s not usual to make a physical scale model and test things to get the insights needed to fill any knowledge gaps. To give engineers early insights into a system’s behaviour – which helps us find the best solution faster – we used to use simple hand calculations or one-dimensional models, but it is now becoming more common to use CFD and other advanced tools earlier in a project’s life.

Advantages of CFD in practice

Let’s look at a real-world example: understanding the overtopping of a dam wall with an upstream parapet wall during an extreme flood.

In this project, only hand calculations were to be used to work out the relationship between water flow rate and water depth above the wall. But during the hand calculations, it wasn’t clear if the water, after flowing over the parapet wall and then flowing over the rest of the crest, would build up and affect the upstream water levels by submerging the parapet. If the parapet was submerged, this would change the hand calculation method. There was a knowledge gap.

Initially, some testing was done with a one-dimensional numerical model, but this didn’t provide much insight into the hydraulic behaviour. So a simple CFD model was quickly built based on some hand sketches. The CFD model made it clear that there was no submergence of the parapet, allowing the use of the correct hand calculations. It filled the knowledge gap.

Now that the CFD model had been built, it could also be used to help validate the key inputs to the flow–depth relationship over the dam. The CFD model therefore benefited the qualitative understanding of the system’s physical behaviour as well as providing a second approach to solving the initial problem and improving confidence in the solution.

So what’s the lesson here?

CFD wasn’t initially considered when the overall project was scoped, as CFD was traditionally considered to be too expensive. In the end, though, it was a valuable key to filling a knowledge gap and provided unplanned secondary benefits.

CFD isn’t going to be the answer for every hydraulic modelling project – but the general solution is to use the most accurate method that can be afforded as early in a project or operation as possible. There will always be a balance to be found in when to invest in accurate assessments, but the decision should be based on the contemporary lower effort to use and get results from these approaches, and the power gained by the extra knowledge they can provide.

If you’d like to talk with Entura about your water or dam project, contact Richard Herweynen.

About the author

Dr Colin Terry is a civil engineer at Entura with three decades of experience in Australia and New Zealand. His experience includes modelling, planning, design and construction support. He has worked on multidisciplinary projects across various parts of the water cycle including catchment management, water supply, hydropower, land development, transport, and water quality in natural systems – with a focus on surface and piped water.


New circumstances, new projects, new regulations

It’s a major challenge to keep an existing local project running during these tricky times (let alone an interstate or international project!), but how can we start new projects as the ground shifts around us and as regulations around Australia change?


In this third article from Entura’s environment and planning team, we feature a recent win in the national water infrastructure space – the detailed design, and planning and environmental approvals for a new off-creek storage in the Northern Tablelands of New South Wales. And we take a look at how regulatory changes are playing out around Australia to provide greater flexibility to respond to current constraints.

Starting a new project during a pandemic

Entura, working together with Hunter H2O, is now assisting Walcha Council with a regionally significant project despite COVID-19. The township of Walcha is currently serviced by one small off-creek water storage, which means that stringent water restrictions are needed during periods of drought. The regional council, supported by federal government funding, is investing in improving Walcha’s water reliability and security, which will also deliver social benefits to the community.

Our team tendered successfully when COVID-19 was yet to hit our shores, but in a mere few weeks we found ourselves loading up our office gear to set up from home. The same week that our engineering, planning and environmental specialists were scheduled to fly to Walcha to meet with Council on site, travel restrictions intensified and flying out of Tasmania was no longer an option. We adapted by taking to virtual platforms to communicate with our client about the challenges imposed by COVID-19 and how we could still keep the project moving, albeit with some deviations from the original schedule.

As a multidisciplinary firm capable of working across many jurisdictions, we pride ourselves on the relationships we have established with local contractors. In these times we are even more aware of the benefit of these associations to help keep the work flowing. For this project, collaboration with local contractors and swift adaptation has allowed the team to keep the project moving forward. Local geotechnical contractors have begun their investigations to feed information to our teams. Meanwhile, our environmental and planning experts have studied databases and existing literature to determine potential terrestrial, aquatic and regulatory constraints that may affect the design of the new off-creek storage.

Lockdown restrictions are starting to ease across the nation, but for now we are sitting tight and waiting until it is safe to visit the site. We need to ensure that storage design works are undertaken only when our technical specialists have stepped foot on the site themselves and have a thorough understanding of the site context. In the meantime, we continue to provide value through virtual meetings and workshops with our client. Hunter H2O and Walcha Council share our view regarding both the safety of our people and the quality of design required for the project.

On this constantly shifting ground, we are keeping the regulators up to date with the progress of the project, and we are also ensuring we keep up to date with any regulatory changes which may affect the project and that these are well-communicated with our client.

Regulatory changes for flexible responses

Across the country, state governments are establishing new measures to accelerate projects to shovel-readiness to help buffer the social and economic impacts of the pandemic. They’re also making temporary orders to existing legislation to provide flexible planning and environmental responses.

New South Wales

In New South Wales, the Planning System Acceleration Program has been introduced to fast-track State Significant Developments, rezonings and development applications, as well as provide support to decision-makers to speed up local and regionally significant projects to approval. Temporary orders have been implemented to allow some infrastructure construction work to be carried out on weekends to maintain productivity and employment in the sector. In NSW, temporary changes to the Environmental Protection and Assessment Act 1979 (EP&A Act) allows the Minister for Planning and Public Spaces to authorise development to be carried out on land without any approval under the EP&A Act where that development is required to protect the health, safety and welfare of the public during the COVID-19 pandemic.

Other recent legislative change in NSW is the long-awaited amendment of the NSW Bilateral Agreement under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (Cmwth), which was required after the introduction of the new Biodiversity Conservation Act 2016 (NSW). This updated bilateral agreement has allowed environmental assessments and offsets to be streamlined, including endorsement of the NSW Biodiversity Offsets Scheme for the purposes of offsetting for a Commonwealth approval.

Queensland and Western Australia

In Queensland, COVID-19 has been declared an applicable event under planning legislation, thus allowing the Planning Minister more flexibility to suspend or extend any statutory timeframe across the planning framework if required. Similarly, in Western Australia, the Minister for Planning has issued a two-year extension for all current development approvals to assist job-creating projects during the recovery stage, along with other exemptions from planning approval for essential local community services.


The Victorian Government has announced temporary measures to make sure that planning and approval processes can continue to function despite remote working arrangements, including allowing local government planning authorities to make decisions under delegation to facilitate efficient application turnaround times. The Victorian Government has also established the Building Victoria’s Recovery Taskforce to explore planning and investment opportunities to boost the development industry. Additionally, the new Victorian Environment Protection Amendment Act 2018 (EPA Act), which is relevant to many infrastructure projects, was to take effect from 1 July 2020 but has been deferred until July 2021 to ensure developers, consultants and regulators have time to adapt to changes in workload and workflow as a result of the pandemic.


Tasmanian planning reform continues with the exhibition and assessment of local planning schedules as part of the transition to a statewide planning scheme. Consultation has also concluded on the proposed process for major projects, which, if enacted, will be the state’s first multi-permit approval process.


The Commonwealth Environment Protection and Biodiversity Conservation Act 1999 is also currently being reviewed, and our planning and environmental consultants are ensuring that they keep pace with the impending changes and implications for ongoing and new projects.

Managing change

For the Walcha project, the approval process is comparatively simple and the changes to approval processes are not likely to impact the project. However, for some of our other projects, these changes create challenges. Most notably, physical distancing requirements have meant temporary shutting of council offices and town information centres where application documents and technical studies are usually displayed. Instead, full suites of application documentation are being published online or, when specifically required, hardcopies are being mailed out. With postal services already under pressure, one way to ensure the community has a fair opportunity to provide feedback is to lengthen comment and consultation timeframes.

Although the global pandemic may have been disruptive to our work arrangements, smart and innovative ways to juggle project commitments and changed circumstances have fostered strong relationships which will persist beyond COVID-19. Elevated levels of trust and virtual teamwork with clients will surely present more opportunities to collaborate once the ground settles and we reach a new equilibrium.

If you would like to discuss how Entura can help you with your environmental or planning project, please contact us.


Don’t let COVID-19 stop your project

A vital part of the success of all projects, whether they are new or operational, is maintaining progress towards milestones and retaining currency in the social and regulatory realms. How can we achieve this during a global pandemic?


With the COVID-19 crisis affecting people and businesses across the globe, employers and employees alike are racing to find normalcy. Fortunately for Entura, we’ve already been working and collaborating virtually for many years across country and state borders, with dispersed office, client and project locations. So, even though our teams are working from home, it is still business as (mostly) usual, in unusual times!

Although COVID-19 hasn’t thrown us completely, travel restrictions have pushed us to think differently about many of our projects and methods. This is the time to explore proactive ways to ensure projects do not come to a grinding halt or fall off a community’s or regulator’s radar.

Keeping environmental and planning projects moving forward

Entura’s environment and planning team works frequently in the field – lakes, forests, roadsides, development sites and many more – so COVID-19 travel restriction have taken a hit at our ability to undertake survey and monitoring programs or to conduct site visits, but it hasn’t led to tools down.

We may miss out on our chance to hit the frosty outdoors this autumn and winter, but there are still many ways that we can and will continue to make progress and deliver value. It’s about thinking creatively about how we can be proactive. And that means finding measures and activities for the short and medium term that will keep the project moving towards the longer term project milestones and goals (without the anticipated longer term extending into the much further horizon!)

For example, there are proactive things we can do to prepare us better for when we can once again visit the site. We have access to a wide range of data and can undertake thorough desktop investigations early in the project. We will then be able to step on site well prepared and looking to fill knowledge gaps or to verify what should be there. That puts us in a better position to be alert to anything unexpected we might find when we’re physically on site in future. Unusual discoveries and observations will be more pronounced. Such approaches can help shorten project timelines post-COVID-19 compared with the inevitable blowouts that would be caused by downing tools completely.

Policy and regulatory reforms are also still happening across the country – some as a result of COVID-19, others associated with larger reform programs to update antiquated legislation. Our discipline experts continue to engage with the regulators and relevant government agencies and authorities to ensure we understand the nuances of these changes and how they may influence the scope of existing and future projects and programs of work.

More proactive, less reactive

The restrictions caused by COVID-19 have highlighted the need to be proactive so that we can be better positioned for the longer term. It’s natural for a consulting paradigm to tend towards the reactive and process-driven, but this is the time to shift such tendencies.

With a future-focus and forward thinking, we can all seek out proactive solutions to keep projects and processes running as smoothly as possible, to meet any milestones that are still feasible, and to do everything that is reasonably possible in the present circumstances that will minimise delays once the pandemic has eased.

This needs to be a shared process. If as consultants and clients we put our heads together, we can develop shared understandings of the opportunities, risks and issues affecting all parts of the project and all the players involved. With team work and good communication, together we’ll find the most innovative and workable solutions, and together we will survive and thrive.

Beyond the immediate

The circumstances of the pandemic are also an opportunity to think beyond the immediate projects on our desks. This is a great time for our clients to review their projects and environmental and social management practices, to be better positioned for the post-COVID-19 future. This could include being more informed about potential risks or thinking through changes that you could make to your management practices to better address ongoing or emerging issues.

In our next article, we will highlight some of the projects we are currently working on, and how we have adapted them in light of COVID-19. We will also dig down into some of the key regulatory reforms happening across the country, and what implications they may have on projects during the COVID-19 period and beyond.

At Entura, we will continue to respond to government measures as they surface, and we will continue to be here to assist all our clients to better understand the opportunities, risks and issues associated with keeping your project alive during COVID-19.

A message from our team to yours

And to finish on a light note – Entura’s environment and planning team has nimbly settled into their new branch offices, from urban Melbournian set-ups to peri-urban workplaces at the foothills of the majestic kunanyi/Mount Wellington in Tasmania. From our team to you or yours, here are a few handy tips which we have found to help with this transition to working from home:

  • Stay connected – drop your colleague or manager a line and ask how they are going, and where possible (bandwidth permitting), turn on the video during your virtual meetings.
  • Schedule regular team catch-ups, and why not end the week with an optional virtual gathering to kickstart some weekend banter?
  • Don’t be embarrassed if your pets or children make an appearance – it helps lighten the mood and may provide the laugh that someone really needed.
  • Get some fresh air before you start work – imitate that commute to work by going for a walk or cycle.

If you would like to discuss how Entura can help you with your environmental or planning project, please contact us.

Pictured, clockwise from top left:

  • Senior Social and Stakeholder Consultant, Dr John Cook
  • Land Use Planner, Bunfu Yu
  • Senior Aquatic Scientist, Dr Malcolm McCausland (and friends)
  • Team Leader Environment and Planning, Raymond Brereton
  • Senior Environmental Planner, Cameron Amos
  • Senior Planning and Environmental Consultant, Scott Rowell (about to head out for a ride)
  • Environmental Consultant, Rachael Wheeler


Engineering – by humans, for humans

When engineers think about the future, do we get so engrossed in the complex technical problems that we don’t attend enough to the human angle?


Engineers have a reputation, whether rightly or wrongly, for being poor communicators, working obsessively and in isolation, and focusing on the immediate goal rather than its impacts on communities. Often, clichés have a basis in truth. If we are going to shift perceptions, we need to start by thinking about the way we work and the leadership we show to the next generation of engineers.

There’s no way we can predict the major developments, challenges or solutions of the next five or six generations of engineering careers. What we should focus on is what we can do right now to lead change in our profession and our communities – and I think the keys are communication, collaboration and community.


I recently listened to a podcast in which two energy market experts talked with a power system engineer. They discussed all sorts of technical matters relating to frequency and voltage control. I love those topics, but this conversation was limited and uninspiring because the participants simply didn’t have a common language or understanding.

We need to learn to communicate in ways that a variety of people can understand. That will mean better conversations with the people who can help our work have greater impact, and it will help our communities to appreciate the importance of our work in their lives.

It’s too easy for us as a profession to sit at our desks or stand under our hard hats and luxuriate in how clever we are, and then bemoan how so many people have no idea what we do and don’t value our work.

When things that involve engineers go wrong, a flurry of opinions erupts. Failures such as the blackout in South Australia, or the cladding issues at the Grenfell Towers, or issues with airlines or bridges or dams all lead to our communities questioning and debating engineering practice. Engineers tend to try to stay out of this rough and tumble for fear of being misrepresented. Yet maybe it’s better that we do engage where we can, since being misrepresented on a small issue is better than allowing a groundswell of misguided public opinion due to a lack of understanding of engineering principles. 

We need to try to better explain our work and find simple ways to convey the complexities of the decisions that we make. 


The world is far more complex now than it was a century ago – but it is impossible to imagine what level and pace of change future generations will experience. If we want to transform our world or help build a better future, we can’t do it by ourselves. 

Engineering no longer operates in isolation, if it ever did. We must collaborate across the engineering team and across other professional disciplines to achieve truly effective development for our communities. Sometimes we may need to focus a little less on technical delivery as a primary outcome, and increase our recognition of the value gained by engaging successfully with the communities on whom the project relies for success.

Collaboration makes our work more effective, and exposes us to a wider range of inputs and values that we can incorporate into our designs and processes. Engineering can be a leader but it can also be a facilitator for better outcomes when we draw on, listen to and learn from the other experts involved in other aspects of our projects.


Engineering work almost always benefits more people than merely the one who pays the bill. Much of my work is in connecting wind farms and solar farms to the grid. Mostly my work is paid for by the owner of the farm, and while it delivers direct benefits to the owner through return on investment, it also affects everyone connected to the nearby network. It affects the network service provider and market operator, it pays salaries, and it supplies the clean energy that helps the country reduce emissions and meet its international targets. In other words, my work, which may seem intangible, has tangible effects in the real world.

If we agree that our labours produce real impacts, we need to take better care to fully consider the wider consequences of our work, which often has the potential to cause ‘collateral damage’. We can’t build a road or a wind farm without changing the landscape. When we build a machine, it uses energy and may emit pollutants; and it reduces reliance on manual labour, which may put someone out of a job. There may be a risk to lives, livelihoods or the environment if something goes wrong.

Do we always make decisions about these matters with the community front of mind, or do we place our clients on the higher pedestal? This is a tricky area and I’m not espousing a puritanical approach. However, if we knew in 1919 what we know now about lead poisoning, acid rain, greenhouse gases, scarcity and general sustainability principles, what different choices could have been made?

In a time of automation, we need to think about benefits and risks and how they affect our communities. On one occasion early in my career, I designed a controller to turn on and off a couple of compressors at a power station. I wrote some code to balance the run hours. A few months after the new system was commissioned, I asked one of the operators how the system was going, in terms of the run hours management, and he said ‘you’ve done me out of a job’. I hope he was joking. The task he’d been doing wasn’t particularly important, but there was value in having a person who was in tune with the equipment to take care of it, and there was also value in giving that person dignity through work.

My point is that we must keep our communities foremost in our minds as we go about our work. It’s not just about what we produce. It is the way we work and the people we choose to work with and for. Our influence on the development of the next generation of engineers perhaps has more impact on communities than our actual work outputs.

Through communication, collaboration and community, engineering can be both ‘more human’ and ‘for humans’.

About the author

Donald Vaughan is Entura’s Technical Director, Power. He has more than 25 years of experience providing advice on regulatory and technical requirements for generators, substations and transmission systems. Donald specialises in the performance of power systems. His experience with generating units, governors and excitation systems provides a helpful perspective on how the physical electrical network behaves and how it can support the transition to a high renewables environment.


Early action is the best approach for operational environmental management

Building, maintaining and operating power and water assets involves a level of environmental risk. If you can identify and manage these risks early, your projects or operations are far less likely to run into trouble down the track.


Power and water utilities can incur major penalties when natural values are insufficiently understood and poorly managed. Not only could the environment be damaged, but there could also be penalties for a compliance breach, increased costs and conditions for construction and operation, significant remediation costs, project disruption and delays, and delivery overruns.

On top of all of this, there’s no doubt that poor environmental management will damage your corporate reputation and reduce your level of acceptance by and engagement with the community and stakeholders, both at and potentially far beyond the local area.

Power and water asset owners and developers manage or have influence over large areas of natural assets. These environments often include flora and fauna on land and in waterways that are listed as threatened under state and national environmental legislation and/or international agreements.

A land manager or owner with a strong environmental management system will know and proactively manage these values. However, in many areas there is a lack of knowledge of natural values, which are consequently not included in an environmental management framework. These values are therefore at risk of adverse effects from operational decisions.

So what can you do to make sure you have a handle on your environmental risks?

Find out what you’ve got

A thorough review of available information will help you better understand the values you need to manage.

This means using existing data-sets and reports to understand the current knowledge base and identify any gaps. In other words, create an inventory of natural values for all your land and water assets. You will need to identify the flora, fauna and ecological community values on your land and in your waterways and lakes, and record their condition and their status.


To understand the social values associated with your assets, you may also need to engage with other stakeholders and local communities to understand how they value and use your natural assets (e.g. fisheries, recreational users, water supply, transportation), as this will also influence management.

Incorporating the data into a spatial database accessible to everyone in the business will allow easy searching for flora and fauna values that may be affected by maintenance activities or new projects and ensure that relevant information about your natural assets is readily available for managers and field staff. However, this phase only identifies issues, and the degree of impact of a proposed management action on flora and fauna values is likely to require further interpretation by an ecologist.

If gaps are detected in the data or there is doubt about accuracy, field surveys can identify and verify natural values and record their condition. For example, vegetation and /or habitats have often been mapped from aerial photos and not verified in the field, so errors can arise in the attribution of a vegetation community or habitat type.

Understand your compliance requirements

Once you know what’s on your land or in your water, you can identify the potential regulatory and compliance issues.

Are there threatened species or communities listed under state or national legislation or international agreements? Are there weed or pest species or communities that have legislative requirements? Does analysis of existing water quality data highlight any trends that may affect values within the water-body or downstream (e.g. increased nutrient loading)?

If you already know what natural values you have on your land or water, you’ll be in a much better position to respond effectively to any legislative changes. You may even be ahead of the game!

Identify potential risks and their significance

Identifying and understanding risks to natural values under current and future operational scenarios is critical to successful and proactive environmental management. This requires some ‘big picture’ thinking in which the whole landscape, both terrestrial and aquatic, is considered.

A big-picture approach focuses on risks to ecological communities or functional ecosystems (e.g. wetland, lake or river) rather than extrapolating from localised information that may not reflect the broader risks. For example, to manage species at a habitat level rather than at site level, you need to identify and map habitat for threatened species across your natural assets as well as assess habitat quality.

In another example, a big-picture approach to water quality would involve having an understanding of the natural range of parameters at the local catchment scale, which may be different to recommendations in national water quality guidelines due to natural local conditions (such as the relatively low pH of tannic water bodies in peatland landscapes).


Many project risks can be mitigated if they are properly anticipated early and managed throughout the life of the project, minimising corporate, technical, environmental and social impacts and their associated costs. Having a comprehensive inventory of your natural assets will allow any threatened species or important ecological communities to be identified early in the planning phase for upgrades of existing assets or new projects. This will make the difference in understanding the effort required to avoid or minimise impacts.

The planning process is likely to be expedited because you will already know what your potential environmental impacts are and will have accounted for them in your project design, planning approval documentation and operational management plan.

This informed management approach also applies to maintenance programs, particularly weed and vegetation management, on easements and around assets. If you know where your high-value natural assets are, they can be accounted for in the maintenance program so that they will be protected.

Develop management approaches

Knowing which natural values require active management and which values may be best left alone is another key factor for successful environmental management.

Some natural values may be protected by default because they are associated with assets that are not accessible to the public (e.g. remote assets or those closed to the public because of safety risks). These natural values, particularly in intact remote wild areas, may be best managed by being left alone without any management intervention because they are not under pressure from human activities.

Other natural values may need active management and protection because they are under threat from human activities, introduced species or diseases. In this case, you need to consider the potential issues and consequences, plus the likelihood of them occurring, to evaluate the potential risk and significance of the issue.

Where the risk level is considered to be high, identify how the risk can be mitigated (e.g. restricting public access to a sensitive area while directing access to another less-sensitive area). Potential mitigation measures are generally best identified in consultation with other stakeholders, including user groups and the local community, to ensure that the measures are supported and endorsed by the community for greater success.

For example, an important conservation site such as a lake that supports threatened fish as well as recreational fish species will require a management approach supported by the angling community. That might mean developing hardened access points (e.g. tracks and boat ramps) in less-sensitive areas supported by anglers. Otherwise anglers will continue to develop their own access points, degrading lakeside habitats and potentially affecting important breeding or foraging habitat for threatened species.

Identify opportunities

If you proactively identify and manage the environmental values for which you are responsible, you may even stand to reap a range of extra benefits. You may identify natural values with potential economic and environmental value beyond the obvious.

For example, native vegetation in good condition on your land could be used to offset the loss of native vegetation associated with other projects you undertake. Or, possibly, land in good condition could be made available to other proponents for purchase as offsets for their projects. These hidden opportunities could be very valuable and make a major difference to project viability.

If you can make structured and systematic efforts to manage environmental issues proactively, you are far more likely to achieve environmental sustainability, as well as pave the way for project success, social licence and a positive reputation. For power and water asset developers and utilities, a genuine commitment and responsible approach to achieving greater operational sustainability is increasingly recognised as a key marker of success and corporate reputation.

Don’t wait. Act now to understand and manage your environmental risks.

If you would like to discuss how Entura can assist you with minimising risks and increasing sustainability, please contact Ray Brereton on +61 417 336 407.

About the author

Dr Eleni Taylor-Wood is Entura’s Principal Consultant, Environmental and Social Science. Eleni has 20 years’ experience successfully managing large-scale, complex projects, as well as providing expert advice and independent review for a range of infrastructure and planning projects. She has worked on projects around the world including in Australia, Mozambique, South Africa, Iceland, Colombia, India, Malaysia, China, Solomon Islands, Fiji and Papua New Guinea. Her experience includes environmental and social impact assessment and management, strategic management of wetlands and waterways, feasibility and approvals for new hydropower projects, environmental flow determination and assessment, and sustainability assessments. Eleni is currently one of eleven accredited assessors worldwide under the Hydropower Sustainability Assessment Protocol.

Raymond Brereton is a senior ecologist with 30 years’ experience in the field of fauna and flora survey and management. He has been involved in assessing the impacts of development on flora and fauna and their habitats, as well as providing advice on the development and implementation of policy and prescriptions for fauna and flora management across south-eastern Australia (Queensland, New South Wales, Victoria, South Australia and Tasmania). Raymond has a high level of technical expertise in the assessment and the management of threatened species and communities in both terrestrial and aquatic ecosystems in compliance with regulatory requirements


‘Nexus thinking’ for a secure and sustainable future

As the global population continues to grow, how can utilities and water managers balance the increasing and interrelated pressures on water, energy and food?

The complex triangular relationship among these three pillars of life is known as the ‘water-energy-food nexus’. It’s an intricate puzzle, in which the increased demand for each limited resource can significantly affect the security of all three.


According to the International Renewable Energy Agency, over the next few decades, global growth in population, economic development and urbanisation are expected to raise demands for water and food by 50% and to double the demand for energy. Water, energy and food are all fundamental to growing economies, alleviating poverty, and improving health and educational opportunities worldwide. To create a sustainable future, we must seek holistic and integrated solutions for water, energy and food challenges , as well as the appropriate balances amongst them.

With water being so central to food security and energy security, the potential impacts of climate change on water resources are of increasing concern. Climate change is likely to raise average temperatures in many locations, change the patterns of rainfall and inflows, and affect the frequency and severity of extreme weather events such as drought or floods – all of which increase vulnerabilities for water, food and energy resources already under strain.

A nexus approach

Our experiences throughout Australia and the Asia-Pacific region demonstrate that there is no single solution to the challenges of this nexus. It is really about a way of thinking and approaching decisions rather than a fixed solution or response.

Click on the image to download infographic.

Click on the image to download infographic.

These five broad considerations are likely to contribute to improved nexus outcomes.

Promoting and adopting ‘nexus thinking’

‘Nexus thinking’ means considering and understanding water, food and energy and their interrelationships, rather than viewing any in isolation. It is a strategic and holistic style of thinking that considers long-term implications across the nexus, weighing up and balancing social, economic and environmental goals.

Nexus thinking looks at the big picture: considering the whole catchment or river basin, trans-boundary issues, multiple uses (existing and future) and cumulative effects. It also involves thinking across agencies and organisations where responsibilities for water, food and energy lie.

Gathering the best information to understand nexus challenges

Responses to nexus challenges are more likely to be effective and sustainable if they are based on an informed and risk-based understanding of present conditions and possible future scenarios (taking into account interrelationships across sectors and regions). 


This means that decision-makers need to understand the resource availability, current demand, known impacts, development opportunities and potential climate change implications in a given situation. They also need to understand what stakeholders and communities need, and explore opportunities for additional benefits to be realised.

Fostering collaboration among government, regulators, industry and communities

All stakeholders can benefit from collaborative and cooperative responses to the nexus and to stewardship of resources. The potential wins include better economic outcomes, improved reputation, reduced risks, avoided conflict, and opportunities for greater synergies. Reaping the benefits will require partnerships and cooperation among food-producing industries, the energy sector and other water-dependent industries, as well as local communities.

It’s also essential that governments, regulators and communities are closely involved in all decisions and developments affecting water, energy and food resources so that different priorities and opportunities can be considered. At a policy and regulatory level, cohesive and stable governance, policy and strategies are needed to facilitate and encourage the right collaboration that brings benefits to all stakeholders.

Assessing risks and building climate resilience

The water-energy-food nexus brings risks as well as opportunities . Interrelationships between water, energy and food, and the threats posed by climate change, should be built into risk assessments in each sector. State-of-the-art data collection, modelling and forecasting can assist businesses, governments and communities to better understand and mitigate their specific climate-related vulnerabilities and take action towards building greater resilience to future climate change impacts.


In the water, energy and food sectors, technological and other innovations continue to expand the opportunities for improving productivity and resource efficiency for long-term sustainability of pressured resources.

Nexus challenges may also bring opportunities

The nexus is not only a dynamic of ongoing resource competition. Integrated planning offers opportunities for potential synergies and benefits among sectors.

For example, in the hydropower sector, electricity generation is intrinsically linked with water availability. The need for water for irrigation to produce food and to drive agricultural productivity may compete with water requirements for hydropower generation. Hydropower’s water needs may also compete with the requirements of urban water supply, other industries and environmental and social needs.

However, renewable energy resources such as hydropower can also offer benefits to the water and food sectors through improving water resource management, providing multipurpose storages, contributing to the development of water supply infrastructure and, of course, generating the electricity critical to food-producing industries.

Many existing hydropower storages, both in Australia and internationally, were developed solely to supply water for energy generation. However, over time and with increasing competition for water and food, the storages have become multipurpose, often providing water for domestic supply, irrigation, and commercial and recreational fisheries.


In South-East Asia, some hydropower storages are now more important as a source of irrigation water for downstream communities than for the energy they generate. By providing water to the downstream communities, irrigation and food production has increased significantly since development of the schemes, lifting the economic development of the region and providing benefits across the community.

Integrating other renewable energies into water supply, irrigation and food production can also provide mutual benefits, such as utilising renewable energy for pumping on farms or for water desalination. Incorporating small hydropower into existing water infrastructure can improve efficiencies and create new low-carbon income streams to support effective water supply delivery. Another innovation of attaching solar PV to covers on water storages provides electricity for pumping while minimising evaporation and maximising water availability.

Whether at small-scale single utility or local geographic area or at a national or multinational scale, nexus thinking can bring about mutual benefits for energy, water and food outcomes .

If you would like to find out more about how Entura can help you develop a sustainable water or energy solution or respond to the challenges of the water-energy-food nexus, contact Dr Eleni Taylor-Wood on +61 3 6245 4582 or David Fuller on +61 438 559 763 

About the authors

Dr Eleni Taylor-Wood is Entura’s Principal Consultant, Environmental and Social Science. Eleni has more than 20 years’ experience successfully managing large-scale, complex projects that run over several years, as well as providing expert advice and independent review for a range of infrastructure and planning projects. She has worked on projects around the world including in Australia, Mozambique, South Africa, Iceland, Colombia, India, Malaysia, Mekong, Solomon Islands, Fiji and Papua New Guinea. Her experience covers a vast gamut of studies including: environmental and social impact assessment and management; strategic management of wetlands and waterway; feasibility and approvals for new hydropower projects, environmental flow determination and assessment, and sustainability assessments. Eleni is currently one of eleven Accredited Assessors under the Hydropower Sustainability Assessment Protocol worldwide.

David Fuller is Entura’s Principal Consultant, Water Management and Technology. David has more than 30 years’ experience working on water management projects across Australia and overseas. He has successfully delivered projects for local, regional, state and national government agencies; and for private sector clients in the irrigation, coal seam gas, mining and energy generation sectors. David specialises in engineering and environmental hydrology, and water management. He also has expertise in data management systems, statistics, hydraulics, water quality, ecological risk assessment and natural resource economics.


Keeping safe around dams

When we hear ‘dam’ and ‘safety’ in the same sentence, it’s natural to think first of catastrophic dam failures and their devastating impacts on downstream communities. However, keeping the public safe around dams also involves considering and mitigating some more common and less documented risks…


Dams, water courses and water bodies typically offer a range of recreational benefits enjoyed by many. But where there’s water, there’s inherent danger, including the risk of drowning.

Asset managers know much more about the numbers of fatalities relating to dam failures than about the fatalities associated with the overall ongoing presence and operation of dams. But we do know that drownings in dams and waterways make up more than a third of total drowning statistics in Australia, and the situation is similar around the world.

Regardless of the specific circumstances of each of these fatalities, it is clear that owners and regulators of dams and water courses need to take action to help protect the public from these largely avoidable deaths.

In 2012 the International Committee on Large Dams established a working committee to start identifying these public safety risks, describe the international state of practice to manage and mitigate the risks, and develop a guidance bulletin on best practice measures and public education about safety around dams. This project is well underway, and here I’ll take a look at some of the key risks and possible mitigations being considered.


The general public tends to underestimate the hazards linked to activities around dams and waterways, particularly the possibility and effects of sudden changes in water level and flow.

Accidents may happen around dams and water bodies during a range of activities – not only those considered more overtly dangerous (such as abseiling or rock climbing), but also during activities such as swimming, kayaking, boating or fishing. Falls from heights and other activities not associated with access to water are also of concern.


However, many drownings are due to the particular risks relating to hydraulic structures and the inherent nature of their operation, and to rapid changes in water levels and conditions.

Hazards around dams are often associated with swift and turbulent currents near intakes and spillways. These currents may be created by the changes in flows and water levels during normal operations of spillways or during flooding. Unexpected rapidly rising water levels can result from weather conditions, but also from sudden changes in output from hydropower stations, and have the potential to cause people to be inundated or swept away.

Around the world, a large proportion of drownings have been associated with a particular subset of hydraulic structures referred to as ‘low-head weirs’. Under certain flow conditions, these can display a particularly dangerous hydraulic phenomenon, earning them a common description as ‘drowning machines’. This type of structure has particularly attracted attention, and has been investigated, in the United States as it constitutes a large proportion of preventable death in a number of states.


Where people are undertaking recreational activities with a recognised level of risk, there is an implied responsibility to observe regulations and warnings, take common safety precautions, and be capable and in a suitable state to undertake the activity.


However, the absence of such behaviours does not remove the liability of the asset owner or manager. In fact, their responsibility is even higher in inherently hazardous site conditions, conditions posing a hazard that is not readily identifiable, or where changes in operations lead to changes in the hazard level.

So, what actions should a dam owner or manager take to best protect the public? While not all incidents can be avoided, the possible actions below form a comprehensive approach to minimising risk and reducing probability and consequences.

Develop a public safety policy and plans, ensuring compliance with laws and regulations

Start by documenting your commitment to public safety in a policy statement identifying your statutory and legal requirements, and establishing your objectives, tolerance criteria and targets.

Translate your policy into a public safety management plan indicating how you will manage the public safety risk at each site. This should be based on a risk assessment of the facility, identifying the hazards, assessing the degree to which the public is exposed, identifying appropriate control measures and assigning responsibilities.

Conduct a risk assessment, incorporating comprehensive local insight and regular review

The risk assessment process is an important step in managing public safety risk as well as complying with statutory and common law obligations. It helps focus on the risks that really matter.

Most organisations have an accepted method for analysing, assessing and managing risk; this may be tailored to incorporate public safety risks.

Consider such factors as seasonal and daily weather effects. For example, during summer, or other periods of low flow, the public may anticipate a lower likelihood of rapidly changing conditions. There may also be a general lack of awareness that spills can result from other factors than adverse weather, such as changes in generation or earlier precipitation upstream.

The quality of the risk assessment and the effectiveness of control measures depend on the degree of site-specific knowledge which is best obtained from staff working at the location or engaged in its operation. The risk assessment should be periodically reviewed to ensure the assumptions remain valid.

Exclude the public where necessary through fencing, gates, artificial and natural barriers

The selection of exclusion devices and layout depends on the particular site and requires input from people with a good local understanding. 

Note that the effectiveness of public exclusions can vary over time as usage of an area changes or as the public becomes complacent or desensitised to the hazards.

Warn the public of dangers and of changed conditions through signage and other audible and visual alarms


Signage and alarms warn of changes in operations (e.g. gate opening) and conditions (e.g. water level or flow). Carefully consider their placement, maintenance, language, readability, and use of terms and symbols.

In some circumstances, audible and visual alarms may be appropriate.

As with physical barriers, over time the effectiveness of warnings may diminish, particularly if there is a real or perceived lack of connection between the activation of the warning and the occurrence of the hazard. 

Educate targeted populations and the general public


Best practice suggests that education applied well either via mass media or to targeted populations can have a significant impact.
Train supervisory personnel, including in intervention and rescue techniques and incident management

Training supervisory personnel in hazard identification, risk assessment, compliance assessment and enforcement is important. This can include specific training and simulations in intervention and rescue techniques where appropriate.

Many dam owners are reducing the site presence needed to meet operational requirements; but determining the appropriate presence required should take account of the need to maintain a public profile and awareness of public interaction. Periodic patrols are also valuable to identify changed patterns of public use.

A public safety incident may be managed by local intervention or could escalate into an emergency, crisis or disaster for an operator depending on the nature and scale of the incident. Effective incident management must go beyond the immediate need to contain the incident (e.g. perform a rescue), by also considering the implications for risk assessment, education, and the return to business operations.

Decommission the dam where appropriate In some circumstances, decommissioning may be an appropriate method to reduce risk. Public safety may add weight to a decision based on other business or operational considerations.
Monitor, report and review

Incident reporting relating to public safety around dams is often poorly undertaken and lacking sufficient detail. There are also very few reports of near misses, which can provide important lessons about mitigating risks, and very limited databases or documented case studies available.

To improve this situation, the forthcoming guideline from the ICOLD committee will propose an incident reporting process that can be applied by owners and regulators to improve their practices regarding public safety around dams.

The ICOLD bulletin will form a valuable tool for owners, operators and regulators to manage and mitigate this significant risk area. A good way to start the process is by seeking the assistance of others who have experience in assessing and managing the public interaction with dam and waterway assets.

Every life lost in a dam-related accident is a tragedy. Through these best practice measures, dam owners and managers have a much greater opportunity to help reduce the many hundreds of dam-related fatalities occurring around the world each year.

If you would like to find out more about how Entura can help you improve safety around dams, please contact Phillip Ellerton on +61 439 010 172 or Shekhar Prince on +61 412 402 110.


More water storage needed for a sustainable future

Global declines in water storage are increasingly troubling. With greater hydrological variability due to climate change, more storage will be vital to provide the same level of security of water, food and energy.


Water storage is a fundamental protection from the impacts of a changing climate, safeguarding the supply of water, and the water–food–energy nexus, even during extended drought.

For thousands of years, dams have stored water to irrigate crops, control flooding, supply water for industrial and household use, and generate hydroelectric power – contributing enormously to food security, human development and economic growth.

These days, many dams serve more than one function, but remain the primary mechanism for coping with the variability of water supply and demand. During the last century, more than 45 000 dams higher than 15 m have been constructed worldwide, creating a combined storage capacity estimated to be between 6700 and 8000 km3, representing 17 per cent of global annual runoff.

Security of water, food and energy are inextricably linked. For example, approximately 50 per cent of all large dams worldwide are used for irrigation. Without sufficient water storage, irrigated agriculture (the largest user of water at the global level, contributing 40 per cent of the world’s food) is at the mercy of changing patterns of rainfall and runoff. 


Understanding water storage issues is essential for successfully managing water resources. At the simplest level, it is a matter of ‘inflow (water supply) less outflow (water demand) equals change in storage’. But it is particularly important to understand whether storage declines relate to reducing supply, increasing demand, or both. The answer is both, and more.

Key factors influencing storage are greater variability of inflows due to climate change, increased demand due to population growth, reduced net storage due to sedimentation, and less dam construction occurring worldwide due to environmental and social impacts.

Climate change

The effects of climate change are predicted to increase and to result in greater magnitude and frequency of hydrological extremes, such as prolonged droughts and significant floods. With prolonged drought, inflows to storages will reduce. If demand remains the same, stress on existing water storages will increase.

Population growth

It is estimated that in 2017 Earth supports around 7.5 billion people, yet 200 years ago the number was less than 1 billion. Population and water demand are strongly linked. With our world population increasing at around 80 million people per year, rising demands for basic services and growing desires for higher living standards will intensify the demand for water and put additional strain on existing storages.


Many of the larger reservoirs worldwide have had their lifespans reduced significantly due to deposits of sediment within the storages, diminishing net storage in many regions of the world. Globally, the annual rates of loss relative to installed storage capacity are generally estimated to range between 0.5 and 1.0 per cent, equating to a total worldwide loss of storage of around 40 to 80 km3 per year.

Reduced dam construction

Installation of large reservoirs peaked during the 1960s and 1970s, both in number and storage volume. However, some of these larger reservoirs caused significant environmental and social damage, bringing dam construction under great scrutiny and ultimately decreasing dam construction worldwide.

With less dam construction, some decommissioning of older dams and loss of storage due to sedimentation, net storage worldwide is falling, most dramatically in storage per capita. Such reduction in storage is likely to undermine reliability of supply.

Source:  GW Annandale, GI Morris & P. Karki, Sediment Management at Reservoirs and Hydropower Plants: New World Bank Technical Note, ICOLD International Symposium, Johannesburg, May 2016.

Source: GW Annandale, GI Morris & P. Karki, Sediment Management at Reservoirs and Hydropower Plants: New World Bank Technical Note, ICOLD International Symposium, Johannesburg, May 2016.

Few kinds of development projects arouse as much controversy as dams. However, large dams vary considerably in their environmental and social impacts. The severity of environmental impact is largely determined by the dam site. While dams at good sites can be very defensible from an environmental standpoint, those proposed at bad sites will be inherently problematic even if all feasible mitigation measures are properly implemented. The challenge is to find the good dam sites to enable these necessary water storages to be developed.

How can we take action?

The following actions form a useful response to reduced worldwide storage and the pressing need to increase water storage to maintain reliable water supply, irrigation and energy systems in a changing climate:

  1. Prioritise managing existing storages well, and recognise the importance of storages for maintaining reliable supply. Appropriately manage sedimentation and its impact. Employ near-real-time management of water based on improved information systems to ensure the best economic use of existing reservoirs. 
  2. Explore opportunities to increase the storage capacity of existing reservoirs by raising dams or by improving interconnection. Often, this can be more cost-effective and have lower environmental impacts than a new dam project.
  3. Identify dam sites, either on-stream or off-stream, which will minimise environmental and social impacts. Good site selection is the most effective environmental mitigation measure.

The net decline in global reservoir storage demands a different mindset for analysing the economics and construction of sustainable dam projects. Rather than debating whether more dams are required, decision-makers must accept that more storage will be needed and should plan accordingly. 

If you would like to find out more about how Entura can help you develop a sustainable water storage solution or respond to these worldwide challenges, contact Richard Herweynen on +61 3 6245 4130 or Shekhar Prince on +61 412 402 110.

A version of this article has been previously published in the International Hydropower Association blog.

About the author

Richard Herweynen is Entura’s Technical Director, Water. Richard has three decades of experience in dam and hydropower engineering, and has worked throughout the Indo-Pacific region on both dam and hydropower projects, covering all aspects including investigations, feasibility studies, detailed design, construction liaison, operation and maintenance and risk assessment for both new and existing projects. Richard has been part of a number of recent expert review panels for major water projects. He participated in the ANCOLD working group for concrete gravity dams and is the Chairman of the ICOLD technical committee on engineering activities in the planning process for water resources projects. Richard has won many engineering excellence and innovation awards (including Engineers Australia’s Professional Engineer of the Year 2012 – Tasmanian Division), and has published more than 30 technical papers on dam engineering.


Maximising irrigation certainty and security with the right data

Perhaps the greatest gift to any agricultural region is increased certainty of reliable, available water.

Agricultural communities thrive when they can depend on irrigation. Confidence in a reliable supply of irrigation water is critical for increasing agricultural productivity, diversifying businesses, creating new opportunities for investment, and strengthening rural and regional communities.


To be successful, an irrigation scheme must deliver adequate and secure water to users when required. In an increasingly volatile climate, secure water supplies can only be guaranteed through careful management and through well-informed planning and decision-making.

But how can irrigation managers decrease the risks to their storages and supply systems, and increase the effectiveness of their plans and decisions?

The answer lies in the quality of the data and analysis on which their decision-making depends. Irrigation storages and systems are huge investments, and getting the best out of them should also involve some targeted investment in a state-of-the-art data management and decision-support system.

The key components of a water management system


Water managers considering implementing a water management system should look for the following key components and features:

  • accurate measurement and data capture from well-maintained field sensors and telemetry
    (including automated quality checking to detect major data errors or missing data)
  • historical data, or a representative dataset, that shows inflow patterns and generates stochastic inflow data
  • an optimal hydrological model of the catchment and storage that models inflows and water levels and how the storage varies (models should be reviewed periodically with the most recent data to ensure that the parameters are still optimal and that forecasts are performing as expected)
  • forecast rainfall data for the short term, directly incorporated into the system from the relevant meteorological forecasting agency
  • user-friendly customisable dashboards or apps that allow rapid oversight and interpretation of the state of the system and short-term forecasts
  • cloud-based storage of information in a robust database, providing a reliable, fully hosted and maintained service, continuously operated and improved by experts, without the need to invest in hardware or directly employ specialist technical expertise.

In combination, these features provide the foundations for a successful water management system, and a worthy investment in water security, providing resilience to climate variability and shifts.

An award-winning integrated water management system in operation

Tasmanian Irrigation engaged Entura to design, develop and deliver an integrated water management system for Meander Dam in northern Tasmania. This dam provides irrigation water to an agricultural area with further development potential, regulates seasonal environmental flows, and also generates hydropower to help offset operational costs.


Entura’s water management system delivers a full picture of the dam’s current status and possible short- and long-term water storage and power output scenarios, providing reliable information to help deliver irrigation certainty while maximising hydropower generation and ensuring dam safety.

The system harnesses real-time rainfall and flow monitoring data captured by a network of catchment telemetry. This information is combined with a hydrological model of the catchment and weather forecasts from the Bureau of Meteorology to produce short-term (7 day) and long-term (up to a year) forecasts and simulations, showing a range of possible scenarios and probabilities for water storage and power output.

These forecasts and simulations offer the necessary insights to understand the immediate and longer term implications of management actions, and to make operational decisions based on different risk profiles.

The dam’s current status and possible future scenarios are presented via a user-friendly dashboard interface. The data can be delivered in whatever format or platform the client desires, and is able to integrate with other applications or have other features added to it.

Real-time information from water meters on pumps within the irrigation area is also brought into the system to give the operator a complete water balance in the area fed by the dam.


Because Entura’s solution is cloud based, it is robust, ensures continuous effective operation and maintenance, and allows very high reliability (99.995% uptime) to be achieved for reasonable cost.

Entura backs-up the system with 24/7 expert support to keep it performing at an optimal level. This is a cost-effective and secure way for an irrigator to access the expertise behind a specialist best-practice system, avoiding the need to purchase and maintain expensive hardware, reducing the requirement for any specialist technical capacity on staff, and eliminating the risk of system error or outage.

Benefits of the water management system

Certainty of water supply

In the region dependent on Meander Dam, Entura’s system contributes to Tasmanian Irrigation’s ability to deliver certainty of water supply, which is crucial for increasing agricultural output and productivity and maintaining resilience. Water security delivers greater confidence for investment in these individual farms and high-value crops, but also increases the confidence and development of the region as a whole, strengthening the community through increased employment and economic activity.

In the 2015–16 irrigation season the region experienced below-average rainfall that resulted in reduced inflows into Meander Dam and increased demand for water supply to irrigators. With the aid of the integrated water management system, Tasmanian Irrigation was able to match demand from predicted storage levels, fulfilling irrigator expectations and retaining sufficient storage capacity to be able to extend water delivery for an additional month. This ensured that irrigators were able to finish final crops and also maintain pasture growth for livestock and dairy activities.

Maximum hydropower generation

The water management system also allows optimisation of the dam operating rules to get the most out of the dam’s integrated hydropower facility, while still maintaining security of irrigation supply. The system enabled Tasmanian Irrigation to maximise hydropower generation after the end of the 2015–16 irrigation season, as the predicted rainfall allowed increased generation which also minimised the potential for the dam to spill.

Dam safety in severe weather

A further benefit of the system is improved decision-making regarding water resources and dam management during severe weather. This offers direct benefit to the health and safety of the local community, the local environment and the productivity of the local economy through reducing drought-related costs and impacts (e.g. loss of farm productivity, mental health impacts, maintenance of minimum environmental flows) and mitigating flood risks and impacts (e.g. maintaining dam safety, minimising spill, and managing downstream safety and environmental impacts).

The Meander Dam integrated water management system was the winner of the Australian Engineering Excellence Awards Tasmania 2016 in the category ‘Control Systems, Networks, Information Processing and Telecommunications’.

Entura has extensive experience supporting water managers to make the best use of their storages for multiple water uses (whether for hydropower, irrigation, environmental flows, or domestic or industrial purposes), and in creating innovative decision-support systems to manage water risks through reliable and accessible data.

To discuss how Entura can support you to increase the efficiency and security of your water storages through the right operational decisions, please contact  David Fuller on +61 438 559 763 or Phillip Ellerton on +61 439 010 172.

About the authors

David Fuller is Entura’s Principal Consultant, Water Management and Technology. David has more than 30 years’ experience working on water management projects across Australia and overseas. He has successfully delivered projects for local, regional, state and national government agencies; and for private sector clients in the irrigation, coal seam gas, mining and energy generation sectors. David specialises in engineering and environmental hydrology, and water management. He also has expertise in data management systems, statistics, hydraulics, water quality, ecological risk assessment and natural resource economics.


Do your water assets hold unexplored potential?

The right data and analysis could unearth new strategies to get more from your infrastructure, and that’s too good an opportunity to miss.

The most valuable, cost-effective and sustainable power and water infrastructure is that which is thoroughly explored, properly understood, and used to its fullest capacity. This means analysing project data to design and develop solutions that are practical and meet the particular objectives of the project, while always keeping an eye open for innovative solutions that can get even more value from the investment by unleashing its full potential.

When comprehensive and accurate data is cleverly analysed to uncover new opportunities from existing infrastructure, you’ve got a solid foundation for the best business decisions.

Getting power from water assets

Water asset owners can get the very best out of their infrastructure by assessing their existing portfolio for the potential to incorporate renewable electricity generation from technologies such as wind, solar or hydro. In this article, I look at some examples of one possible solution: incorporating mini-hydropower systems into existing water supply infrastructure in cities.

Water supply networks may offer valuable opportunities to generate renewable energy through mini-hydropower generation. High pressure in water supply pipelines is usually dispersed by pressure-reducing valves or break-pressure tanks. If these devices are replaced by mini-hydropower turbines, the pressure can instead be used to generate clean, renewable electricity, which can help offset costs and reduce greenhouse gas emissions, benefiting a business’s bottom line and carbon budget.

Although the output of individual mini-hydropower systems may be relatively small, if all feasible potential sites within a water supply network are identified and developed, the combined power output can be significant, offering big wins for water managers without compromising water supply to customers.  So assessing mini-hydro potential throughout a water supply system can be a rich, and often untapped, opportunity to reap more from existing infrastructure.

Although mini-hydro opportunities may look like a clear win, each water supply system is unique, and there’s no one-size-fits-all solution. Confidence is needed that the project is designed to best capitalise on the particular site characteristics, that the project can generate the right amount of both power and revenue, and that all the project assumptions are based on reliable data.  Getting the right data, good analysis and tailored design are therefore crucial for confident investment in the infrastructure and for project success.

Tapping the full potential of Durban’s water supply

Entura’s study of the potential to generate hydropower from the existing water supply networks in Durban, South Africa, offers a methodology for assessing and adopting similar solutions worldwide, and provides an example of how the right data and analysis contributes to project and business success.

To assess the potential for eThekwini (Durban) Water and Sanitation to include mini-hydro systems of between 50 kW and 1 MW into Durban’s existing water supply infrastructure, Entura developed a screening process to identify viable and profitable opportunities.

The first step in the process of assessing hydropower potential in the water supply network was gathering, modelling and calibrating a broad range of data about the water supply system. Generally, existing water supply infrastructure collects pressure data, as this is used for monitoring and controlling the supply network. However, to adequately assess hydropower potential, data was also needed on the water supply system’s flows, pipe sizes, and operating regime. Once all the necessary information was collated, hydropower potential was assessed by calculating flow, head and installed capacity at each site. Next, screening criteria were applied to identify sites with the greatest potential.


A range of factors was considered in assessing the potential of existing water infrastructure assets: load centres, power generation potential, sustainability concerns, network issues, technical and construction challenges, risk assessment and cost-benefit analysis.

The project particularly considered where hydropower could directly supply pumps or be directly connected into the grid, to maximise the value and uptake of the renewable generation. Sites were identified where mini-hydro technology could be supplied in modular units (on a fixed bedframe, or in a standard shipping container) to reduce the time and cost of more traditional construction.

Of more than 150 potential sites, Entura’s screening process returned a list of 47 sites worthy of further investigation, offering a combined installed capacity of 10 MW.  More work still needs to be done to fully determine the number of economically feasible sites in the eThekwini water supply network. Of the 47 shortlisted sites, eThekwini Water and Sanitation expects that more than 10 sites will be developed.

Getting more out of Melbourne’s water system

Melbourne Water, an Australian water utility, had recognised mini-hydro’s potential to recover surplus hydraulic energy, generate greenhouse reduction benefits and provide financial returns, without requiring any changes to the operation of the water supply system; without affecting flow, pressure or water quality to customers; and without any increase in operational risk.

Entura assessed the feasibility of each of the six schemes on Melbourne Water’s system to provide the necessary data to determine that the schemes were technically and economically viable. These schemes progressed to implementation and were successfully constructed to Entura’s designs, adding 6.75MW of new clean energy generation into the local electricity distribution network without disrupting water supplies.

These mini-hydro schemes have significantly contributed to Melbourne Water’s movements towards carbon neutrality and helped it to offset its costs, and Melbourne Water is continuing to explore further opportunities to identify and extract the full rewards from its water infrastructure.

To discuss how Entura can help you uncover and exploit the full potential of your water assets, contact Nick West on +61 408 952 315, Phillip Ellerton on +61 439 010 172 or Shekhar Prince on +61 412 402 110.

About the author

Nick West is a civil engineer with 15 years’ experience, primarily in the fields of hydraulics and hydropower. Nick’s skills range from the technical analysis of the layout of hydropower projects to the preparation of contractual project documents and computational hydraulic modelling. Nick’s involvement in the recently completed Neusberg Hydro Electric Project extended from the first visit to the site where the project layout was conceived right through the development of the project and now into troubleshooting operational issues. As a project manager, Nick has successfully completed projects ranging from hydraulic design for small residential developments to the feasibility study of a cascade of four large hydroelectric projects in Malaysia.


Smarter data management rewards power and water operations

For power and water businesses, information is one of the most valuable assets. But good data you can’t find or use is a wasted opportunity.

Data is most useful when it is integrated and accessible, so that it can help a business make smarter decisions about how to best operate and maintain complex assets for maximum efficiency and return on investment.


Water managers and power generators typically collect large amounts of information to help them make decisions. Organisations are also increasingly using sophisticated monitoring and communications technologies to make assets ‘visible’ around the clock and remotely, to achieve better results with less worker time, effort and travel.

However, these valuable sources of information are usually stored in disparate systems or repositories, including SCADA, telemetry, GIS, document repositories, field notes and CCTV systems. As well, these systems often predate the Internet, and, as a result, may not be easily or securely accessed, and may be confined to office or station networks.

For this asset data to yield insights and optimise operations, the different sources of information need to be unified and displayed in meaningful ways that add value to the basic data.

Managing data to maximise water flow for hydropower generation

Entura worked with its parent company Hydro Tasmania, Australia’s largest water manager and producer of renewable energy, to tackle this data challenge in relation to the canal system that brings water to Tarraleah, a hydropower station in the central highlands of Tasmania.

Managing the flow of water into the canal system is critical for maximising the available water to Tarraleah (and hence its capacity to generate valuable electricity), as well as maintaining the station’s safety and reliability.

As a canal is not a natural waterway, one might assume that keeping it running at the highest possible water level should be easy and predicable. However, the combined effects of uncontrolled inflows, automatic pumps, and unwanted plant growth in the canals make management of water levels in these canals much more complex.

Water levels can rise unexpectedly, spilling valuable water and potentially damaging infrastructure such as roadways or even the canals themselves.


To achieve more efficient and remote management of the water flow into the Tarraleah canal system, Hydro Tasmania aimed to embrace and integrate the latest technology to monitor the live condition of the canals through SCADA, telemetry and manually read data, and make this data more readily available via a single online interface.

The first step towards this goal was understanding the existing limitations of the available information and access to data. GIS provided an excellent overview of the canal system, and was relatively straightforward to use and access via a web browser, but it did not contain any real-time or historical time series information.

The telemetry system contained some information about monitoring sites, but very little about how the data related to other aspects of the system. Also, it could only be accessed from specific computers, and required training and expert knowledge to use. The SCADA system recorded its data to an interface which provided little information about site relativity or purpose, and the interface could only be used within the power station. Some of the more valuable information about the canal system was kept by engineers in isolated document repositories.

These issues acted as barriers to understanding the canal system, hindered the ability to explain it to other people, and made it difficult to find the appropriate data for analysis.

Developing a data solution

To make Tarraleah’s canal information more useful, a data solution had to be interoperable, real-time, secure, synchronised, spatially integrated, contextualised and meaningful, and cost-effective.

interoperable To achieve interoperability across multiple devices and operating systems, a web-based platform provided the most suitable and cost-effective solution. A standards-based approach was used in developing the interface, so that the resulting system was able to work seamlessly across devices, with data accessible through a single user interface on laptops, tablets and smart phones.



‘Seeing’ the status of infrastructure in real-time called for the data being displayed to be as current as possible, with each point in the chain of data transfer eliminating any unnecessary latency. Performance between the source of the data and the server was streamlined, and latency between the server and the user device was minimised through WebSockets, a new technology using highly efficient two-way binary connections to transfer data with minimal overhead. This allowed an extremely efficient flow of data (less than 500 ms).
secure It was essential that the design did not introduce security risks for the sake of efficiency. To maximise efficiency and minimise security risks, all data was collected from the source and pushed over encrypted links via proxy servers to a cloud server, where it could then be pushed to the waiting client devices. The cloud provider chosen to store the data was considered one of the more secure in Australia, and one of only a few to feature the highest security certifications required by large utilities and mining companies. The software architecture used best-practice methodologies to isolate the data and keep it secure.
synchronised With data stored in a variety of different systems, and ranging from real-time to historical, multiple systems required synchronisation, which was achieved via a configurable ‘data bridge’ solution using plug-in architecture.
spatially integrated The system collated large amounts of spatial information, from maps or GIS or other business systems, into simple reusable formats for display. This required a versatile web-based mapping platform, with the ability to represent the canal, indicate its water level, represent and describe work orders, and link to other internal systems and information to allow easy visualisation of that item of work.
contextualised and meaningful (via metadata)

With thousands of different data sources under management, the system needed to classify data so that users of the system could easily locate data relevant to their requirements. Meta tree structures were used to classify all the data, allowing hierarchical associations. Each data source was tagged with multiple different types of metadata (such as state, scheme, power station, data owner, site type, status), and grouping structures allowed nested grouping of information, such that users could filter information specific to their needs.

The metadata structures could also be used to build dynamic security- sensitive dashboards of data, including any new data added to the system tagged with the appropriate information. This saves the time needed to configure dashboards, and makes sure all relevant data is available to the people that need access to it.

cost-effective The system used technology that Entura had already developed to deliver similar projects for other clients, minimising the need to develop new software. The system itself is ‘cloud’-based, allowing the cost of the infrastructure to be shared among a larger group of customers.

Simplifying access to data is helping Hydro Tasmania maximise the day-to-day operational efficiency of the Tarraleah canals, make better long-term operational decisions, and reap enhanced returns on investment. Employees now have a live view of the canals on iPads or tablets, enabling them to ‘tune’ the canals for maximum efficiency.


Similar solutions to those developed for this project can be used by power and water asset owners and managers to solve a range of data management challenges, including monitoring remote power stations, forecasting floods, and managing irrigation storages.

When we overcome barriers such as restrictive technologies and lack of metadata, we can make the most of our data. Interlinking multiple sources of information and displaying the results meaningfully leads to smarter decision-making and greater insights into how to operate our assets for maximum efficiency and value.

To discuss how Entura can help you manage your data to reap greater operational rewards, contact David Fuller on +61 438 559 763, Phillip Ellerton on +61 439 010 172 or Patrick Pease.


Getting the bigger picture from your data

Like having a pile of puzzle pieces but no box, are you drowning in data but unsure what it is telling you about your power and water assets?


Gathering and interpreting complex data to detect emerging problems is an important aspect of asset safety worldwide. Avenues for collecting data are becoming more sophisticated and accessible and less expensive. We routinely gather data and explore data gaps, data quality and data processing, but how often do we rethink the fundamentals of presenting and communicating data?

For data to be useful, it has to help us diagnose issues and design solutions to keep our assets, our operators, and the public, safe. To do this, it must be understood. Traditionally we have used 2D methods to present data, but forming a picture of an asset from 2D information is very time consuming, often requiring site visits and hours exploring drawings, drill logs and construction photos to understand the complexities of the asset’s design and construction.

Because we have evolved in a 3D world and our senses have evolved to match, the human brain has significant and sophisticated resources dedicated to visual processing and understanding objects in three dimensions. This makes 3D models a naturally efficient medium for rapidly displaying, interpreting and communicating complex information relating to our assets.

Bringing data to life

With advances in technology, we are now able to quickly convert raw data to build 3D models from 2D drawings, and also to animate data in 3D to show change and movement over time. In 3D, assets can be quickly visualised and explored digitally from any angle. This spatial representation allows us to see important things that may otherwise be hidden, or not stand out, in the context of the overall design and layout of an asset.


Features normally hidden can be drawn into a 3D model, such as internal layouts or features under the ground. These can all be independently switched on and off, so that elements critical to the analysis can be considered individually, or contextually against other features to get the bigger picture.

With 3D information at their fingertips – whether on desktops in the office or on smartphones or tablets in the field – engineers, data analysts or field inspectors can better understand assets in significantly less time, reducing costs, complications and misunderstandings.

Time changes everything

To understand our assets, we rarely look only at the here and now. Change is the key to identifying and preventing potential failures or problems – so we must look carefully at past and present data and continue to watch our data into the future. In the past, representing change over time could only be economically achieved in 2D because manually updating 3D models was laborious and time-consuming.

Specialist power and water consulting firm Entura has developed systems that allow data sets (from Excel, Access or other programs) to be automatically processed and displayed onscreen, producing 3D ‘snapshots’ or even animating data directly in 3D. The systems have been developed to allow quick tweaking of model parameters to show different data sets individually or in combination, to exaggerate movements where critical changes are too small to directly detect by eye, or to use colour coding to clearly represent critical parameters.

Perhaps the most significant advantage is that these models can be updated in a matter of minutes rather than days, by individuals with little or no CAD experience, simply by adding new data into the model’s database.

Should seeing always be believing?

Like any tool, 3D representations have some limitations. However, with experience and a little caution, the power of 3D representation can be fully exploited with minimal risk.

Just as 2D drawings can have mistakes or exclusions, 3D models are only as good as the data from which they are built. If incorrect drawings are used to build a model, or the wrong data is used in animations, 3D outputs will not represent the real world but may still look very convincing.

Like any engineering analysis, when 3D models are first produced, a clear review and approval process is needed, and model results must be verified against expected performance to ensure that the tool is robust and can be used reliably into the future.

The real challenges of complex assets

Entura has applied advances in 3D data modelling and presentation to support the management of a range of water and power assets including hydropower stations, water pipelines and dams.

In each of these three examples, 3D modelling delivered a comprehensive picture of system behaviour over time:

  • Our use of 3D modelling to explore the movement of turbine plinths at Hydro Tasmania’s Gordon Power Station contributed to a clearer understanding of a pattern of ongoing movement. This helped to identify potential causes and inform future remedial works.
  • Developing a 3D model of a steel pipeline made it much easier for an asset owner to understand and make decisions about the extent and possible causes of unwanted movement of the pipeline and its supports. Our model clearly indicated the extent of movement, leading to a targeted engineering solution that directly addressed the root cause of the problem without unnecessary investigation, over-design or delay.
  • When we applied 3D modelling to a hydropower dam built on a geologically complex foundation including dissolvable limestone, the resulting model combined the dam’s foundation profiles, underlying geology and leakage rates, and animated 3D water levels in the foundation. The 3D model is helping the owner to quickly and fully understand the data and easily monitor the performance of this complex asset.

In each of these cases, new data can be quickly integrated, allowing easy ongoing monitoring and clearer communication of the current and likely future behaviour of these assets.

With a bit of caution and experience, 3D data presentation tools can offer powerful benefits to asset owners and their stakeholders, putting all the pieces of the data puzzle together to quickly and easily reveal the full picture of an asset’s condition and performance over time, supporting decision-making for cost-effective and timely maintenance and upgrades.

To discuss how Entura can help you get the full picture from your data to better understand and manage your assets, contact Phillip Ellerton on +61 439 010 172 or Shekhar Prince on +61 412 402 110.


Using risk assessment to guide dam safety upgrades

Whether your focus is on a single dam or a whole portfolio, a risk assessment process helps you decide how best to intervene, and when, to get the maximum improvement in safety from your investment.


Using a risk assessment process to assess a whole portfolio of dams helps asset owners prioritise their limited resources for safety upgrades. Richard Herweynen, Entura’s Principal Civil Engineering, introduced our portfolio risk assessment program in his article ‘Dam safety: protecting lives and driving efficiencies’. Now we explore how a similar process can be used for a single dam to guide investigations, prioritise the order of a staged upgrade, and manage safety risks during construction, using the example of Hydro Tasmania’s Rowallan Dam.

The challenges of an ageing dam

Rowallan Dam is a 43m-high earth and rockfill dam built in the late 1960s, with two embankments on either side of a spillway located on a knob of very hard quartzite. The reservoir plays a key role in Hydro Tasmania’s hydropower system: it is a large storage at the top of the catchment and operates over a large range of water levels, capturing the high winter flows and then releasing them over the summer months through a cascade of five power stations downstream.

A dam portfolio risk assessment (PRA) completed by Entura in 2006 had identified Rowallan Dam as one of the potentially higher risk dams in Hydro Tasmania’s portfolio, with a number of suspected but not confirmed deficiencies. The potential deficiencies included a relatively high probability of a piping failure (internal erosion of the earthfill) as the filters were suspected to not meet modern standards and the dam had suffered a piping incident adjacent to the spillway walls when it was first filled.

As well, the PRA identified other potential deficiencies including questions regarding the spillway capacity, liquefiable foundations, potential for landslide hazards at the reservoir rim, structurally deficient spillway walls, and a limited capacity for dewatering.

With multiple potential deficiencies such as these, a range of challenges arise: Which deficiencies do we tackle first? Do we need to address all the deficiencies? To what level do they need to be addressed? How quickly should we address the deficiencies? And how do we justify to the business a large capital expenditure that will not generate any additional returns?

Reducing uncertainty

The original scope of the PRA was to assess the dam portfolio based only on the existing available information with the exception of preliminary dam-break modelling and consequence assessment. To allow the PRA to be completed within a reasonable timeframe and budget, this inevitably meant that significant gaps in our knowledge of the dams were filled with assumptions and best estimates.

A very targeted investigation program was then required to fill the gaps in our knowledge of Rowallan Dam’s particular possible failure modes and to prepare a fully justifiable business case. Entura led the investigation and concept development phase, working closely with external parties. The necessary investigations included:

  • geological mapping of the potential landslide features (to determine whether they were in fact glacial features and not of concern)
  • investigation into the core, filters and rockfill of the embankment (to confirm their properties)
  • more detailed dam-break modelling (to confirm whether the original estimates of consequences of failure were correct)
  • drilling of the left embankment foundation (to demonstrate whether liquefaction was a significant concern)
  • full modelling of the flood hydrology (to confirm the flood risk)
  • structural analysis of the spillway walls supporting the embankment on either side of the spillway chute

The spillway wall failure mode had not been identified in the PRA and was included in the investigation program to demonstrate that it was not a concern; however, it turned out to be the failure mode with the highest probability, and became the highest priority of the upgrade program.


Developing the upgrade program

When the specific investigations for Rowallan Dam were complete, the risk assessment for the dam was revised. The revised risk assessment determined the potential failure modes (in order of probability) to be failure of the spillway walls; piping along the spillway walls; piping through the upper part of the embankments; piping through the lower part of the right embankment; and overtopping of the dam during an extremely rare flood (rarer than a 1 in 10 000 year flood).

Developing an integrated, effective and progressively implemented solution that would not increase the dam safety risks during construction was a major challenge. Many alternatives for the outlet works, spillway augmentation and spillway walls were developed by Entura for resolving each dam safety risk while considering the construction flood risks and overall project risks.  This allowed Entura to find the right package of solutions to minimise the risks as well as the capital outlay. The ultimate solution included:

  • increasing the monitoring of the spillway walls: To provide early warning of a possible failure, inclinometers were telemetered and alarmed. Monitoring picked up a possible deterioration in one wall, which was temporarily propped until a permanent solution could be implemented.
  • increasing the dewatering capability of the dam: The riparian valve was replaced with one of greater diameter, and the controls of the turbine relief valve were modified to allow emergency bypass. This increased dewatering capacity was critical to managing flood risks during the later stages of construction and improved the ability to control any potential piping failure.
  • strengthening the spillway walls on the inside of the existing walls: This approach incurred less risk of overtopping during construction than if the walls were strengthened on the embankment side. The replacement walls were designed to accommodate higher future discharges.
  • installing modern, compliant embankment core filters: Installing these filters would protect the embankment from piping, but required major localised excavation adjacent to the spillway walls, including from the embankment crest to foundation, and reconstruction of the top seven metres of the embankment.


Lower risks, greater compliance

The major upgrades at Rowallan Dam have now reduced the dam’s safety risks. By considering a wide range of upgrade options and demonstrating that the selected option would significantly reduce the risk of failure through very targeted capital works, the Rowallan Dam risk assessment played a key role in developing a sound business case to demonstrate that the capital investment was both necessary and efficient – for a safer dam, both now and long into the future.

To find out more about how Entura can work with you to assess and remedy the safety risks of your dams or other water infrastructure assets, please contact Paul Southcott on +61 3 6245 4145, Phillip Ellerton on +61 439 010 172 or Shekhar Prince on +61 412 402 110.

About the author

Paul Southcott is a specialist civil engineer at Entura. He has more than 28 years of professional expertise in civil and dam engineering, as well as expertise in geotechnical, foundation, structural, hydraulic and hydropower engineering. Paul’s dam engineering experience spans geotechnical and hydrological investigation; feasibility and options studies; concept, preliminary and detailed design; engineering assessment, consequence assessment and risk assessment; safety reviews; monitoring and surveillance; and emergency planning. He has particular expertise in dam risk assessment and project managed the Hydro Tasmania portfolio risk assessment of 55 large dams, Southern Water’s 18 dams and most recently SA Water’s 18 large dams.  He was the technical leader for the Rowallan Dam upgrade project overseeing all aspects of the project including the detailed design of the spillway wall upgrades.


Dam safety: protecting lives and driving efficiencies

Humans have been damming rivers since 3000 BC for water retention and supply.

People can fish in the lakes formed by dams, sail on them, swim in them. They are important to life, providing water supply, irrigation for crops and power generation. But if a dam fails, causing devastating flooding downstream, the results can be catastrophic.

The worst dam failure in history occurred in China in 1975 when the Banqiao Reservoir Dam and other dams in Henan province failed, killing an estimated 171 000 people, with 11 million people losing their homes.

Safety is the key

Dam safety is a crucial aspect of modern dam building. Ensuring the safety of existing dams is a key concern of any dam owner, whether the dam is for generating power, protecting a nearby population from potential flooding or for the age-old reason of water supply.

Specialist power and water consulting firm Entura provides dam safety programs for Gordon Dam, the largest concrete arch dam in Australia, and other assets owned by Entura’s parent company, Hydro Tasmania, and for government and corporate clients around Australia, south-east Asia and southern Africa.

Hydro Tasmania is Australia’s largest water manager, so it needs to ensure that the risk of a failure across the portfolio is very, very small. With 55 large dams and many smaller ones, Hydro Tasmania needs to be able to identify the highest risk dams, so it is able to prioritise work on maintenance and refurbishment.  This is achieved using a process undertaken by Entura called a portfolio risk assessment (PRA).

Hydro Tasmania is committed to the safety of its assets for the people of Tasmania and its PRA enables the business to prioritise where it focus its financial resources, management and dam safety efforts.


What’s the level of risk?

Energy and water asset owners are increasingly choosing to implement a dam safety program to quantify and manage operational risks, evaluate high risks and find solutions for identified risks or deficiencies. Entura believes that a risk-based framework like a PRA is the best way to achieve an efficient and effective dam safety program.

Older dams or dams located upstream from populated areas are often high risk. The inspection regime for high-risk dams is understandably more robust and rigid than for low risk dams. However, it’s not just ageing that creates risks for dams. In Australia, the methods used to predict and anticipate floods are equally important, as is the increased knowledge that we’ve gained of the various causes and mechanisms through which dams can fail.

Entura’s PRA reviews the consequences of failure of a dam by looking at the impact that it may have on downstream populations, and also looks at the chance of failure occurring by considering extreme events such as floods and earthquakes, taking into account the specific site conditions.  It is the combination of the chance of failure with the resulting consequence that determines the level of risk.

A world-wide issue

A number of dam owners across the Asia-Pacific region are now looking at Entura’s PRA program, especially when they have a significant dam portfolio already developed. Our clients in the region are exploring how they can best use their resources and how to prioritise expenditure on their assets.

Having undertaken safety reviews and dam safety work in the Philippines, China, Indonesia, Malaysia, New Zealand, Papua New Guinea, Fiji and India, Entura understands the typical safety needs and drivers of dam owners across the world.

Australia has well-developed dam safety legislation in which Malaysia, for example, with its increasing number of dams, is very interested. Malaysia has experienced the tragic results of a dam safety incident, with the death of a number of people due to water releases through the spillway gates of Sultan Abu Bakar Dam.

On behalf of the Ministry of Public Utilities, Sarawak, Malaysia, Entura used its dam risk framework, similar to that used in a PRA, to assess whether the Bakun and Murum dams were ready to be impounded as construction reached conclusion. This dam risk framework looked at the potential scenarios that could lead to the sudden release of reservoir water, the likelihood of these scenarios occurring, and the corresponding consequences. Through this process the key dam safety risks were identified, and actions were determined to either eliminate or reduce the risks to an acceptable level.  These actions needed to be addressed prior to impoundment.

Dam safety is an ongoing concern

The safety and risk-level of a dam can change with time.  As dams or assets age, the way they are managed needs to change and they often need upgrading to ensure continued safe operation and desired life expectancy. But undertaking upgrades can potentially increase the risk of the dam during the construction phase – due to the removal of shoulder material from an embankment, or restricting the discharge capacity in a spillway chute. To contain the risks during the construction phase, operational practices might need modification, for example, operating a dam at a lower lake level during the period of construction to ensure the overall risk is not significantly increased.   This is why it is so important to have a plan to manage the safety of the dam during its entire lifecycle.

Five steps to assess dam safety risks

5618-Entura_Dam Safety Infographic-02

Risks can be reduced in a range of ways and, in many cases, a number of risk treatment options are used together:

  • reducing the likelihood of the risk occurring (e.g. strengthen a dam)
  • reducing the consequences if the risk does occur (e.g. upgrade emergency planning)
  • staging risk treatments (e.g. address most cost-effective risk mitigation works first)
  • balancing the resources required to treat a risk with the benefits of reducing the risk (e.g. examine various levels of investment and their respective risk reductions).

Entura’s portfolio risk assessment approach has five key steps:

1 – Flood hydrology Flood hydrology is a key input as it is used in both the engineering and consequence assessments. Generally the hydrology is based on current best practice. For some low-hazard dams, an innovative regional flood hydrology approach has been developed that provides sufficiently robust answers at minimal cost.
2 – Engineering assessment The engineering assessment is a critical part of the process as it requires all potential failure modes to be identified and then the probability of failure to be estimated for each mode. The engineering assessment gathers all the information about the dam including design, construction, geology and operations that may assist in defining the potential failure modes. This is presented as response curves (i.e. conditional probability of failure). The level of detail varies with the hazard category of the dam (i.e. a high-hazard-category dam receives more intense scrutiny than a low-hazard dam). The engineering assessment also ensures an assessment of compliance with current engineering standards.
3 – Consequence assessment Key steps in the consequence assessment method include developing a dam break model; mapping the inundation zones; assessing the population at risk and probable loss of life; assessing the financial and economic losses; and qualitatively assessing the environmental, social and intangible consequences.
4 – Risk assessment The risk assessment uses event trees that evaluate societal and individual life risk and financial risks. Risks can be aggregated across a range of load conditions and failure modes to give a total risk position, retaining visibility of the scenarios that contribute to the total risk. Where the risks are unacceptable, upgrade concepts are developed and their impact on reducing risk is plotted.
5 – Reporting The results of the risk assessment are reported, summarising the potential failure modes, consequences and risk profile for each individual dam. Summary data across the portfolio is also presented, including information on the failure modes, and risk of all the dams against societal life risk and financial risk criteria in a simple but meaningful format.

Resource levelling

All businesses need to share resources across many activities besides risk mitigation works. For a hydropower company, a significant reinvestment in generating plant is required to both manage risk and maintain asset capability. Resources are also needed for investment for growth and diversification.

Within the dam portfolio, it is important to ensure that resources, both human and financial, are not applied to risk mitigation projects at the expense of the fundamentally important surveillance and monitoring activities. A balance is needed between reducing risk and maintaining and enhancing surveillance and monitoring instrumentation.

An ongoing effort

Finally, it is important to realise that the capital works program for dam safety risk reduction is not a static program, locked in and then implemented without change. Rather, it is an active program that is reviewed regularly, actively managed and needs to remain responsive to new or changed risks, developing understanding of dams engineering, shifts in business priorities, delays to projects, and new developments in risk management processes.

The same process can be applied to other assets

The PRA process can also be used for other assets that have a low chance of failure but high consequences if failure were to occur.  At Entura, we have successfully applied our PRA process to penstocks and pipelines, and to canal systems, identifying key risks and prioritising the actions needed in a way that most effectively manages resources.

If you would like to discuss how we can assist you with assessing your dam risks or developing a resource-effective and comprehensive dam safety program, or apply the same PRA process to other key assets, please contact Richard Herweynen on +61 3 6245 4130.

About the author

Richard Herweynen is Entura’s Technical Director, Water. Richard has three decades of experience in dam and hydropower engineering, and has worked throughout the Indo-Pacific region on both dam and hydropower projects, covering all aspects including investigations, feasibility studies, detailed design, construction liaison, operation and maintenance and risk assessment for both new and existing projects. Richard has been part of a number of recent expert review panels for major water projects. He participated in the ANCOLD working group for concrete gravity dams and is the Chairman of the ICOLD technical committee on engineering activities in the planning process for water resources projects. Richard has won many engineering excellence and innovation awards (including Engineers Australia’s Professional Engineer of the Year 2012 – Tasmanian Division), and has published more than 30 technical papers on dam engineering.