Dammed if you don’t…

World Water Day
March 22, 2019

As world water day draws to a close around the planet, there has been a renewed effort to promote the fundamental human right to water as declared in UN Resolution 64/292. The 2010 resolution calls on all the world’s nations to provide the “indispensable human right” to safe, clean, accessible, and affordable drinking water.

While I agree with and completely support that effort, as a flood modeller I generally find myself looking at water from another perspective, focussing on protection from water rather than access to water. Protection from floodwater is a basic, water-related human right that should be just as inherent as access to drinking water. Within that set of protective human rights lies the fundamental right to an early warning system for those living in flood-prone areas; unfortunately, the failure to provide that particular human right has been demonstrated by some recent, catastrophic dam failures around the world.

A Brazilian woman named Paula Alves became a local legend for serving as the heroic but tragically inadequate early warning system for the flood wave unleashed by the 2015 Samarco Dam collapse. Watch her story here. When history repeated itself in January 2019 with the Brumadinho Tailings Dam collapse, unfortunately she and her motorbike were 100 km away, and most of the victims had little to no warning of their fate.

In these sorts of situations, it is easy to point the fingers of responsibility at others in hindsight; but to me as a practicing engineer operating in both the mining and dam sectors, these tragedies represent a collective failure of the entire industry to recognize the inherent risks. In most developed areas, permitting requirements for the construction and operation of a dam include an early warning system guided by the results of thorough dam breach analyses. In less regulated environments, however, the cost of implementing and maintaining a functional early warning system is all too often dismissed as prohibitive.

These systems can certainly be expensive, but they typically amount to a very small fraction of the overall budget; if an element of that scale is enough to sway the cost:benefit ratio for a particular dam, perhaps it shouldn’t be built or operated at all! The toll from a single, missing early warning system is incalculable. Given enough time – and enough aging dams around the world – this particular form of Russian Roulette is sure to be fatal in the end as the staggering human tolls of the recent collapses have demonstrated.

If I were in a position to add a few clauses to the UN resolution on water, it would include the indispensable, fundamental, inalienable right to a functional early warning system for people who live or work within a dam breach inundation zone. Permits to operate dams should be contingent on the demonstrated operability of the emergency warning system, regardless of a nation’s economic status. Global consulting firms should refuse involvement in a project – and forsake the profits – if these criteria cannot be met.

When analyses show that even an operable early warning system would not provide sufficient protection – as was the case with those working immediately downstream of both the Samarco and Brumadinho dams – planning processes should at least attempt to locate critical facilities outside of these zones. Perhaps that is unrealistic or idealistic given the thousands of existing dams with millions of people already in that situation, but at a bare minimum, the results of dam breach analyses should be made public so that all potentially affected people can make their own decisions around acceptable risks under full disclosure.  

Australian context

Following a record period of heat and drought in 2018, torrential rainfall in January and February 2019 brought relief to some of the hardest-hit areas of Australia – a fitting dichotomy for the proverbial land “of droughts and flooding rain.” The relief was tempered somewhat in Townsville, Queensland, where the swelling Ross River Dam required unprecedented spillway releases that flooded many properties and triggered widespread evacuations:

Ross River Dam Release

At the same time in Brazil, search and rescue efforts tragically turned to recovery operations as hopes faded for hundreds of victims buried under the concoction of mud, debris, and tailings that overtook them as they tried to flee the destructive path created by the collapse of the Brumadinho Tailings Dam:

Brumadinho Dam Collapse

Whether a downstream flood wave results from intentional releases, deliberate decommissioning, or catastrophic failure of a dam, recent hardware and software advances allow for increasingly realistic and sophisticated simulations of inundation and flood hazard zones associated with dams – with the potential to reduce the tremendous human, environmental, and financial costs of a failure. Modelling results provide input and optimisation for early warning systems, community planning processes, and emergency response efforts that can ultimately save lives.

While the Ross River Dam itself was considered to be safe from failure – despite a peak level that reached almost 250% of the reservoir’s volumetric capacity – the results of a hypothetical failure assessment can still be quite shocking to the downstream community; recently published emergency action plans, for example, show just how devastating the failure of the Ross River Dam would be – inundating the greater part of Townsville and its surrounding suburbs:

Luckily for Queenslanders, early warning systems and detailed evacuation plans are in place, and the Ross River Dam has been thoroughly evaluated for a vast range of contingencies including climate change, earthquakes, terrorist attacks and even meteorite strikes! In many areas around the world, however, the risk posed by potential dam failure is poorly understood, as demonstrated by the workers who stood below the Samarco Dam in Brazil and continued filming as it began to collapse in November 2015 – perhaps overconfident in the structure’s design integrity and apparently unaware of just how powerful the imminent flood wave would turn out to be:

While still under investigation, early reports on the Brumadinho collapse indicate that the 42-year old dam had been declared safe by international dam safety experts just a few months before failing. Meanwhile hundreds, if not thousands of dams around the world have received lower safety ratings yet continue to operate – sometimes with downstream populations that are completely oblivious to the fact that they live and work inside the dam breach inundation zone.

The Samarco and Brumadinho dam failures occurred within a few years of each other and less than 100 km apart. But while these two failures happen to be associated with strikingly similar circumstances, the Brazilian tragedies represent a collective failure of the entire industry to recognise and mitigate for the hazard associated with unsafe dams – and to learn lessons from historical collapses. Many other dams around the world face eerily equivalent threats, as demonstrated by last year’s deadly Saddle Dam collapse in Laos:

Each of the cases cited above pertain to regulated structures that had been designed and operated under guidance from international experts in their respective fields. In that light, it is particularly harrowing to consider the number of unlicensed and illegal dams that have been constructed in some areas and are operated without any regulation or industry oversight whatsoever; in any case, the recent failures in Laos and Brazil make it clear that improvements to the design, operation, monitoring, remediation, and regulatory processes are urgently needed, including enforceable guidance that can be aided by the increasing prevalence of dam breach modelling data.

When engineers and hydraulic modelers are asked to assess a dam failure scenario, they may be bound by non-disclosure agreements to avoid leaking the results – particularly if their findings might alarm the downstream population. Dam owners may be reluctant to release information about potential inundation zones due to fears of increased accountability for remedial actions or even perceived impacts to real estate values or insurance premiums. Study results should rightly be subject to an intensive review process prior to publication in order to avoid the dissemination of incorrect hazard mapping and other critical data, but the deliberate withholding of proprietary information to avoid disappointing shareholders has in the past demonstrably led to unnecessary loss of life, environmental damage, and in some cases the eventual prosecution of those found responsible for a dam’s collapse.

We now have tools that allow better, faster, and more efficient production of dam breach inundation data than ever before. In conjunction with the availability of increasingly detailed global terrain data, these advances allow additional opportunities for third-party peer reviews, comprehensive sensitivity analyses, and more thorough quality control efforts that provide badly needed scrutiny and can end up reducing the historically proprietary nature of dam failure studies.

For a wide-ranging overview of the latest advances in dam breach modelling, please view the Australian Water School’s free webinar on the subject here:

Free Dam Breach Modelling Webinar

More free webinars and additional dam breach modelling resources are available here, with material specific to tailings dam breach modelling posted here. 

Further advances in technology are providing additional benefits, such as the ability to link early warning systems to interactive models with real-time adjustments that can be relayed to emergency services as conditions change. As another example, gridded rainfall data sets allow hydrologic and hydraulic models to be tested over a range of spatially and temporally varying storm events; in some cases, Doppler radar data can be applied to update model results with up-to-date meteorological conditions, informing spillway release strategies and providing more accurate advance warnings to affected residents. These innovations could certainly have benefitted flood-affected communities such as Townsville this year, further improving evacuation strategies, but the analyses require tremendous computing power exceeding the capacity of typical desktop computers – with computational time requirements that push the availability of results well past the recession of the flood and therefore beyond any useful real-time application.

Cloud-based computing, AI-aided analyses, and advanced Monte Carlo simulations are contributing toward improved capabilities in dam breach modelling. If you are interested in these topics, additional dam breach modelling resources are available here, including a database of almost 4,000 historical dam failures and courses in which attendees set up, run, and animate a dam breach models from scratch using freely downloadable software.

In conclusion, there is a lethal minefield of massive proportions awaiting future generations as the aging dams that dot the globe reach the end of their functional lives. In some cases, as these assets become unsustainable liabilities, dam owners may disappear into liquidation or try to relinquish their overwhelming responsibilities for maintenance.

The scale of the risk is staggering, but so is the scale of the available data and computational opportunities. People armed with accurate information have the collective power to demand action; in this case those actions might include demands for the implementation of early warning systems, dam upgrades, spillway improvements, and – if needed – the revocation of operating rights.

As we’ve seen from the news clips emanating from Brazil, it’s a serious business that warrants a serious response – which should be aided by a serious assessment of the risks! And I for one believe that proper assessment of the inherent risks associated with dam failures can help to avoid a repetition of the recent catastrophes.

I do hope you’ll join us for one of our interactive training sessions to dive further into this critical subject – and that we can collectively learn from each other in doing our part to help improve the science. I look forward to future advances and collaboration. Hope to see you online or in person soon!

Krey Price, Surface Water Solutions