Satellite technology could be used to prevent catastrophic events like dam failures.
Dam failures can be catastrophic for areas downstream, causing loss of life and damaging ecosystems. When the Brumadinho tailings dam in Brazil collapsed in 2019, 11.7Mm3 of mining waste was released and 270 people were killed.
The incident was not an isolated one and engineers believe satellite technology could hold the key to predicting and preventing such failures.
Craig Goff is HR Wallingford’s technical director for dams and reservoirs and is also its emerging technologies sector lead. He says the failure rate of tailings dams is one in 100 compared to one in 10,000 for water storage dams.
He explains that tailings dams are more prone to failure because they are often poorly monitored and because they are made from unstable materials like dried sludge. Many of these dams are also abandoned after mining stops.
Earth observation data – satellite data about the physical, chemical, and biological systems of the planet – is increasingly available for civilian use, having originally been developed for military applications. As a result, HR Wallingford’s team decided to investigate how different types of satellite data could be used to improve dam monitoring. Currently dam monitoring relies on visual inspections, onsite instrumentation and surveys using aircraft or drones.
“We wanted to turn that [earth observation] data into usable information from an asset management point of view,” says Goff. This led to the development of the Damsat remote dam monitoring system, which won the Technology Leader Trailblazer Award at NCE‘s 2021 Tech Fest.
Development and testing
The Damsat story started in 2017 when HR Wallingford applied to UK Space Agency’s International Partnership Program (IPP) for funding to develop the system. The IPP is funded from the Department for Business, Energy and Industrial Strategy’s Global Challenges Research Fund (GCRF).
The GCRF, part of the UK’s official development assistance programme, aims to contribute to the sustainable development of developing countries through research and innovation. UK Space Agency head of IPP Ray Fielding says that his focus is on satellite-based solutions to address particular development challenges facing developing countries. The aim is to deliver societal and economic benefits.
Fielding says that Damsat was assessed as being “viable and very likely to deliver quality results”, securing £3.4M in funding from the agency.
One of the knock on benefits of this whole system is that it has raised the awareness of dam safety
HR Wallingford built a multi-disciplinary team comprising dam safety engineers, earth observation data scientists, statisticians and machine learning experts.
The system the team developed uses data from satellites and real time monitoring from in-situ devices to track changes in the normal behavior of dams – expansion or contraction; greening and browning; settlement; and steady seepage – to detect dangerous movement and leaks. Damsat enables users to identify the causes of such incidents by comparing current and older satellite images.
Using 10 day satellite weather forecasts the system can predict the effect of forecast rainfall on reservoir water levels. It uses numerical models to predict the possible downstream impacts of a failure.
Cloud based platform
All the information is integrated and stored on a cloud-based platform, with the system generating alerts when it detects changes or unusual weather conditions that could cause a dam failure.
Damsat was tested on 31 dams mainly – tailings dams – in the Peruvian Andes. Peru is on the UK’s aid list but was also selected because it has a large number of dams in remote locations. Between early 2019 and March last year, the HR Wallingford team worked with the Peruvian institutions responsible for dam monitoring and earth observation technologies.
Those institutions acting as end users of the system, allowed the team to assess how it was being used in order to refine it.
Testing was successful. The system detected movement in large active tailings dams at Cajamarca, northern Peru and at Pasco in central Peru.
“The highest velocities – up to many milimetres per year – were identified higher up on the slopes and at the crests of both dams, which could have been consistent with settlement occurring in those areas,” says Goff.
A small leakage incident occurred at another tailing dam, where some tailings were released from a broken pipe. Damsat’s ability to detect this type of anomaly was verified on the ground where local teams took photographs and gathered field data.
All of this data enabled operators to analyze the severity of incidents and better understand safety issues.
Goff says that one of Damsat’s major benefits is that it closes information gaps. “Damsat is always there in the background, running, grabbing new data when it becomes available and filling in a few of the gaps in your [asset owners] knowledge basically.
“In between visits or the processing of the manual monitoring data, these extra tools are available,” he says, adding that the system allows whole surfaces to be monitored rather than specific points.
According to Goff, the system enables a better allocation of resources, as asset owners can focus on those dams that the system identifies as being high risk. He also says that Damsat can reduce surveying costs because it is cheaper to operate than carrying out aerial surveys.
“One of the knock on benefits of this whole system is that it has raised the awareness of dam safety among asset owners and regulators that came to events we ran,” says Goff.
The Damsat team has held several training courses in Lima and online focusing on the potential for using satellite images in risk related work; the basic principles of remote sensing; remote sensing technologies for pollution detection; hydrological models and flood forecasting; estimation of flood risk areas and estimating the potential consequences for flooding evacuation models.
From Andes to the UK
Following the successful trial, Damsat is now available for commercial use on tailings and water dams.
Water supplier Bristol Water is the first UK user of Damsat technology and for the past six months has been using the technology to remotely monitor its 15 reservoirs.
Bristol Water head of asset management Alex Mortlock says Damsat technology provides additional data that cannot be collected through visual inspections. “Movement might be invisible to the naked eye, but with the satellite you get very accurate points of data and you can monitor that very closely over time,” he says.
The need for such a system in the UK was highlighted in August 2019 when damage to the auxiliary spillway at Toddbrook Reservoir in north west England prompted fears that the dam would fail. This led to the evacuation of 1,500 people downstream. The incident showed that catastrophic events can happen in the UK if asset owners fail to pay attention to monitoring and maintenance.
Mortlock says that with most UK dams over 50 years old and more frequent extreme weather events, “the chances of failure only increase”.
“That’s the reason we will always look at new technology and systems like this that help us manage those assets and make sure they are there in another 100 to 150 years,” he says.
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