To tame rivers for flood control and electricity generation, engineers face formidable technical challenges. Here are four different dam types and the engineering principles that guide their construction.
By Lachlan Haycock and Heath Dunn
Dams have evolved from simple irrigation walls to some of the largest structures ever built. By taming rivers, they provide flood control, irrigation, electricity and water security.
The below infographic summarises four key dam types and outlines some of the challenges implicit in their construction.
Regulating risk
In many ways, the bigger the structure, the bigger the safety concerns. For Chris Salkovic FIEAust, CEO of Dams Safety NSW, the matter, unsurprisingly, is one of managing risk.
“A common denominator for all regulators, whether you’re working in environmental protection or whether you’re a police officer, is preventing harm,” he explained, adding that any dam safety issues that arise are more often the result of complacency than wilful negligence.
“It’s very easy for a new dam owner or the senior executive of an organisation to go, ‘That dam’s been there for 50 years. Nothing’s gone wrong. Let’s revisit our need for investment in ongoing monitoring and surveillance.’ But, like many civil assets, issues can emerge not quickly, but over time.
“Therefore, if they’re not regularly maintaining a dam, not regularly inspecting it, not doing the necessary surveillance – that’s when a dam owner can get themselves stuck.”
The increasing awareness of the impact of a changing climate on increasing rainfall intensities has triggered positive action.
“It reinforces the need for dam owners to conduct regular risk assessments of their dams,” Salkovic said. “That’s essentially what our state legislation talks about, and it’s one of the things we check.
“The most important thing is that risk assessments are carried out by competent engineers – and regulators like Dams Safety NSW actually define what that means in practice.”
Take the discussion of dams and water infrastructure further at Engineers Australia’s Hydrology & Water Resources Symposium in November. Early-bird discounts are available until 25 August.
It is disappointing that we continue to fail to acknowledge the enormous environmental impact of dams – especially on freshwater fish, whose populations have collapsed internationally by at least 90% over the last 100 years. While the technical complexity associated with dam construction and risk management are acknowledged as significant, we are gravely in danger of blinding ourselves to the major ecological issues associated with dams that need to be solved NOW.
Well done, Create! That was a great read about megastructure dams and informative for working engineers and students alike.