The most common causes identified for the breaks are reactive clay soils transitioning through hot and dry seasons to wet and cool, leading to 3940 breaks and leaks recorded.
Although the increase is above the previous year, the total number of incidents sits below both 2015 and 2016 levels in a pattern indicated since records from 1992.
SA Water’s Senior Manager of Asset Management Peter Seltsikas said there is a seasonal cycle of water main incidents that have been tracked through the past 27 years.
“Conversely, in our state in 2017, there were milder transitions between seasons, which resulted in more stable levels of moisture in the soils, and therefore fewer main breaks,” Mr Seltsikas said.
Professor of Geotechnical Engineering at the University of Adelaide Mark Jaksa said there is a strong correlation between weather variability and underground piping issues.
“The ground, as you can imagine, is a natural beast and it can be quite complex, so that makes prediction of what it will do to a water network particularly challenging,” Prof. Jaksa said.
“With the seasons, the reality is that the ground is variable from one location to another and we get uneven amounts of swelling and shrinkage, and that puts particular stress on the pipe network.
“The state’s arid climate also causes Adelaide’s soils to dry out and wet far deeper than any other urban area in the country.”
Despite numbers recorded in 2018, the overall trend shows a decrease in the volume of water main breaks, with smart technology adoption preventing 30 breakages in the Adelaide CBD since July 2017.