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Water main consequences
Technical Director, Hydrology, GHD; Bachelor of Engineering (Civil and Environmental), University of Technology Sydney
Hunter Water Corporation (HWC) has more than 5000 km of pressure mains in its water supply network, but in recent years the utility has suffered significant water mains breaks and leaks that attracted widespread media attention and community concern.
Minor breaks and leaks are common for ageing pipeline infrastructure, but the 20 large breaks the utility was experiencing yearly were putting people at risk in homes and on roads, damaging property and infrastructure, interrupting water supply and delaying trafﬁc. There were also considerable repair and clean-up costs.
In 2018, HWC approached GHD for a solution. Nicholas Deeks, Technical Director, Hydrology, and his team applied an innovative combination of technology and data to predict the consequences of these failures at every possible failure location.
“The leading industry solution would be to predict the ﬂ ow direction using topography, and overlay this with road and property data to approximate the effects. But this wouldn’t adequately meet HWC’s needs,” Deeks says.
“The ideal solution was to build two-dimensional ﬂood models that account for the unique properties of each failure location.”
Deeks and his team applied an innovative combination of technology and data to predict the consequences of these failures at every possible failure location.
Spatial data for the entire Hunter region, New South Wales, was analysed and processed using innovative methods. Using in-house coding, the team entered the data into ﬂood models every 5 m along each pipeline — the equivalent of 57,000 two-dimensional models. In-house coding was also used to process and analyse 35 billion ﬂood hazard combinations.
The result was a database of consequences for every water main segment, meaning that HWC would be able to target the high consequence mains for monitoring, renewal or replacement.
“Traditional manual methods used to build each ﬂood model aren’t possible for 57,000 models,” Deeks says.
“So I needed GIS tools and processes to automate the build.”
By automating the modelling process, Deeks made the project scalable; the method can be used for 100 km or 100,000 km of pipes.
“This innovative project overcame several challenges to achieve success. Developing new methods for estimating hydraulic roughness and building outlines are also features of this project. The beneﬁts ﬂow to the community in reducing property damage; to the client, in being able to optimise their resources; and to GHD in terms of capability development, which means it is better able to serve its clients.
“There are also beneﬁts in being able to conserve the precious resource water. The reusability of the approach is also important; this is a solution that can be applied elsewhere, which allows the beneﬁts to be scaled up.”