Scientists monitor locations in a distribution system to track water
Water Tracking through Fingerprint Checking
Traditionally, the flow of water in pipelines and distribution systems is predicted using hydraulic models which are calibrated using pressure readings and the occasional addition of chemical tracers.
A recent Flagship project has developed an alternative approach to track water movement through distribution systems. Scientists found that natural fluctuations in water quality recorded by on-line sensors can be used to assign fingerprints to individual water parcels. These fingerprints can be tracked over a distance of several kilometres with associated time delays of a few hours.
“This new approach enables the development of a real time water tracking system,” research leader Dr Roger O’Halloran says. “The traditional method gives good results only for the large trunk mains, and rarely gives accurate predictions of water travel time. This severely limits the ability to identify stagnant water zones, and likewise constrains the reliable identification and tracking of contaminants in the distribution system.”
Scientists’ first attempts at estimating the travel time employed Markov Chain Monte Carlo (MCMC) methods, which are computationally slow and require batch processing.
“Then we discovered that sequential Bayesian estimation methods allow estimates to be calculated in less than one millisecond, which makes real time computation of water transit time feasible,” Dr O’Halloran says.
The research team is using these findings to develop water parcel tracking software and sensor systems to accurately track water movement through distribution systems. This is a major advance because it will allow water utilities to characterise water flow in distribution systems in the absence of a hydraulic model.
The future system will be able to detect and track the movement of contaminated water in a distribution system, to facilitate dynamic hydraulic models and to assess the effect of alternative water supplies, such as desalinated sea water.
“A combination of water sources could cause problems with water quality,” Dr O’Halloran says. “In a case of ‘mixed supplies’ the new system allows us to identify travel time and percentage of each water type at each location, in real time. This will enable water utilities to mount a rapid response to ensure our water is safe for drinking, as well as allowing better control of water quality changes associated with mixed supplies.”
The water parcel tracking research was originated in CSIRO, and was further developed with funding support from the Water Research Foundation (formerly AwwaRF) as an extension of an existing project, and the Water Corporation of Western Australia.
“Further research is required for the system to be feasible, because although the current results are encouraging, they require a trained operator and may be somewhat subjective,” Dr O’Halloran says. “The development of an automated tracking procedure would enable the system to be widely adopted and to give reproducible results.”
Roger O'Halloran, CSIRO Land and Water