Easier determination of leakages and open boundary-valves
Underground water distribution networks are occasionally subject to leakages. These are not always easy to determine, nor are the associated losses. Peter van Thienen has developed a method of quickly determining leakage losses: the Comparison of Flow Pattern Distributions (CFPD). Thanks to this innovative method, water companies can make use of the data they already collect to target their efforts in determining the causes of inconsistencies in water balance, as well as gaining more insight into their data and network.
Based on the supply patterns for different periods, the CFPD can characterise and quantify the demand changes and the changes in water losses due to leakage in a specific area. The method was developed in 2011 for the water companies and is being tested in 2012 at PWN and Evides Waterbedrijf.
At PWN, the method demonstrated how the presence of tourists on the island of Texel influences demand patterns and detected, among other things, an open connection to another, neighbouring supply area. At Evides, also, an open connection between the Delft and Westland supply areas was rapidly detected. “We observed a water balance in Westland that we couldn’t explain,” says Henk de Kater of Evides. “Using the CFPD method, we noticed that in one area there was a ‘plus’, while in the other there was a ‘minus’. We studied the situation and it turned out that there was an open boundary-valve, so that water was being transferred from one area to the other. Such situations can easily remain unnoticed and disturb the water balance, but the new method brought it quickly to our attention.”
Monitoring operational management
The CFPD method is quick and simple. It uses measurement data exclusively and is therefore independent of assumptions or uncertainties, which are typical of many models. Thanks to CFPD, water companies can use measurement data, which they already collect as part of normal operations, to gain a better understanding on how water is used and what the causes of changes in demand are. This can limit damages, save costs and increase insight. “Apart from determining leakage losses,” says De Kater, “you can use it to effectively monitor – and, ultimately, adjust – your operational management. We’re definitely going to continue with this, and will implement the method together with other filters to check our measurement data.”
The CFPD method has been developed within the water sector’s joint research programme (BTO), and further development is ongoing within the framework of KWR’s innovation research. A number of water companies are interested in the development of a CFPD tool that they themselves can use. KWR is also working with the European INCOM project – for example, the method is being implemented to research a large dataset of Eau de Paris, and a test network is being set up in Lille.
© 2018 KWR Watercycle Research Institute
Peter van Thienen