After initial meetings about suspected leakage and NRW losses with Craig Needham and Piotr Kozeil from Yorkshire Water a trial was arranged to use the GUTERMANN AQUASCAN TM2 correlator. An initial location on an 18” Cast Iron trunk main was identified from Longwood Service Reservoir feeding four large DMAs. Other leak detection methods had previously been carried out with a point of interest which were to be compared and followed up with the AQUASCAN TM2.Challenge
The Cast Iron main had several hydrants where we could use hydrophones at approximately 900 metres apart; the area is built up with a mixture of domestic and industrial properties also several large trees along the route of the proposed correlation.Solution
The AQUASCAN TM2 using hydrophones was set up at 900 meters apart using aerial extensions to avoid signal loss which can be caused through tall buildings and large trees between the sensors. The pipe information was input into the AQUASCAN TM2 and a correlation ran. This was a long distance and it was expected to allow the correlation to run for some time, after approximately 5 minutes a peak developed at 520 meters with a quality of 100%. We measured out the distance to find a supply feeding a mill running with the meter not registering the flow. Other points of interest have been identified using peak suppression on this length of main.
Longwood CT29 – 18” Cast Iron. Correlation 1-2 (900m, 18” main CI). Peak 520 m from Sensor A (sensor 1).
A good noise was found on the supply (possibly missing consumption estimation of 300m3/d). This had not been picked up on previous leak detection exercises.
CT29 Flow Profile, Missing Consumption (Longwood) 2.197l/s (254m3/d).
18” Main CI – Under Investigation. ICA job raised to check customer meter.