Field testing is an important process in retrieving the flow and pressure data which reflected the real DMA behaviour. This will be later analysed and used for running leakage model and calibration. Two major steps in field testing describe as below.
Planning
As mentioned earlier the involvement of the hydraulic modelling team during the early stage of the project is important as this will reduce the requirement of the field test scope.
The modeller will utilize the model developed in previous stages to design for the field test. All the field test points and associated site enabling works will be confirmed after discussion and site visit with the MWA’s representative.
The list of enabling works will be submitted to MWA for action. It is imperative that these enabling works are carried out within the agreed timeframe.
The modeller will work out a detail field test plan describing all the location of field test points and the required field test equipment. In general, field test deployment will include as below:
Pressure Logger:
• Hydrants (1 for every ~ 300 connections)
• Upstream and downstream of all control valves (such as Pressure Sustaining Valve, Pressure Reducing Valve etc)
• All model boundary/transfer points.
Flow (Probe/Flow meter/Logger)
• All model boundary/transfer points.
Number of pressure logger are based on total count of customer in the DMA as below: -
Implementation
Upon confirmation and agreement from the MWA, the field test team will start to deploy site measurement equipment.
The field test will be carried out at least seven days to cover weekdays and weekend measurement. This is to enable the modeller to choose a calibration day which can represent the system under normal operating conditions. During field test, the field team will do constant check on critical measurement points such as the boundary flow measurements to ensure satisfactory data is recorded.
Equipment will be retrieved with data downloaded once the field test is deemed successful and over the minimum seven days period.
GPS for all field test points will be carried out during the seven days period and it might require extension depending on the size of the field test. This exercise will gain elevation data which required during the head analysis and also calibration.
There is bound to be measurement failure during field test. In this aspect, the team will need to discuss with MWA to establish criteria for field test acceptance. Only field test with failures which prevent satisfactory model calibration will require retest after thorough discussion with the client. It is an acceptable practice of retesting certain section of the model and calibrates the area on a different calibration day.
The number of equipment proposed will able to run 1 DMA per field test at one time. Therefore 3 weeks required for field testing and another week for deploying, dismantling loggers, downloading and GPS points.
Table 3 List of equipment required
Item Description Qty
1 PrimeLog (Standard) data logger and accessories
PrimeLog1P (10 bar, +/-0.5%) pressure data logger 15
Logger programming cable (USB type) 2
Hydrant box + chain + lock 15
5 Accessories
Coiled pressure hose 20
Hydrant cap 15
1/8" male threaded quick release coupling 20