Explicit Consideration of Spatial Flowrate Distribution in Network Model Calibration

Distribution network models are commonly calibrated based on the agreement between computed pressures and pressures measured during field surveys. Other than via a global flowrate balance, little consideration is given to the accuracy of the temporal and spatial distribution of flowrate. However, the use of water quality models is becoming more widespread with an accompanying emphasis on the accuracy of the flowrate solution calculated by simulation software. This has prompted the development of an automated method for the empirical estimation of travel-times within a distribution network. The method involves increasing the conductivity of a pocket of water entering the network, via the addition of a sodium chloride tracer solution, and tracking its progress using conductivity loggers. The method yields results of good accuracy via a simple, highly automated procedure which utilises low man hours and a cheap, freely available innocuous tracer. It is recommended that at the time of model calibration, information from tracer studies is utilised as well as information from pressure surveys.