Use of Pressure Dynamics for Calibration of Water Distribution System and Leakage Detection

The quality of Water Distribution System (WDS) models depends on how well they have been calibrated. Calibration of a WDS model with pipes of different age is a complicated problem. The first aim of the paper is to show that the Levenberg-Marquardt algorithm (LMA) may successfully be used for calibration if a correct step along parameters is used for the calculation of partial derivatives. The LMA has been tested on the WDS containing thousands of pipes. Short computer time requirements of the LMA allowed accomplishing more intensive analysis of the WDS. Another aim of the paper is to show that the use of pressure differentials for the calibration of an operational water distribution system will exclude systematic errors, wrong data on elevation of junctions and will significantly eliminate the influence of leakages on calibration. Thorough analysis of the differences between the measured pressures and pressures, calculated by the calibrated model, will allow finding areas with leakages and areas with incorrectly registered demand. Information on the location of leakages in turn will enable to use the optimization procedure for distinction between real losses and apparent losses. This procedure is based on the demands pattern and dynamics of leakages obtained on the basis of pressure dynamics. The information obtained will be used for the new iteration of calibration.