Use of modelling error dynamics for the calibration of water distribution systems

The calibration of a water distribution system remains a complex task. Leakages create additional difficulties if their proportion is high. Not all leakages are real. A part of them are apparent leakages. An optimization procedure is proposed to obtain the proportions of real and apparent leakages. The distribution of the leakages over a WDS may be made easier by analyzing the dependence of modelling errors on water flow. It is suggested that pressure measurements should be ranked according to the closeness of measurement to the water source and that modelling errors should be analysed separately for the measurements of different order (from the first to the highest). The advantage of this approach is that the analysis is confined within points of measurements of one order and it allows to redistribute fluxes of leakages (real and apparent) more reliably. Nonlinear optimization with linear constraints is used for the redistribution of leakages over a WDS. The methodology proposed allows to exclude the influence of systematic errors on the result of calibration.