Uncertainty of infrastructure leakage index (ILI)

Abstract

In many water systems, especially in developing countries, data on the elements of the system, flow measurements and water consumption have great uncertainty. This uncertainty in the further calculations is propagated to the calculated values of performance indicators - PI. Large data uncertainty may lead to wrong conclusions and thus lead to incorrect management decisions. Analysis of errors and uncertainties involves the study and quantification of uncertainty, and the obtained results are the basis for taking the necessary measures to minimize. This paper presents the application of ISO [1] methodology, which includes the law of propagation of uncertainty, the estimation of uncertainty of measurement and its propagation to the PI of water distribution systems - WDS. Example of the city of Pozarevac (central Serbia), provides a method for reducing the uncertainty of input parameters for calculating components of the water balance and ILI indicators.

U velikom broju vodovodnih sistema, naročito u zemljama u razvoju, podaci o elementima sistema, merenja protoka i potrošnje vode imaju veliku neodređenost. Ova neodređenost se u daljim proračunima propagira na izračunate vrednosti indikatora prerformansi sistema - PI. Podaci velike neodređenosti mogu da navedu na pogrešne zaključke i samim tim dovedu do pogrešnih upravljačkih odluka. Analiza grešaka i neodređenosti obuhvata proučavanje i kvantifikovanje neodređenosti, a na osnovu dobijenih rezultata preduzimaju se mere za njeno minimiziranje. U ovom radu je prikazana primena ISO metodologije [1], koja uključuje i zakon propagacije neodređenosti, za procenu neodređenosti merenja i njene propagacije na PI vodovodnih distributivnih sistema - VDS. Na primeru grada Požarevca (centralna Srbija), prikazan je postupak za smanjuje neodređenosti ulaznih parametara na osnovu kojih se računaju komponente vodnog bilansa i indikatora ILI.