Publication Details
Abstract
Non-revenue water (NRW) is the single most important indicator of the technical condition of a water distribution network, and in aging systems its physical (real-loss) component is dominated by pressure-dependent leakage. This paper presents an integrated framework for characterizing that leakage and reducing it through district-metered-area (DMA) zoning and active pressure management. The framework rests on the Fixed and Variable Area Discharge (FAVAD) concept, in which leakage is proportional to pressure raised to an exponent N₁ that reflects whether the leak paths are rigid or expanding. We show how N₁ is inferred from minimum-night-flow (MNF) analysis within a DMA, how the resulting pressure-dependent relationship is embedded in a hydraulic model so that leakage responds automatically to pressure changes, and how the network is partitioned into pressure zones on the basis of elevation and hydraulic structure. Applied to a representative model of the Karshi network in arid southern Uzbekistan, the method delineates three elevation-driven DMAs, isolates a large pressure-driven leakage component in the night flow, and predicts leakage reductions as an explicit function of pressure reduction and N₁. For the case network, N₁ values in the range 1.0-1.6 imply that a realistic 20 % reduction of average zone pressure lowers real losses by roughly 20-30 %. The paper provides a transparent, data-modest workflow that regional utilities can apply to quantify and reduce NRW where input data are incomplete and capital is limited.