Calibration of intermittent water supply systems hydraulic models under data scarcity

Abstract

Intermittent water supply systems (IWSSs) are unable to meet customer demands due to water scarcity from the sources or due to economic or/and technical scarcity. Conversion to continuous water supply as a means of tackling IWSSs’ inherent problems of inequitable water distribution, limited water supply hours, high non-revenue water, system operation and maintenance costs, and poor water quality is essential for sustainable water supply. Modelling and optimisation techniques have been used to aid the conversion process, optimisation of the operation of these systems, and guiding leakage reduction actions. However, modelling IWSSs have several challenges. These include the lack of accepted existing modelling techniques that include leakage modelling and the lack of comprehensive methodology for calibrating IWSS hydraulic models under limited calibration data. This study proposes a methodology for calibrating IWSS hydraulic models that include leakage modelling. The proposed methodology involves distinct steps to mitigate the problem of data scarcity, it eliminates the trial-and-error procedure of determining the leakage emitters' coefficients by using optimisation and it presents an approach for estimating the lower and upper bounds of the emitters' coefficients. The methodology was applied to a case study in Zambia. The calibration procedure gave accurate results given the limitation of data. HIGHLIGHTS Development of a comprehensive calibration methodology for intermittent water supply system models that include leakage modelling.; A model calibration approach that selects leakage emitter exponent and coefficients automatically through optimisation.; An approach for setting the lower and upper bounds of the leakage emitter coefficients.;

Keywords

• calibration
• hydraulic modelling
• inequitable water distribution
• intermittent water supply systems
• leakage modelling