Abstract

TZATCHKOV, Velitchko G.  and  ALCOCER-YAMANAKA, Víctor H.. Stochastic Method Water Demand Variation Modelling. Tecnol. cienc. agua [online]. 2016, vol.7, n.3, pp.115-133. ISSN 2007-2422.

Despite its importance, water demand variation in current practice is estimated very approximately by observing water flow in a pipe supplying certain zone, and the demand variation curve thus obtained is assumed to be valid for any other pipe in the network, regardless the number of water users served. This paper describes a methodology for obtaining the daily instantaneous water demand stochastic variation based on statistical parameters of water consumption at individual homes, given leakage level, and observed flow variation at the supplying pipe. Continuous and intermittent supplies are considered. The methodology is applicable to a single home or a group of any number of homes. It provides a rational base for determining water demand variation at any aggregation level and can be combined with the corresponding traditional way of such determination, or substitute it. The results were compared with field measurements in a Mexican city where water supply is continuous. Flow variation in intermittent water supply pipes, or in continuous supply pipes with ground level cisterns and roof tanks, is very different from that in continuous supply pipes. The hourly water demand coefficient is higher in intermittent water supply, compared to continuous supply, but lower in networks with continuous supply and ground level cisterns and roof tanks.

Keywords : Stochastic water demand; PRP method; Hourly demand variation curve; Hourly demand variation coefficient; Water demand aggregation; Continuous and intermittent water supply.