Procedure for Defining a Pressure-Outflow Relationship Regarding Indoor Demands in Pressure-Driven Analysis of Water Distribution Networks

The definition of the relationship between the actual flow delivered by a node of a water distribution network and the available nodal pressure head is one of most crucial problems in Pressure Driven Analysis (PDA). The paper proposes a procedure, based on two models (building model and supplied urban area model), by means of which it is possible to generate and to simulate numerous different scenarios regarding the water delivery in the urban area supplied by a distribution network node. The scenarios are achieved by reproducing, through appropriate random generators, several urban and hydraulic situations, which are defined by various parameters governing water delivery. The statistical processing of the simulation results allows to define a representative pressure-flow relationship which reproduces, on average, the complex and varied set of phenomena governing the actual water delivery. Two application examples are also presented; the results of these study cases allow to calibrate the Tanyimboh and Templeman (2010) relationship, which is good for incorporation in PDA algorithms, because it is continuous with its first order derivatives in the whole field of pressure head values