General Purpose Demand Allocator (DALLOC)

As part of their recently completed water master plan, the City of Phoenix, AZ required a demand generator that would produce a demand set for hydraulic modeling based on user input for time-of-day, day-of-the-year, and year during the study period. The demand allocation had to be able to predict instantaneous demands at any point in the system, formulate base demands, and create an aggregate peaking curve for use with hydraulic models. Such a model was developed using the City's comprehensive GIS, the Visual Basic programming language, and a Microsoft Access relational database seeded with attributes required by common pipe network analysis software. The resultant model provides extreme flexibility. Demand nodes can be seeded using several methodologies, ranging from a simplistic inverse pipe-diameter model to comprehensive polygon overlay processing with nodal weighting, where weights can either be automatically generated or user defined. Subsequent to the Phoenix study, the demand allocator has been successfully applied to other smaller systems.