A Tool for Preliminary WDN Topological Analysis

Hydraulic modelling of Water Distribution Network (WDN) is crucial for design, operation and management purposes. WDN models should pursue correct representation of hydraulic behaviour, flexibility to accommodate any WDN topological change and computational efficiency. An effective preliminary analysis of WDN topology might be valuable in terms of resizing of the simulation problem, analysis of WDN functioning, correct statement of calibration problem and understanding of results. This contribution presents the key features of a tool which incorporates some recent outcomes on preliminary topological analysis of WDN. They include different kinds of skeletonization, automatic detection of network components and identification of pipe segments associate with deployed isolation valves. All these utilities for manipulation of WDN topology take advantage from the simplification of network topology with respect of serial nodes. In the case of hydraulic simulation such a simplification can be performed while preserving the correctness of the energy and mass balances as in Giustolisi and Todini (2009) who proposed the Enhanced Global Gradient Algorithm (EGGA). The paper also presents the adopted input data structure which is conceived to accommodate, besides other data, hydraulic and topological information about removed serial nodes, valves, pumps, pipe unitary hydraulic resistance, minor head losses, leakage parameters. Although it does not significantly differ from more widely adopted data structures (e.g. in EPANET) it easily accommodate tabular data formats (e.g. from MS-Excel spreadsheets), thus facilitating its integration with other software applications. The final part of the paper shows some strategies to accomplish demand-driven and pressure-driven analysis on the simplified WDN which reflect different types of approximations in network representation.