Modelling of pressurised water supply networks that may exhibit transient low pressure – open channel flow conditions

On account of an ever increasing scarcity of potable water, ineffective water distribution networks (WDNs) and growing demand, several water distribution systems exhibit intermittent flow behaviour, either inevitably or under the deliberate action of operators, when they are expanded beyond their design capacities. This tendency is generally undesirable due to the fact that it leads to reduced service levels and consumer dissatisfaction. Moreover, due to inadequate system pressures and insufficient flows, the analysis of intermittent flow behaviour requires unconventional approaches, ultimately complicating network management. In this paper, a description is given, of tools that were developed to aid the analysis of WDNs during situations of low or non-existent pressures. Testing of the tools revealed that they could represent network behaviour fairly accurately.