Equity analysis of intermittent water supply systems by means of EPA-SWMM

Abstract

Intermittent water supply (IWS) is a frequent operation approach in developing countries. A number of factors contribute to IWS, such as leakage and water shortage, leading to inequitable water distribution. A way to reduce the inequity in IWS systems is by planning or adapting the network for equitable water distribution, which requires software capable of describing IWS conditions, including not only pressurized flow but also free-surface. In this paper, a new index for equity analysis is presented and compared with the existing indices available in scientific literature. The comparison is based on the EPA-SWMM modelling framework and standard IWS operations, including pipe emptying and filling, have been considered. Results reveal that EPA-SWMM has great potential in simulating IWS systems, especially in the application for equity analyses, as it provides a more realistic description of the pipe filling and emptying operations compared to standard water distribution modelling software. Furthermore, a novel equation called volumetric coefficient was developed which has a significant advantage in identifying the nodes with a higher impact on network equity, and ensuring the fair distribution of supply along the distribution network, considering the relevance of nodal demand, which none of the other indexes in the literature were addressed. HIGHLIGHTS A novel equation was developed for calculating the supply equity in the network, named volumetric coefficient (VC).; The findings indicate that the VC has an advantage over other equations found in recent literature, on the analysis of equity in intermittent supply.; Simulation of flow patterns in the network during filling and emptying operations was analysed using EPA-SWMM.;

Keywords

• equity analysis
• intermittent water supply
• pressurized flow
• transient flow
• unpressurized flow
• volumetric coefficient