Modeling Intermittent Water Supply in SWMM: A Critical Review With Reproducible Recommendations and a Python Package

Distinctly, Intermittent Water Supply networks cycle between filling, pressurized supply and draining, leading users to withdraw water and store it for later consumption. While intermittent networks serve one in five piped water users, their characteristic hydraulic features cannot be readily represented in available, open‐source hydraulic modeling software. Several hydraulic modeling methods have been proposed in the literature, but these methods disagree in their construction and assumptions, and most are not reproducible, hindering the exploration of techniques to improve the quality and equality of service in intermittent networks. To improve the reproducibility, consistency, and numerical stability of hydraulic models of intermittent supply, we synthesize the best modeling practices in the literature into a recommended, reproducible method: SWMM for Intermittent Networks (SWMMIN). We outline and demonstrate how SWMMIN models network pipes and user behavior: withdrawing water subject to available pressure in the network, storing water, and consuming from storage for their various activities. For experienced IWS modelers, we provide quantitative evidence of numerical stability and mass conservation within SWMMIN (from >1,000 simulations of 3 network models); we recommend spatial and temporal discretizations that result in solution speeds between 40 and 200 m/s. To facilitate the adoption of our recommended modeling procedures, we share a Python package (GOSWMMIN) that automates the implementation of SWMMIN. Lastly, we propose a model reporting template to bolster reproducibility and call on fellow modelers to use it; accessibly and reproducibly described models of intermittent supply have the potential to accelerate research and transform practice.