Comment on "An Effective and Efficient Method for Identification of Contamination Sources in Water Distribution Systems Based on Manual Grab-Sampling" by Ji et al.
Abstract
The original article proposed a sampling method for detecting continuous contamination sources, a method that does not require elaborate water quality data or real-time sensors. The method has practical merit for many water utilities but the authors' work has some limitations not discussed in the article that we comment on here. First, the authors use terms like "real-world system" to refer to a study done with a model, which may mislead readers. Second, the method is advertised as simple but actually requires some advanced tools and steps that are not fully described and that may not be available to practitioners. Third, determination of flow directions is not always explicit and usually requires a hydraulic model, which the authors happened to have, but may not be available for every system. Fourth, the authors do not adequately describe the hydraulic model; their figures show networks that differ from the provided models and may have differing lengths or flow directions that affect the analysis. Finally, the study data are not provided as per the Data Availability Statement, but doing so could help overcome these limitations and make the method more useful.