Davis Michael J, Janke Robert
Argonne Associate of Seville, Environmental Science Division, Argonne National Laboratory, Argonne, Illinois, USA.
National Homeland Security Research Center, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA.
Drink Water Eng Sci. 2018 Jan 4;0:1-25. doi: 10.5194/dwes-2017-39.
The effect of limitations in the structural detail available in a network model on contamination warning system (CWS) design was examined in case studies using the original and skeletonized network models for two water distribution systems (WDSs). The skeletonized models were used as proxies for incomplete network models. CWS designs were developed by optimizing sensor placements for worst-case and mean-case contamination events. Designs developed using the skeletonized network models were transplanted into the original network model for evaluation. CWS performance was defined as the number of people who ingest more than some quantity of a contaminant in tap water before the CWS detects the presence of contamination. Lack of structural detail in a network model can result in CWS designs that (1) provide considerably less protection against worst-case contamination events than that obtained when a more complete network model is available and (2) yield substantial underestimates of the consequences associated with a contamination event. Nevertheless, CWSs developed using skeletonized network models can provide useful reductions in consequences for contaminants whose effects are not localized near the injection location. Mean-case designs can yield worst-case performances similar to those for worst-case designs when there is uncertainty in the network model. Improvements in network models for WDSs have the potential to yield significant improvements in CWS designs as well as more realistic evaluations of those designs. Although such improvements would be expected to yield improved CWS performance, the expected improvements in CWS performance have not been quantified previously. The results presented here should be useful to those responsible for the design or implementation of CWSs, particularly managers and engineers in water utilities, and encourage the development of improved network models.
在案例研究中，利用两个供水系统（WDS）的原始网络模型和简化网络模型，研究了网络模型中可用结构细节的局限性对污染预警系统（CWS）设计的影响。简化模型被用作不完整网络模型的替代物。通过针对最坏情况和平均情况的污染事件优化传感器布置来开发CWS设计。将使用简化网络模型开发的设计移植到原始网络模型中进行评估。CWS的性能定义为在CWS检测到污染存在之前，自来水中摄入超过一定量污染物的人数。网络模型中结构细节的缺乏可能导致CWS设计出现以下情况：（1）与使用更完整网络模型时相比，对最坏情况污染事件的防护能力大大降低；（2）对污染事件相关后果的严重低估。尽管如此，使用简化网络模型开发的CWS对于那些影响不在注入位置附近局部化的污染物，可以有效减少后果。当网络模型存在不确定性时，平均情况设计可能产生与最坏情况设计类似的最坏情况性能。供水系统网络模型的改进有可能在CWS设计方面带来显著改进，以及对这些设计进行更现实的评估。虽然预计这种改进会带来CWS性能的提升，但此前尚未对CWS性能的预期提升进行量化。此处给出的结果应对负责CWS设计或实施的人员有用，特别是水务公司的管理人员和工程师，并鼓励开发改进的网络模型。
