Full Description

A Contaminant Warning System (CWS) seeks to quickly detect contamination within awater distribution system so that action can be taken to minimize consequences. The goal of the U.S. Environmental Protection Agency's (USEPA's)Water Security Initiative (WSi) (formerly WaterSentinel) has been to design, deploy, and evaluate amodel CWS. Deployment of the CWS at the first pilot utility in Cincinnati, Ohio occurred in Spring of2007.Water quality monitoring is one component of the CWS pilot, and inclusion of this component is basedon a growing body of data that suggests anomalies in standard water quality (WQ) parameters mayprovide an indication of contamination. Deviations in one or more WQ parameters from an establishedbase-state can provide early warning of contamination, but only if the anomalies can be picked out ofnoisy background data. To facilitate this, event detection systems (EDS) are used which rely uponalgorithms of various degrees of sophistication to detect anomalous conditions. While such tools havebeen used in other applications, there is little experience applying them to the detection of anomalies indrinking water systems.The WSi-CWS pilot provides a unique opportunity to collect data necessary for a rigorous evaluation ofEDS tools, including data from 17 WQ monitoring stations, each with a suite of 7 WQ sensors. So far, 2EDS tools have been implemented at the pilot utility, and evaluation of these tools continues with theobjectives of improving understanding of EDS tool capabilities, quantifying the performance of EDStools, and investigating the influence of factors such as site WQ variability on EDS tool performance.In the study described in this paper, data from Greater Cincinnati Water Works was used to evaluate two EDS tools, Canary[Hart, et al, 2007] and Hsub2/subO Sentinel [FTI, 2006]. This paper provides some results from theevaluation and discusses some lessons learned from implementing the evaluation. All examples andfigures used in this document were taken directly from data and results from the 2007 evaluation.However, location names and details about events are removed to maintain security and confidentiality. Includes 3 references, tables, figures.

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Edition: Vol. - No. Published: 04/01/2008 Number of Pages: 12 File Size: 1 file , 830 KB