Patterns in Potential Impacts Associated with Contamination Events in Water Distribution Systems

Assessing potential impacts associated with contamination events in water distribution systems : a sensitivity analysis.

“…However, use of such an approach has excessive computational requirements. Variability in impacts for different simulations with the model is relatively small; the relative standard error in impacts obtained for multiple simulations for Network 4 is about 2% or less (Davis and Janke 2010). Consequently, a single simulation with the model provides results that are acceptable for this study.…”

“…Although definite patterns exist in responses that extend across networks, as is shown here and in Davis and Janke (2010), substantial inter-network variablility limits the current ability to generalize quantitative results from a limited sample to new applications. Individual water distribution systems should be treated as unique systems with some similarities in the magnitudes and patterns of impacts during contamination events.…”

“…We found that the results for impacts versus dose level (as illustrated by Figures 3.1, 3.2, and 3.3) obtained using all the nodes did not differ significantly from those obtained using only NZD nodes. (A quantitative comparison is provided in the supplemental material for Davis and Janke (2010). )…”

“…No study has examined the sensitivity of potential exposures to contaminants to major factors used in the simulation considering the actual exposure process and systems of significant size (i.e., thousands of nodes). Separately, we have analyzed potential exposures associated with contamination events using 12 models of actual water systems serving populations ranging from about 10 4 to over 10 6 persons, while considering the exposure process (Davis and Janke 2010). Using these same models and extending that work, this report examines the sensitivity of potential exposures to (1) a number of major factors that define the nature of a contamination event and (2) assumptions that are used in assessing exposure to the contaminant.…”

Protecting Water Supply Critical Infrastructure: An Overview

“…The ability to consider the influence of multispecies interactions on estimating consequences was provided with the update of Threat Ensemble Vulnerability Assessment Sensor Placement Optimization Tool (TEVA-SPOT) to include the EPANET-MSX capability in 2011 (U.S. EPA 2013). Davis and Janke (2011) and Davis et al (2010) showed that consequences are dependent on the contaminant, where it is released or injected into the distribution system, and the quantity released. The work of Davis and Janke (2011) and Davis et al (2010) supported the earlier findings of Allman and Carlson (2005).…”