Modeling a Hydraulic Response to a Contamination Event

In responding to contamination incidents that may occur in a water distribution network, a variety of actions (e.g., public notification and operational changes) can be pursued. A relatively common and effective operational response option utilized by water utilities to address water quality concerns is flushing. The effectiveness of flushing alternatives can be evaluated by modeling the water distribution system dynamics. Two approaches to modeling hydrant flushing as a hydraulic response are examined in this paper: a fixed flushing rate and flow emitters. In addition, the effects of knowing the source location and the expected contamination spread are explored. The paper generally demonstrates that the effectiveness of flushing depends on the accuracy with which the initial contaminant plume location is known. In modeling flushing as a response, use of flow emitters instead of fixed flow to model hydrant discharge should provide a more realistic description of system response to flushing.