AWWA WSC67780

Many utilities maintain hydraulic and water quality models for operational and planning purposes; however continuous, real-time modeling of a system to inform response actions during a crisis is not viable, especially for large, complex networks. To date, there has been no guidance developed to help determine where best to collect samples in response to a system-wide contamination threat. In response, the U.S. Environmental Protection Agency and the Greater Cincinnati Water Works collaborated to develop a Contaminant Transport Field Guide which can assist utility emergency response personnel in creating a sampling plan during the initial stages of such a threat. This work is based on a simplified representation of a distribution system that was evaluated using the utility's existing hydraulic model to predict contamination transport. This was accomplished by dividing the distribution system into defined pressure, or "pito" zones, tracking the spread of contamination from zone to zone under different demand conditions over several time intervals, and then presenting the impacts in the form of a matrix. Further, each zone was then investigated to identify sampling locations that were representative of the water entering and, where applicable, leaving that zone. The evaluation and presentation of the model in this fashion has several notable impacts for consequence management. This paper details the development, uses and benefits of this innovative Field Guide, and the model-based matrix it is built from. Includes figures.