Probabilistic design of a riverine early warning source water monitoring system

Source water protection involves safeguarding water supplies from contamination and depletion. Despite best efforts, spills cannot always be prevented from entering a source water body. However, many spills can be prevented from entering a drinking water treatment plant if an early warning source water monitoring station is used. These stations provide downstream water utilities with advanced notification of spills so the utilities have time to implement their responses. This paper addresses the design of an early warning monitoring station for a riverine source of drinking water. Riverine water supplies face many threats related to accidental spills, which are inherently uncertain in nature. Therefore, designing a monitoring station for the detection of these events requires a probabilistic modelling approach. The design objectives include maximizing the probabilities of detection and of having a threshold amount of warning time. The methodology is applied to a water supply intake on the Grand River in southern Ontario.