Source Identification in Water Distribution Systems Using the Adjoint Method with Non-Ideal Sensors and Non-Detect Measurements

It is important to identify the source of contamination in a drinking water distribution system to discontinue the event and determine ways to prevent future contamination from entering the system. Previous work has demonstrated the effectiveness of an adjoint method using contaminant concentration measurements from system sensors to probabilistically determine the source of contamination in a drinking water system. The method can be applied in systems with either steady-state or transient hydraulics. The method uses publicly available software (EPANET) coupled with a particle backtracking model (BTX) and a conditioning method to probabilistically identify the contamination source and release time. Prior work assumed perfect sensors capable of measuring the exact concentration of contamination. In this work the method is enhanced to account for measurements from more realistic, nonideal sensors that identify the range of contamination at the sensor (e.g., high, medium, low), rather than the precise concentration. In addition, the method is augmented to use nondetectable measurements, i.e., sensor measurements for which the measured contamination is below the limit of detection.