Enhancing the reliability of a contamination detection sensors network in water distribution systems during a cyber-attack

A water distribution system (WDS) plays a critical role in the delivery of clean healthy water at required water quantities and qualities. As a distributed system it is exposed to different kinds of attacks, both physical and cyber, as well as accidental contamination events. In the past years, several events occurred in which contaminants polluted the drinking water. Most of these cases were accidental but there had been also criminal acts involved. Placing water quality monitoring sensors in designated locations throughout the water distribution system is considered as one of the most effective protection methods for coping with deliberate or occasional water quality contamination intrusions. Sensors, which comprise the water quality monitoring system, are communicating over a cyberinfrastructure layer (via radio, cellular, satellite, or wire), and as such are exposed to cyber-physical attacks. Traditionally, sensor placement methodologies included objective functions such as the polluted volume of water consumed or the time for the first detection of possible pollution. However, so far, water quality sensor placement algorithms and tools, have not considered cases where the sensor network itself is attacked or malfunctions in a way that part of its components, are deactivated. In this study, we propose to develop and demonstrate a methodology for evaluating the impact of a cyber-physical attack on a sensor network compromising part of its sensor's functionality. Our proof-of-concept, using a simple network and a simple attack scenario, has revealed that there is potential in analyzing the performance of sensor networks under attacks, and can provide valuable information for decision-makers in the water utilities and regulators.