Defense in depth

Background:

This defense in depth discussion scenario is an intentional cybersecurity attack on the water utility’s SCADA system. It occurs during the fall after a dry summer in Fringe City. The water utility’s Information Technology (IT) person did not receive an expected pay raise and decides to reprogram the SCADA system to shut off the high-lift pumps. The operator’s familiarity with the SCADA system allows him to reprogram the alarms that typically notify operators of a high-lift pump failure. In addition, he prevents access to the SCADA system by others. A wildfire breaks out on the outskirts of the city. Please identify what type(s) of new countermeasures should have been implemented to prevent this cyber attack from occurring.

Question:

Start a discussion thread and discuss what type(s) of new countermeasures should have been implemented to prevent the cyber attack described above from occurring. Be specific in recommending countermeasures for this scenario.