Beware the Black Swans

By definition, Black Swans are critical, and rare occurrences. However, a platform of critical failures tends to underlie such events. Applying the principle of root cause analysis to a typical catastrophic event illustrates several key elements that can undermine efforts to plan for and prevent failures.

Compared to other types of infrastructure, water distribution systems are relatively vulnerable to disruption, either in the form of a deliberate attack or accidental contamination.

The possibility of water supply contamination increases greatly in communities that have no treatment facility. For example, about 650 residents of Gideon, Missouri, became sick in 1993, as a result of contamination of the untreated water supply caused by birds and bats in the standpipe reservoir. The lack of disinfection and poor system and standpipe maintenance contributed to the contamination...

Disruptions involving distribution systems also are possible. After undergoing disinfection, water in the mains seldom receives additional treatment. The lead contamination incident in Flint, Michigan, offers a case of what can happen to water supplies on their way to consumers. In 2014, municipal officials decided to change their water supply treatment system, switching to a more corrosive source...

Although less susceptible to deliberate attack, sewer systems and water resource recovery facilities (WRRFs) are no strangers to disruption. Hazardous materials or other contaminants that are spilled onto the soil can enter leaky sewers as a result of groundwater infiltration. Similarly, chemical accidents, gasoline spills, and firefighting activities often result in hazardous materials entering...

Black Swan events resulting from the failure of critical equipment can be prevented by keeping an extra set of the equipment on standby. However, purchasing and storing duplicate equipment can be costly. Given the current focus on “just-in-time” delivery of products, coupled with the financial pressures facing many utilities, the expense of maintaining equipment on standby may be...

Weather-related Black Swans can come in many forms, including snow, ice, rainfall, tornadoes, hurricanes, and even wind and drought. To a certain extent, some of these events can be forecast by meteorologists. However, they are the first to admit that their forecasting record is far from perfect.

A true Black Swan event — something so far beyond what is considered credible that no one plans for it — can occur. However, far more common are unfortunate events that could have been prevented by existing knowledge. In fact, extensive information often is available, but unknown, or unrecognized, by those who could have used it to avert a tragedy.