In March of 2008, salmonella infiltrated the public water system of the town of Alamosa in southern Colorado. The resulting disease outbreak infected an estimated 1,300 people, over 14% of the town’s population. Of those infected, one person died and 20 more were hospitalized. The Alamosa outbreak was the second-largest water-borne illness outbreak in the United States that decade.
Though teams worked as quickly as they could to sanitize the water system, the people of Alamosa were unable to use the water for weeks. While some people were able to get water from friends who had wells or were otherwise not connected to the system, most had no options. Without undertaking the major operation to deliver and distribute bottled water for drinking and cooking, it would have been extremely difficult for the town to weather the outbreak.
Before I became a designer, I spent five years as a public health emergency planner. I planned for and responded to disease outbreaks, tornados, and pandemics. When the Alamosa outbreak occurred, I was part of a nine-person team dispatched to help manage the first week of the incident. What played out in Alamosa was not unique. The story is a microcosm of a larger issue that carries through much of what we humans create.
When we design systems and products, we do it based on a set of defined scenarios, or use cases. These scenarios help us define how the thing we’re designing will be used, so we can determine the required features, interactions, materials, capacity, and so on. The scope of those scenarios is a key determinant of how tolerant our design will be to changes in the environment and user behavior.
The water system in Alamosa was built on a deep well aquifer, a water source thought to be protected from contamination because of its depth. The system was designed to operate as a closed system devoid of harmful pathogens, and in 1974 Alamosa was granted a waiver to not include chlorination as a disinfecting step in the water treatment process. When the scenario changed and the closed system was breached, the design lacked the resilience to handle it; a chlorination step would…