Dam breaks: from alarmist views to technical reality

Abstract

The concerns over the risk of dam failures have intensified following the two most severe disasters of this kind in Brazil: in Mariana/MG on November 5, 2015, and in Brumadinho/MG on January 25, 2019. These accidents, associated with large-scale mining ventures, resulted in the loss of lives, severe environmental damage, and economic and urban infrastructure losses. Following these failures, reports on dam breaks began to receive more media attention, feeding the public's perception of risk. However, the majority of cases involve smaller dams, as demonstrated by accidents in the municipalities of Sairé/PE on June 15, 2020, Irupi/ES on January 24, 2020, and Pedro Alexandre/BA on July 11, 2019. This paper illustrates how these events were portrayed in the media and proposes a technical approach to assess the contribution of dam breaks to the disasters that occurred. The findings suggest that simplified modeling of the rainfall-runoff process and flow routing from the dam break to cities provides an indication of the dam's actual contribution to the overall impact. In the studied dam breaks, it is estimated that they contributed to up to a 36% increase in the magnitude of the natural flooding. The results suggest that media coverage sometimes inappropriately blames dams for the damage caused by floods. A more balanced and informative approach in media coverage is suggested, involving participation in disaster prevention and preparedness actions, support for mitigation actions during events, and assistance in post-disaster data recording.