Don't Go With the Flow! Identifying and Mitigating Hydraulic Hazards at Dams

摘要

Between 2015 and 2016 there were more than 100 documented drownings at dams in the United States, and many more near misses or serious incidents that almost led to tragedy. The increasing number of incidents from hydraulic hazards at dams is a disturbing trend. According to Dr. Bruce Tschantz, professor emeritus at the University of Tennessee and long-time researcher involved in monitoring incidents at dams, there have been more than nine times as many fatalities from hydraulic hazards at dams than there have been from dam failures over the past 35 years. Examination of these incidents shows that the vast majority were the result of transient hydraulic conditions that were not identified or addressed by the dam owner. In other words, the hazardous hydraulic condition did not normally occur at the dam, but occurred unexpectedly as a result of sudden operational or hydrologic circumstances. The purpose of this paper is to provide descriptions of the seven primary hydraulic hazards at dams that have resulted in loss of life along with actual incident examples. A brief discussion of effective strategies to mitigate each hydraulic hazard is also provided. When performing a hydraulic assessment at a dam site, considerations should be given to simulating flows which represent a reasonable worst-case scenario where the public or maintenance staff have interaction at the site. The intent is to define the extent of hazardous water areas created specifically by the operation of the facility in the immediate vicinity of the dam, in the reservoir, and in downstream reaches of the river. The information included in this paper is intended to help dam owners, regulators and designers become aware of the potential hydraulic hazards at dams and develop successful mitigation and risk reduction strategies to address each hazard.