Seite - 167 - in Book of Full Papers - Symposium Hydro Engineering

The IFT identified a multifaceted array of human factors, additional to those specific to the spillways, which contributed to the incident:  DWR was significantly overconfident and complacent regarding the integrity of its SWP civil infrastructure. This was not atypical among large dam owners in the United States, and was influenced by a belief that the SWP was designed by the “best of the best” and a lack of prior major incidents at dams owned by DWR. In addition, less attention was generally paid in the United States dam engineering and safety industry to spillways as compared to main dams, which contributed to complacency in managing spillway risks.  DWR was largely in a mode to react to problems with its civil infrastructure as they arose in the short term, rather than taking preemptive actions to proactively prevent problems. This approach was not atypical among large dam owners in the United States, and was influenced by external and internal pressures to control costs, while focusing on the needs of operations, water delivery, and hydroelectric power production.  The dam safety culture and program within DWR, although maturing rapidly and on the right path, was still relatively immature at the time of the incident, and was about in the “middle of the pack” as compared to other large dam owners in the United States. DWR had been too reliant on regulators and regulatory processes, including associated periodic inspections and reviews, with the assistance of its numerous consultants. In addition, there was no clear identification of a senior executive within DWR who was responsible for dam safety, and the Chief Dam Safety Engineer, while highly dedicated, was not in a position to best influence either investment or emergency decisions related to dam safety.  DWR’s information management system was not sufficient to efficiently and effectively handle the very large amount of accumulated information associated with its dams, and thereby ensure that the right information was in the right hands at the right times. This factor was particularly impactful when judgments regarding the quality of the rock at the spillways were being made.  DWR’s two regulators, FERC and DSOD, like other dam safety regulators in the United States, faced numerous challenges and limitations with respect to maintaining sufficient qualified technical staff to meet workloads, addressing uncertainties when trying to balance the costs imposed on dam owners versus the risks imposed on the public and the environment, and gaining compliance from dam owners with regulatory requirements and expectations.  DWR, and to some extent its regulators and consultants, also lacked necessary technical expertise in some areas of dam engineering and safety, with expertise generally tending to be stronger for dams than for appurtenant structures. Influencing factors for DWR included excessive organizational pride, organizational insularity, emphasis on electrical and mechanical aspects as compared to civil engineering and geologic aspects, and cost pressures and bureaucratic constraints related to technical staffing. An influencing factor for the United States dam safety industry was that the available technical literature 167