Page - 168 - in Book of Full Papers - Symposium Hydro Engineering

was not organized as a set of integrated and regularly-updated national guidelines which could readily be found and navigated by engineers and others involved in dam safety.  Internal relationships within DWR were strained for decades prior to the incident, especially between DWR’s Division of Engineering and its Division of Operations and Maintenance. While this strain was not atypical among large dam owners in the United States, it had a negative impact on DWR’s decision- making and deployment of technical expertise related to its dams, both during the half-century prior to the incident, as well as during the incident response. 6. LESSONS TO BE LEARNED In the opinion of the IFT, the following are some of the general lessons to be learned by the broader dam engineering and safety community:  In order to ensure the safe management of water retention and conveyance structures, dam owners must develop and maintain mature dam safety management programs which are based on a strong “top-down” dam safety culture. There should be one executive specifically charged with the overall responsibility for dam safety, and this executive should be fully aware of dam safety concerns and prioritizations through direct and regular reporting from a designated dam safety professional, to ensure that “the balance is right” in terms of the organization’s priorities.  More frequent physical inspections, primarily based on visual observation, are not always sufficient to properly identify problems, determine risks, and manage dam safety. Some problems can only be identified through records review and/or subsurface investigations or non-destructive testing.  Periodic comprehensive reviews of original design and construction records and subsequent performance reports are necessary, especially for large and high-hazard dams and their appurtenances. These reviews should be based on complete records and need to be more in-depth than periodic general reviews, such as the current FERC-mandated five-year reviews.  Appurtenant structures associated with dams, such as spillways, outlet works, power plants, etc., must be given attention by qualified individuals. This attention should be commensurate with the risks that the facilities pose to the public, the environment, and dam owners, including the risks associated with events which may not result in uncontrolled release of reservoirs, but may still result in reduced control of the reservoir or otherwise be highly consequential.  Shortcomings of the current Potential Failure Mode Analysis (PFMA) processes in dealing with component failures and complex systems must be recognized and addressed. A critical review of these processes in dam safety practice is warranted, comparing their strengths and weaknesses with risk assessment processes used in other industries worldwide and by other Federal 168