Description & Background

“While relatively uncommon, dam failures continue to occur, sometimes with catastrophic consequences. Investigations of such failures have typically focused on the physical factors involved, which is understandable given the technical orientation and background of engineers. However, the creation and management of dams always involves interacting physical and human factors, and this broader dynamic system is responsible for both safety and failure of dams.

“Moreover, because physical processes are assumed to deterministically follow physical laws, with no possibility of physical ‘mistakes’, we can assert that failure of dams  is ultimately always due to human factors. Traditionally, it has commonly been assumed that safety is the default for dams and other systems, and that failures are therefore due to atypical physical factors and/or egregious ‘human errors’. However, research over the past few decades suggests that this paradigm should be reversed, with the new default view being that a natural tendency is for systems to move towards disorder and failure (in line with the concept of increasing entropy), and with continual human effort thus being needed to maintain order and prevent failure.

"Moreover, because physical processes are assumed to deterministically follow physical laws, with no possibility of physical 'mistakes', we can assert that failure of dams is ultimately always due to human factors."

“This paradigm reversal leads to the question of why human efforts do sometimes fall short, allowing failure to occur. The most fundamental answer is that we humans, both individually and in groups, are highly fallible and limited. For example, our data and knowledge are incomplete, our models are unavoidably inaccurate to various degrees, our cognitive ability is finite (we have ‘bounded rationality’), we take heuristic shortcuts and settle for ‘satisficing’ rather than optimizing, we’re subject to a host of cognitive biases at individual and group levels, we forget things, and our intuition can be highly unreliable when dealing with unprecedented situations.

“As if all of this weren’t challenging enough, the norm is that we’re continually faced with finding appropriate tradeoffs between conflicting goals stemming from competing social, economic, political, professional, personal, and other pressures. For example, on one hand, we’re tasked with responsibility for safety, but on the other hand we face pressures to increase system efficiency, productivity, profitability, compliance with deadlines, competitiveness, etc.

“Studies in a variety of domains within and outside engineering have shown that major failures are usually preceded by a series of steps involving physical and human factors interacting over a relatively long period of time, often years or even decades. Dams are no exception to this general pattern. Each of these steps may be small, often small enough to go undetected or not elicit a response if detected (e.g., ‘minor’ seepage, erosion, or cracking), and with no step or factor sufficient by itself to produce failure. However, when enough factors accumulate and ‘line up’ appropriately, they can become jointly sufficient to produce observable incidents and failures.

“Assessment of the daunting challenges we face due to our limitations in dealing with complexity, uncertainty, and conflicting goals could be cause for pessimism. For example, ‘normal accident’ theory suggests that a substantial rate of major failures is inevitable for many kinds of complex systems. Yet, the empirical fact is that modern dam engineering has had a successful track record overall – in the US, there have been hundreds of dam failures among tens of thousands of dams – and the same applies in many other domains involving complex systems, including systems dealing with rapidly evolving adverse situations.

View from downstream of rapid release of the Teton Reservoir after failure during the first filling.  The first filling of the reservoir lacked proper planning and caused water levels to reach design elevations prior to the construction of the auxiliary spillway and outlet works.

Teton Dam reservoir is released after the dam breached in 1976. The dam failed as a result of failure to thoroughly investigate and account for defects in the abutment and foundation it was built on (Courtesy of A.G. Sylvester).

“Even in these challenging environments, organizations have been identified which have a long track record of success, thus becoming known as ‘high-reliability organizations’ (HROs). In general, HROs reduce rates of substantial failures by being preoccupied with avoiding failure. HROs are mindful, skeptical, cautious, and humble, actively searching for and promptly addressing indicators of trouble before problems grow too large, and making good use of all the information, expertise, and tools available to them to do so. Even with such traits, dam failures may not be entirely preventable, especially if we want continued innovation and progress, but we can still reasonably expect that shifting towards HRO traits – in our personal practices, our organizations, and the broader dam safety community – will significantly help reduce occurrence of failures."¹

(1) Alvi, I.A. Human Factors in Dam Failures. ASDSO Annual Conference.




Case Studies

Austin (Bayless) Dam (Pennsylvania, 1911)

Austin Dam (also known as Bayless Dam) was constructed between May and November of 1909 just outside Austin, Pennsylvania, a town of approximately 2,500 people in Potter County.

Learn More

Lake Delhi Dam (Iowa, 2010)

Lake Delhi Dam was originally constructed by the Interstate Power Company between 1922 and 1929 for hydroelectric power generation. The dam is located in Iowa approximately 1.4 miles south of Delhi on the Maquoketa River and impounds the nine-mile-long Lake Delhi. Reaching a maximum height...

Learn More

Laurel Run Dam (Pennsylvania, 1977)

Constructed between 1915 and 1918, Laurel Run Dam was a rockfill dam erected across Laurel Run near Johnstown, Pennsylvania. It was built to replace a smaller dam in order to provide water for drinking and industrial needs...

Learn More

Malpasset Dam (France, 1959)

Malpasset Dam was a concrete arch dam located on the Riveria in the Cannes District near Fréjus, in Southern France. Exhibiting curvature in both the plan and section directions, the double-curvature arch structure spanned the Reyran River. At the time of completion in 1954, it was reported...

Learn More

South Fork Dam (Pennsylvania, 1889)

South Fork Dam was an earth- and rock-fill dam located about 8 miles east of Johnstown, PA. Originally constructed in 1852, the dam’s primary purpose was to provide a source of water for a division of the Pennsylvania Canal. The dam was approximately 72 feet high...

Learn More

St. Francis Dam (California, 1928)

Located approximately forty miles northwest of Los Angeles, California, St. Francis Dam was a curved concrete gravity dam constructed between 1924 and 1926 in order to provide a storage reservoir for the Los Angeles Aqueduct system...

Learn More

Aerial view of original Taum Sauk Reservoir after failure showing the 656 ft breach.

Taum Sauk Dam (Missouri, 2005)

Taum Sauk Pump Storage Plant was constructed by United Electric in Reynolds County, Missouri between 1960 and 1962 to provide a means of hydroelectric power generation during peak demand periods. The plant consisted of an Upper Reservoir situated atop Proffit Mountain...

Learn More

Teton Dam (Idaho, 1976)

Teton Dam was located in southeastern Idaho about 15 miles from Rexburg in the valley of the Teton River. The dam and its reservoir were the principal elements of the Teton Basin Project designed by the Bureau of Reclamation to control flooding as well as provide a source of...

Learn More

Additional Case Studies (Not Yet Developed)

  1. Vajont Dam (Italy, 1963)
  2. Ka Loko Dam (Hawaii, 2006)
  3. Big Bay Dam (Mississippi, 2004)

Best Practices

Other Resources

Human Factors in Dam Failures

Author: I.A. Alvi

Technical paper published by Association of State Dam Safety Officials

2004 Failure of Big Bay Dam

Author: I.A. Alvi

Presentation from ASCE Geo-Institute

Human Factors in Dam Failure & Safety

Author: I.A. Alvi

Presentation given at ASDSO Northeast Regional Conference

Failure of Sella Zerbino Secondary Dam in Molare, Italy

Author: I.A. Alvi

Technical paper published by Association of State Dam Safety Officials