When we think of dams, we often picture monumental feats of engineering that provide us with water, power, and protection from floods. They are silent, static giants on our landscapes. But like any man-made structure, they have a lifespan and require constant, vigilant care. When that maintenance is neglected, or when designs become outdated, these structures can transform from assets into catastrophic liabilities, holding back unimaginable destructive force. The integrity of a dam is a matter of public safety on a massive scale.
Across the globe, thousands of dams are classified as having high-hazard potential, meaning their failure would result in significant loss of life and property. Aging infrastructure, increased rainfall due to climate change, and insufficient oversight are pushing many of these structures to their limits. It’s a sobering reality that underscores the importance of ongoing inspection and investment. This list of 15 Dangerous Dams That Could Collapse at Any Moment highlights structures where concerns are particularly acute, serving as a reminder of the fragile balance we maintain with the water we rely on.
What Makes a Dam Unsafe?
Before we look at specific examples, it’s helpful to know what engineers look for when assessing a dam’s risk. The most common causes of failure aren’t always dramatic explosions, but often slower, more insidious processes. Piping, or internal erosion, occurs when water seeps through the dam or its foundation, carrying soil particles with it and creating hidden tunnels that can lead to a sudden collapse. Overtopping happens when a reservoir fills beyond capacity and water flows over the top of the dam, eroding the structure from the top down. Other risks include foundation defects, spillway inadequacy, and seismic instability. Many older dams were built using now-outdated methods and for climate patterns that no longer exist, making them vulnerable to today’s extreme weather events.
15 Dangerous Dams That Could Collapse at Any Moment
This list is compiled from various international reports and risk assessments. It includes dams with known structural issues, those in politically unstable regions where maintenance is challenging, and others facing unprecedented environmental pressures.
1. Mosul Dam, Iraq: Often called the “most dangerous dam in the world,” it was built on unstable gypsum bedrock that continuously dissolves, requiring constant grouting to fill the cavities. A failure here could unleash a wave on Mosul with little warning.
2. Oroville Dam, USA: In 2017, its main and emergency spillways failed, forcing the evacuation of nearly 200,000 people. While repairs have been made, the incident exposed the fragility of even modern, well-regarded infrastructure.
3. Kariba Dam, Zambia/Zimbabwe: The largest man-made reservoir in the world is threatened by a crumbling plunge pool at its base, which could undermine the dam’s foundation. A collapse would be catastrophic for communities downstream along the Zambezi River.
4. Whaley Bridge Toddbrook Reservoir, UK: A near-collapse in 2019 saw the dam’s auxiliary spillway liner tear away during heavy rains, requiring a massive emergency response to prevent a breach and highlighting the risks at many older British dams.
5. The Dams of the Tigris and Euphrates, Syria/Turkey: A series of dams in this region have been targets in ongoing conflicts, and the ISIS-occupied Tabqa Dam suffered from severe neglect, raising global concerns about its stability.
6. Mantaro-Tablachaca Dam, Peru: This dam shows significant signs of erosion and structural weakness. A collapse would devastate the Mantaro Valley, a key agricultural and population center.
7. C. J. Strike Dam, USA: Located in Idaho, this dam is considered at high risk due to seismic activity in the region. An earthquake could cause liquefaction of the soil in its foundation.
8. Dams in the Himalayas, India/Nepal: Many dams in this seismically active and ecologically fragile region are considered high-risk, facing threats from earthquakes, glacial lake outbursts, and landslides that could overtop them.
9. Llyn Brianne Dam, Wales: While currently safe, this dam has a unique and extreme “worst-case scenario” inundation map, showing the potential for catastrophic flooding in the event of a total failure.
10. Wivenhoe Dam, Australia: During the 2011 Queensland floods, this dam came perilously close to overtopping, which would have flooded the city of Brisbane far more severely than it already was.
11. Wolf Creek Dam, USA: This dam on the Cumberland River in Kentucky underwent a massive, multi-year rehabilitation project to address severe seepage and piping issues that put it at high risk of failure.
12. Dams in North Korea: Several dams built upstream from the South Korean border are a source of constant anxiety. A catastrophic failure, whether by accident or intent, could send a wall of water into the heavily populated Han River basin.
13. Herbert C. Bonner Bridge Area, USA: While not a dam itself, the threat of a bridge collapse into a major reservoir in North Carolina illustrated the interconnected risks to water infrastructure.
14. Matilija Dam, USA: This dam in California is a classic example of a structure made obsolete by siltation. It is now so filled with sediment that it’s functionally useless and poses a collapse risk, leading to plans for its removal.
15. Aging Dams Across the American Midwest: Thousands of small, often privately-owned dams from the early 20th century are reaching the end of their design life. Many are in poor condition and lack a clear owner responsible for their maintenance or removal.
What Can Be Done to Prevent Disaster?
The situation, while alarming, is not hopeless. Proactive measures can significantly reduce the risk. First and foremost is investment in infrastructure. Governments and utilities must prioritize funding for inspections, repairs, and, in some cases, the controlled decommissioning of obsolete dams. Improved monitoring technology, including satellite surveillance and networks of sensors, can provide early warnings of seepage or movement. For communities living downstream, it is crucial to know your risk and be aware of local emergency evacuation plans. Public awareness and pressure can often be the catalyst that pushes authorities to act before a warning becomes a catastrophe.
Ultimately, the story of these dangerous dams is a cautionary tale about the long-term responsibility that comes with controlling natural forces. They are not permanent fixtures but dynamic structures that demand our respect and continuous care. By learning from past near-misses and investing in the future, we can work to ensure these essential structures remain safe guardians, not sleeping threats.