Why Dams Fail
A "dam" is an artificial barrier that has the ability to impound water, wastewater, or any liquid-borne material for the purpose of storage or control of water (different types of dams). Dams can fail for one or a combination of the following reasons:
- Overtopping caused by floods that exceed the capacity of the dam.
- Deliberate acts of sabotage.
- Structural failure of materials used in dam construction.
- Movement and/or failure of the foundation supporting the dam.
- Settlement and cracking of concrete or embankment dams.
- Piping and internal erosion of soil in embankment dams.
- Inadequate maintenance and upkeep.
Dam Failures in the United States
A series of dam failures in the 1970's caused the Nation to focus on inspecting and regulating dams.
- On February 26, 1972, a tailings dam owned by the Buffalo Mining Company in Buffalo Creek, West Virginia failed. In a matter of minutes, 125 people were killed, 1,100 people were injured, and over 3,000 were left homeless.
- On June 5, 1976, Teton Dam, a 123-meter high dam on the Teton River in Idaho, failed, causing $1 billion in damage and leaving 11 dead. Over 4,000 homes and over 4,000 farm buildings were destroyed as a result of the Teton Dam failure.
- In November 1977, Kelly Barnes Dam in Georgia failed, killing 39 people, most of them college students.
The Johnstown Flood
At 4:07 p.m. on the afternoon of May 31, 1889, the residents of Johnstown, Pennsylvania heard a low rumble that grew to a "roar like thunder." After a night of heavy rains, the South Fork Dam had failed, sending tons of water crashing down the narrow valley. Boiling with huge chunks of debris, the wall of flood water grew at times to 60 feet high, tearing downhill at 40 miles per hour and leveling everything in its path.
Thousands desperately tried to escape the wave. Those caught by the wave found themselves swept up in a torrent of oily, muddy water, surrounded by tons of grinding debris, which crushed some, provided rafts for others. Many became helplessly entangled in miles of barbed wire from a destroyed wire works.
Although it was over in 10 minutes, for some the worst was yet to come. Darkness fell, thousands were huddled in attics, others were floating on the debris, while many more had been swept downstream to the old Stone Bridge at the junction of the rivers. Piled up against the arches, much of the debris caught fire, entrapping forever 80 people who had survived the initial flood wave.
Last Modified: Monday, 17-Apr-2006 12:21:42 EDT