The failure of the dam may be caused either due to bad workmanship or due to faulty design or due the occurrence of unanticipated floods. Luckily, these disasters have been comparatively rare in this century. Dams used to give away in olden times, but due to engineering advancement in modern times their failure has been considerably reduced taking care of design, keeping in view the various forces which are going to face, proper and rational design, good supervision and constant vigil and watch during maintenance periods ensures their safety. The Boulder Dam on Colorado River in U.S.A can not fail in one attempt, how furiously these river may try to move their foundations. But sometimes we have to pay for this confidence with tragedies.
|The "Reyran" river flowing well few hundred meters below the dam.|
In 1954 the Malpasset Dam, a 200 feet high arch dam on the Reyran river, was completed. This dam failed in December 1956 causing 421 persons to die in floods. This was due to failure of foundation.
|Vega de Tera Dam|
A very confident dam called Vega de Tera Dam in Spain failed in January 1959. The town Rivaldelago was fattened. Telephone poles were snapped like matchsticks. With in moments, 123 villages were drowned. Several hundred luckier ones were saved, but were rendered homeless. This time this dam was not built strong enough to bear the full weight of its intended reservoir. Heavy rains wrecked it.
|Vega de Tera Dam|
Sometimes excessive and unanticipated earthquakes may result failure to a dam. In 1968 earthquake, the Koyna Dam in india was at the verge of failure. The engineers saved that dam by toiling hard day and neight.
|Shakidor Dam Brust|
The other failures are South Fork Dam due to spillway design error, Shakidor Dam due to extreme rainfall and Dale Dike reservoir, Taum Sauk pumped storage plant due to human, computer or design error.