Introduction

Dam is an artificial structure to holds back the flow of water. The purposes are hydro electric power generation, safe river navigation, and agricultural irrigation, water supplies and flood reduction. In India as there are 5264 large dams and 437 under construction. A majority of existing dams are aged more than 50 years. About 36 dam failures are occurred so far. In 1979 an earthen dam was failed in Gujarath (Machchu2). That was due to heavy rain fall and flood, disintegration of soil.

Reason for Dam Failure

a)      Over topping. It occurs when the level of water in the dam is exceeded more than its capacity or height of the dam. This can be caused by an inadequate spillway, Or settlement of the dam crest. Due to flash flood water rises rapidly without warning. This is the case of earthen dam in Marvi dam failure in Gujarat. This happened in 1979.

b)     Piping and Seepage. Embankment dams which are semi-permeable can be compromised when too much water leaks through the structure. If is internal erosion the dam may fail. This is called piping.

c)      Foundation defects. Weight of a dam has an impact on soil beneath it, if it is settled unequally it may fail due to leakage through the cracks. Concrete dams are failed due to defects in foundation

Inadequate maintenance, substandard construction materials, spillway design error, geological instability, extreme inflow, earthquakes, human, computer or design error

Conclusion 

Suggestions, planning for natural disaster management related to water-based disasters

Remedial measures for the dams which have completed their stipulated life time.

Constructing small dams should get priority; construction of large dams should be avoided

Constant and vigilant auditing of dam safety.

Use of latest technology for forecasting and early warning system for floods

Dams should not construct in earthquake prone zone