A rigid dam that is built of either stone or brick masonry or massive concrete is called a concrete gravity dam. Since solid gravity dams resist overturning moments due to all external forces (such as water pressure, kiln pressure etc.) only due to their own weight, they are known as solid gravity dams. Such a dam is very strong and rigid and requires minimal maintenance.
Benefits of Gravity Dam
Gravity dams have the following advantages:
- These are more suitable in steep valleys where earthen dams can slip.
- In these dams, the excess water may be released through sluices provided in the body of the dam or over spillway constructed at the appropriate site of the dam.
- Such dams can be built to the maximum practical height when built on a strong foundation.
- Gravitational dams do not break suddenly. Their failure can be foreseen in advance so as to avoid loss of life and property.
- They have lowest maintenance cost and highest benefit to cost ratio.
- They are found more beneficial in areas with high rainfall and heavy snowfall.
- In these dams, sedimentation of the reservoir can be cleared through deep set sluices.
Disadvantages of Gravity Dam
Following are the disadvantages of gravity dams:
- The initial cost of their manufacture is high.
- Their construction time is comparatively longer.
- For this a strong and strong foundation is needed.
- Once a dam is built, it cannot be extended.
- Maintenance of concrete dams requires skilled labor.