Gravity Dams – Advantages & Disadvantages

The rigid dam which is constructed either with stone or brick masonry or mass concrete, is called a solid gravity dam. As solid gravity dams resist the overturning moments due to all external forces (such as water pressure, slit pressure etc) by its own weight only, these are known as solid gravity dams. Such a dam is very strong and rigid and requires least maintenance.

Advantages of Gravity Dams

The gravity dams possess the following advantages:

1. These are more suitable in steep valleys where earth dams may tend to slip.
2. In these dams, surplus water may be discharged through the sluices provided in the body of the dam or over spillway built in a suitable location of the dam.
3. Such dams, when built on strong foundation, may be built upto a maximum practical height.
4. A gravity dam does not fail suddenly. Their failure can be predicted well in advance so that loss of life and property may be saved.
5. Their cost of maintenance is least and benefit of cost ratio is highest.
6. These are found more advantageous in the regions of high rainfall and heavy snowfalls.
7. In these dams, sedimentation of the reservoir, may be cleared through deep set sluices.

Disadvantages of Gravity Dams

The following are the disadvantages of a gravity dam:

1. Their initial cost of construction is high.
2. Their construction period is comparatively more.
3. These require a strong and sound foundation.
4. Dams once constructed, cannot be raised further.
5. For the supervision of concrete dams, skilled labor is required.