CURRENT AFFAIRS FOR UPSC IAS

The National Dam Safety Authority (NDSA) has formed a six-member panel to examine the three barrages of Kaleshwaram Lift Irrigation Project (KLIP)- Annaram, Medigadda and Sundilla barrages. The committee would investigate the reason behind the sinking of Medigadda barrage pillars and any potential damage in the two upstream barrages, Annaram and Sundilla.

1: Dimension: Indian dams, more vulnerable to deterioration

Over 75% of the country’s dams are over 25 years old and about 164 dams are more than 100 years old.  With the increasing number of dams becoming older and older, dam failures are more expected now.

• Earthen-built structure:India's dams are more vulnerable to deterioration because a large proportion of them are earthen--built by compacting successive layers of earth, and not concrete--and are hence more prone to ageing.
• Concentrated rainfall:Secondly, the country gets concentrated rainfall every year for a designated time period as opposed to distributed rainfall, which contributes to the dams' vulnerability. 
• Siltation:Siltation leads to a reduction in the storage capacity of the dams. 
• Flood disasters in downstream areas:The downstream areas are often exposed to flood disasters even without a dam breach, in which water creates an opening in a dam due to rapid erosion of a section of the embankment. 

2: Dimension: Older dams, a threat

Ageing dams could be associated with a number of deleterious and long-term consequences:

• Safety risks:Older dams pose greater safety risks, cost higher in terms of maintenance and have declining functionality due to sedimentation.
• Loss of life and property:Unsafe dams are a hazard and dam break may cause disasters, leading to huge loss of life and property.
• Impact on Food Security:When soil replaces the water in reservoirs, supply gets choked. Consequently, the cropped area may begin receiving less and less water as time progresses. As a result, the net sown water area either shrinks in size or depends on rains and groundwater (which ultimately gets over-exploited).
• Increased Flooding:The flawed siltation rates reinforce the argument that the designed flood cushion within several reservoirs across many river basins may have already depleted substantially, due to which floods have become more frequent downstream of dams.