CWC to study sediment deposition in reservoirs

Vijay Mohan

Tribune News Service

Chandigarh, October 24

The Central Water Commission (CWC) will undertake sedimentation studies at major reservoirs across the country to assess the change in their storage capacity as well as to determine their life expectancy.

According to sources, a list of 32 reservoirs in different states, including those situated in North India, has been drawn up where the level of sedimentation and its effects will be examined. Funding for the project has been received from the World Bank.

Sedimentation is the process where loose soil, silt, rock and debris flow in with the water that enters reservoirs and deposit on the bed. The level of sedimentation depends upon the terrain, geology and environmental conditions of the area through which the feeding rivers and tributaries flow. Sedimentation, according to sources, is unavoidable and over a period of time, reduces the storage capacity of the reservoirs. This has detrimental effects on the dam’s intended benefits such are provision of water for drinking and irrigation, flood control and power generation.Large-scale deforestation, unscientific agricultural practices, industrial processes and anthropogenic activities in the catchment areas tend to increase in silt load in rivers and aggravates sedimentation of reservoirs.

Citing the example of the Bhakra Dam on the Sutlej in Himachal, an official said over the past about 50 years, the designed capacity of the dam’s reservoir may have reduced by almost 25 per cent due to deposit of silt.

Sources said the surveys would be carried out through integrated hydrographic and integrated bathymetric systems that include employment of drones and use of artificial intelligence.

What is sedimentation

• Sedimentation is the process where loose soil, silt, rock and debris flow in with the water that enters reservoirs and deposit on the bed. The level of sedimentation depends upon the geology of the area through which rivers flow.
• Citing the example of the Bhakra Dam on the Sutlej in Himachal, an official said over the past about 50 years, the designed capacity of the dam’s reservoir may have reduced by almost 25 per cent due to deposit of silt.