According to a study released this week by the United Nations, more than 50,000 big dams might lose more than a quarter of their storage capacity by 2050. It would happen as a result of silt buildups, compromising the security of both water and electricity worldwide.
The United Nations University stated that it is necessary for all to take an action to solve the issue. We must safeguard the crucial storage facilities. As things are now, they predicted that dam capacity will decrease from 6 trillion cubic meters (cu m) to 4.655 trillion cubic meters by 2050.
What is the problem with the dams?
Silt builds up in reservoirs when natural water flows experience interruption. Hydroelectric turbines may suffer harm, which would reduce power production.
Additionally, limiting sediment flows along a river can damage downstream habitats and increase the risk of flooding in upstream places.
Silt accumulation in dams and reservoirs is a common problem that can negatively impact the efficiency and longevity of these structures. Silt is made up of small particles of sediment, such as clay, sand, and rock. The water carries them and deposits them in the reservoir.
Over time, the accumulated silt can reduce the volume of water storage, decrease the capacity of hydroelectric power generation and irrigation, and increase the cost of maintenance. Moreover, the accumulation of silt can change the water chemistry and leads to negative impacts on aquatic life.
To mitigate the problem, dams and reservoirs may employ a number of techniques. Such are dredging, desilting and sediment flushing to remove accumulated silt. However, these methods can be costly and logistically challenging. They may also have negative environmental impacts. Another approach would be to minimize sedimentation upstream, by reducing erosion from construction and agriculture, which is the main source of the sediment.
U.N. studied dams in 150 countries
Data from more than 47,000 dams in 150 nations examined for the U.N. study found a loosing of 16% of the initial capacity. By 2050, they expect the United States to lose 34% of its economy, while Brazil, India, and China probably will lose 23%, 26%, and 20% respectively.
Longtime opponents have cautioned that the benefits of large dams are greatly outweighed by the long-term social and environmental costs.
One of the study’s authors and the head of the UN University’s Institute for Water, Environment, and Health, Vladimir Smakhtin, claimed that the number of dams built globally dramatically fell, from 1,000 a year at the turn of the 20th century to about 50 today.
He said: “Considering that the governments phase dams out, I would suggest that the question we should ask right now is what are the alternatives to dams, especially in generating power.”
China continues to dam major rivers
Hydropower is a crucial component of China’s goals to reduce its reliance on fossil fuels and reduce greenhouse gas emissions, although projects like the Three Gorges, the largest hydroelectric plant in the world, have had negative social and environmental effects.
Aside from changing the terrain and endangering the livelihoods of millions of farmers, China’s construction of dams on the Mekong river has also interrupted the flow of sediment into countries downstream.