YB WEB DESK. Dated: 7/31/2020 10:31:36 AM

China is facing the worst floods in the last one hundred years despite having made the largest numbers of dams in the world. We too are facing floods in Bihar despite having arrested flood waters in the Tehri Dam. The reason is that we consider the rivers only as carriers of water and ignore their role as the carrier of sediments. We forget that the land mass from Haridwar to Kolkata has been made by the sediments brought by the Ganga. The water of the Ganga has been spreading all around for thousands of years and depositing the sediments. These sediments which have now become the states of Uttara Pradesh, Bihar and West Bengal. Yet, floods also cause human suffering. Question is how should we deal with this? Ganga has the highest load of sediment among the major rivers of the world. She deposits some sediments in her channel every year. Then, these sediments are pushed to the sea during a major flood that comes in five or ten years and the channel is restored to its earlier depth and high capacity to carry water. However, we have stopped such major floods by making the Tehri Dam and removing much water from the Haridwar and Narora Barrages for irrigation. As a result the sediments being deposited in her channel every year are no longer being pushed to the sea; the level of the channel is gradually rising; the Ganga’s capacity to carry the flood waters is getting reduced; and even a “small” flood now inundates the banks and cause huge damage as being seen in Bihar today. We have actually increased the flood fury by making the Tehri Dam. The Farakka Barrage has made the problem worse. Hydrologists tell us that even making the pillars of a bridge cause serious obstruction to the flow of the river and reduce its velocity and ability to carry the food waters. It follows that the velocity of the Ganga is reduced even if all the gates of the Farakka Barrage are opened. The reduced velocity leads to the river depositing more sediments upstream of Farakka. This leads to double reduction of the capacity of the Ganga to carry the flood waters. The reduction in velocity directly reduces the amount of water that she can carry to the sea; and reduction the depth of the channel further reduces the amount of water that she can carry. As a result, the floods in Bihar are increasing. Some scientists believe that the flow of the Ganga has been reduced from Barh to Farakka while others believe that the flow has been reduced from Buxar onwards. The capacity of the tributaries like Kosi and Gandak has been reduced in tandem because the Ganga cannot accept the water brought by them just as it is difficult to enter a Second Class railway coach that is already full. No wonder Chief Minister Nitish Kumar has been asking for a reassessment of the Farakka Barrage.


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