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Dam It! Altering River Flow Does No One Any Good

Due to lack of operational rules and effective warning systems, dams are actually aggravating floods

Dam It! Altering River Flow Does No One Any Good
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In April 2022, the North Eastern Electrical Power Corporation (NEEPCO) issued a circular. It warned that the water levels in Ranganadi Dam were reaching dangerous levels. People living in the downstream area should stay away; otherwise, they would face 바카라serious incidents at their own risk.바카라 Flooding at Ranganadi dam has become a yearly phenomenon. In 2018, authorities were compelled to open three gates of this dam when the water levels reached a dangerous height. This caused massive flooding and as a result 76 villages were submerged.

This year, the flood in Assam has affected over 32 million people and left around 180 dead. The calamity has raised various questions, especially about big dam projects. As per a report by NewsClick, people in Raha, Kampur of Nagaon district, and Hojai district of Assam, were in an abysmal situation as the flood due to heavy rain was exacerbated by water released from various dams like Ranganadi Dam. Many studies have found that due to lack of operational rules and effective warning system, dams are actually aggravating floods, even though one of their functions is to moderate floods.

Take the case of the 2018 Kerala flood that killed 493 in the state, and affected millions of people. Advocate Jacob P Alex, the amicus curiae appointed by the Kerala  high court in 2019 to assist it in flood-related cases, told the court that the intensity of the flood was aggravated due to the sudden release of water from different reservoirs during the torrential rains. India바카라s first Prime Minister Jawaharlal Nehru called huge dams 바카라temples of modern India바카라. Apart from being a recreational spot, dams can easily absorb small and medium intensity floods. Kerala-based civil engineer, James Wilson, says, 바카라Due to no occurrence of small floods, people start constructing on the floodplain of the river as they presume the area is safe.바카라 When a high intensity flood occurs, people cannot anticipate the damage. Dumping of waste and unplanned construction on the riverbed intensify this damage. 바카라Riverbeds are used for all kinds of wrong activities like dumping waste, illegal construction, and sand mining which make flooding even more damaging,바카라 informs environmental activist and water expert Himanshu Thakkar.

바카라There is a need to measure the operational safety of dams,바카라 says Wilson. 바카라When we talk about dams, we are only concerned about hydraulic safety바카라if a dam is capable of managing the flow of water바카라and structural safety. How the dam is operated is often overlooked,바카라 he adds. Dam operators are often not well-informed about weather prediction and rainfall patterns. On top of it, 바카라no accountability바카라 exacerbates the operational safety of the dam. 바카라For flood moderation in downstream areas, the dam must be kept empty to a certain extent. Only then, it can absorb the flood. But dam operators don바카라t care until water rises to a high level,바카라 says Thakkar.

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Calamitous memories A house in Kozikhode district collapses in the 2018 Kerala floods.

Instead of moderating the flood (throughout the year), dam operators release water to the downstream area during the monsoon, when the water level rises. 바카라Many dams are not designed for flood control. Most of these are multipurpose dams used for hydroelectric power, irrigation, etc,바카라 says Wilson. So, the flood cushion바카라a temporary storage capacity바카라is often low. When high intensity floods occur, dams fail to absorb it and collapse, he adds.

One of the major causes is the smaller catchment area. 바카라The catchment area of dams in the North east and Kerala is small, which adds to the problem,바카라 says Wilson. He gives the example of Idukki Dam on the Periyar River in Kerala. The catchment area of Idukki Dam is only 650 sq km compared with Hirakud Dam, with a catchment area of 83,400 sq km. A bigger catchment area means more time to manage the flood.

"Many dams are not designed for flood control. Most are multipurpose dams meant for hydroelectric power, irrigation, etc." James Wilson, Civil engineer, Kerala

There is a notion that 바카라flood equals disaster바카라, which is completely wrong. People traditionally never saw floods as disasters. 바카라We made it into a disaster,바카라 says Thakkar. For the rivers Krishna, Ganga, and Brahmaputra, the flood used to spread out and deposit the silt carried over the floodplain, making it more fertile. When a dam is built on a river, silt and boulders get deposited in the dam. The water that flows over these deposits and the water that gets released from these dams is mostly silt-free or contains less silt. In geomorphology, this is called 바카라hungry water바카라. 바카라This hungry water makes the river flow faster and has much greater capacity to erode the downstream area, which again increases its damage capacity,바카라 says Thakkar.

Flooding also depends on the quality of the catchment area, says Thakkar. If the catchment area includes good forest, watershed, wetlands, and maintains a lot of water bodies, then excessive rain will take much longer to convert into a river flow. But 바카라due to mindless mining, construction, and deforestation, the catchment areas are getting destroyed,바카라 informs Thakkar.

On top of this, climate change has altered rainfall patterns and they have intensified, even though there바카라s no significant change in the total quantum of rainfall. There are many high intensity rain events over short periods followed by long dry periods, 바카라which is aggravating the intensity of the flood, and also making it tough to forecast,바카라 adds Thakkar. Indian climatic conditions are creating further complications. 바카라It is hard to predict rain. While the Indian Meteorological Department is working hard and rainfall is being predicted with more accuracy, it is still a challenge,바카라 adds Wilson. That makes the area of operational safety of a dam even more important.

Another factor often overlooked, but has a crucial role in flooding is embankment바카라artificial banks built along rivers. The biggest example is the Kosi River, known by the metaphor 바카라sorrow of Bihar바카라 for creating floods. Journalist Kanak Mani Dixit writes in a 2020 article for Scroll that since the late 1950s, the connivance of politicians, technocrats and bureaucrats in Bihar is strengthening and protecting the embankments of Kosi River, which he calls a 바카라mad idea바카라.

Bihar has witnessed over eight dangerous breaches of the embankments, since these were constructed. Thakkar believes embankments are temporary measures, bound to be breached. 바카라It is not about 바카라if바카라 the embankment will breach, but only a question of when and where it will breach. The point at which it breaches will create a massive flood.바카라  Thakkar gives the example of Kosi and Brahmaputra, both high silt-carrying rivers. 바카라Over the years, with the deposition of silt and sand, the riverbed levels in many places have gone up higher than the land surrounding it outside. Since the river is embanking all  along, where will the water coming from higher to lower levels go? Naturally, it will create flooding.바카라

(This appeared in the print edition as "Hold the Gate!")

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