We all know what a dam is.
We all know what a dam is. But still, to recapitulate, let’s cover the meaning and definition of a dam. A dam is an artificial barrier created across a river or underground streams, to restrict the flow of water. A dam not only restricts the flow of water but also presents a wide range of advantages like flood suppression, irrigation, consumption, etc. Different dam structures are made according to the needs (for example, arch dams, gravity dams, etc). But besides a humongous range of advantages, dams confer several negative externalities that have adverse impacts on the ecosystem. Thus, we need an alternative to big dams, which is the topic for today’s discussion- Alternative to dams.
[Image will be uploaded soon] Why do we need an alternative to big dams? Besides being an abode to a large number of advantages, dams confer a large number of disadvantages that make us look for alternatives. Some of these Advantages are listed below
One of the major drawbacks of constructing a dam is that it displaces a huge amount of human as well as cattle population. In the past two centuries, more than 500 million people have been displaced due to the construction of reservoirs behind a dam. The area surrounding the dam and the reservoir gets flooded frequently, and thus, the area that was previously available for numerous purposes cannot be now used for any activity including habitation, farming, or cattle-rearing.
When the surrounding area of the reservoir gets submerged in water, it leads to decay of the vegetation of that area. The decayed plants eventually start releasing greenhouse gases like methane, which is 20 times better reflector than carbon dioxide. Besides, massive forest areas are also destroyed for constructing a dam. When trees are lost, the level of carbon dioxide increases in the atmosphere due to the reduced amount of photosynthesis processes.
Since large areas of forests are destroyed for the construction of dams, the impact on the local ecosystem is also drastic. The dam creates a barrier in the free flow of water, which hinders the movement of aquatic animals, which is necessary for their breeding and migration, and thus, the local aquatic biome is destroyed. Besides, rivers have certain sediments that are necessary for the survival of marine life. Lack of such sediments leads to temperature changes, imbalance in the chemical composition and shoreline stability, and much more. The riverbed also gets eroded.
When the riverbeds start deepening, it starts affecting the groundwater levels i.e. groundwater level starts falling. It becomes difficult for the plants to reach for water. It can also affect the mineral and salt content in the groundwater, thus, affecting the soil composition.
Seeing the above-mentioned disadvantages conferred by big dams, we can conclude that dams are a great way for channelizing water to several uses, but not the best. Humans are not the only species on the earth. We coexist with other species. But with dams, we are, intentionally or unintentionally, destroying the natural regimes of other coexisting species. Thus, we need to search for an economically, socially, and environmentally feasible alternative to big dams for reducing their adverseness. Some alternatives that can replace or reduce the need of constructing Big Dams are given below:
[Image will be uploaded soon] The Three Gorges Dam (China) is the world’s largest dam (181m in height and 2.34 km in length) and the heaviest concrete structure ever built, weighing more than 144 million tons. Its electric station has a capacity of 22,500 megawatts, powered by 32 main generators.
Ques. Explain the alternatives to energy production and flood management uses of dams. Ans. Dams play a crucial role in flood management. But there are several other ways of flood management, such as reducing water run-off, Riparian and in-river flood management, separating the people and the threat, etc. Dams also play a vital role in hydroelectricity production. Some alternatives to reduce the damage caused by dams are efficient end-use, the use of newer technologies like solar energy, thermal energy, etc.
Ques. How do dams affect local marine life? Ans. Since large areas of forests are destroyed for the construction of dams, the impact on the local ecosystem is also drastic. The dam creates a barrier in the free flow of water, which hinders the movement of aquatic animals, which is necessary for their breeding and migration, and thus, the local aquatic biome is destroyed. Besides, rivers have certain sediments that are necessary for the survival of marine life. Lack of such sediments leads to temperature changes, imbalance in the chemical composition and shoreline stability, and much more. The riverbed also gets eroded, which might extend to hundreds of miles. Ques. Explain any 2 alternatives to big dams. Ans. The two alternatives to big dams are: Recycling/Reuse of water: One of the ways of doing so is reusing or recycling the water. By recycling or reusing, we mean the process of sewage treatment. Sewage treatment plants can put the sewage or grey water into use again and thus, helping in meeting the water supply for non-portable purposes like industrial processes, irrigation, toilet purposes, etc. Groundwater recharge: Groundwater recharge or deep drainage is the process of replenishing the groundwater level of an area during rains. When talking about sandy soil, it takes just 2 days for the water to percolate through the soil and thus, is the quickest way of replenishment.
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