Disadvantages of Dams
A dam is a structure built on rivers and streams for the sole purpose of conserving water. Throughout history, dams have played a vital role in the growth and advancements of civilizations. Civilizations have utilized dams to funnel water through cities and agricultural fields. They are mainly used as reservoirs, utilized for irrigation, energy generation, prevention of floods, regulate the flow of water in rivers and streams, and so on. Dams offer a wide range of advantages over economic, environmental, and social use cases of water conservation and management. Today dams are vital for storing and providing sufficient water. They fulfill the water demand in agriculture, industries, and domestic use. One of the most important purposes of a dam is to generate hydroelectric power. They are also a tourist spot as well as a site for boating, fishing, and other recreational activities. During water scarcity or drought, dams become vital.
As there are numerous advantages of building a dam, a country invests quite a lot into its construction and maintenance. But there are certain disadvantages to building dams as well. The environmental consequences of huge dams vary with respect to time, place and might lead to a direct impact on the biological, chemical, and physical properties of rivers, streams, and their associated environment. Some of the major disadvantages are -
Dams and their importance is broadly discussed in Class 10 Science Chapter 16 Sustainable Management of Natural Resources as they are a remarkable feat of infrastructure.
Factors Affecting Diffusion
- Impact on Aquatic Animals: The aquatic animals rely on the flow of streams and rivers for their reproduction as part of the aquatic life cycle. This is threatened by the construction of dams. The dam acts as a blockade for migratory fishes and thus causes a significant negative impact on aquatic life.
- Impact on Erosion: The construction of dams and conservation of water eats up most of the surrounding landmass. It’s been noticed that the landmass encompassing reservoirs undergo landslides near the shoreline. This gradually causes significant destruction in the surrounding landmass.
- Impact on Cost: The design and construction of dams is a very expensive feat of engineering and is time and labor-intensive. Even if the dam is utilized for power generation and/or for recreational purposes, it would still take years or even decades to compensate for the investment in the creation of the dam.
- Impact on Relocation: Due to the instability as mentioned in the other impacts, sometimes it is essential to relocate a population to prevent catastrophic events such as earthquakes or landslides which can potentially harm human life. This in turn implies that a majority of the population might lose their lands, businesses, and properties over the relocation.
- Impact on Water Bodies: Sediments that are beneficial for aquatic life and are known to play a vital role in the carbon cycle are blocked due to the erection of dams. This causes a significant imbalance in the water bodies as they might have to create their alternative paths or log over a single place over time and potentially cause geological imbalance.
- Impact on Ecosystem: The water body conserved by the dam causes a significant transformation of the habitat in terms of temperature, chemical composition, physical and biological changes. These changes make the habitat hostile for the once, native aquatic lives and might act as a host for non-native or invasive species. This can cause a significant extinction of the marine life associated with the location of the dam. This impact is important as it is irreversible over time.
- Impact on Groundwater: The reservoir can gradually deepen the river bed and in turn, reduce the groundwater. This can cause a significant impact on the nearby trees and plants in the landmass surrounding it as it won’t be able to have access to the groundwater. The salts and minerals form a rocky layer in the river bed due to the stationary waterlog. This can ruin the balance of both marine and terrestrial lifeforms.
- Risk of Disaster: An accumulation of disasters such as earthquakes, landslides, extinction, erosion, and so on can occur over time due to the effects mentioned in the other impacts above. The collapse of major dams can cause a massive catastrophe as it can induce earthquakes and hurricanes. Prevention of flow of water between two countries or states can cause territorial and political issues.