By Ella Stone
Dams are being proved to not be as helpful as we originally thought they were. Dam construction is one of the oldest but most preferred ways of managing freshwater as it makes up nearly two thirds of the globe’s major water systems, but the price the environment is having to pay continues to add up.
Only 37% of rivers longer than 1000 km are free flowing and only 23% flow remains uninterrupted to the sea. These dams have contributed to the 84% decline of the freshwater wildlife population since 1970. Many people think that dams produce clean energy, but that is actually false. Dams do generate hydropower by blocking rivers and creating fake reservoirs, but this is not emissions free. There are options available to us as of now, to remove existing dams and not build more, to balance the needed energy and the environmental harm. Some believe that removing them; however, is a lost cause, but science proves removing dams quickly restores carbon storing watersheds and revives wildlife.
Dams emit methane by drowning natural carbon sinks like grasslands and forests. They create stagnant waterways that end up releasing methane that is a potent greenhouse gas. Which can contribute to climate change by the excessive release of CO2 into the atmosphere. They also threaten wildlife and ecosystems. Dams block free flowing rivers resulting in water quality degrading, temperatures rising, and algae bloom forms and oxygen levels decrease which kill off key species.
When dams are built they change the course of the free flowing river. This causes sediments to deposit behind the dam and form new physical features and may end up altering biodiversity. They also disrupt and cut off migration routes which limits their ability to access spawning habitat.
Fish like salmon and river herring depend on a steady flowing river to guide them, but dams are causing rivers to be stagnant. They are also altering the timing of flows, these irregular releases destroy natural seasonal flow and trigger natural growth and cycles. It also blocks the progression of water to other states or regions. It also puts a risk of flooding if you live near a dam. Failures or malfunctions of dams release dangerous flood flows which can pose a safety risk to the unaware public. Even though dams do conserve some river water that would otherwise be wasted, these cons outweigh the pros.
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