Dams are a symbol of human ingenuity and engineering prowess—controlling the flow of a wild river has not been a problem for decades. Most dams existing in the U.S were constructed between 1950 and 1990. As much as the infrastructure is changing, most of these river dams are aging and in need of repairs, rehabilitation, or even removal if they have outlived their original purpose.
In the modern-day of environmental awareness, more and more people are questioning the viability of dams and the impact they have on the environment. Is a little hydroelectric power worth destroying riparian ecosystems? Do we need these dams in the first place?
Boy, this is a tough one. This topic is one of the most controversial issues played out at both the local and international levels. Although dams are associated with many advantages, they can also lead to disastrous effects if not appropriately managed. Although there is no set moral compass on dams, we will provide you with the various pros and cons of damming rivers and let you be the judge.
Pros of Damming Rivers
This factor is perhaps the most celebrated use of dams all over the world. While everyone is busy trying to save the environment by reducing their carbon footprint, dams are equally in the battle against global warming, chipping in with hydropower. Hydropower provides 19 percent of the world’s supply of electricity, with approximately 3,000 terawatt-hours generated annually. Three thousand terawatt-hours are supposed to be a lot.
Hydroelectricity harnesses the kinetic power of flowing water and transforms it into electricity usable at home. Hydropower is clean and helps reduce the dependence of the pollutants known as fossil fuels.
Regulates Water Supply
Damming a river means restricting the flow of the previously flowing water to form a human-made reservoir. This process allows surrounding areas to collect freshwater during the rainy season and use it later during the drought season for home use and irrigation. Dams also control floodwater and can provide a buffer for unpredictable weather.
As sediments and chemicals runoff from dry land into the dams, the dams filter the flow before it is released into open water. Plants and microorganisms in the water, for example, absorb nutrients from these farm chemicals. Sediments also settle at the bottom after reaching an area with slow water flow.
Besides, dams help reduce the risks associated with waterborne diseases. A barrier can trap toxic components in water and, in turn, protects the environment.
Cons of Damming Rivers
Floods Surrounding Areas
When a river is dammed, water accumulates, and the surrounding former dry areas are transformed into riverbeds and riverbanks. Many are times when this flooding leads to the displacement of human beings and wildlife living near the water reservoir.
This process leads to the disruption of local activities like agriculture. Above that, when the vegetation is engulfed in water, the decaying plants release methane into the environment. This process, in turn, leads to an increase in the production of greenhouse gases. So much for saving the environment.
Disrupts the environment
Flooding of surrounding areas displaces the existing wildlife and can disrupt the whole ecosystem. Fish being the primary beneficiary of rivers, relies heavily on the free flow of water to guide them. Stagnant reservoir pools disorient moving fish and can greatly add the time of their migration.
Although fish passage structures have been installed in modern dams, they limit the accessibility of the fish to access spawning habitats, food resources and escape predation.
Dams Alter Habitats
As stated earlier, dams change the way rivers operate. They end up trapping sediments and burying rock riverbeds where fish spawn. Logs and other essential habitat features can also get trapped behind dams. This feature negatively affects the creation and maintenance of more complex habitats downstream.
So, this brings us to the big question once more. Are river dams good or bad for the environment? In our opinion, dams can be good or bad, depending on the situation. Properly managed dams can provide many benefits to wildlife and the environment in general. In the same case, a dam that has outlived its purpose can cause many harmful effects to the environment and should be decommissioned.