top of page

Blog! Blog! Blog!

  • Writer's pictureColeman Earnest

Exploring Consequences of Damming

What is a Hydroelectrical Dam?

Dams have been around for centuries and have mostly been used to control flow regimes (The pattern of flow in wet and dry seasons) and provide consistent access to water. Hydroelectrical dams are a newer discovery, with the first being built in the 19th century.

Benefits of Dams

There is obviously a benefit to damming as the behavior has convergently evolved in beavers and humans. Damming allows beavers to create a large body of water to protect themselves from predators. Humans also utilize dams to create large bodies of water, but not for protection. Humans create dams for a reliable water resource, power, and access to land with great soil for agriculture. It is for this reason that as industrialization increased, dam building was seen as essential to vitalize rural areas and bring growth to budding cities. While all these things provide a benefit for humans, they can come at a huge ecological cost. 

Ecology of Rivers and Wetlands

Rivers are the givers of life to many landscapes and are immensely important in the function of ecosystems. They shape landscapes from season to season while distributing nutrients and water to the life along its banks. Wet seasons create high flow rates and allow overflow into wetlands. When the flow of a river is constricted, it chokes off the water supply needed to support wetlands. Humans, animals, and plants all suffer from the destruction of wetlands as it provides huge ecological value to the landscape. These wetlands are also a natural system that prevent severe flooding downstream. 

Ecological consequences of Dams

In the modern world, pollutants in fresh bodies of water are a reality many have suffered from. Some scholars have asserted that the amount of pollution within freshwater systems is related to the amount of damming on them. Locks and dams greatly influence flow regimes and reduce the peak flow of rivers, which is essential for diluting pollutants in water systems (Luo 2012). This results in worse water quality and water ecology. Dams are often located near agricultural lands or residential areas. This proves to be problematic as many water pollutants come from runoff of agricultural projects. The impermeable surfaces in residential areas also enable the depositing of pollutants into the waterway. 

Water quality is greatly affected by the closing and opening of the locks stemming from seasonal increases and decreases in precipitation. Closed locks during the dry season cause a low flow which is unable to properly dilute the pollutants in the water. When the flow increases and the locks open in the summer, the water quality will improve because of the higher flow. It is because of the winter, or dry, season that many locks will close to prevent water loss from the area. This stagnant water is what allows for pollutant build up that leads to algae and invasive aquatic weed flourishing (Luo 2020). 

Algae blooms have been known to create large fish kills and dirty the drinking water source for many residential areas. Aquatic weeds, like duckweed or Aquatic hyacinth, are known to also cause mass deaths of aquatic organisms while also causing problems for residents of the area. The Akosombo Dam in Ghana has created a huge bloom of aquatic hyacinth which makes it extremely difficult to travel across the water, something that is essential for the people of the area (Miescher 2021). However, aquatic ecosystems can be highly adaptable, and the effects of dams and pollutants requires long term data collection to gain a better understating of the effects of dams on water ecosystems (Luo 2020).

Understanding the direct way in which dams affect aquatic life is not completely clear, but comparisons of ecosystems before and after the removal of a dam can provide much needed insight. Edwards dam situated on the Kennebec river in Maine was removed in 1999. This was the first removal of a hydroelectric dam in the US. Prior to the removal of the dam, the river was filthy and used as a place for industries to dump their waste. This destroyed the ecology of the river and greatly decreased the water quality in the area. After the removal of the dam fish populations returned and insect counts tripled; the river was restored (Crane 2009). 

Spiritual and Cultural Connections to Bodies of Water

Humans need freshwater. Residence next to freshwater is a part of our evolutionary history, because of this many different cultures have risen with intense connections to bodies of water. These connections have been stifled by the damming of sacred sources of water. Many people have been displaced by the building of dams; the Akosombo Dam in Ghana displaced around 80 thousand people. This destroys the lands of people along with pieces of their heritage and way of life. Humans are not the only life affected by damming. Dams can eliminate sensitive species within an aquatic ecosystem that bring a high degree of natural beauty, life, and character to their respective bodies of water. 

The text says, “We don’t want the dam. The dam is the Mountain’s destruction.” This message was coin by activist Sundralal Bahuguna.

Many have fought against the building of poorly thought-out dam projects and for the destruction of existing dams. The US has seen many dams lose their license and destroyed due to political action from residents living near old and harmful dams. Failure to successfully oppose the construction of dams is also very common with large amounts of money and powerful individuals within government supporting the projects. The Tehri Dam in India is a prime example of this. The dam was built despite the many who opposed it due to environmental and spiritual reasons. The water is currently drinkable, but there have been changes to the surrounding nature since the construction of the dam (Dudeja 2013). Most concerning is the fact that the dam is built on a fault, making it vulnerable to huge earthquakes which could be devastating to the surrounding communities (Gupta 2012).

Future Global Growth and Consequences of Damming

The future of dams in the United States is a question of which dams to get rid of rather than where should new dams be built. The surge of dam building in the 20th century brought about many dams that are now becoming old and battered, posing a huge risk to surrounding areas. Older dams were also often built without considering ecological costs and therefore have a worse effect on the surrounding ecosystems. In addition to the ecological effect, aging dams have large maintenance costs that make them an economic liability. A large-scale assessment of the 85,000 dams in the United States is needed immediately to gain insight on this issue (Ho 2017).

Dams are still being built somewhat frequently in countries outside of the United States, specifically nations in the global south, because of many populations requiring a more consistent water resource. Many governments are calling for more dams to be built because of less predictable precipitation patterns and food scarcity. The funding for these large projects often come from Chinese banks and investors. There is a large incentive for these investments as they offer significant returns as well as framing the investment as a climate change mitigation strategy (Siciliano 2019). 

The decrease in water quality globally will have many negative consequences to the environment due to connected issues that endanger water quality. There have been many examples in recent history of eutrophication tainting water supply. One being the 2012 event outside Seoul which lead to residents having to boil water before drinking (Park 2012). Hydroelectricity is also becoming more prominent as it is a somewhat easy way to deliver power to more rural communities. Bringing electricity to those areas will likely increase urbanization. As the world becomes increasingly more urban, the negative effects of urban adjacent dams on water ecology and quality will likely become worse.  Being pickier about where dams are built and doing in depth studies on the area before approval is essential in moving forward to ensure minimum ecological cost. Removal of older dams must also occur to end negative environmental effects and financial waste.


Luo, Zengliang, Q. Shao, Q. Zuo, Y. Cui. (2020). Impact of land use and urbanization on river water quality and ecology in a dam dominated basin. Journal of Hydrology 584: 1246555.

Park, S. (2012).  Algal blooms hit South Koreanrivers. Nature.

Miescher, Stephen F. (2021). Ghana’s Akosombo Dam, Volta Lake Fisheries & Climate Change. Daedalus, 150: 124-142. 

Crane, Jeff. “Setting the river free”: The removal of the Edwards dam and the restoration of the Kennebec River. Water History, 1: 131-148.

Dudeja, D., Bartarya, S.K. & Khanna, P.P. (2013). Ionic sources and water quality assessment around a reservoir in Tehri, Uttarakhand, Garhwal Himalaya. Environmental Earth Sciences. 69: 2513– 2527.

Ho, Michelle, et. al., The future role of dams in the United States of America. Water resource research. 2017. 53: 982-998.

Siciliano, Giuseppina, et. al. (2019). Environmental justice and Chinese dam-building in the global South. Environmental Sustainability. 37: 20-27.

Gupta, S., P. Mahesh., Sivaram, K., S S. Rai. (2012). Active fault beneath the Tehri dam, Garhwal Himalaya – seismological evidence. Current Science (Bangalore). 103: 1343-1347.


Recent Posts

See All


bottom of page