The Environmental Impact of Water Reservoirs
A water reservoir can be defined as a humanmade lake where water is stored and disposed of in a controlled way. In most cases, water reservoirs are the result of dam construction across rivers. Approximately 40% of all river water discharged worldwide is obstructed by dams, and the respective water is stored in adjoining reservoirs for future use (Cunha et al., 2020). Following the current climate change conditions, water reservoirs showcase positive outcomes, which include addressing the context of water shortages and storm tides. In addition, water reservoirs assist communities to have adequate drinking and irrigation water, hydroelectric power, proper flood control systems, recreational opportunities, and so on. Unfortunately, many environmental impacts are associated with the establishment and functioning of a water reservoir, which is far worse than the advantageous scenario. Natural ecosystem destruction, human habitation elimination and migration, change in rainfall patterns, GHG emissions, water pollution, and sedimentation are all environmental consequences.
First of all, the water reservoir’s physical properties include temperature transposition, chemical formation, and dissolved oxygen at a higher rate. In critical consideration, all these environmental phenomena are not that suitable for aquatic animals and plants. Most importantly, the physical properties of water reservoirs also allow the inhabitance of invading and alienated species, which often undermine the respective river’s natural ecosystem (Devic, 2015). In short, the ecosystem imported by the water reservoir’s characteristics causes mass destruction to the river’s ecosystem. Secondly, the natural flow of life within or around a river is significantly dependent on the river’s flow quantity and frequency. Artificial water storages are meant to discharge water in a controlled way while directing the flow in the desired direction. De-watering conditions in river reaches can be caused by disturbed and modified water flows (Devic, 2015). In this way, water reservoirs can uproot the river’s ecological network, which triggers the elimination of respective human inhabitances, surface plant life, and aquatic life. This situational context forces humans to move to a different place. Thirdly, the orientation of a water reservoir causes far greater evaporation than in the earlier context. The higher evaporation rate often results in excessive down-pour in the surrounding area. As a result, excessive rainfall deprives traditional rainfall scenarios, causing additional problems for surrounding ecosystems and communities that rely on the previous rainfall pattern.
Furthermore, yearly GHG emissions from worldwide water reservoirs are estimated to be 12.9 Tg CH4-C, 50.8 Tg CO2-C, and 0.04 Tg N2O-N (Yan, Thieu, and Garnier, 2021). The world’s water reservoirs are annually producing greenhouse gases in an amount roughly equivalent to 1.07 gigatons of carbon dioxide (Ferguson, 2021). Ferguson has signified this small amount by stating that it is still more GHG emissions than Germany, the sixth largest emitter in the world. In addition, reservoirs also cause water pollution and sedimentation. Improper waste disposal results in contaminating the reservoir and supply of water, whereas sedimentation results in flooding in upstream areas, destroying forests, human inhabitance, and overall life over the surface.
Water reservoirs are essential to address issues like fresh water and food shortages, insufficient power supply, flooding, etc. On the other hand, the negative impacts associated with water reservoirs are undeniable. More research and funding are necessary to minimize the negative environmental impacts.
References
Cunha et al. (2020, May 08). Environmental Impacts of Dam Reservoir Filling in the East
Amazon. Frontiers in Water. https://doi.org/10.3389/frwa.2020.00011
Devic, G. (2015). Environmental Impacts of Reservoirs. Research Gate.
10.1007/978–94–017–9499–2_33
Ferguson, W. (2021, June 01). Greenhouse gas emissions from water reservoirs higher than
previously expected. WSU Insider. https://news.wsu.edu/press-release/2021/06/01/greenhouse-gas-emissions-reservoirs-higher-previously-expected/
Yan, X., Thieu, V., and Garnier, J. (2021, July 20). Long-Term Evolution of Greenhouse Gas
Emissions From Global Reservoirs. Frontiers in Environmental Science. https://doi.org/10.3389/fenvs.2021.705477
