Effects of Hydroelectricity and Dams Have upon the Ecosystem - Term Paper Example

?Effects of Hydroelectri and Dams Have upon the Ecosystem Introduction Freshwater and electri are very essential resources that all humans depend on. Without dams, people could find it hard to get fresh water in dry seasons and more still; dams have been used as a source of food since fish and other edible aquatic animals can be reared in dams. Dams also have been utilized for a long time to control river flows while ensuring a constant supply of fresh water in dry seasons. More dams will be required in future since there is a rapid increase of population and consumption of water is on the rise. However, the idea of constructing more dams in various places has been welcomed with great opposition. Many economic and social arguments have been raised against the construction of dam, but the most profound fact that has overshadowed all other arguments is the major ecological effects that large dams have on the ecosystem. Considering hydroelectricity, hydropower is actually a renewable energy since it depends on the water cycle on earth for the generation of electricity. The cycle of water begins when the water evaporates to form clouds which in turn condenses and precipitates back to the earth and gets back to the water reservoirs. Despite the fact that hydropower pose no effects on the quality of air, the process of constructing and operating large hydropower dams can have significant impact on natural ecosystem such as river systems wildlife and aquatic life population. The assessment of how hydropower affects the environment can be effectively done by reviewing different cases. This paper aims at discussing the effects that hydroelectricity and dams have upon the ecosystem. Effects of Dams upon the Ecosystem Dams have significant effects on both the downstream and upstream ecosystems. Dams comprise hindrances on rivers longitudinal exchange and they alter numerous processes in the natural environment. Flooding of dams in the upstream brings about total damage to the terrestrial ecosystems via a process known as inundation. Flooding eliminates all terrestrial animals and plants inhabiting the affected areas. Water reservoirs inhibit some aquatic species from migrating by obstructing their pathways1. On the downstream, there are obvious changes in sediment transport, water quality and temperature, and flow regime. These particular changes occur gradually and they are not easy to predict. The very common effect of large dams downstream is the reduction of annual water discharge; this lead to an increase in low flows and a decrease in high flows. Flood peaks reduction decreases the period, degree and frequency of floodplain outpouring. A decrease in the channel-formation shrinks the chances of channel migration. Transportation of sediment in the reservoir brings about complex alterations in aggregation and deprivation on the dams surface. Regulation alters the chronological flooding prototype, an effect that desynchronizes temperature systems and yearly water flow. These particular alterations have a direct influence on some dynamic factors affecting the heterogeneity of habitats and the integrity of the river ecosystem ecology. Changes in water quality, water to land interface, and thermal regime have direct impact in primary production, which translates to long term effects on aquatic life and other members in the upper food chain. Dams may also bring about alterations in the ecosystem even at a distance far from the dam2. For instance, any alteration on the transportation of sediments may result in changes in floodplains, coastal delta and river morphology numerous of miles from the dam site. The river ecosystem responds to dams in several, complex, and diverse ways. Subsequently, while endeavouring to establish the impacts of dams on the ecosystem there is need for large bank of information relating to: riparian vegetation and related fauna; quality of water; rivers hydraulic features; geomorphologic features; aquatic animals and their environment; importance of river’s floodplain and resources to the local inhabitants. There is a requirement for primary research that links alterations in abiotic processes as a result of dam construction to ecological changes, especially in regions with tropical climates where there is a high potential of new dams constructions, and no valid research has been carried out to date. The figure above shows a framework for assessing the significant effects of dams on the ecosystem of the river. The complicated relationship existing between dams and their immediate environment hinders the prediction of the adverse consequences that a dam construction can pose to any ecosystem of a river. Each dam has its own unique impact and this is does not only rely on the structural features of the dam, but also the supply of local sediment, climate, geomorphic confines and the fundamental appraisals of the local biota. Nevertheless, the climate has a pronounced impact on the essential catchment processes. The major setback facing the persons accountable in the management of water and power concerns the particular means that dams affect the ecosystem and the methods by which these impacts can be assessed and dealt with by stake holders. Effects on the ecosystem impact the society directly and require to be considered in the initial stages while planning to construct a dam. If the costs are not included in the plan conflict may build-up between the society and the developers. Dams can also pose unfavourable social effects. Recent reports estimate that construction of dams and creation of lakes over the last few centuries has taken approximately a quarter of a million square kilometres of land3. An estimation of 40-80 million people has lost their homes due to the construction of dams. Large dams’ reservoirs have also been associated with certain health risks especially in areas where interference of the natural drainage system offers a breeding ground for waterborne disease carriers. Increased malaria spread in Africa and south Asia has been directly attributed to the construction of large dams. Another health risk attributed to big dams construction is the accumulation of toxic materials in the dams that can leak out and flow downstream into supplies of fresh water used by human beings. Big dams constructions in tropical regions need to be controlled to avoid the risks at hand. Effects of Hydroelectricity upon Ecosystem Hydroelectricity power has always been considered as an environmentally friendly undertaking since it represents the sources of energy that are clean and renewable. Renewable in terms of hydropower stands for the hydrologic sequence that circulates water back to where it came from i.e. streams, lakes, and rivers every year4. At a hydropower plant, water is used in place of fuel for electricity generation contrary to fossil fuels that must be excavated from the earth and then burned to produce energy which in turn generates electricity. Hydroelectricity is also termed as clean because it does not pollute air, lead to acidic rain or contribute to global warming. While there are many advantages of using hydroelectricity power as a source of energy, there exist also some remarkable ecological effects which are generally linked to how a hydropower project affects the ecosystem of a river and the surrounding habitats. Despite the fact that power plants are controlled by the federal laws to protect the environment and health of the inhabitants, there exists a broad range of environmental effects related with technologies used to generate power5. This sections endeavors to discuss the effects of hydroelectricity upon the ecosystem. In terms of air pollution, hydropower impact on air is very negligible since there is no burning of fuel. Nevertheless, if there is lot vegetation along the riverbanks when the dam is constructed, it can rot in the dam that is built; resulting to a buildup of methane gas which when released to the atmosphere produces an intoxicating greenhouse gas. Some hydropower technologies demand the use of dams. These dams can pose a great challenge on the natural flow of rivers thus changing the ecosystems and negatively affecting the inhabitants and wildlife that rely on those rivers for survival. Actually, the water found at the bottom of the dams is hostile o the aquatic life such as fish since it is poorly aerated thus lacking enough oxygen and very cold as compared to the water at the top of the dam. When this oxygen-less, cold water is allowed to flow into rivers, it can be fatal to the fish existing downstream that as used to well oxygen aerated warm water. Moreover, some selected dams reserve water for long periods then release it abruptly, causing a sudden flood at the downstream. This particular action can cause a disruption or interference to the wildlife and plants habitats and contaminate the supplies of fresh drinking water. However, the water release by the hydroelectric power stations after generating electrify is not contaminated by just passing through the dynamos turbines. Using water to generate electricity does not necessarily create large amounts of solid waste. Another effect of hydroelectricity is the impact on land that is caused by the construction of hydropower stations. Hydropower plants occupy sizable sections of land when constructing dams and creating lakes thus, flooding land portions that were once scenic sites, home for wildlife, and farming lands6. Hydroelectric dams can bring about soil erosion along the beds of the river both downstream and upstream, causing further interference to the population of fish and animals ecosystem. The population of fish is affected by hydroelectric power stations is many different ways. Recently in Northern west, a certain species of salmon fish populations that rely on rivers to produce, have decreased drastically by the construction of a big network of dams along the basin of Columbia River. As the salmons swim downstream to the ocean, they risk death by being hacked by the big turbine blades at the base of the hydroelectric power plants. As adult salmons travel upstream for reproduction purposes, they may not manage to pass through the dams. Due to this setback, some hydropower dams have in them special structure on their sides to allow the fish move upstream. Hydroelectric power plants affect the environment by altering the courses of rivers, altering the amount of water in the rivers thus affecting those inhabiting along the downstream of the river. Although hydroelectricity project are essential to us human beings, we should also consider the negative effects they may pose to our health, wildlife, and plants ecosystem. Terrestrial and aquatic Wildlife is a source of income to most countries in the world therefore; a keen consideration should be put in place to ensure that the impact of hydroelectricity on the environment is greatly reduced to avoid disruptions in the ecosystems. Conclusion As discussed above, reviewing the effects of dams and hydroelectricity upon the ecosystem need to be given more weight since the impact they have on the environment is adverse. Dams have been found to interfere with marine life, river structure (altering the course of the river), and human inhabitants (providing breeding ground to disease vectors). Hydroelectricity have been found to interfere with land set aside for human habitation (has caused displacement of millions of people from their homes) it has also disrupted the drainage cycle and altered the courses of rivers in the process of constructing large dams Works Cited Honningsvag, Bjorn. Hydropower in the new millenium: proceedings of the 4th International Conference on Hydropower Development, Hydropower '01, Bergen, Norway. Oxford: Taylor & Francis, 2001. McCartney, M, C. Sullivan. Ecosystem Impacts of Large Dams. Centre for Ecology and Hydrology, UK IUCN – The World Conservation Union. Retrieved on September 28, 2011 from: http://www2.wii.gov.in/eianew/eia/dams%20and%20development/kbase/contrib/env244.pdf Coface. Hydroelectric power stations and large dams. Retrieved on September 28, 2011 from: http://www.adb.org/water/topics/dams/pdf/barragesgb.pdf Read More