Dams are barriers constructed across a river to either store or to redirect water. They are deliberated to change the natural flow of the river sequentially to meet human needs. Such needs may hydroelectricity, irrigation purposes, and drinking water reservoir among other needs (Patrick, 2001). However, dams can also create adverse ecological and environmental impacts. Whereas the impacts of dam flooding are immediate, succeeding ecological effects can be far-reaching. Thus, there is a growing concern that dam construction or projects are causing irreversible environmental changes that are complex, multiple and generally negative (Bengtsson et al. 2012). As such, there is a need to care and examine any current regulation put in place, and the outcomes without such regulations, and the pros and cons of methods that are proposed to mitigate the impacts of dam projects.
Discussion of Issue
The ecosystem and environmental impacts of dams come under increasing scrutiny as the world demand for water and energy increases and the number of dams increase. Most of these impacts are difficult and in most cases impossible to predict with certainty. Mostly the theories of the environmental dynamics of rivers are based on short term evaluations of small rivers in temperate regions. As such, there is limited understanding of on how big rivers in other regions (tropics) function (Bengtsson et al. 2012). The regions within the tropics are characterized with few research funds, thus the only scientific examination done is where a dam can fit best.
Delegate your assignment to our experts and they will do the rest.
There are two main classifications of ecological impacts of dams. Those which are intrinsic to dam construction and those that come as a result of the way the dam operates. The outcome of these interrelated ecological disruptions is that they tend to fragment the river line ecosystem; separating inhabitants of species living up and downstream of the dam subsequently cutting the movement and migration of other species. Moreover, most dams reduce the normal flooding and also fragment ecosystem by separating the stream from its floodplain, turning it into a reservoir (Penczak et al., 2009). It is no doubt that fragmentation of a river's environment has resulted in a substantial decrease in the number of species. Since the dam changes the conditions to which the local flora and fauna have adapted, the general impact created by the dam is to reduce species diversity. Although dams pose such huge impacts on the local ecosystem much has not been done to reduce these impacts.
The current regulation that is aimed to curb these impacts is mitigation. This measure is basically geared to minimizing these negative impacts that cannot be avoided in totality (Patrick, 2001). Without the further incorporating other mitigation measures, these impacts may cause adverse ecological effects to both plants and animals near and far from the dam. Thus, it would be correct to incorporate other regulation strategies to reduce these impacts.
Regulatory methods
Different methods have been proposed to control the ecological and environment impacts brought about by construction and operation of dams. These methods include avoidance, mitigation, and compensation (Lee et al., 2011). Avoidance as a measure completely excludes as many negative impacts as possible. As such, it is considered as the most effective regulatory measure. This measure is adopted during the planning or conceptualization process of the project. It is given consideration only after adequate evaluation of other options has been done. The advantage of this measure is that it is an option of avoiding impacts to the ecosystem (aquatic and terrestrial) by avoiding the construction of a new dam (Penczak et al., 2009). The disadvantage is that it gives considerations for construction of a dam in any other location.
Mitigation regulatory measure is generally integrated into and existing dam project or into a new one in order to cut the negative environmental impacts (Lima et al., 2016). In the case of new projects, a mitigation measure is aimed to reduce the foreseeable adverse impacts by modifying the structural or the operational elements of the development. The advantage of this measure is that it is effective to the already constructed project thus negative ecological impacts can be curbed effectively. The disadvantage of this measure is that it cannot bring back the natural ecosystem that existed before disruption was done.
Compensation as a regulatory measure entails some form of repayments for probable undesirable impacts or for realized adverse effects. Compensation for lost resources may be in form of preservation or restoration of existing environmentally importance places to replace those already lost as a result of dam construction (Lima et al., 2016). Other approaches can also be employed as a compensation measure to ensure the continuance of some environmental services. The advantage of this measure is that compensation guarantees the continuances of an ecosystem in another locality. The disadvantage of compensation is that it cannot guarantee the existence of species in a different ecosystem, thus it might lead to extinction.
Dam construction without adequately assessing the ecological and environmental outcome may create irreversible impacts to the ecosystem as evident above. Equally, effective regulatory approaches should be put into place to avert the impacts that may arise from dam construction. Approaches such as mitigation and compensation will be helpful as discussed above. Lack of adequate research studies is a major shortcoming of prevention ecological and environmental impacts of the dam. Allocation of adequate study and research funds is the ultimate sacrifice for such shortcoming.
References
Bengtsson, L., Herschy, R. W., & Fairbridge, R. W. (2012). Encyclopedia of lakes and reservoirs: Geography, geology, hydrology and paleolimnology. Dordrecht: Springer.
Lee, Y., Yoon, T., & Shah, F. A. (2011). Economics of integrated watershed management in the presence of a dam. Water Resources Research, 47, 10.)
Lima, A. C., Agostinho, C. & Monaghan, K. A. (2016). Alternative ways to measure impacts of dam closure to the structure of fish communities of a neotropical river. Ecohydrology, 9, 5, 860-870
Patrick M. (2001). Rivers No More: The environmental Effects of Large Dams. Retrieved from https://www.internationalrivers.org/rivers-no-more-the-environmental-effects-of-large-dams
Penczak, T., Gomes, L. C., & Latini, J. D. (2009). Impacts of a reservoir on fish assemblages of small tributaries of the Corumbá river, Brazil. River Research and Applications, 25, 8, 1013-1024.
