Dams are constructed worldwide to generate electricity, control flood, and to store irrigation water. However, despite of the advantages they provide, dams contains a number of drawbacks associated with constructions of these dams. Some of the draw backs associated with flood control dams is that these dams act as a disease breeding grounds especially in tropical areas. Dams promote breeding of snails and mosquitoes promoting the spread malaria and bilharzias. In addition, floods submerge plants in these dams where they decay anaerobically producing methane and other greenhouse gases which contribute to the environment pollution. Flood dams construction also results to displacement of huge number of people, changing their lifestyle. Dams can also turn to be catastrophic especially to population in the downstream when they break, causing destruction of plant, animals and life to some extent (Sanguri & Stonecypher, 2013).
Dams are also constructed to act as a reservoir; however dam’s ability to work as a receiver can decrease its storage capacity and eventually lower its effectiveness. This is because the flood water carries sediments with it from the upstream to the dam. This deposition accumulates with time, lowering the depth of a dam. As this continue, the dam’s capacity to hold water reduces and eventually, the dam is not able to hold enough water that the population can depend on. However, the rate at which this deposition takes place depends on the dam’s location and the intensity of the rains. Normally, dams located on the base of step landscape experiences more deposition as compared to a dam located in a flat plane. Therefore the first one will lose its effectiveness faster as compared to the second one (Puff & Hart, 2002).
Puff, N. L., & Hart, D. D. (2002). How dams vary and why it matters for the emerging science of dam removal. BioScience, 52(8), 659-738.
Sanguri, M., & Stonecypher, L. (2013). Negative impacts of hydroelectric dams. Retrieved from < http://www.brighthubengineering.com/geotechnical-engineering/71200-negative-impacts-of-hydroelectric-dams/>