User:Jakepaxton/sandbox

Dam Construction

           Dams are made around the world for many different reasons and have a variety of uses. There is a lot to consider when constructing a new dam. The location must be inspected, the purpose of the dam has to pass certain criteria and the effects of possibly removing the dam must also be taken into account. Barrage dams in specific are a form of dam that has a series of gates that control the amount of water passing through it. A barrage dam can be used to divert water for irrigation needs or limit the amount of water down-stream. In most cases, a barrage dam is built near the mouth of the river. The site of dam construction needs to be thoroughly investigated to insure that the foundation is strong enough to support the dam and has low possibility of failing. When dams are created, they are given a safety rating depending on the type of dam, location, and the possible effects in case of failure. The ratings are from one to five, five having the highest danger rating. The rating of five would be given to dams built with a town or city downstream that would have higher possibility of injury to people in the case of dam failure. New designs have been made that are able to sustain greater amounts of water. An improved wedge-shaped block technology was developed by Rafael Moran and Miguel Toledo. The new structure is able to withstand severe flooding and use less materials, reducing the production cost. Not only could this design save money, but it also can save lives and would increase the safety rating.

picture of barrage dam

Environmental Impacts

           Dam construction comes with several impacts that can affect the economy and the environment. In specific, there are several ways in which the environment can be affected from dam construction. Specie richness is usually measured to determine the effect of a dam on the ecosystems surrounding dams . To observe the specie richness, scientists collect data on the fish and animal populations before and after construction of the dam. With that data, they are able to see how the population size increased or decreased. In some cases, it was found that the specie richness was less downstream from a dam compared to further upstream. Inhibiting the volume of water was shown to be detrimental to species diversity and richness. Also, at the entrance of dams, there is less nutrients due to the high-water flow reducing the ecosystems reproduction standard. Along with the specie richness, plankton diversity can be an indicator of the ecosystems ability to handle the newly built dam. It has been shown that dams can have an effect on the migration of fish leading to less reproduction. There are many small factors that can have relatively large impacts that effect the river ecosystems, such as the specie richness, volume of water, and nutrient levels. Different experiments have been done that look into each of these individually and were able to determine why some dams cause such impacts. While there is substantial evidence and case studies that point to dam construction having environmental impacts, there are also studies that show less damage than expected. Looking at plankton near some dams have shown that plankton are able to continue to live although changes to their habitats. Changes such as the pH levels near dams have been recorded and plankton were minimally affected. Other species, however, such as trout, are more affected due to the physical dam inhibiting their migration and reproduction paths. Barrage dams control the amount of water going through them, leading to differences in the amount of water up and downstream from the dam. This discrepancy has different effects on different species native to the area. While there can be reduced flow downstream, there can also be problems upstream. Dams can have buildup of pressure that fish are not accustom to and they migrate further upstream causing that part of the river to have reduced population sizes. Although there are environmental impacts that come with building new dams, there are also many economies that benefit from a dam. Without dams, it would be much harder to farm and grow livestock. The irrigation technology that comes with building a dam can exceed the risk factor.