This documentary focuses on the eco-system and targets the environmentally conscious public. The movie debates in regards to the United States of America (USA) as a Dam Nation and how the existence of more than 75,000 dams in USA has a negative impact on water consumption and the fish species. Knight and Rummel attempt to explain the pros and cons of dams. The movie also features the tale of salmons, which are unable to return to their original spawning grounds due to dams. These create issues for fish companies, the hatcheries that go at a loss due to reduction of number of fishes.
The documentary advocates for change in the United States of America …show more content…
With less water in the rivers, the growth of plants and flow of nutrients is limited causing a high migration rate of fish and other water wildlife. Large mountains of sediment that carry nutrients to ecosystems are evident when dams are destroyed. These dams have held back the sediments for decades, collecting at the bottom upstream. Small fish passages on a dam can allow fishes to freely move around a dam, however, most times dams make it unsafe for the free movement of fishes. The fish species Salmon for instance requires a steady water flow to swim down the river in their early stages and guide them on to the upper side of the river during the spawn period. Stagnant reservoir pools interrupt the migration of fish, consequently expanding their duration of their …show more content…
As a result silt is collected at the bottom of the river. Accumulation of silt in water reduces the amount of water for human consumption. The accumulation of silt buries the fish-spawning habitat hence reducing the chance of fish reproduction. Consequently the fish population reduces due to lack of reproduction. Accumulation of silt above the dam leads to accumulation of pollutants such as heavy metals. The pollution of water is dangerous to both humans and the fishes. It may lead to outbreak of diseases, for instance cholera or typhoid. Heavy metal is carcinogenic hence threatening the human life. The slow flow of rivers trap the gravel, logs and other debris on the upper side of the stream hence lowering its use as food and habitat at the