Article Title: Down Go The Dams
Author: Jane C. Marks
There has been a controversy about whether dams are beneficial or harmful. Some of the pros of dams are that they control flooding and serve as navigation, by stabilizing flow. Their reservoirs provide a supply of water for drinking, irrigation, and recreation. Some cons of dams are that they ruin vistas, trap sediments (needed for deltas, riverbanks and beaches), hinder migratory fish, destroy ecosystems in and around waterways, and displace people. There are about 800,000 functioning dams around the world. However, many countries such as the U.S., Canada, Australia, France, and Japan, have removed or are planning to remove dams. For the past decade or so, the rate of dam removal has exceeded the rate of dam construction. The removal of some dams has been successful; in places where they were removed, water clarity and oxygen levels increased and fish and aquatic insects thrived. However, the downsides of dam removal can cause the release of sediments that have been trapped behind a dam’s walls which can choke waterways, muddying the environment and wiping out insects and algae, which are important food for fish. Also, sediments that aren't washed downstream may provide rich soil for invasive species as they dry out. Before removal of dams, researchers carefully plan on what to do with the accumulated sediments, whether to manage the fishery as a native one, and how to protect the reservoir-resident frogs. The biggest issue with removing dams is how to control what can be a huge accumulation of dirt and debris caused by sediments stuck behind the dam.
I have only seen the Hoover Dam (not in real life, but in the movie San Andreas) and it was HUGE. Removing dams that size will take an enormous amount of money, time, and planning. I think dams are important; they generate energy and their reservoirs provide water for drinking and irrigation. But not all dams are helpful; I guess it depends on the location and environment of the dam. I think it's better to remove small dams instead of those huge, ginormous ones. If dams are going to be removed, scientists need to create the best way to carefully remove dams without releasing sediments and damaging the ecosystem and environment. Otherwise, I think dams are great!
Author: Jane C. Marks
- There are a total of 800,000 dams operating worldwide; most were built after World War II.
- Dams control flooding and some serve as navigation, by stabilizing flow. Their reservoirs provide a supply of water for drinking, irrigation, and recreation.
- Some cons of dams are that they ruin vistas, trap sediments (needed for deltas, riverbanks and beaches), hinder migratory fish, destroy ecosystems in and around waterways, and displace people.
- The rate of dam removal has exceeded the rate of dam construction for the past decade.
- Researchers expect dams to be taken down, especially small ones. Canada, Australia, U.S., France and Japan have removed or are planning to remove dams.
- The removal of some dams has been successful; the Edwards Dam in Maine was removed in 1999 and within years, scores of fish and insects returned.
- In places where dams have been removed, water clarity and oxygen levels increase as flow comes back and fish and aquatic insects thrive.
- Sometimes, dams have blocked invasive species and protected threatened species.
- However, the downsides of dam removal can cause the release of sediments trapped behind a dam’s walls which can choke waterways, muddying the environment and wiping out insects and algae, which are important food for fish. Sometimes the mud trapped by the structures is contaminated.
- Sediments that aren't washed downstream may provide rich soil for invasive species as they dry out.
- Dam removal can create dangers for people living nearby, especially in places with threats of high flooding.
- Before removal of dams, researchers carefully plan on what to do with the accumulated sediments, whether to manage the fishery as a native one, and how to protect the reservoir-resident frogs.
- The biggest issue with removing dams is how to control what can be a huge accumulation of dirt and debris caused by sediments stuck behind the dam. The amount of sediment is weighed against the ability of the waterway to wash them away.
There has been a controversy about whether dams are beneficial or harmful. Some of the pros of dams are that they control flooding and serve as navigation, by stabilizing flow. Their reservoirs provide a supply of water for drinking, irrigation, and recreation. Some cons of dams are that they ruin vistas, trap sediments (needed for deltas, riverbanks and beaches), hinder migratory fish, destroy ecosystems in and around waterways, and displace people. There are about 800,000 functioning dams around the world. However, many countries such as the U.S., Canada, Australia, France, and Japan, have removed or are planning to remove dams. For the past decade or so, the rate of dam removal has exceeded the rate of dam construction. The removal of some dams has been successful; in places where they were removed, water clarity and oxygen levels increased and fish and aquatic insects thrived. However, the downsides of dam removal can cause the release of sediments that have been trapped behind a dam’s walls which can choke waterways, muddying the environment and wiping out insects and algae, which are important food for fish. Also, sediments that aren't washed downstream may provide rich soil for invasive species as they dry out. Before removal of dams, researchers carefully plan on what to do with the accumulated sediments, whether to manage the fishery as a native one, and how to protect the reservoir-resident frogs. The biggest issue with removing dams is how to control what can be a huge accumulation of dirt and debris caused by sediments stuck behind the dam.
I have only seen the Hoover Dam (not in real life, but in the movie San Andreas) and it was HUGE. Removing dams that size will take an enormous amount of money, time, and planning. I think dams are important; they generate energy and their reservoirs provide water for drinking and irrigation. But not all dams are helpful; I guess it depends on the location and environment of the dam. I think it's better to remove small dams instead of those huge, ginormous ones. If dams are going to be removed, scientists need to create the best way to carefully remove dams without releasing sediments and damaging the ecosystem and environment. Otherwise, I think dams are great!