Topic: Down Go the Dams
Author: Jane C. Marks
Main Points:
Author: Jane C. Marks
Main Points:
- Decommissioning dams is becoming a regular occurrence as structures age, provide an inconsequential share of a region's power, become unsafe or too costly to repair, or as communities decide they want their rivers wild and full of fish again.
- Removing a dam does not automatically mean a long-altered ecosystem will flourish once more.
- Reality often proves far more complex and intricate than people anticipate.
- People are trying to minimize negative results of removing dams
- 800,000 dams worldwide, 45,000 are large
- Benefits- hydroelectric power makes up of 20% of all electric supply and energy is clean and renewable.
- Dams control flooding and provide a reliable supply of water for irrigation, drinking and recreation.
- Dams displace people and have been controversial in developing the world.
- Structures ruin vistas, trap sediments, stymie migratory fish and destroy ecosystems in and around the waterways
- Conservationists have a long history of opposing dams
- Downsides of dams have become more widely recognized
- Rate of dam removal has exceeded the rate of construction for the past decade or so.
- In previous two years alone, 80 dams have fallen and researchers following the trend expect that dams will continue to come down.
- Successes have driven much of the activity of destroying dams
- Water clarity and oxygen levels increase as flows come back and aquatic insects thrive again.
- As water moves more freely, temperature falls and cold-loving fish return.
- People, in addition to flora and fauna return to enjoy the rivers.
- Biologists have observed these benefits from Wisconsin to South Wales in Australia.
- Problems: release of sediments trapped behind a dam's walls can choke waterways, muddying the environment and wiping out insects and algae which are important food for fish.
- Wave of turbidity can eliminate habitat for filter feeders.
- Mud is rife with contaminants.
- Dams blocked invasive species from moving upriver and into zones above the dam
- Dam removal can pose dangers for people living nearby in places where flood control is crucial
- Sediments stuck behind dams are proving crucial variables when dams are taken down.
- Biggest issue is how to contend with what can be a massive accumulation of dirt and debris.
- If sediments contain high level of pollutants, cost of removing them has to be weighed against the ability of the waterway to wash them away.
- If sediment load is very high and the river's flushing capacity low, engineers might opt to remove the dam in stages, allowing small amounts of sediment to be released at a time.
- Managers and scientists are using all available information about dam removal to make decisions.
- Gaps in our knowledge about ecosystems remain and those working on decommissioning dams recognize they are conducting long term experiments that may have unanticipated results.
Author Purpose:
Author purpose is that they dominion over flooding and contribute a supply of water for irrigation, drinking and recreation. The drawback is that it disturbs homes of humans and the marine organisms that call that area home. The retirement of dams also has pros and cons. Pros of the removal of dams include clearer water. If a dam is removed, the DO levels increase over some time. Cons from removing dams is the worry over sediment. Removing dams can release sediment that would choke waterways and mudify the water. An idea to preserve dams is that they can become part of the restoration plans. Ideas like these could assist the promise to an organization that wants the removal of dams and the organization that wants to keep the dams where they are
Author purpose is that they dominion over flooding and contribute a supply of water for irrigation, drinking and recreation. The drawback is that it disturbs homes of humans and the marine organisms that call that area home. The retirement of dams also has pros and cons. Pros of the removal of dams include clearer water. If a dam is removed, the DO levels increase over some time. Cons from removing dams is the worry over sediment. Removing dams can release sediment that would choke waterways and mudify the water. An idea to preserve dams is that they can become part of the restoration plans. Ideas like these could assist the promise to an organization that wants the removal of dams and the organization that wants to keep the dams where they are
My Thought's:
After reading this article it provided points of both the pros and cons of removing dams. A pro is that it can enhance the location. This means that there would be an increase in tourism, economic benefit to the city/state that has control of the body of water that had a dam. Another pro was that removing dams would permit biodiversity to also increase. A con could be the risk of flooding. Without a dam to stop the water, flooding could cause serious damage.
After reading this article it provided points of both the pros and cons of removing dams. A pro is that it can enhance the location. This means that there would be an increase in tourism, economic benefit to the city/state that has control of the body of water that had a dam. Another pro was that removing dams would permit biodiversity to also increase. A con could be the risk of flooding. Without a dam to stop the water, flooding could cause serious damage.
So what?
Dam's has negative and positive things in earth.
What if?
They weren't any negative sides.
Says who?
Jane C. Marks
What does this remind you of?
Things that has negative and positive values.
Dam's has negative and positive things in earth.
What if?
They weren't any negative sides.
Says who?
Jane C. Marks
What does this remind you of?
Things that has negative and positive values.