Скачать или смотреть Dams and Reservoirs - Health Risks and Benefits

Learn about the purposes and consequences of dams and reservoirs e-learning explainer video.
https://dynamicearthlearning.com/dams...

A dam is a barrier that prevents or restricts the flow of water or groundwater. Dams have been used for agricultural, industrial purposes, and domestic use for thousands of years. In this graphic article, we’ll consider different ways dams and reservoirs help achieve economic, environmental, and energy goals.

Lesson plan:
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IRRIGATION
Irrigation refers to the process of providing water for crops to meet their water needs. It provides water for growth, development, germination, and other related functions of plants. 30-40 percent of the lands that are irrigated globally rely on irrigation dams. Studies show that irrigation dams typically fail to reach the expected target because of the managing or engineering deficits. However, irrigated areas have increased from 70 to 100 percent for the past ten years.

HYDROELECTRIC POWER
Hydroelectric power
These dams can collect gravitational potential energy to provide a portion of needed electrical power. Around 19 percent of the electrical power supply worldwide comes from hydroelectric dams.

Most hydroelectric power generation comes from the energy of flowing water that drives turbines and generators, so basically, the power is extracted from the water current.

SUPPLY WATER
Most commonly, reservoirs are enlarged natural or artificial lakes created using a dam. Reservoir water can be used to supply water to our homes and factories, after it is sent to special treatment plants, to make it safe for drinking.


FLOOD CONTROL
Reservoirs can prevent downstream flooding by maintaining and regulating the water flow during floods. They also balance water flow based on weather conditions, by holding water back during heavy rains and releasing more during a dry spell.

ENVIRONMENTAL AND SOCIAL COSTS OF DAMS
Dams and reservoirs are created to provide a benefit to people, but they also can have a disastrous impact on our environment. People that live close to dams are especially impacted.

Environmental Impacts include:

Changing Aquatic Ecosystems

Building a dam in a river leads to vast changes in aquatic ecosystems, causing habitat loss, which is the biggest cause of extinction. Also, reservoirs can change the chemical balance and temperature of a body of water. These changes can make it less suitable for certain fish, which eventually leads to the loss of some of the species or enables predators to easily reach them.

Sedimentation

Dams and reservoirs can decrease the biodiversity of an area. As the flow of water decreases, sedimentation increases. Sedimentation is when particles that would normally flow through an area get caught in one place and settle in the water. Sediment can bury rock beds where fish lay eggs or cover up other important food and habitat features.

Greenhouse Gas Emission

The reservoirs cause rotting vegetation in the water. Through the process of decomposition, the greenhouse gases, methane, and carbon dioxide are released.

Evaporation

Open surfaces of the reservoirs speed up water loss by the evaporation process. Generally, much more water is lost from reservoirs than is lost from the flowing rivers they replaced. Increased evaporation can affect the microclimate and ecosystems of an area.

Seismic Activity

Did you know that large dams can trigger seismic activity (earthquakes)? This is due to changes in stress of the weight of water, or increased groundwater pressure that decreases the strength of the rock under the reservoir.

SOCIAL EFFECTS
Displacement Of People
Population displacement caused by dam and reservoir construction is the most serious social consequence. An estimated 80 million people worldwide have been displaced by dam projects and affected populations are rarely compensated after the displacement.

Human Health Risks
Reservoirs are an ideal breeding ground for parasites, especially mosquitoes. These parasites spread disease to nearby areas and can create serious health problems.

STEPS THAT MUST BE TAKEN
The crucial steps that need to be taken to reduce the social and environmental impacts of dams include:
Demolition of old dams and reservoirs
Increase the effectiveness of existing hydroelectric dams
Alternative energy research and effective usage of water in agriculture
Build new dams in an area where environmental and societal damage will be minimal

To sum up, ensuring that the construction of dams is in the least environmentally harmful areas will be hard, since the most environmentally friendly may not be the most economical. #middleschool #distancelearning #onlinelearning #homeschool #virtuallearning #earthday #sustainabilityeducation #scienceteacher #middleschoolscience