A dam is a hydraulic structure used to store water to generate hydroelectric energy. A dam is a barrier built across the upstream flow of a river to create a reservoir. Some other uses of dams include reducing the flooding caused by water in large amounts, and storage of water forming an extensive depth water body is also included in the benefits of dams.

Parts Of A Dam

• Crest: this is the top part of the dam, usually used for transportation from one end to the other. 
• Parapet walls: protective walls on either side of the crest
• Heel: part of the dam which is in contact with the case of the water body on the upstream end.
• Toe: part of the dam in contact with the water body on the downstream end.
• Spillway: an outlet for water removal when the water level rises more than the maximum value. 
• Freeboard: space between the highest water level and the top of the dam.
• Dead storage level: the minimum level of water that will always be maintained inside a dam.

Classification Of Dams Based On Function

Dams perform various functions that help us realise the importance of dams in our everyday lives. 

1.Storage dam

As the name suggests, a storage dam is used to store water during the rainy season. This water is later used during the summers. The water stored in a storage dam can be used to generate hydroelectric energy and also for a flood control project. The water from storage dams can also be used for dishes and aquatic life maintenance.

2.Detention dams

The fundamental purpose behind a detention dam is to reduce the effects of floods. The floodwater capable of causing immediate damage to the surrounding structures is kept trapped inside detention dams and is later released at slower rates. 

3.Diversion dams

These are the dams used to divert the flow of the water towards a conduit. The primary purpose behind a diversion dam is to facilitate irrigation. The height of a diversion dam is comparatively tiny with respect to the other dams.

4.Cofferdams

It is built around a construction site to restrict the entry of water inside the construction site and ensure a dry area for construction. 

5.Debris dams

This dam is used to retain debris such as gravel and wood. This is used for clearing the water passing through the debris dam.

Classification Of Dams Based On Usage

1.Saddle dams

It is a subsidiary dam constructed across a low point along the perimeters of a reservoir. 

2.Weir dams

It is a small overflow dam that we use within the river’s channel for the abstraction of water from it. 

3.Dry dam

As the name suggests, a dry dam is a flood retarding dam that stores water until its capacity to cause flooding is reduced. It is then released in small amounts. 

4.Check dams

These dams check the effects of soil erosion.

5.Underground dams

These dams trap the groundwater for usage in a localised area. 

6.Diversionary dam

The name suggests that a diversionary dam is responsible for diverting the flow of water from a water body.

Importance Of Dams

Some of the advantages of dams are:

1.Power generation

The water stored inside dams can be used to generate hydroelectric power, which is generated when waterfalls from heights. Power generation is included in the importance of dams.

2.Water supply

During the rainy season, water can be stored inside dams, which can then be used during Summers to supply water in arid areas or have a water shortage.

3.Flood prevention

Dams built across a river prevent high flowing water from entering the plains, thus avoiding the occurrence of floods. 

4.Water diversion

Dams can be used to divert the flow of water, which is then utilised to irrigate the fields. 

Effects Of The Construction Of A Dam On the environment

Although the importance of dams in our ecosystem is high, the dams can cause various problems that include: 

1. Setting up dams across the river prevents the migration of fishes from one end of the dam to the other, thus separating possibly rearable fishes, causing barriers between their reproduction and spawning.
2. Dams are capable of causing erosion of the river beds. 
3. Dams reduce the groundwater table.
4. A water reservoir such as a dam is considered the breeding ground for mosquitoes that cause various diseases. 
5. Dams cause the displacement of people from low lying areas around the dams to the high lying areas. 
6. The building of a dam across the river changes the fundamental physical properties of water, such as dissolved oxygen level, chemical changes, change of temperature, etc.

Conclusion

Dams are reservoirs of water that can be used to store water for various purposes. The importance of dams is very high. So, the main uses of dams is that it is used as water reservoirs. The main advantages of dams are the prevention of flood holding water for irrigation and recreational purposes. The primary purpose behind building a dam includes the production of hydroelectric power. Some of the negative impacts of dams include soil erosion, fertility issues, and population displacement.