What Is Dam? | Parts of Dam | Types of Dams


What Is Dam?

A dam is an artificial barrier that prevents the flow of surface water from moving forward.

Reservoirs are formed by collecting huge amounts of water through dams. The dam can supply water for various activities like irrigation, human consumption, industrial consumption, and aquaculture.

Hydropower plants can be set up together with various dams to generate electricity. Dams are commonly used to store water.

Different types of dams are used in different situations in the world. These dams include Gravity Dams, Earth Dams, Rockfill Dams, Arc Dams, Butters Dams, Steel Dams, Timber Dams.

The construction of the dam is done to satisfy the above objectives. Or it may be intended to accomplish more than one goal. Dams are known as single-purpose and multi-purpose dams depending on the number of purposes.

Parts of Dam

1. Crest

The uppermost part of the dam is called the creat. Which is sometimes used for roads/pedestrians etc.

2. Heel

This part contacts the ground of the base surface of the dam in the upstream portion.

3. Toe

This part of the dam is located downstream portion side. This part contacts the bearing surface of the ground at the bottom of the dam.

4. Parapet Walls

This part of the dam is built to build protective walls on both sides of the road on the crest.

5. Spillway

A reservoir formed by a dam has a system near the top of the dam to allow this excess water to pass in the event of a sudden overflow of the dam. Which is called a spillway.

6. Abutments

This part is the defense structure on both sides of the end of the dam. Abutments are protective structures made for the sloping side of the ground.

7. Gallery

It is constructed in the main part of the dam for seepage/leakage and other maintenance.

8. Sluice Gate

A sluice gate is used in the dam to clear silt deposits in the reservoir.

Types of Dams in Construction

1. Gravity Dams

Gravity Dams

The gravity dam is large in size made mainly of concrete or stone. This type of dam is capable of holding a large amount of water behind them.

Gravity dams have the ability to withstand various external forces by their own weight or self-weight. The construction of a gravity dam can usually be done using masonry or concrete.

Various external factors on this gravity dam include pressure, uplift pressure, wave pressure, ice pressure, earthquake pressure, etc.

Therefore a strong and durable base is required to build this type of dam.

The cross-section of the gravity dam is almost triangular in shape. In this type of dam, a gallery is provided inside the dam to resist uplift pressure.

2. Buttress Dam

Buttress Dam

A buttress dam is a type of dam. This type of dam is supported by a series of slight buttresses at downstream side intervals. In this type, the wall of the dam can be straight or curved. Most of the Buttress dams are made of hollow-type reinforced concrete.

The construction of Buttress Dam includes face slab, buttress, and base slab, etc. In this type of dam, the face slab is provided on the upstream side and this slab is supported by a series of buttresses on the downstream side.

The design of the buttress dam can be made straight or curved in the plan. The number of buttresses is determined by the height of the dam. This type of dam is preferred where the soil is very weak. This type of dam can be used for many purposes like installation of water purification plant, power plant installation, etc.

3. Arch Dam

Arch Dam

The arch dam is built with a curved structure over the right location. It resists various external forces coming on the dam through its arch-like structure. This type of dam can be constructed using masonry or concrete. But gravity is less expensive than dams.

Abutments should be strong in this type of dam. Because all the load is transferred over this abutment. Abutments for the construction of this type of dam are usually natural structures like hills. Arch dams are especially preferred for narrow valleys.

Since this type of dam is used in a valley-like location, its length is less than its height. As a result, arch dams are economically advantageous. This type of demo can be made to a greater height in a special case.

4. Embankment Dam

Embankment Dam

embankment dam is an artificial type dam. It is formed by the placement and compaction of various materials of sand, clay, or rock. The surface of this type of dam is semi-extensive like waterproof, dence, and impervious core.

Embankment dams are divided into three different types.

4.1 Homogeneous Embankment

Homogeneous Embankment

Only one type of clay is used for the construction of this type of dam. This is commonly called homogeneous embankment. This type of dam allows water to seepage.

4.2 Zoned Embankment Type Dam

Zoned Embankment Type Dam

Formation of this type of dam An impermeable soil zone is formed within the zone-wise soil layer. In this type of dam, the soil is mixed between the rocks to form an impenetrable area. Normal clay is used to strengthen the outer layer.

4.3 Diaphragm Embankment Dam

Diaphragm Embankment Dam

The formation of this type of dam is the formation of a diaphragm within the soil layer. The design of this diaphragm can be made of concrete, steel, and wood. Which are made using strong materials. This type of Diaphragm Embankment Dam prevents drainage.

5. Steel Dam

Steel Dam

Steel dams are constructed from steel structures. In this type of steel dam, the water pressure is transmitted directly through the struts to the foundation.

A series of footings anchored to the ground has been made for the steel dam. The load of the struts series is shifted on this footing. A load of a series of deck girders is transferred over a series of these struts.

This type of dam is used up to a height of 15 to 18 meters.

Types According to Dam Functions

6. Storage Dam

Storage Dam

Storage dams are usually constructed to store water flowing into the river during the rainy season. This type of dam is used when there is a high demand for water in dry weather conditions. The water stored by this dam can be used for various purposes like power generation, irrigation, water supply etc.

7. Debris Dam

Debris Dam

Debris dams have been constructed in the river to prevent debris in the river water. Materials like sand, gravel, driftwood, etc. are carried in river water. Clear water flows downstream through this type of dam.

8. Diversion Dam

Debris Dam

Diversion dams are typically designed to divert water to other rivers or canals. These types of dams are commonly used to deliver water to irrigation canals.

9. Detention Dam

Detention Dam

The purpose of this type dam is to control floods caused by incessant rains. This type of dam protects the downstream side from flood damage by storing water during the flood period. After the flood period, water collected from this type of dam is released downstream at a controlled rate.

10. Cofferdam

Cofferdam (1)

The cofferdam is commonly used as a diversion dam. A cofferdam is a temporary structure that can be used to divert water flow to other reservoirs to provide a dry area for the construction of the main dam. It is typically built on the upstream side or around the construction site.

11. Hydro-Power Dam

Hydro-Power Dam

Hydro-power dams are mainly used to generate electricity. This dam is used to generate electricity by turning turbines with the help of water moving from top to bottom.

Type According to the Hydraulic Design of the Dam

12. Overflow Dam

Overflow Dam

An overflow dam is a type of dam. surplus water flows from the upstream side through this type of dam. This type of dam allows flow from the crest. This type of dam is also called a spillway dam or over fall dam.

13. Non-Overflow Dam

Non-Overflow Dam

This type of dam does not allow excess water to overflow from the crest. A spillway-like structure is usually constructed in the dam for the release of excess water.

Type of dam according to the storage of the dam.

14. Small Dam

Small Dam

A dam with an approximate total storage capacity of between 0.5 and 10 mcm (million cubic meters) can be defined as a small dam. The hydraulic head of this type of dam can usually be around 7.5 to 12 meters.

15. Medium Dam

Medium Dam

A dam with an approximate total storage capacity of between 10 and 60 mcm (million cubic meters) can be defined as a Medium Dam. The hydraulic head of this type of dam can usually be around 12 to 30 meters.

16. Large Dam

Large Dam

Dams with a total storage capacity of more than 60 MCM (million cubic meters) can be defined as large dams. The hydraulic head of this type of dam can usually be more than 30 meters.

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