Hydraulic Structure :Dam - Weir - Barrage

HEADWORKS

Hydraulic Structure which supplies and regulates the supply of water to the off-taking canal is known as headwork.

TYPES OF HEADWORKS

Hydraulic Structure are of two types:

1. Storage Headwork

2. Diversion Headwork

STORAGE HEADWORK

DAM

Storage headwork involves the construction of dam to store the excess water during monsoon and to supply the same during dry period.

Dam is an obstruction built across a stream or a river. At the bank of this barrier, water is collected.

PURPOSE OF DAM

Irrigation, Water supply, Hydro power generation, recreation, flood control

FACTORS GOVERNING THE SELECTION OF DAM SITE

a) Foundation

b) Economy

c) Topography

d) Spillway

e) Material

f) Water tight reservoir basin

g) The value of land property

h) Easy accessibility

i) Healthy living environment

TYPES OF DAMS

Based on use:

i) Storage Dam

ii) Diversion Dam

iii) Detention Dam

Based on Hydraulic Design

i) Overflow Dam

ii) Non-overflow Dam

Based on Material used

A) Rigid dam

  i) Gravity Dam

  ii) Arch Dam

  iii) Buttress Dam

  iv) Steel Dam

  v) Timber Dam

B) Non-Rigid Dam

  i) Earth Dam

  ii) Rock-fill Dam

DIVERSION HEADWORK

It diverts the river water into the canal:

a) It diverts the river water into the canal

b) Regulates the intake of water into canal

c) Controls the silt entry into the canal

d) Reduces fluctuations in the level of supply in the river

e) Stores water for balancing the demand supply over small periods.

PARTS OF DIVERSION HEADWORK

1. Weir / Barrage

2. Divide wall

3. Fish ladder

4. Log channel

5. Pocket or approach channel

6. Scouring sluices

7. Silt prevention devices  

8. Canal head regulator

9. River training works

10. Piers and abutments

11. Protection works

WEIR

Solid obstruction put across to raise it's water level and divert the water into the canal.

TYPES:

1. Vertical drop weir

2. Sloping weir

    a) Masonry or concrete slope weir

    b) Dry stone slope weir

3. Parabolic weir

SILT PREVENTION DEVICES

Minimum velocity 2-3 m/sec

1. Silt excluder 

2. King's vanes

CANAL HEAD REGULATOR

i) 90 to 127 degrees to the axis of weir 

ii) For minimum sediment entry into the canal, 109 to 110 degrees

iii) Crest of regulator 1m higher than under sluice crest.

RIVER TRAINING WORK

i) Protect river from changing it's course and to avoid out flanking (leaving) of structures like bridges, weirs, aqueduct.

ii) To prevent flooding of surrounding area

iii) To prevent the river banks

iv) To prevent minimum water depth

TYPES OF RIVER TRAINING WORK

i) Marginal embankment / levees

ii) Guide banks

iii) Groynes or spurs

iv) Artificial cut-off

v) Pitching of river banks

vi) Pitched Islands

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Engineering & Technology:

Introduction:

When we roam all around, we see a lot of products, high precision machines, and beautiful structures. Some of these are created by nature and some are manufactured by humans to save our time and money.

Have we ever think, why human created these Machines, Structures, Factories, Malls, Hospitals, Schools, Colleges or beautiful buildings.

First use of engineering:

If we talk about ancient time, the first engineered machine was a circular wheel used to transfer stuff from one place to another. Subsequently human wonderfully come to know, how to ignite fire for cooking food.  Have we ever think, how this curiosity comes in human mind to do something innovative and creative for saving time and money.

Engineering:

Engineering is the art of application of Science, Mathematics, advance numeric methods, Physics, common sense and intelligence to solve problems and to help mankind.

Technology:

Technology is up-gradation of engineering techniques to solve problems in lesser time. It may be costly at initial stage but with the passage of time and mass production, cost will come down and it will definitely economical.

Necessity of Engineering and Technology:

Today, world is shrinking. Person at one place can connect with another human mind sitting in far away.  He/ She may be in another country or in another planet. Person can do business or purchase things digitally from another distant corner of world. This all happening due to advancement of technology and engineering techniques.

Direction for implementation of Technology:

One major thing, which I would like to mention that use of technology should be done for the development of human kind in a good way. It will make human more prosperous, happy and save our planet mother Earth from adverse environmental conditions.

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