give you the information about the components of irrigation system.why Dam, barrage, head works, canal, major canal ,minor canal, water courses and field channels are made and how these works, all these are discussed in this

1. COMPONENTS OF
IRRIGATION SYSTEM

2. WATER SHED
• Water shed is an area which receives precipitation/rainfall and contributes to
the formation of natural flow leading to the development of rivers
• Rate of runoff depends on the vegetations , land topography , degree and
length of slope shape and infiltration characteristics of the water shed
• Appropriate management of watershed can plays an important role in
controlling sediments inflow into the irrigation system

4. RIVERS
• A river is a natural stream which develops as a result of runoff produce
by the watershed
• It receives water from watershed and conveys to downstream system
components through dams and barrages
• Indus , Jhelum and Chenab are the some of the examples

6. DAMS
• A dam is a control structure built across a river
Functions of Dam
1. Storage of water for regulating the flow regimes
2. Originate irrigation canals to facilitates water supplies to irrigation land
3. Raise the head of water for operating irrigation canals
4. Hydropower generation to provide electricity for domestic and industrial use
5. Major dams include Terbela and Mangla though also serves as water storage
resevoir

8. BARRAGES
• A barrage is also a control structure which is built across the river mainly
to raise the level of water and create a limited temporary storage for
facilitating canal operation
• A Barrage diverts river water to the canal through gate operation
• The examples include Trimu, Rohri and Sukkur barrages

10. HEAD WORKS
• A head work is a diversion provided over a main canal to raise the water
level in the canal and to divert the water to branch canals or distributries
• The examples includes head Faqirian

12. MAIN CANALS
• Main canal receives its water supply directly from the river through a
dam or a barrage
• Direct irrigation usually not carried out from the main canal therefor
there are no canal outlets on the main canal
• The examples include upper Jhelum, lower Jhelum, Upper Chenab, lower
Chenab, upper Bari doab and lower Bari doab

14. BRANCH CANAL
• Branch canal take off from the main canal through divergent structure
such as head works and convey water to different parts the irrigated
area through distributaries
• The branch canal usually are not provided with outlets for delivery of
water to the fields excepts special cases
• These include Gugera and Rakh branch canals

16. MAJOR DISTRIBUTARY
• Major distributary (usually called distributaries or rajbah ) take off canal
and some times from main canal and supply water to miner distributaries
or directly to the main water courses through canal outlets
• Examples of major distributaries are Niazbeg,Shahkot and Nasrana

18. MINOR DISTRIBUTARY
• Minor distributaries(usually called minors ) take off from major
distributaries and rarely from branch canal
• These supply water to water courses for irrigation
• Examples include Kamogil minor and Thatti minor as the minor
distributaries of Niazbeg distriburay

20. WATER COURSES
• A water course is defined as any channel that receives water from a
canal or distributary and leads to the farms and fields
• It is operated and managed by the provincial irrigation department (PID)
but maintained by the formers
• One or more water courses based on the size of irrigated area serve
each village

22. FIELD CHANNEL
• Field channel or former branches carry water to the individual field form
the main water courses
• These are constructed , operated , and maintained by the formers
themselves individuals or a groups
• Generally the size of field channel as the same as that of main water
courses because they have carry full flow received from the main water
courses