Lec-7 Types of Canals

Based on the Nature of Supply Source

1. Permanent Canal: Gets a constant water supply from dams or reservoirs. Reliable
and used year-round. Designed for consistent irrigation or other uses.
2. Inundation Canal: Depends on seasonal floods from rivers. Water supply varies with
rainfall. Primarily used in monsoon seasons.

Based on Function

1. Irrigation Canal: Provides water to agricultural fields. Enhances crop production.

Vital for farming in arid regions.
2. Navigation Canal: Built for transportation of goods and people. Connects different
water bodies. Reduces transportation costs.
3. Power Canal: Channels water to hydroelectric power plants. Generates electricity.
Supports industrial and residential power needs.
4. Feeder Canal: Supplies water to other canals. Acts as a distribution link. Ensures
water reaches various canals.

Based on Discharge

1. Main Canal: Primary canal with the highest discharge. Transports water from the
main source. Feeds branch and minor canals.
2. Branch Canal: Derives water from the main canal. Moderate discharge capacity.
Distributes water to smaller areas.
3. Major and Minor Canal: Smaller than main canals. Deliver water to fields and local
regions. Ensure even water distribution.
4. Watercourse: Smallest canals directly supplying fields. Connects to minor canals.
plays a crucial role in ensuring that water reaches the fields where crops are grown.
Without effective watercourses, the water transported through the main, branch, and
minor canals would not efficiently reach the actual agricultural land, affecting
irrigation and crop yield.
 Based on Lining Provided or Not

1. Lined Canal: Has a lining of concrete, brick, or stone. Prevents water seepage.
Increases efficiency and lifespan.
2. Unlined Canal: No protective lining. the canal is constructed without any artificial
lining, such as concrete, brick, or stone. Instead, the canal bed and banks are made up
of the existing soil found at the construction site. This type of canal is more prone to
water losses through seepage and erosion.

Types of Water Losses in Canals

1. Evaporation:
o Water loss occurs due to the sun's heat.
o Significant in hot, dry climates.
o Can reduce the water available for irrigation.
2. Seepage:
o Water seeps through the canal bed and banks.
o Common in unlined or poorly lined canals.
o Leads to substantial water loss over time.
3. Percolation:
o Water moves downward through the soil layers.
o Recharges groundwater but reduces surface water.
o Influenced by soil type and canal structure.
4. Absorption:
o Water absorbed by the soil and vegetation along the canal.
o Part of natural processes around the canal area.
o Reduces the effective water delivery to the end users.

Water loss in canals can be avoided by:

1. Lining the Canal: Use concrete, brick, or other materials to prevent seepage.
2. Covering the Canal: Use covers or shade structures to reduce evaporation.
3. Regular Maintenance: Fix leaks and clear blockages to ensure efficient water flow.

4. Installing Check Dams: Use small barriers to control water flow and reduce seepage.
5. Using Efficient Irrigation Techniques: Implement drip or sprinkler systems to
minimize water wastage.
The canal system greatly benefits Pakistan's agricultural system in several important ways:

1. Reliable Water Supply: Canals provide a consistent flow of water to farms, which is
especially important in areas that do not get enough rainfall. This helps ensure that
crops always have the water they need to grow.
2. Increased Crop Production: With a steady supply of water, crops can grow better
and produce higher yields. This means farmers can harvest more food, which helps
feed the population and can increase their income.
3. Expansion of Farmland: Canals make it possible to farm in regions that were
previously too dry. This allows for more land to be used for agriculture, increasing the
overall amount of food that can be produced.
4. Improved Livelihoods: By providing a reliable water source and increasing crop
yields, the canal system helps improve the livelihoods of farmers. Better crop
production leads to higher incomes, which supports the local economy and improves
living standards.
5. Support for Multiple Crops: With reliable irrigation from canals, farmers can grow
a variety of crops throughout the year, not just during the rainy season. This diversity
in crops helps ensure food security and allows farmers to maximize their land use.
 Lec-8 Pakistan Canal System:

• Overview: The canal system in Pakistan is primarily fed by the Indus River and its
tributaries.
• It consists of a network of canals and distributaries that supply water for irrigation
• In Pakistan there are 12 interlink and 45 canals to meet commercial, domestic and
irrigational need of Pakistan

• Importance: The canal system plays a crucial role in sustaining Pakistan's

agricultural economy,

as agriculture is a significant sector contributing to the country's GDP and employing a large
portion of the workforce.

• Types of Canals:
o Perennial Canals: These canals flow throughout the year, providing a steady
water supply for irrigation.
o Non-Perennial Canals: These canals flow seasonally typically during the
monsoon season or when there's sufficient snowmelt from the mountains.
o Inundation canal :Rainy water and seasion is the only time when these canal
run

• Five Major Canals in Pakistan:

• The five major canals in Pakistan include the:

1. Indus River
2. Jhelum River
3. Chenab River
4. Ravi River
5. Sutlej River

A. Indus River: Tibet

• The lifeline of Pakistan's irrigation system,

• The Indus River is one of the longest rivers in Asia,
• originating in Tibet and flowing through China, India, and Pakistan.
• In Pakistan, the river enters from the north and split in Punjab and Sindh provinces,
providing water for irrigation
 A. Jhelum River: Himalayas in Indian-administered Kashmir

1. Originating from the Himalayas in Indian-administered Kashmir,

2. the Jhelum River flows into Pakistan and joins the Chenab River near the city of
Trimmu to form the Chenab River.
3. The Jhelum River irrigate vast agricultural lands in Punjab province, particularly in
the districts of Jhelum and Gujrat.
4. The Mangla Dam, constructed on the Jhelum River, is a key water storage and
hydroelectricity generation facility

B. Chenab River:

• The Chenab River is formed by the confluence of the Jhelum and Chenab rivers near
the city of Trimmu in Punjab province.
• It flows through the heart of Punjab, providing water for irrigation to the surrounding
agricultural lands.
• The river also supports hydroelectric power generation through dams like the Tarbela
Dam and the upcoming Diamer-Bhasha Dam, contributing to Pakistan's energy needs.

C. Ravi River: Himalayas in Indian-administered Himachal Pradesh

• Originating in the Himalayas in Indian-administered Himachal Pradesh,

• In Pakistan, the Ravi River flows through Punjab province,
• where it once had a more significant role in irrigation before its waters were largely
diverted for other purposes.
• Efforts have been made to revitalize the Ravi River and utilize its waters for irrigation
and water supply projects in Punjab

A. Sutlej River:

• the Sutlej River flows through the Indian states of Himachal Pradesh and Punjab
before entering Pakistan.
• In Pakistan, the Sutlej River flows through Punjab province, providing water for
irrigation and supporting agricultural activities in the region.
• The river also contributes to hydroelectric power generation, Sukkur Barrage
harnessing its waters for both irrigation and electricity production.

B. Disputes:

In 1948 after partition of Punjab, India cut off flow of canal water to west Punjab

Stopped water of river Ravi and Sutlej because India wanted to damage Pakistan
economically
Ferozepur and Madhupur head-works were given to India and India cut-off supplies from
Ferozepur on 1st April 1948 which stopped water in Sutlej river

Pakistan also purchased water from India to avoid economic disaster

C. Indus River Treaty:

Background: The Indus Waters Treaty is a deal between India and Pakistan, made with the
help of the World Bank in 1960. Key Points:

• India got three rivers (Ravi, Beas, and Sutlej), Pakistan got three (Indus, Jhelum, and
Chenab).
• It set rules for sharing water data and solving fights.
• India can use some water from Pakistan's rivers for specific projects.

The canal system greatly benefits Pakistan's agricultural system in several important ways:

I. Reliable Water Supply: Canals provide a consistent flow of water to farms, which is
especially important in areas that do not get enough rainfall. This helps ensure that
crops always have the water they need to grow.
II. Increased Crop Production: With a steady supply of water, crops can grow better
and produce higher yields. This means farmers can harvest more food, which helps
feed the population and can increase their income.
III. Expansion of Farmland: Canals make it possible to farm in regions that were
previously too dry. This allows for more land to be used for agriculture, increasing the
overall amount of food that can be produced.
IV. Improved Livelihoods: By providing a reliable water source and increasing crop
yields, the canal system helps improve the livelihoods of farmers. Better crop
production leads to higher incomes, which supports the local economy and improves
living standards.
V. Support for Multiple Crops: With reliable irrigation from canals, farmers can grow
a variety of crops throughout the year, not just during the rainy season. This diversity
in crops helps ensure food security and allows farmers to maximize their land use.
Lec-9

Regulation Works HR,CR,DHR,CF,CE,CO

Any structure constructed to regulate the discharge, velocity in a canal
is known as Regulation Work
Types, Locations, and Functions of Regulation Works:

1. HR (Head Regulator or Head Sluice): This refers to a structure located

at a barrage, weir, or dam, which controls the flow of water into the main
canal from the river or reservoir. Its primary function is to regulate the
entry of water into the canal system, ensuring a controlled and steady
flow for irrigation purposes.
2. CR (Cross Regulator): This is a structure positioned on the main or
parent canal. Its function is to regulate the flow of water within the main
canal and divert some of it into off-take channels or distributary canals.
Cross regulators help in distributing water to different areas or fields
according to their irrigation needs.
3. DHR (Distributary Head Regulator): This refers to a structure located
on off-take canals, which are smaller canals branching off from the main
canal. The distributary head regulator controls the flow of water into
these off-take canals, ensuring that each receives the required amount of
water for irrigation.
4. CF (Canal Fall): This term denotes a structure situated along the main or
off-take canals. Its function is to lower the water level in the canal,
typically by creating a small fall in the canal bed. Canal falls help
maintain a consistent slope in the canal, facilitating the smooth flow of
water downstream.

types of canal falls:

1. Ogee Fall: A smooth, curved structure in the canal that slows down water
flow gradually to prevent erosion.
2. Rapid: A section where water flows swiftly over rocks, maintaining its
speed without causing turbulence.
3. Stepped Fall: Built with steps or levels in the canal bed to reduce water
velocity by allowing it to descend in stages.
4. Notch Fall: A V-shaped opening in the canal bed that controls water flow
by creating a drop in water level.
 5. Vertical Drop: A direct descent of water from one level to another, used
to manage water levels effectively.

5. CE (Canal Escape): Canal escapes are structures that allow excess water
to be released from the canal system, preventing overflow and potential
damage to canal embankments during periods of heavy rainfall or sudden
increases in water flow. These structures are vital for managing water
levels and ensuring the safety of the canal infrastructure.

Canal Escape Types Based on Purpose:

• Scouring Escape: Releases excess water to prevent sediment buildup and maintain
canal capacity.
• Surplus Escape: Discharges excess water during high flows or heavy rainfall to
prevent canal overflow.
• Tail Escape: Located at the end of a canal, releases water after use to manage
irrigation efficiency.

Canal Escape Types Based on Design:

• Regulator Type: Uses gates or valves to control water flow for precise level and
distribution management.
• Weir Type: Utilizes a low dam-like structure across the canal to create shallow
overflow, managing water levels and preventing flooding.

6. CO (Canal Outlet): This refers to a structure located on distributing

canals, which are smaller canals that deliver water from the main or off-
take canals to individual fields or watercourses. Canal outlets provide
controlled access to water for irrigation purposes, allowing farmers to
regulate the flow of water to their fields according to their needs.
The purpose of an off-take channel is to divert water from a main canal to smaller distributaries or
directly to fields for irrigation purposes.