Development of Water Resources

Q) What is meant by natural resources?

Natural resources are the resources made available to man to fulfill their needs by nature.
It can be categorized into:
 Renewable Resources: are those resources, which replenish or renew themselves over a
period of time. Theoretically they are inexhaustible.
 Non-renewable Resources: present in limited quantity and once used cannot be used.

Rivers – Major source of water supply:

Indus System:
 Eastern tributaries include rivers Jhelum, Chenab, Ravi and Sutlej.
o These rivers rise in Himalayas, and passing through Kashmir, they enter the
plains. At Panjnad, all had joined which then joins Indus near Mithan Kot
before entering the Arabian Sea.
 Western tributaries include rivers Swat, Kabul, Khurram, Tochi, Gomal and Zhob.
o These are smaller in size and carry less water than eastern tributaries of Indus.
Rivers of Balouchistan follow these patterns:
 Rivers flowing into Indus like River Zhob, Khandar and the Kalachi river.
 Rivers absorbed into Kachhi Sibbi Plain (located to the West of Sulaiman mountains)
like river Loralai, Bolan and Mula.
 Rivers draining into the Arabian Sea like Hub, Hingol, Mashkel.
 Inland drainage or Hamuns – small rivers with no outlet to the sea. Draining into
shallow depressions called Hamuns.

Q) Explain the water cycle/ hydrological cycle?

 Water reaches the ground from the atmosphere in various ways like rain, hail and snow,
referred to as precipitation.
 Once on surface, water either runs off as rivers and streams (run off), or is utilized by
plants, and soaks into the ground (ground water).
 Water returns into atmosphere through evaporation and transpiration.
Q) What is the importance of rivers to Pakistan?
  Rivers provide water to even those areas where rainfall is extremely low e.g. Southern and
South Eastern Sindh.
 They add to the scenic beauty of an area and provide good picnic resort.
 They help to generate hydro-electricity in mountainous areas.
 Rivers increase fertility of the land by carrying alluvium and organic matter.
 Fishing is practiced in rivers and lakes.
 Rivers provide water for domestic and industrial purposes.
 Rivers supply water for irrigation by canals leading out from dams and barrages.
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Ground Water
Q) What is ground water?
Water that seeps into the ground and saturates by filling pores/spaces in the soil is called
ground water (thus water underground).
Q) How does ground water table rise?
Ground water table rises/ or is recharged by rainfall, river flooding or irrigation network
(perennial canals, dams and barrages).
Q) Problems of rising ground water table?
After canal irrigation, the ground water table rises in all doabs. As a result,
 Salinity &
 Water logging developed
 Agricultural land is lost after the above-mentioned factor, and crops cannot be grown
there.
 Dumping on waste in ground can make ground water toxic.
Q) What are the uses of water?
Water can be used in the following three sectors:
Domestic sector: water uses include drinking, cooking, washing and sanitation.
Industrial sector: water is required in almost all industries. In some industries, it is used as a raw
material, but in other industries it is used for cooling or washing purposes. The amount of water
used varies from industry to industry. For example iron and steel industries require large
amounts of water, whereas cosmetics industries require very little water.
Agricultural uses: at present, over 95% water is used for irrigation purposes in the agricultural
sector.

Q) What is irrigation?
Irrigation is the artificial means of providing water for plant growth.
Q) Why we need irrigation in Pakistan?
In Pakistan, about 75% of the cultivated area is under irrigation. We need irrigation for the
following reasons:
 Most of the areas of Pakistan experience arid to semi-arid conditions.
 Rainfall in Pakistan is inadequate and ineffective, as Pakistan is at the tail end of both
wind systems (Monsoon and Western Depression).
 Spells of high temperature increase the rate of evapotranspiration.
 Monsoon winds (bringing rainfall) are extremely variable in timings and distribution.
 There are long and frequent dry spells after short rainy season.
 Rainfall that occurs in heavy showers is of little use to farmers as land either absorbs too
much water or it drains away too quickly.
For all these reasons, Pakistan needs a well-developed irrigation system.

Q) Name two traditional methods of irrigation and explain them.

 Shaduf: In shaduf system, water is drawn from a well, river or canal by a bucket which
is attached to a pole on one side, and weight on the other.
The bucket is dipped into water by manual labor, and the weight at the other end of the
pole helps in easy lifting of the bucket. (Only a small area can be irrigated by this
method)
 Charsa: In charsa, animal power is used to pull out water from the well.
 Persian wheel: In this, a number of buckets attached to an endless chain (wheel) are
lowered into the well or pond. Another wheel kept on rotating by an ox keeps the buckets
moving in a circle. Each bucket is dipped in the water, filled and emptied into a channel,
which irrigates the land.
(The above three are also called lift irrigation.)
  Karez system: It is a horizontal underground canal in the foothills, having vertical
shafts on the surface. I brings underground water to the surface. It is practiced in
Balouchistan. The underground minimized the water loss through evaporation.
 Inundation canals/flood canals: These are long canals taken out from large rivers.
o They receive water when river is high enough or flooding, which normally
happens in summers.
o So they have water in them only in summers, and provide water to Kharif
(summer) crops.
 Tank irrigation is practiced by constructing mud banks near small streams, making a
small reservoir to store water in rainy or flood season.

Q) What are the disadvantages of traditional/conventional methods of

irrigation?
 These irrigate limited area of land as they can obtain small amount of water only.
 They require manual labor or animals, and are more time consuming.
 They are difficult to build, maintain and use (e.g. karez).
 Inundation canals only flow during rainy season, or when snow melts, water enters the
rivers in summers.

Modern Methods of Irrigation

Q) Name and explain four modern methods of irrigation.
 Perennial Canals:
 These are linked to dams and barrages.
 These have water in them throughout the year.
 Perennial canals provide water to both Rabi and Kharif crops.
(Due to greater water seepage, also cause water logging and salinity)
 Tube wells:
 Tube wells have diesel or electrically operated pumps that can raise water from a depth
of 92 meters.
 Tube wells can irrigate farms of more than a 1000 hectares.
  Tube wells help to lower the water table, thus protecting land from water logging and
salinity.
 Sprinkler/Spray irrigation:
 Sprinklers are connected to public water supply.
 Water is sprayed with the help of powerful water pumps.
 They are used mainly in orchards and market gardening.
Q) Describe the advantages and disadvantages of spraying method
of irrigation for crops.
 Controlled amount of water is sprayed.
 Waste of water is checked.
 Effective for water scarce area.
 Machinery is costly and small farmers cannot afford it.
 It needs electric supply which is not available everywhere.
 Tankers:
 Collect water from the ponds and lakes and provide it to households and fields in case
of emergency.
 This method is expensive and is rarely used for irrigation.

Q) Explain what is a multi-purpose hydal plant or a dam?

 A multi-purpose hydal plant/dam serves more than a single purpose.
 It stores water in the reservoir of the dam.
 Generate electricity.
 Prevents floods.
 Can also be used for fish culture.
 Also lake can be used as a picnic spot.
 For navigation purpose.
Q) What are the differences between small and big dams?
Small Dams Large Dams
 Store water for irrigation (on smaller  Store water for irrigation (on larger
scale). scale).
  Irrigates local areas only.  Irrigates a vast area.
 Supply little or no electricity.  Major suppliers of HEP.
 Silting problem is easier to solve.  Silting problem is difficult to solve.
 Require comparatively low initial  Initial investment cost is very high.
investment (More suitable to Pakistan’s  Maintenance cost is high.
economy).  Construction time is more, no quick
 Maintenance cost is low. results.
 Construction time is less, yields quick  More important for flood control.
results.  More people displaced as a result of dam
 Less important for flood control. construction.
 Less people displaced (have to be  Large dams have greater impact (more
evacuated). negative, and loss of species and
 Small dams have little impact on rivers ecosystem).
and aquatic ecosystem.

Q) What are the differences between a dam and a barrage?

 Dams require mountainous terrain for construction.  Barrages do not require mountainous terr
 Cost of construction is high. could be constructed on flat areas even.
 Dams are primarily built for storage of water and  Cost of construction is comparatively low.
electricity generation.  The purpose of the barrage is to store wat
 Example: Tarbela dam is about 9000 feet in length however, little or not electricity is generate
and 485 feet in height, holding a (man-made) lake  Sukkur barrage is built in Sukkur near S
of 50 miles in length. across river Indus. It is about 5000 feet
It has 66 gates of 18 feet height, and eac
60 feet.
Q) What is meant by siltation?
 Siltation/silting means deposition of silt, mud and sand on the bed of the reservoir.
 It is done as a result of erosion by the river, mostly taking place when river passes
through hilly areas.
 The material brought down by the river is deposited in dam or reservoir.
Causes:
  Rivers erode materials and bring it to the reservoirs.
 Cutting of trees.
Effects:
 Blockage of canals.
 Dams foundation is weakened.
 Reduced storage and electricity generation capacity of reservoir.
Control:
 Afforestation on large scale.
 Cemented embankments of canals to make cleaning easier.
 Installation of silt trap before the water flows into the dam.
 Raising height of the dam to increase the capacity of the reservoir.
Q) How has canal irrigation created problems of water logging and salinity?
 Earlier water available during summers only.
 There was less or no water for the rest of the year – balance maintained between
precipitation (rain etc) and evapotranspiration.
 Water remained available throughout the year, after introduction of canal irrigation,
which increased water seepage and raised ground water table leading to water logging and
salinity.
Q) What is meant by water logging and salinity?
 The rise of the water table (ground water) to the surface due to continuous seepage of
water is called water logging.
 After the evaporation of water, salty patches appear on the ground, which is called
salinity.
Q) What steps can be taken to solve the problems of water logging and
salinity?
 Lining of canals to control seepage of water.
 Canal closure on temporary basis, so that water passes through only when needed for
irrigation.
 Installing tube wells to lower the water table.
 Provide extra water to flush out salts from the soil.
 Planting eucalyptus trees.
  Surface drain to divert water to nearby river or lake.
 Applying Gypsum to soil to treat salinity.
Q) What causes water pollution?
 Dumping of industrial and agricultural waste into lakes and rivers.
 Oil seepage from ships is another cause.
 Dumping of waste into ground can make ground water toxic.
Q) What is meant by the term SCARP?
 Salinity Control And Reclamation Projects – the project used to reclaim water logged
and saline land for agricultural use.
 Tube wells, surface drains are used to lower the water table

Q) Why was the Indus Water Treaty signed?

 With the creation of Pakistan in 1947, Punjab was also divided into East (Indian) and
West Punjab (Pakistan).
 The headworks of Madhupur and Ferozpur canals over Sutlej and Ravi rivers were
handed over to India.
 India came to have control over water flow in these canals, whereas these canals would
drain Pakistani land.
 In April 1948, India threatened to stop the water supply from these headworks.
 A temporary agreement was signed in May 1948 between India and Pakistan.
 However, in September 1960, Indus Water Treaty was signed after a long period of
negotiations, by which Pakistan was given rights over the water of three Western rivers
(Indus, Jhelum, Chenab), and India got three Eastern rivers (Ravi, Sutlej, Beas).
 The treaty was signed through mediation of World Bank, and under this Pakistan was
to construct 2 large dams, 5 barrages, 1 gated syphon, and 8 link canals (a link canal
diverts water from western rivers Indus, Jhelum, Chenab to eastern rivers Ravi etc.).
 Indus Water Treaty was thus signed to resolve water dispute between India and
Pakistan.

Dams
 Mangla dam:
 o River Jhelum
o 147m high
o 4.7MAF storage capacity
 Tarbela dam:
o River Indus
o 148m high
o 9.3MAF storage capacity
 Tanda dam:
o River Kohat
 Rawal dam:
o River Korang
 Hub dam
o Hub river
Barrages
 Chashma barrage (River Indus)
 Rasul barrage (River Jhelum)
 Marala barrage (River Chenab)
 Qadirabad barrage (River Chenab)
Link Canals
 Marala-Ravi
 Chashma-Jhelum
 Rasul-Qadirabad

A link canal diverts water from western rivers to the eastern rivers of Pakistan.

Q) Name two institutions set up by the government to build dams.

 WAPDA
 Small dams organization