Water Resources of Pakistan

Water Resources of Pakistan

1.Rainfall

The major sources of rainfall in pakistan are western depression (december-march) and monsoons (july-september). During the kharif and rabi seasons, the entire indus plain receives an average rainfall of 212mm and 53mm respectively.

In recent years, there has been an increase in the intensity and the incidence of floods which is unfortunate for a country where nearly 40% of the people are directly affected by climate change especially as rainfall patterns have become unpredictable. From 1998-2001, the southern and central parts of the country experienced extreme drought conditions while in 2010, severe flooding destroyed over 700,000 homes.

2.Glaciers

Of pakistan’s total area, nearly 13,680 sq km is covered by glaciers that help boost river turnoff in warm weather. According to scientists, in just a period of 30 years, glaciers in the himalayas have diminished by nearly one-fifth and it is believed that glaciers in this region will have disappeared by 2035 the effects of which will be devastating for the 1.3 billion people living in downstream river basins provides food and energy. (AFP, 2011)

The hindu kush-himalayan-tibetan region is also known as the ‘third pole’ for its potential in contributing to rising sea levels as the area has experienced a rise in temperature of 1.2 degrees celsius over the past 120 years which is greater than the increase in the global temperature. (AFP,2011) as a result of this enhanced warming, glacial retreat is accelerating across much of the region, with himalayan glaciers retreating faster than the world average.

3.Indus River System

Watered by the glaciers of the hindu kush and the karakoram, indus is the largest river of pakistan and the primary source of freshwater,it helps fulfill household and industrial needs and support nearly 90% of agriculture. The eastern tributaries of the indus are jhelum, ravi, chenab and sutlej. According to the indus water treaty (1960), india was given control over beas, ravi and sutlej due to which they are left with less water as they flow into pakistan.

There are number of small rivers which join the west of the indus of which biggest river is kabul. Other rivers include swat, tochi, kurram and gomal. The volume of these rivers increases during summers due to the melting of snows but decreases during the winter season.

4.Dams

Of the two major dams, the mangla reservoir had an initial capacity of 5.88 million acre-feet (maf), which came down to 4.674 maf in 2005 owing to sedimentation. This created the need for a dam raising project aimed at raising the height by that was completed in 2009 at a cost of rs. 101.384 billion. This project effectively raised the dam height to 1242 feet from 1202 feet and increased storage capacity to 7.39 maf.

The tarbela dam (constructed to store water for the indus) is the largest earth filled dam in the world and the reservoir has a surface area of nearly 250-square-kilometre (97 sq mi). It was initially predicted that the lifespan of the dam would be around 50 years due to the fact that the river carries huge amounts of sediment (estimated at about 430 million tons per year) which is now expected to extend to 85 years since inception. (Naseer,2013)

5.Surface water

River indus and its tributaries supply 154 maf of water annually: the westerns rivers contribute144.91 maf of water while the eastern rivers bring 9. 14maf. Of the 154 maf, 104.73 maf is used for irrigation purposes, 39.4 maf flows to sea and about 9.9 maf is lost to seepage, evaporation and spill during floods. (Ahmed, Chaudhry and Iftikhar, 2007:7)

The indus basin irrigation system consists of 16 barrages, 3 major reservoirs, 2 head-works, 2 siphons across major rivers, 44 canal systems, (23 in Punjab, 14 in Sindh, 5 in KPK and 2 in Balochistan), 12 inter river link canals and more than 107,000 water courses where the total length of canals is nearly 56,073 km. According to pakistan water strategy report, the system also makes use of 41.6 maf of ground water in addition to canal supply with the help of 500,000 tube wells.

However, with increasing pollution owing to inadequate sewage disposal systems and dumping of industrial and agricultural waste, the quality of surface water is deteriorating. The effects of pollution are not just limited to surface water- groundwater is equally threatened by it. Already about 36% of groundwater is classified as highly saline due to salt intrusion and excessive mining has caused water tables to fall. (Naseer,2013)

Literature Cited

1.     Ahmed, A., H. Iftikhar and G.M. Chaudhry . PSDE23. Pakistan Institute of Development Economics.

http://www.pide.org.pk/psde23/pdf/Ayaz%20Ahmed.pdf (accessed 16-02-16).

2.     AFP. "Scientists confirm Himalayan glacial melting." Pakistan Today.

http://www.pakistantoday.com.pk/2011/12/05/news/foreign/scientists-confirm-himalayan-glacial-melting/ (accessed 16-02-16).

3.     Naseer, E.2013. Pakistan’s Water Crisis.

http://spearheadresearch.org/SR_CMS/wpcontent/uploads/2014/01/Pakistan_Water_Crisis_part-1.pdf (accessed 16-02-16)