Pakistan's Water Resources: -- Problems and Remedies
Pakistan is largely an arid to semiarid country with an average annual rainfall of about less than 100 mm in parts of lower Indus plains to more than 750 mm in the northern foothills, against crop water requirements ranging from 1487 mm in Jacobabad, Sindh, to 900 mm in Paraehinar, NWFP, 1280 mm in Faisalabad, Punjab, and 1400 mm, Turbat, Balochistan. Therefore, agriculture in the country heavily depends on the irrigation supplies delivered by the Indus Basin Irrigation network. This Indus Basin Irrigation System comprises three storage reservoirs. 19 diversion barrages, 12 link canals, 43 canal commands, and over 100,000 community watercourses irrigating an area of about 16 million hectares (Mha) out of about 31 Mha of cultivable land available. Most of the development of this irrigation system took place because of the Indus Water Treaty signed in September 1960 between India and Pakistan over water conflict.
Soon after independence on April 1, 1948, India unilaterally stopped the water supplies to Central Ban Doab Canal (CBDC) and Dipalpur Canal, claiming her sovereign right over the water passing through its territory. The control of the headworks regulating flows to these canals was with India. The border line between the two countries was drawn in disregard to the irrigation supplies. This water conflict, however, was settled through good offices of the World Bank in the form of Indus Water Treaty. As a result of this treaty, India was given the right to make exclusive use of the three eastern rivers (Ravi, Sutlej and Beas) with an average annual flow of about 43 million acre-feet (MAF. Under this treaty, Pakistan got the right to make full use of the three western rivers (Indus, Jhelum and Chenab) with an average annual flow of about 140 MAF. Also, the World Bank provided assistance to Pakistan to augment its irrigation supplies by diverting water from the western rivers to the eastern rivers so that areas af fected by this treaty can be irrigated. Under this agreement, two reservoirs (Mangla and Tarbela), eight link canals (Trimmu-Sidhnai, Sidhnai-Mailsi, Mailsi-Bahawal, Rasul-Qadarabad, Qadarabad-Balloki, Ballok-Suleimanki, Balloki, Balloki-Suleimanki, Taunsa-Panjna, Chashma-Jhelum), and six diversion barrages (Chasma, Rasul. Qadirabad, Marala, Sidhnai, Mailsi Syphon) were constructed to provide alternative sources of water to feed the eastern canals affected by this treaty.
After construction of Tarbela reservoir in 1974, no single reservoir has been added to the Indus Basin Irrigation system so far, while India and Turkey built 24 and 65 dams respectively during the same time period to meet the food, and fibre demands of their growing population. The population of Pakistan has crossed the limit of 140 million in year 2000 and will be doubled in 2025 with its present alarming growth rate of 2.8 per cent. More than 70 per cent of the country's population is engaged directly or indirectly in the agriculture sector. Agriculture is considered the backbone of Pakistan's economy and its sustainable production depends on the irrigation water availability. Pakistan is facing acute shortage of water supplies and water availability per capita has reduced from 5300 cubic meter in 1951 to 1200 cubic meter in 2000 against the international standard of 1500 cubic meter. Moreover, flows in the Indus river to the Arabian sea after Kotri barrage has been found to vary from eight MAF in 1999-2000 to 45 MAF in 1996-1997, which need to be conserved.
The situation of water storage reservoirs in the country is also discouraging because the storage capacity of the two main reservoirs (Mangla and Tarbela) is being lost at the rate of 0.033 MAF, and 0.15 MAF per year, respectively, due to silt deposition. Mangla reservoir has lost its storage capacity by 20 per cent and Tarbela by 43 per cent in year 2000.
According to an estimate, water deficit will increase from 41 MAF in year 2000 with population estimate of 148 million to 108 MAF in year 2013 with the projected population of 207 million. …