(i) Systems On Upper-Indus Tributaries
The principal canal systems are:from the Jhelum,(a) Upper Jhelum canal,which starts from Mangla,joins the Chenab at Khanki to give its surplus water to the lower Chenab canal,and (b) the Lower Jhelum canal which starts from Rasul:from the Chenab (a) the upper Chenab canal starting from marala and joining the Ravi near Ballokin to supplement the water supply of the Lower Bari Doab canal,(b) the lower Chenab canal from Khanki,and (c) the Haveli system of canals from the Trimu weir below the junction of the Chenab and the Jhelum;from the Ravi,(a) the upper Bari Doab canal,which begins in Madhopur (India),irrigating mainly the Indian Punjab,with only its Lahore branch reaching Pakistan,(b)the Lower Bari Doab canal from Balakot and (c) the Sidhanaj Canals from the left bank of the Ravi at Sidhnal ;from the Sutlej,the Sutlej valley project,in which canals depart from the river Gandas in Ghwala,Sulaimanke,Islam and below the juction of the Sutlej with the Chenab at Panjnad.
The upper Jhelum,the upper Chenab,and the lower Bari Doab canals together form The Triple Project ,which was designed to carry surplus water from the Jhelum to the Chenab ,and from the Chenab to the Ravi.
(ii) Systems On The Indus
The largest dam on the Indus has been built at Tarbela.Other barrages,in descending order along the river,are Jinnah barrage near Kalabagh,part of the Thal project;Taunsa Barrage 290 km.further downstream,which has 100,000 kw power station in addition to diversion works;Guddu Barrage,150 km.upstream from Sukkar;Sukkur or Liodyd Barrage,the oldest barrage on the river,and Ghulam Mohammad Barrage,near Kotri.
(iii) Systems West of The Indus
These include (a) the Swat Canals departing from the river at Malakand (upper Swat canal) and Abazal (Lower Swat Canal); (b) the warsak Multipupose Project on the Kabul River 30 kms.north west of Peshawar which includes a 160,000 KW power plant;and (c) the kurram Garhi Project on the kurram and barren rivers in Bannu tehsil.
In addition to these major projects.Some smaller dams have also been built by the Water and power Development Authority (WAPDA).These include reil Dam,Gomal Dam Multi-Purpose Project Khanpur Dam,and Hab Dam.The Agricultural Development Corporation has set up the small Dam Organization to construct dams of localized utility storing the flood water of hill stream.A number of such dams have been constructed in the dry sub-mountain areas of the north west.
Mangla And Tarbella Dam
The Mangla Dam
Under the Indus Basin Treaty,this is the second largest multi-purpose project designed to control and conserve the flood water of the Jhelum for use mainly as replacement irrigation supplies for the area which was served by the three eastern rivers.On the Jhelum river near the village of the Mangla,about two miles upstream from the regulator of the upper Jhelum Canal and about 20 miles from Jhelum town,a dam of the embankment type has been built.The dam has crest length of about 11,000 feet and its height is 380 feet.The reservoir created by the dam is about 40 miles long,having a storage capacity of 5.5 million acre feet.It is the second largest earth filled dam of our country.The project is providing 400,000 kilowatts of electricity and 88 lakh acre feet water for irrigation purposes.The design of the dam has a provision for future extension.Its height can also be increased about 99 feet and storage capacity can also be increased upto 9.6 million acre feet and electricity generated can also be increased from the present 400,000 k.w. to one million k.w. The Mangla lake has been developed as a fishing centre and a health and tourist resort.This project was completed in 1967.
The Tarbela Dam
This is one of the largest earth and rock filled dam in the world.This dam has been built on the river Indus at Tarbela,15 miles from maripur and 30 miles from Attock.This is also a multipurpose project .The dam has a gross storage capacity of 11.1 million acre feet.It is 9,000 feet long and 485 feet high.A 50 mile long lake has been built behind it.It will provide 21 lakh kilowatts of electricity and 93 lakh acre feet of water for irrigation when completed .It construction started in 1968 under the Indus Basin Treaty,and the dam was completed in 1974.The installation of 10 units of electricity has been completed in 1985.There is proposal of or the tarbela project that 2 large off-channel reservoirs will have to be built to increase storage and lengthen the life of the generating facilities,since silting is expected to reduce the life of main dam.Water from Tarbela will be used in the Haro and Soan Basins and for replacement the supplies will be diverted to the Chashma Jhelum link canal and thence to the Trimmu-Sidhnaj-Mailsi-Bahawal link system.This project will help other barrages to retain the supply of water.