Water Resources of Pakistan

Land & Water Resources of PakistanDr. Muhammad Anwar Baig6th February 2013THE INDUS VALLEYThe Indus Valley has been regarded in the history for its outstanding agriculture and industry. The River Indus has been playing a pivotal role for the large civilizations emerged around its banks. The major cities of theIndus Valley Civilization, such asHarappaandMohenjo-daro, date back to around 3300 BC, and represent some of the largest human habitations of the ancient world.The Indus has formed a natural boundary between the Indian Subcontinent and its frontier with the Iranian Plateau, a region which includes Pakistan's Balochistan, Khyber Pakhtunkhwa (KPK) as well as Afghanistan, Tajikistan and Iran. Originating in the Tibetan plateauof western China in the vicinity of Lake Mansarovar in Tibet Autonomous Region, the river runs a course through the Ladakh district of Jammu and Kashmir and then enters Pakistan via the Northern Areas (Gilgit-Baltistan), flowing through the North in a southerly direction along the entire length of Pakistan, to merge into the Arabian Sea near the port city of Karachi in Sindh. The total length of the river is 3,180 kilometers and it is Pakistan's longest river.

THE INDUS BASINThe Indus River Basin is spread over four countries Pakistan, China (Tibat), Afghanistan and India. About 65 percent of the Basin is located in Pakistan, while 10 percent is in China, 10 percent in Indian Occupied Kashmir, 8 percent in Afghanistan and 7 percent is located in India.

Indus River Basin is the largest Basin of the country and covers 70 percent of the area of Pakistan. It consists of mountainous areas of the north and the west, the Indus Plain, the Kacchi Plain, the desert areas of Bahawalpur and Sindh and the Rann of Kutch. On the north, it is surrounded by Hindu Kush range, on the north-east by Karakoram and Harmosh ranges, on the western side by Sulaiman and Kirthar ranges while Arabian Sea forms its southern boundary. The Himalayan mountains have highest peaks in the world (8600 m above MSL) with vast deposits of snow and ice having the capacity to block and capture the monsoon winds and their moisture. Hindu Kush and Karakoram mountains form the great divide which separates the Indus Basin waters from that of the Central Asia. About 43 percent of the area of the Basin is mountainous while the remaining consists of dissected plains or flat plains The Indus and its major tributaries flow in longitudinal valleys in structural troughs parallel to the mountains and after cutting through the mountains following steep and confined channels, emerge into the alluvial plains which stretch over a distance of some 1500 km to the tidal delta near the Arabian Sea. These vast alluvial plains of the Indus Basin are called the Indus Plain.The Indus Plain has been formed by the enormous amount of alluvium brought down by the mightily Indus and ancient rivers in geologic times and the modern tributaries of the Indus meandering in the plains over thousands of years.The total length of the Indus from Mansarwar Lake to the Arabian Sea is 3,178 km.The catchment area of the Indus River System is 944,164 Sq. km.

Climate and MeteorologyClimate of Pakistan is Desert or near DesertHalf of the country receives < 250 mm(10) rainSome zones receive over 2000mm (800 rainfall in northern portion of countryHighest elevations receive upto 500mm (20)Max precip received a 4000 6000 feetDistribution of rainfall is seasonal- in summer it monsoon circulation from southwest originating from Bay of Bengal .Move across Gangatic plains and by the time reaches Indus plains, its intensity decreasesThe highest rain falls at the strip of landbelow foothills in Sialkot, Jhelum, Gujrat and Rawalpindi

Rainfall Intnsity towards Himalayas decreases and similarly towards south plains it is lowArabian sea also generates summer storms but intensity decreases as it moves inlandSouthern Punjab and Northern Sindh areas receive lowest rainfallWinter precip is from west and northwest windsAbove salt range the area of Pothowar and districts of Jhelum, Attock, Rwp and Mianwali are Barani areas

The Indus river system is combination of Indus and its tributaries has great amount of variability in flow over time and space.Indus is more of a snow fed riverIs tributaries viz Jhelum, Chenab, Ravi and Sutlej depend on rainfall for their flowsMost of the flow come as a single flood following snow melt or heavy rains unless captured b reservoirs Heavy rains cause flooding in the plainsGeology of Indus and other PlainsPakistan area has THREE categories namely:Sedimentary and Volcanic rocksOphiolites and Melange rocksIntrusive and metamorphic rocksThe second and third are in upper mountainsNorthern part of Pakistan are in Tectonic belts where activities have been observed

The Punjab plain is a sedimentary plain with a gentle southward slope averaging 0.019% .The only break in the alluvial monotony is a some broken outcrops between 35 to 500 m (100 to 1600 feet) near Sangla and Kirana