Pakistan

Pakistan is a low income country in the northwest of the economically poor region of South Asia. For about 200 years prior to 1947 all of South Asia was either directly or indirectly under British colonial rule. When the colonial rule ended in 1947, the British partitioned their possessions in the subcontinent into the two sovereign states of India and Pakistan along religious lines. The modern state of India was predominantly Hindu, while Pakistan was predominantly Muslim. Pakistan has four federating units, Sindh, Punjab, North Western Frontier Province (NWFP) and Balochistan. Pakistan also holds a third of the disputed mountainous region of Kashmir. From the very outset, Pakistan has faced a range of environmental and resource based challenges including, water resources management, environmental hazards (primarily floods, droughts and earthquakes), land degradation, deforestation, rural poverty, and rapid urbanization.

The most important physiographic feature of Pakistan is the Indus basin and its five eastern and one western tributary river. More than 90 percent of Pakistan's population resides in the Indus Basin, which has almost all the arable land of the country. Also, being a predominantly agricultural country, close to 70 percent of the population of the country directly or indirectly depends upon agriculture. Irrigated agriculture is the backbone of Pakistan's agricultural economy. The Indus Basin is home to the largest contiguous surface irrigation system in the world covering approximately 16 million hectares. The irrigation system has enabled the largely semiarid country to have significant increases in agricultural productivity. Most of the agricultural productivity has, however, been achieved by increasing the total irrigated area and not by increase in per unit area yield of crops. Nevertheless, green revolution, high-yielding seed varieties coupled with surface irrigated area expansion have allowed the country to be a major producer of cotton, rice, and to a lesser extent wheat and other food crops.

The contribution of irrigated agriculture to total agricultural production is undeniable. However, the Pakistani irrigation system has been characterized by chronic issues of conveyance inefficiencies, inequity in water distribution, water pollution, and irrigation related water logging and salinity. Pakistan's irrigation system is gravity based where water, diverted from the main stem rivers, flows by gravity to main canals, then to tributary canals, then to individual village water courses. Most of the canals and water courses are unlined, resulting in high seepage losses. The seepage losses in fresh groundwater zones are generally retrieved by farmers by tubewells and water pumps. In brackish groundwater zones, the water becomes unusable once it mixes with the brackish groundwater.

The pervasive water seepage from irrigation channels also leads to raising of the water table [Page 1327]which at times can reach the surface, causing waterlogging of the soil. The groundwater on the surface can subsequently evaporate, but as it evaporates it deposits the salts it leeches from the ground by capillary action on the surface. The deposition of a salt layer on the surface through this process is called salinity. Both waterlogging and salinity render the land unusable for agricultural purposes. Every year Pakistan loses thousands of acres of land to waterlogging and salinity, necessitating either abandonment of the land, or expensive groundwater drainage projects.

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