The Indus Basin Irrigation System (IBIS) of Pakistan is the fourth largest and among the most depleted basins in the world. It supplies water to all sectors and considered the backbone of the economy. The Indus is the main tributary and the others are Jhelum, Chenab, Ravi, Sutlej and Kabul. Over the time the 3 mega reservoirs, 19 barrages, 12 inter-rivers and 45 irrigation canals, and over 120,000 watercourses are installed. The agriculture sector plays a vital role in the national economy, contributes 22 percent to gross domestic product (GDP), employed 45 percent of the labor force.
The IBIS has experienced acute water shortages and has been suffering from intensifying stresses in recent years. Many studies have been conducted to determine the water resources problems just as the World Bank’s “Pakistan’s Water Economy: Running Dry”. It concluded that the capacity of reservoirs is insufficient and likely to decline with increased sedimentation. It would influence on the flows diverted to the canals, and the agricultural economy of the country. Furthermore, the population growth will continue to decline the per capita storage.
Population growth: Water demand is increasing in all sectors, like domestic, industrial, food and energy productions. The population growth not only causes urbanisation, and industrialisation but also enhances the living standards. The current population in the basin is 204 million likely to be 221 million in 2025 and 311 million in 2050. Meanwhile the per capita water availability will be declined to 809 m3 in 2025 and 575 m3 in 2050.
Shift from surface to groundwater use: During the last decades, there has been a shift from surface to groundwater resources, not only for irrigation but also for domestic and industrial purposes. More than 80% of the groundwater exploitation takes place through small capacity private tube wells. In recent years, the number of tube wells for agricultural purposes has significantly increased. That causes an imbalance between extraction and recharges and declining the water table at an alarming rate. There’s an estimated loss of regional water storage of about 10 km3 yr−1. Extreme groundwater table drop has made pumping more expensive. Consequently, many wells have gone out of production, yet the water table continues to decline and salinity increases.
Flooding: Pakistan is the country where heavy flood comes in every third or fourth year. According to the Federal Flood Commission, Pakistan has observed 20 deadliest floods since 1950, affecting 599,459 square kilometers, snatching 11,239 precious lives, and caused losses worth over 39 billion U.S. dollars. Deforestation in the basin has led to increased erosion and sedimentation along with quick runoffs. The depletion of natural wetlands has intensified flooding. The wetlands that once surrounded the rivers regularly took parts of flood waters during monsoon and releasing them slowly in winter.
Increasing the water use efficiency: Irrigation yields in the IBIS are very low; about 25% of the water can be enumerated as conveyance losses in the canal systems. These losses are responsible for the continuous water shortage in Pakistan. The existing irrigation methods are wasteful and larger amount goes to inadequate quality groundwater. The modern methods like drip and sprinkler irrigation enable farmers to utilise the right amount of water in small and frequent quantities. The old infrastructures must be rehabilitated and modernised to avoid water losses and fewer consumptions in domestic, industrial, and agricultural sectors.
Economic measures: The installing licensing and permit systems and establishing tradable property rights did not prove to be effective. Therefore, transforming electricity pricing policies, as the case of Gujrat-India, would have an impact on controlling the groundwater overdraft. There is an urgent need to explore more innovative ways to solve the groundwater over-exploitation problems while maintaining the current levels of agricultural production in view of the increasing population.
Changing food demand patterns: Changing food demand patterns towards more water-efficient food, such as less meat could also be a demand management practice. The meat produced from grain-fed cattle requires twice the water than the vegetables. A diet without meat requires an estimated 2000 L/day to produce, while a diet in grain-fed beef requires 5000 litres of water. Subsidising the fishing could be the better alternative to meat.
Limiting the post-harvest losses: A study conducted by the FAO says that about one-third of food productions are lost or wasted globally. Post-harvest losses of food can be reduced by improving transportation and storage infrastructures. The agricultural wastes during productions and consumption are between 40% to 50%. Per capita food loss in South Asia is about 125 kg/year.
Other possibilities: Apart from the mega reservoirs, the rainwater harvesting, small check dams, artificial groundwater recharge in monsoons, conjunctive surface and groundwater usage, land-use planning, crop diversification, recycling, use of domestic and industrial wastewater for irrigation could be the solutions to Pakistan’s water shortages.