By Dr. William Young
November 15, 2017
Persistent myths, which can misguide policy, are barriers to improving water security for the people of Pakistan. Here are five:
First, this problem of water security is often presented as one of water scarcity. But Pakistan is a water-rich country – only 35 countries have more renewable water. It is true that measured for each person, Pakistan is approaching a widely recognized scarcity level of 1000 cubic meters each year. But there are 32 countries that have less water for each person and most of these countries are much wealthier and use less water for each person. Pakistan needs to shift its focus from scarcity to managing water demand and producing more from each drop of water. It needs to make water allocation more efficient and fair, and offer incentives that reflect how scarce water is to encourage wise use.
Second, Pakistan worries about a lack of reservoir storage. Common but misleading measures cited are “storage volume per person” and storage in terms of “average days of water demand”, typically compared to other countries, while ignoring differences in flow variability. Storage is used to buffer the variability of flows to match the time varying pattern of demand. In the Indus flows do not vary greatly between years, partly because of the significant storage the glaciers represent – an asset most countries lack. Thus, Pakistan has little need for reservoir storage from one year to the next. Rather, it needs storage to even out within year variations associated with the monsoon. However, unlike many countries, in Pakistan the timing of flows is not vastly different to the timing of demand, although some storage is needed to capture the monsoon peak and release this water later in the Kharif season and in the early Rabi season. Additional storage would certainly yield additional useable water, but any increase in water use will inevitably reduce the flow to the sea, which is already at an environmentally unsustainable low level. Given Pakistan’s low economic productivity of water in irrigation and rapid rates of reservoir sedimentation, it is hard to justify the costs of major new storages. Hydropower generation does justify new dams, but these could be run-of-the-river facilities (not storage), with lower social and environmental impacts.
Third, there is concern over the loss of the Indus basin glaciers. Upper Indus flows are strongly dependent on snow melt (22 percent) and glacial melt (41 percent). Climate change appears to be affecting rainfall, snowfall and glacier melt but in complex ways with no clear trends. No significant changes in river flows are projected before 2050. Under different climate change scenarios average flows either increase slightly or decrease slightly. Glacial melt is expected to increase, but be offset by snowmelt reductions. A 20-28 percent reduction in ice volume is projected, mostly at lower elevations. The Indus has a greater share of glacial ice at higher elevation than other Himalayan basins, and although faster rates of warming are expected higher up, the absolute temperatures projected would not be enough to drive rapid melting there.
Fourth, irrigation is commonly believed to be highly inefficient in the Indus leading to a common belief that much water could be “saved” by capturing “losses”. At the basin-scale irrigation is estimated to be more than 80 percent efficient, with only a relatively small proportion of irrigation water lost through evaporation and non-productive plant use. The big “losses” are drainage returns to the river and seepage to groundwater, both of which are then used through diversion downstream or through groundwater pumping. Indeed, it is canal seepage and percolation to groundwater that supports the high and increasing levels of groundwater use in the basin. The problems in irrigation are more to do with inefficient and unfair distribution of the water, and low productivity in terms of the yield and value of crops a unit of water used.
Fifth, the flows to the sea are commonly seen as wastage. Average flow to the sea has been falling for more than 80 years. Firstly, the eastern rivers were diverted to India and then storages were constructed in Pakistan. Average annual flow to the sea has been reduced by more than 80 percent. There is strong evidence that declining flows (as well as pollution, reduction in sediment loads and fragmentation of the river by multiple barrages) is contributing to the declining health of the lower river and delta and underminging the valuable services these ecosystems provide including fisheries and coasal protection. The economic value of these ecosystem services has not been properly assessed.
The Indus basin is most likely over-developed from an environmental sustainability perspective in terms of volumes of water diverted for use. There needs to be more focus on better irrigation service delivery and better on-farm water management, coupled with improvements to boost productivity. With a rapidly growing population, Pakistan will inevitably become more water scarce in a relative sense. But Pakistan can become water secure through efficient and sustainable resource management, improved service delivery, and better risk mitigation.
Prior to joining the World Bank, Dr Young in 2013 was the Director of the CSIRO Water Flagship in Australia – Australia’s largest ($100m pa) multi-disciplinary water research partnership, spanning the engineering, biophysical, social, economic and governance aspects of water research across urban, irrigation, environment, and energy sectors. During 2008/9 Dr Young led the river basin modeling work at the Murray-Darling Basin Authority in Australia that guided the development of the first Basin Plan – a major component of the Australian water reform process.