By Vaqar Ahmed
With the power shortage taking the front stage in the media and in the new government’s pronouncements, an even more important issue has been relegated to the back burner. This serious issue is the future availability of water to support food production in Pakistan.
To put it simply, while we can survive with power shortages, we cannot survive without food. Thus, the criticality of water required for agriculture is even greater than that for power.
While lack of water for domestic use gets attention due to the immediate impact it has on daily life, availability of water for agriculture is brushed under the rug and deferred as there is still enough food to feed the population. This assumption – that sufficient food will be available to a growing population somehow – is closing the eyes to the hard facts relating to the water resources of Pakistan.
Here are the facts:
The Indus Water Treaty (IWT) signed with India in 1961 under the aegis of the World Bank stipulated that the flow from the three Western rivers (Indus, Jhelum and Chenab) will be for the exclusive use of Pakistan while the three Eastern Rivers (Ravi, Sutlej and Beas) will be for India’s use.
The average volume of water flowing into the Indus Basin delta is 142 Million Acre-Feet (MAF). Nearly 95 per cent of this water is used for irrigation. Following is a breakdown of current water usage:
The above figures show that we are close to using all the water. The only additional water that can be made available is 23MAF. To utilise this water, dams need to be built to store it and use it as required. The storage capacity in dams in 2011 stood at 12.1MAF. No new dams have been built in Pakistan since the completion of Tarbela in 1976. Also, the capacity of the existing dams (that was 16.7MAF in 1976), will go down to about 9MAF by 2025 due to silting. There are two projects under construction that will add an additional live storage capacity of 9.3MAF by 2025. These are the raising of Mangla Dam (added capacity 2.9MAF) and the Diamer-Bhasha dam (new capacity 6.4MAF).
One practice that is already causing serious problems is the indiscriminate and excessive use of groundwater (this is the surface water that seeps through the ground) through nearly 1 million tube wells. Groundwater contributes an average of 45 per cent of the total irrigation requirement. While the use of groundwater has greatly profited crop production, the rapid rate at which it is being used is causing serious issues of lowering of the water table and salinity in areas where the water is over-drawn and water logging in areas of below optimal withdrawal.
Supply – Demand Scenarios
The current population of Pakistan is about 173 million and forecasted population for 2025 is 225 million. This is an increase of 30 per cent. Compared to the increase in demand, the additional water available is 19 per cent of the current use. Obviously, this situation would be become much worse by 2050 when the water supply could remain the same, while the population increases to 395 million.
Wapda made an assessment of the water demand for 2025 in the document, “Pakistan National Water Resource Strategy – 2002” and later in a document titled “National Water Policy 2010”. The demand forecast assumes that the cultivated areas needs to increase 48 per cent in 2025 compared to year 2000 in order to support the food requirements of the increased population. Wapda concluded in these reports that since the water supply is limited, it would not be possible to produce sufficient agricultural products if the water and yield efficiency due to non-water means (e.g., fertilizer, improved seeds, better farming techniques etc.) stays at the current levels. Following is a quote from the 2010 Water Policy document:
“In view of past experience, the target of 50 per cent increase in agricultural yields (non water inputs), is achievable and, therefore, additional water of 37 MAF at the canal head should meet all agricultural requirements provided concerted efforts are made, supported by research and other measures besides further improvements in the irrigation network, to enhance the element of demand-based supplies.”
Wapda have thus assumed a 50 per cent increase in crop yield by non-water means to arrive at a demand of 134MAF for 2025. The facts negate this assumption. A comparison of productivity of two major food crops, wheat and rice shows that the productivity increased 29 per cent and 23 per cent respectively during the period 1997 to 2009 (as per Federal Bureau of Statistics). If it is assumed that half of this productivity increase was due to non-water means, the figure drops to 14.5 per cent and 11.5 per cent respectively. Given that Pakistan is seriously lagging behind in agricultural productivity and there is substantial room for improvement a figure of 25 per cent may be achieved by 2025.
For the purpose of determining a range of demand for 2025 and beyond, the following three scenarios have been developed:
Scenario 1: 50 per cent increase in yield due to non-water means (Wapda assumption) Scenario 2: 25 per cent increase in yield due to non-water means (most likely) Scenario 3: No increase in yield due to non-water means (worst case)
Irrigation efficiency of 51 per cent has been assumed for all the three scenarios. Also, 18MAF of storage availability is assumed for all cases.
Scenario 1 in the table below provides the exact calculation used by Wapda to develop the forecast demand for 2025.
Following results and graphs illustrate the water supply-demand for the three scenarios: