LAHORE, March 28: Asia and Africa are facing an acute shortage of fresh water, according to a study on the world water situation which calls for some serious deliberations and measures to ensure a better tomorrow. The report has appeared in the wake of the World Water Day observed on March 22.

Titled “Water and new technologies,” the study has been carried out by the Global Change Impact Studies Centre (GCISC) of the Pakistan government. It reveals that about three billion of the world’s estimated population of seven billion by 2015 will be living in water-stressed countries — those which would find it difficult to provide enough fresh water to meet the food, material, industrial and household needs of their citizens.

This may lead to intensified competition for water both within countries and among them, observes Prime Minister’s Special Adviser Dr Ashfaq Ahmad in his foreword note to the study. He says among the most destabilising consequences of water stress in Pakistan is the increased vulnerability of irrigated agriculture, which accounts for about one-quarter of its GDP and one-half of employment.

“Irrigated agriculture accounts for about four-fifths of the total cropped area of over 50 million acres, mostly dependent upon direct river flows. The prolonged period of drought at the turn of the century highlighted the country’s vulnerability to any decrease in water supply at the farm or in urban areas.”

The study carried out by Dr Hameed Ahmad Khan of COMSATS and PINSTECH and Dr Imtiaz Ahmad of GCISC quotes the United Nations as saying there are about one billion people living in water-stressed regions and as the population increases, it is estimated that up to 3.5 billion people will face severe water shortage by 2025.

Not only the fresh water in the world is finite, there is no substitute for most of its functions. Of all the water on earth, says the UN, around 97.5 per cent is in the oceans and thus the total fresh water is only 2.5 per cent. In the tropical and sub-tropical regions, rainfall and river runoffs occur in large amounts during very short periods, such as during the monsoon season in Asia.

Hence water is not available for regular human use unless it is stored in natural or man-made reservoirs, aquifers or tanks.

By contrast in the temperate zone river basins, adequate water resources are distributed fairly evenly throughout the year. Most of the fresh water (68.7 per cent) is in the form of snow and ice and almost all of it is particularly inaccessible in the polar icecaps. About 31.1 per cent of fresh water in lakes, reservoirs and rivers is only 0.26 per cent of the total amount of fresh water or 0.007 per cent of all water.

The report further says the global net consumption of water in the agriculture sector is about three times that of the domestic and industrial uses and it is six times in developing countries of Asia. The total loss of water by the world’s reservoirs in the form of evaporation exceeds the total domestic and industrial consumption. Large amounts of groundwater make up part of this water use.

About one-third of the world’s population depends upon groundwater. In many countries, including Pakistan and India, groundwater is also widely drawn to supplement surface water from rivers and canals. In Germany, France and the Netherlands, it constitutes over 60 per cent of water supply, it says.

The International Water Management Institute (IWMI) has stated in its report that irrigated area would need to be increased by 29 per cent to meet food and nutrition requirements by constructing additional storage and diversion facilities to develop 17 per cent more of the world’s primary water supplies. In addition, crop yields would also need to be enhanced by 38 per cent by 2025 from a global average of 3.3 to 4.7 ton per hectare.

As regards building of new water reservoirs, the IWMI study says no doubt they would increase usable water runoffs but they silt up at about one per cent annually. Thus, about 25 per cent of their present capacity will have to be built just to maintain the present level over the next 25 years.

Of all the registered large dams in the world, only five per cent are in Africa and Asia, with even fewer large dams (with the exception of China) in the region where there is large seasonal disparity. Most of the economically under-developed and water-scarce countries are located in this region.

About 55 per cent of all large dams are in North America and Europe where there is not this large disparity of runoff and carry only about 18 per cent of the world population.

Reads the report: “There is an emerging consensus on water scarcity issues around the world. Water experts have agreed that water resources are extremely unevenly distributed in relation to demand concentrations; growing regional and local scarcity cannot be addressed by the old supply oriented measures and agriculture is by far the largest consumptive user of water.

“Asia and Africa have about 73 per cent of the world’s population and suffer from water scarcity.”

Pollution, identifies the report, has become one of the most serious issues responsible for unavailability of suitable water for domestic and industrial purposes, and in many cases for agricultural use. Several countries in the arid zones are facing serious problems with salt balance, as river flows have become fully exploited.

The study says typical examples are Pakistan and the Middle East region. The rapid increase of industrial base in developing countries with rudimental protection checks, leads to the disposal of untreated solid waste and liquid chemical effluents into regular water courses, like streams or rivers and sometimes into lakes.

In many cases the discharge of domestic sewage and effluents released by small-scale industries, within large population centres, significantly pollute the streams and rivers draining the city areas. Several watercourses in Pakistan such as the Ravi (Lahore), Malir and Layari (Karachi) and the Leh stream in Rawalpindi are typical examples of this pollution.

The study apprehends that in the coming decades, developing nations will face an enormous challenge with regard to food scarcity as well. Feeding an increasing population will threaten natural resources, as people strive to push into new territories in search of new agricultural lands. The damage is already evident in some areas of the world.

Among the options it comes up with are agricultural intensification in irrigated areas that will require more water, efficient use and new and sustainable methods of food production. Thus the need of the hour is to save the precious fresh surface and underground water in arid and semi-arid regions of the world.

Desalination of water is a promising prospect and it is quite common in the desert nations of the Middle East, the Caribbean and the Mediterranean. At the global level, about one per cent of the world’s drinking water is supplied by 12,500 desalination plants.

The second option is water conservation that requires community participation to avoid excessive waste of drinking water used in toilets, utensil washing, market food factories, laboratories, religious activities, drains, showers, garden watering, car washing and similar activities.

There is also a need to check the underground leakage of water in supply lines. Other steps could be metering of water supplies, water-efficient surveys for inspection of leaky plumbing, offering advice with water-efficient fixtures and low-flow showerheads etc.

Water for irrigation could be saved by lowering the delta for irrigation (level of water in the furrows), watering of alternate furrows, and by adopting new watering options and practices such as by sprinklers and trickle irrigation schemes.

Yet another option is recycling of waste water, specifically domestic. South Africa is currently augmenting its water supply by reuse of 4.6 cubic kilometer per year of its municipal and industrial waste water, adding about eight per cent to its water resources. Similar approach could be adopted by other developing countries, suggests the report.

It adds that the volume of waste water generated in the coming years will be quite high, projected at 326 cubic kilometres in Europe, 431 cubic km in North America, 590 cubic km in Asia and 559 cubic km in Africa.

The study concludes with the message that water should be utilised with utmost care as future prosperity will depend to a considerable extent on how we harness fresh water resources and conserve and treat waste water.

For food security for the increasing population, major changes in agricultural practices and iririgation schemes have to take place in terms of productivity of water, structural distribution and water management practices, besides technological improvements that result in end-use efficiency.