Daily Times

Water and its availability to the people of Pakistan is the most important national issue at this time.

Nothing can survive without water and our previous governments have failed to effectively address the issue in the last 10 years. It is a matter of selecting priorities. What to choose? Perpetuation of personal power or serving the national interest? Now we are so close to water disaster that an emergency may needs to be declared. In seven years Pakistan will face drought. Dams must be built, but it is at least a10 year timeline even if we move at top speed and if funding is provided.

In this situation it is advisable that all such measures be explored which can help the nation to avoid the impending disaster. As one of the concerned citizens, I tried to consult some experts. Luckily a senior director of Wapda and an expert in alluvial channels responded. Chaudhry Ahmed Masud is also associated with the Munda Dam which met with the approval of President Musharraf but it was ignored afterwards. Unfortunately it seems to be a continuing character of all ‘new’ governments that they ignore all projects of the previous governments, irrespective of the merit of the project. On my request, Mr Masud Choudhry wrote a detailed paper on alternate methods to handle this impending emergency. His paper is detailed and I am taking the opportunity to give its extracts for the readers who may like to further the cause of water conservation. The following are his thoughts:

Water is one commodity that cannot be generated but only conserved. Some scientists conjecture that millions of years ago some celestial body comprising of water collided with earth caused depressions on about two thirds of earth surface and left water in these depressions.

Two recent studies of global water resources provide us with well researched quantitative description of water cycle. It is estimated that annual evaporation from the continents is 70,000 cubic kilometres. Against this the total precipitation received by the continents is around 110,000 cubic kilometres. The effect of hydrologic cycle therefore is to transfer about 40,000 cubic kilometres of water from the oceans to the continents. Most of this is returned through river links, about one third as Base Flow and two thirds as Flood Flow. Of the 14,000 cubic kilometres Base Flow, about 5000 cubic kilometres are located in unhabituated regions, so that the effective world water resource is 9000 cubic kilometres per year.

It is estimated that this water resource base can furnish the water needs of 20-25 billion people provided this resource is prudently conserved and applied. The Indus River and its tributaries provide some 181.3 Bcm (147 MAF) surface water. Out of this some 130.8 Bcm (106 MAF) i.e. 72 percent is being diverted into the canal system, meaning thereby, we are either wasting or losing about 28 percent of surface water. As a matter of fact it is 28 percent of water that requires to be conserved.

“It is needless to say that water conservation for Pakistan is not only the need of the hour but a matter of survival. The only plausible solution to meet this emergent situation is to conserve water by creating sub surface storage reservoirs through augmentation of ground water aquifer. This phenomenon neither involves large expenditure nor any gestation period. There are a number of methods through which sub surface water conservation can be achieved which are not only cost effective but of no gestation periods. These methods are discussed as below:

The Indus River and its tributaries provide some 181.3 Bcm (147 MAF) surface water. Out of this some 130.8 Bcm (106 MAF) ie 72 percent is being diverted into the canal system, meaning thereby, we are either wasting or losing about 28 percent of surface water. It is this 28 percent of water that needs to be conserved

1-Sand dams and sub-surface dams store water under the ground. A sand dam is a small dam built above ground and into the riverbed of a seasonal sand river. Sand accumulates upstream of the dam, resulting in additional groundwater storage capacity. Similar to sand dam a subsurface dam obstructs the ground water flow of an aquifer and stores water below ground level. S  and dams and subsurface dams are suitable for rural areas with semi-arid climate in order to store only seasonal available water to be used in dry periods.

2-A check dam placed in the ditch, swale, or channel interrupts the flow of water and flattens the gradient of the channel, thereby reducing the velocity. In turn, this obstruction induces infiltration rather than eroding the channel. Check dams could be designed to create small reservoirs, without the possibility of silting. Such check dams or delay action dams are most suitable in hill torrent areas. These can be built with locally available material and labour.

3-Spreading Basins: This method involves surface flooding of water in basins that are excavated in the existing terrain. For effective recharge highly permeable soils are suitable and maintenance of a layer of water over the highly permeable soil is necessary.

4-Recharge Pits and Shafts: Conditions that permit surface flooding methods for artificial recharge are relatively rare. Often lenses of low permeability lie between the land surface and water table. In such situation artificial recharge systems such as pits and shafts could be effective in order to access the dewatered aquifer.

5-Recharge wells: Recharge or injection wells are used to directly recharge the deep-water bearing strata. Recharge wells could be dug through the material overlaying the aquifer and if the earth materials are unconsolidated; a screen can be placed in zone of injection. Recharge wells are suitable only in areas where thick impervious layer exists between the surface of the soil and the aquifer to be replenished. These are also advantageous in areas where land is scarce. A relatively high rate of recharge can be attained by this method.

Some of the advantages of a subsurface dam are as follows:

1-A subsurface dam does not submerge land in contrast with a surface dam because it stores water underground. Therefore, it does not seriously damage the environment, nor does it cause social problem such as the forced migration of local people.

2-A subsurface dam does not lose reserved water by evaporation because water is stored underground and there is very little evaporation, in contrast with a surface dam that often loses a significant of amount of reserved water due to evaporation in dry season in arid or semi-arid areas.

3-Reserved water using a subsurface dam is of fairly of good quality because it is stored underground, and it can be used like ordinary well water, in contrast with using a surface dam that tends to proliferate, parasites, anopheles that transmit malaria, and germs, and requires purification for domestic use.

4-In general, a subsurface dam is more stable than a surface dam from the viewpoint of dynamics because it is buried underground, and thus does not need maintenance. Even if it breaks, there is no damage to the downstream area because the breakage occurs underground.

5-Shallow groundwater consumed via a subsurface dam system is renewable because it is charged with rainfall. Therefore, subsurface dam does not exhaust water resources.

6-In view of the foregoing the only quick, short term, inexpensive and reliable solution to water conservation is sub surface storage till such time we are able to construct large reservoirs. Action as proposed above if found feasible would need further studies and surveys to locate suitable areas and local indigenous material and works to trap surface flows for conservation in sub surface storage.

These suggestions, which are technically sound, must be seriously considered by the present government. The Imran Khan government has all the good intentions but need expertise to achieve results. They cannot find all expertise within their political party. Distinguished professional do not have time to be active politicians. But there is no shortage of real experts in the private sector, particularly among senior population, who wish well and want to contribute.

The writer is Pakistani theatre, film and television actor, scholar, public speaker, columnist, teacher and dramatist

Published in Daily Times, October 2^nd, 2018.