Oct 21, 2009
Till taught by pain,
Men really know not what good water’s worth;
If you have been in Turkey or in Spain,
Or with the famished boats-crew had your berth,
Or in the desert heard the camel’s bell,
You’d wish yourself where Truth is – in the well.
- George Gordon Noel Byron, English poet (1788-1824).
Two centuries after Byron, we are “taught by pain” that we need not go to Turkey or Spain or sea or desert to discern the truth about water – even the well doesn’t hold it anymore everywhere. For instance, though most of Karnataka is blessed with abundant rainfall and the region is fed by many rivers, the ground water levels are falling at an alarming rate and many bore-wells, open wells and water bodies are drying up. This is a global problem and just as wars were waged for oil in the 20thcentury, wars over water are predicted for the current century. India is witnessing inter-state disputes, often erupting in mass violence, over sharing river waters and many projects for damming river water are blocked due to such disputes. There are also neighbourhood fights over well or public tap water or over sinking new bore-wells.
Admittedly there is increasing awareness about conservation of water and there are programs to recharge the ground by arresting run-off of rainwater through barriers of trenches. There are also plans for rain water harvesting either from roof top or from the ground level. City corporations, like in Bangalore, are making it mandatory for new building plans to make provision for rain water harvesting as precondition for passing them. All this is welcome. But there is one area where there is much potential for conserving water which has not been focused on perhaps even at the level of idea. It is proposed to outline this idea and its central action plan. The water bodies are broadly divided into two - flowing water as in rivers, streams and canals and still water as in wells, ponds, lakes, bunds across streams and dams. This proposal is about still water bodies. The stock in these water bodies is accumulated to the brim by inflow of rain water from their watersheds or by subterranean springs which are very active during the rainy season. As the summer season advances, both these sources tend to dry up. So, what remains in these water bodies is the accumulated water. In other words, they become dead storages.
In this situation, if one draws or pumps out 10 litres of water from a total storage of 100 litres, there should be a balance of 90 litres available for further use. In practice, this does not work out that way. As the summer advances and water level goes down, a part of the water evaporates. The heat of the sun directly impacts the surface of the water body and the evaporation rate increases as the water level recedes and the decreased water level/surface induces higher rate of evaporation. Preventing such evaporation is at the heart of this proposal.
This involves covering the entire water surface with non-heat-conducting flexible heat barrier sheets (or evaporation prevention sheets). This is the basic concept which can be validated by a scaled down experiment as follows.
Take three or four wide-necked jars of equal size and capacity. Fill them with water to uniform height. Leave one jar open to the sun without any barrier cover. In the other jars, cover the water surface with a floating barrier of non-heat-conducting sheets made of different materials like Thermocole or some industrial plastics. (The finally winning material, when commercially produced, will get brand names like AquaProtector or AquaSheild or JontySheet, after John Monty). All jars should be placed side by side, ensuring equal exposure to the sun. Over the days and weeks, measure the level of water in the jars. The jar which retains the highest level of water determines the most effective barrier material (See chart-1). Their relative cost comparisons are relevant – but that is a separate matter at this stage and should not bog us down from validating and operationalising the concept.
The Aqua-protection sheets should be flexible and strong to withstand the harsh elements. Flexibility is also required because, as the water level goes down with advancing summer, the sheets should be able to roll over each other at the edges and mid-water joints and remain in overlapped position – curl (See chart-2). They should be available in various sizes keeping in mind portability for transport and spot-fixing. They could be squares and rectangles (for large ponds) or rounds (for wells) with added smaller pieces for peripheral fixing (See chart-3).
The fixing would be like floor marble sheets or interlocking bricks. Like in the case of expansion joints in road concreting, sheets will have breathing space between them and linked with hooks like in the front of blouses or press buttons of kurthas. This would facilitate maintenance or repair as one can approach any spot by de-linking the sheets by manipulating the buttons or hooks and making an approach and exit passage. For spreading the sheets initially or repairing and maintaining one can use a coracles, dug-out boats or inflatable dinghies used in river-rafting or as used by terrorists to land on Colaba foreshore in Mumbai.
If the concept is commercialized, a range of industries can emerge as was the case when plastics came on the scene. Besides the manufacturers of sheets, there would be a distributor chains as the end-user points would be in the rural interiors. There would be stockists and sheet-fixing contractors. It will call for transporters with light commercial vehicles and fixers like marble-fixers or brick-layers (knowing swimming!). Marine industries will have to supply boats and dinghies of various sizes. A parallel for this industry can be drawn from bore-well industry.
Some allied aspects are to be taken care of. In the case of larger water bodies, landing ramps should be provided and sheet covering operations should start at the far end and work backwards towards the landing ramps so that one does not paint himself into a corner. In the interest of marine life, like fish, one or more breathing windows, depending on the size of the water body, should be provided where fish, for instance, can surface and breathe – as we often see happening in such water bodies. There should also be hard-framed floating (wooden) windows in the covering sheets, close to the edge, for inserting water-drawing pots (in the case of wells) and flexible pipes of pumps. Such windows and expansion joints noted earlier will account for less than 2% of the surface area and will not appreciably reduce the efficacy of the evaporation-protection system.
Water has been in focus from Biblical times. The Bible declares: “As water spilt on the ground cannot be gathered up again” – Samuel XIV 14. We have learnt to lick this problem under the recharging method. But, the seepage of water along the walls of still water bodies is yet to be tackled. The evaporation barrier concept can be combined with water-seeping barriers over the walls of still water bodies. The larger upper reaches of water bodies ingest or absorb (seepage) water while lower reaches may host water-spouting springs. It is possible to extend the surface water evaporation barrier techniques to the higher walls of water bodies without compromising the recharge of water from springs which are generally at lower and bottom levels. Such barriers should cover the lowest water mark reached during summer and reach above the highest water mark recorded during rainy season (See Chart 4). It should be fitted snug to the walls so as to totally prevent seepage. Some industrial adhesive, for snugly holding the barrier sheets along the high and low waterlines, may be available, or can be developed, for this application.
In the case of smaller wells and ponds, if it is determined that they are not spring-fed and are merely rain-water storages, they can be totally- bottom and walls – treated with the aqua- protectors so that there is no loss of water through seepage. This is akin to cement-lining of irrigation canals.
As a measure of control of waste plastic pollution and recycling a resource, used/discarded plastics can be used to manufacture protection sheets noted above.
This serious proposal is concluded on a light but relevant note:
Pure water is the best gift man to man can bring,
But who am I that I should have the best of anything?
Let princes revel at the pump, but peers with ponds make free,
Whiskey, or wine, or even beer is good enough for me.
-Anon. In The Spectator, London, July 31, 1920.
It is said that in some places beer is cheaper than bottled water!
John B. Monteiro, author and journalist, is Editor of his website www.welcometoreason.com (Interactive Cerebral Challenger)
John Monteiro - Recent Archives: