Every year, India gets about 4000 Billion Cubic Meters (bcm) of water by way of mostly rainfall and some snowfall. Out of this, it is estimated that 1869 bcm is the quantity that is available in rivers. However, there is considerable spatial and temporal variation in this availability.
“Spatial variation” means the available water is not uniformly distributed all over the country. There is abundance of water at some places while extreme scarcity at some other places. “Temporal variation” means the availability is not uniformly distributed over the year. There is lot of rainfall, and river flow, at some time of the year and almost no rain and very little river flow at some other time of the year.
It is estimated that out of this 4000 bcm of rainfall and snowfall, almost 80% occurs during four months of monsoon and in those four months also, most of the rainfall takes place as a few spells of intense rainfall.
Therefore the amount of water that can actually be put to beneficial use is much less. The total quantity of water that can be used annually is estimated at 1122 bcm, 690 bcm from surface water sources and 432 bcm from ground water sources. Trans-basin transfer of water, also called interlinking of rivers, will enable utilisation of an additional 200 bcm of water.
Water use may be consumptive, i.e. where the water is “used up” in some way; or it may be non-consumptive, where the water is not “consumed” and is available for further use. The quantity of water used by crops and plants for their growth is a consumptive use. Generation of hydel power is a non-consumptive use, because after rotating the turbines the water is returned back to the river. Even when water is diverted for irrigation, or city use, not all of it is consumptive use and a considerable amount returns back to the river or to ground water formations.
Irrigation has always been, and will always remain, the single largest user of water. It is estimated that by the year 2025, 73 bcm will be required for domestic use, 110 bcm for industrial and other uses, and 910 bcm for irrigation. This adds up to 1093 bcm and is very close to the total availability of 1122 bcm. Thus, by 2025 almost all the available water will be claimed.
No one. The situation in India, as also in most of the world, is : the water rights are still undefined. Traditionally, water is considered as “used by all but owned by none”.
For Ground Water (GW) there is a very old law that gives a person full rights to all the water he can extract from the land owned by him. May be this was satisfactory several decades ago, when the demand for ground water was very little. But it is being felt now that some control is necessary on GW extraction.
As regards surface water there never was, and there still isn’t, any law defining any ownership rights. Whatever right is there, it is for usage of water, and not for water as such. e.g. if a person or group of persons have been using water for a certain purpose, then they have a right to continue to use the water for the same purpose, but not necessarily with the same volume of water. And they certainly do not have the right to continue to use that water for some other purpose. So the right is to usage, not to water.
No, this is not true. Such comments are made by those who either do not understand water management or have a vested interest in spreading wrong information, quite often both.
For cities, the domestic use expressed as litres per person per day (lpd) is 150 to 220 lpd which is much more than that in rural areas. This leads some people to believe, or to argue, that cities use too much water. However, the actual quantity of water used by cities is very little.
Let us examine the water use by Delhi. For a population of 13 million (130 lakhs) and a 200 lpd use, the annual use works out to 0.95 bcm and that is only 0.08% of the total availability of water. Of the total flow of Yamuna at Delhi, the share of Delhi for domestic use and other uses, is only 6 %. More than 80 % of water is used for irrigation, mostly in Haryana and Uttar Pradesh.
a) In urban areas, a considerable quantity of water is required for public places like the offices, railway stations, fire fighting etc. though it gets counted in the per person per day domestic use.
b) Larger cities have to have a centralised sewage disposal system which also requires a larger quantity of water.
c) There is a difference in the urban and rural life styles that can not be simply wished away. This difference is not limited to water supply and sanitation and pervades all aspects of life. It is incorrect, even foolish, to expect that cities can live like huge villages.
If there are problems of water availability in rural areas, these are due to local causes and it is not as if the cities are depriving rural areas of water.
Again an instance of deliberate misinformation campaign by some NGOs and individuals. Incidentally, IWRS-DC is itself an NGO and we hold no brief for the Government. However, it is a fact that the views of IWRS are often different from those expressed by a few other vocal NGOs and activists, and are usually consistent with the views of the Government. There are two simple reasons for this.
§ IWRS members are mostly persons who are professionally qualified and have a responsibility to manage our water resources and therefore it is natural that their views are different from those who are not qualified, and have no responsibility to ensure water and food security.
§ IWRS members are invariably professionals and do not have to take recourse to incessant criticism of the Government to remain in limelight and sustain themselves or IWRS.
(In terms of funds, IWRS could well be the poorest NGO. We prefer to be correct, meaningful and responsible, than be rich).
Finally, it is not as if all NGOs are critical of the Government’s actions. In fact a large number of NGOs are actually doing good work, quietly, in the remote areas, away from the seminars and media glare. It is only a few individuals who are the source of all such critical comments. They are very vocal, pay more attention to PR than to water, therefore get quoted profusely, and this creates an impression that what the Government has done, or is doing, is all wrong.
At the time of independence the Nation was unable to grow enough food for a population of just 330 millions. Immediately after independence the Government took up a program to increase irrigated area through construction of dams, barrages, canals and ground water structures. The result of this is there for all to see. Today the population has increased to 1000 millions and yet we are not only self sufficient in food production, we have built a huge buffer stock and India is now in a position to export food grains to other countries.
Indian expertise in water resources engineering is absolutely world class. We have constructed, with our own technology, tall dams, long dams, large canals, power houses and other related structures and, like in other disciplines, India’s expertise in water resources technology is also sought after all over the world.
This argument is designed to divert attention from our achievements, which are real. Yes, there are people who can not afford two meals. But that is because of poverty, they lack purchasing power. That is unfortunate, but is outside the scope of water management. Unemployment leading to poverty is a serious problem in developing countries, but that has nothing to do with water management. It is not as if our self sufficiency in food production has made them poor. The rural India of today is enjoying a level of prosperity that it has never known before.
In any case, plentiful availability is a must for poor to be able to afford the food. If the availability is less than requirement then the prices will rise and even those who have the purchasing power today will find their purchasing power dissipate. The water management as practised so far has ensured the availability of food, and that is a matter of fact, not opinion.
As explained in answer to Q1 above, we get most of our rainfall in a period of four months. In our rivers 80 to 90 % of the total annual flow occurs within these four months. If not stored, this water will flow away to the oceans. But water is required for various uses round the year. Dams are a way to create large reservoirs where the water can be stored for use when there is no rainfall.
In addition to this main role as water storage devices, dams also play an important role in moderating the floods; generate hydel power which is clean energy and help improve the environment.
Though it may sound surprising, the fact is overall impact of a dam is to improve the environment in several ways. The water stored behind a dam enables regulated releases of water during winter and summer thus maintaining a higher flow in the river, so necessary for the health of the river, for aquatic life, flora and fauna. One of the reasons quality of water in Yamuna near Delhi is so bad is: there is no dam yet on Yamuna upstream of Delhi. Therefore, once the monsoon is over the flow in Yamuna reduces to a trickle and this worsens the water quality.
Dams also produce clean energy thus conserving fossil fuels, reduce air pollution and reduce green house gases. Irrigation brings back to land the water that had drained away because of natural land slope. Although irrigation water is applied to agricultural fields, only a part of it is consumed by the crops. The rest percolates to the ground water formations and this is available to the forests also. The increased ground water leads to increased flow during dry weather and thus helps aquatic ecosystems. Thus canal irrigation actually supplies water for the ecological needs as well.
Further, it must be understood that every human activity causes some damage to the environment. You light a gas stove to cook your food, or use a car to go from one place to other, and you have released some green houses gases, caused some air pollution and have added to global warming. The land on which your house/ office / school/ hospital are built, was a forest at some point of time. No matter what cloth you use, some damage has been done in producing that cloth. And so on. Should we then advocate a return to eating our food raw, living in caves and using animal fur to cover ourselves ?
The point is: it is foolish to discuss these things in terms of “damages” versus “does not damage”. For every activity, the question asked should be (a) how much is the possible damage and (b) whether it is unavoidable.
Some forest land may be submerged in the reservoir area of which some may actually be a forest. But now a days it is common to take up compensatory afforestation, artificially planting new forests, to make up for the loss of forest in the reservoir area. Usually these man made forests are larger and of better grade than the forests submerged in the reservoirs.
Forests get destroyed because of mankind’s demand for wood, and not because of dams. Consider the example of Narmada. In Narmada valley, dams construction has stated only during last decade or so. Since there were no dams till say 1990, the forest area in Narmada till 1990 should have been same as that in 1950, 1900, 1850 or 1800. Do you think that is so ? And if not, then obviously there are some other reasons for reduction of forests.
That is one of the unfortunate aspects of dam construction. However, the number of people who benefit from the construction of a dam is much larger than the number of people who are displaced. Democracy is about “greatest good for greatest numbers”. The affected persons must be rehabilitated. On that there can be no compromise. But that is not what the activists said. Their demand was “koi nahi hatega, bandh nahi banega”. i.e. no one will move, no dam will be made. It is one thing to demand a satisfactory rehabilitation package for the affected people and it is quite a different thing to say that no dams should ever be constructed.
Cost, benefits and life span. Nothing is infinite. Every human endeavour, including we ourselves, has a finite life. So ? But let us compare the cost and benefits of a dam with some other ventures that cost similarly.
A typical passenger aircraft today costs 150 million $ (700 crore Rs.) A midsize airline with say 50 aircrafts spends 7.5 billion $ (34,500 crore Rs.) on the aircrafts, which have a life of about 20 years. (or less, in case of a crash). Even if there is no crash, after 20 to 25 years the entire fleet has to be renewed.
For the same cost a typical large dam will irrigate 3 million (30 lakh) hectares of land, produce upwards of 210 million tons of food grains every year, provide drinking water for 50 million people, and generate 2,400 megawatts (MW) of power, and continue to do all this for 200 or more years !
Do we need to say any thing more on this ?
Silting. Every dam is provided with a storage volume called the “dead storage” approximately equal to the volume of silt expected to settle in the reservoir in 100 or more. Thus, only the dead storage volume will get filled in that time, say 100 years. The reservoir will continue to work usefully much longer, say 200 years or more.
The Mettur reservoir on Cauvery was constructed in 1934; Bhandardhara on Godavari in 1926. Have they got silted up ? These are just two examples. The astonishing fact is: no other human endeavour is planned for such a long life as a dam.
Dam burst. While theoretically a dam can burst and cause floods, in reality it is very rare for a dam to burst and it is even rarer for a mega dam to burst. A dam is designed with many safety factors and larger the dam, more the safety precautions. India particularly has an excellent dam safety record. So far, in India there have been only 4 instances of collapse of a dam of significant size, and these too were relatively small dams. Not a single big dam has ever burst. The safety record of dams is much, much better than that of any other human endevour.
A certain degree of risk of failure is inherent to any human activity. The mankind did not stop ship building because the Titanic sank; or did not stop flying because the Concord crashed. Dams have done much better.
Earthquakes. Finally, the increased risk of earth quakes. This is called RIS, Reservoir Induced Seismisity. It has been found that large reservoirs sometimes (and not always) result in an increased seismic activity. But, a) the activity is invariably in form of mild tremors NOT large earth quakes and b) over a period of time this too dies out. Devastating earthquakes do occur periodically, but not a single one has ever been caused by a dam.
|1769-70||30 lakhs to 1 crore|
First, there is a limit to the amount of rain that can be “caught” by traditional methods like small tanks, kundis, bawdis, or by recharge of ground water. It is estimated that all such structures in entire India have a storage capacity of 3 bcm where as the storage capacity created by the dams is already 175 bcm. Even that is not sufficient, and more will have to be added through dams presently under construction and also by taking up newer projects. Eventually, the capacity created through dams may be about 325 bcm. Thus, there is no comparison of the capacity of these two methods.
Second, rain water harvesting does not create new water. Except for coastal areas – like the city of Chennai – the rain intercepted at one place is the water that would have otherwise contributed to the flow of the river, to be used downstream. Thus, while rain water solves the problem for some one, it can create a problem for some one else.
Therefore, and you may be surprised to know this, in many countries (including USA) rainwater harvesting is banned by law !
Drought and floods are a part of natural hydrologic cycle. There will be some years when the rainfall is less than normal leading to a drought; and some other years there will be spells of very intense rainfall, causing floods. In a large country like India, it often happens that in the same year there is drought at some places and floods at other places.
Droughts. There was a time when drought meant famine and widespread deaths. (see answer to Q13). Now that it is possible to bring in food from distances over thousands of kilometres, drought does not mean famine. Now the main problem with drought is loss of livelihoods, increased poverty, migration in search of work, and related distress; and death of cattle heads.
Ground water is the best protection against drought. Because the ground water level does not fluctuate from year to year depending on rainfall and if the ground water is used in a sustainable manner, there will be sufficient ground water available for domestic use and for cattle even during a drought year. However, in recent years there has been over exploitation of ground water in many areas and this has lead to increased distress during droughts.
There is no doubt that the ground water, for that matter any resource, must be used in a sustainable manner. The main problem with our ground water is not less of recharge, but too much of extraction.
Floods. Flood is a situation when the river flow enters the area where there is human activity going on. When there is a spell of intense rainfall, i.e. a lot of rain occurring in a short period of time, the sudden increase in river flow needs more width and temporarily spreads on a wider area. The areas thus claimed by the river are called flood plains of the river. Population and economic pressures have driven the mankind to create habitations and take up other human activity in the flood plains. In this area, occasional floods are inevitable.
Floods can not be prevented. They can only be managed. The common flood management practices are:
Flood embankments: These are useful in providing quick protection to vital areas like major cities and installations.
Reservoirs. Flood control reservoirs store the flood waters and release them slowly after the flood is over. Construction of a reservoir takes time but is the most reliable method of flood protection.
Forests: Forests intercept some rain, increase the percolation, slow down the overland flow of water and thus reduce the intensity of floods. However it must be understood that the effects of a forest are significant only for small to medium floods. For large devastating floods, the effects of a forest are not so significant.
To understand this further, consider following analogy. Suppose some water is poured over a person’s head and it is intended to observe how much of it will flow down to his shoulders. Does it matter whether the man is bald (no forest) or has a good growth of hair ?
That depends on how much water is poured. If a teaspoonful is poured, it certainly makes a difference. If the man is bald then all the water will quickly flow down to his shoulders while if the man has a good hair, then none will. But this difference will be less significant if a cupful of water is poured. And if a bucketful of water is poured on his head, then it makes no real difference whether the man is bald or hairy.
Likewise, forests will protect from small floods, will reduce the intensity of medium floods and will have only an insignificant effect on large floods.
First, it is not “a project”. It is a collection of several independent projects. Second, the name is slightly a misnomer, in the sense it gives wrong ideas to those not familiar with the river engineering. Rivers can not be linked the same way as highways or electricity lines can be. On a road, the vehicles can move in any direction and thus start at any point and reach any other point. Likewise, the electricity in a wire can also move in any direction. But water can flow only in the direction of slope. Therefore, there can not be a water grid, the way there is a road or electricity grid.
What is intended is to make a canal to take water from one river to another river. Canals have transported water from one place to other for thousands of years. Usually, the origin and the end of the canal are in the same river basin. Some times a canal may cross the basin boundary and take the water to another basin. This is called trans-basin water transfer. At times, instead of digging a canal all the way to intended destination, the canal may discharge its flow in to an existing natural channel (a river) and the water may be transported further in the river. Since this causes water to be transported from one river to other, it is called interlinking of rivers. The more correct description is “trans-basin transfer of water”.
The idea is to bring water from areas that have relative surplus water to areas of deficit. The idea is not at all new. A project based on this concept idea was first mooted by Dr. K L Rao, then Minister for Irrigation. The main component of his idea was a canal from Ganga to Kaveri and therefore it came to be known as Ganga-Kaveri link. However, on further analysis, it was found that the cost- benefit was not favourable.
Capt. D J Dastur, a pilot with an airline, proposed an idea comprising a long East-West canal along the Himalayan foot hills and a U shaped canal, its limbs running North-South, and joining this Himalayan canal at its upper tips. On the map this looked like a garland around the Indian peninsula and therefore came to be known as the “Garland Canal” project. The canals were supposed to be horizontal, capable of transporting water in either direction and also function as storage reservoirs.
Dr. KL Rao was himself an accomplished engineer and thus his idea was sound in its engineering planning. Capt. Dastur was a pilot and his idea was not even technically sound. Therefore neither project was taken up.
In 1982 Government of India setup a specialised agency called National Water Development Agency (NWDA) to methodically investigate the possibilities of trans-basin water transfer. The plan prepared by NWDA is called “National Perspective Plan”. As per this plan, there will be 30 different links to transfer water from various surplus areas to deficit areas. The details are too voluminous to provide under a FAQ column. Click on the link below for more details of the plan.
The plan will enable use of an additional 200 bcm of water, provide irrigation to 35 MHa of land and generate 34,000 MW of electricity. In addition there will be other benefits like flood control, drought mitigation, inland navigation, improvement of river ecology, and also indirect benefits like employment generation.
Trans-basin transfer water is nothing new. It has been done in India and elsewhere in the world. Beas-Sutlej link, IGNP canal, Sardar Sarovar canals, are some of the existing trans-basin water transfer projects.