NIH Water Resources Of India

Water is a precious natural resource vital, for sustaining all life on the earth. It is in a continuous circulatory movement - hydrologic cycle. It is not uniformly distributed in time and space. Due to its multiple benefits and the problems created by its excesses, shortages and quality deterioration, water as a resource requires special attention.

On a global scale, total quantity of water available is about 1600 million cubic km. The hydrological cycle moves enormous quantities of water about the globe. However, much of the world's water has little potential for human use because 97.5% of all water on earth is saline water. Out of remaining 2.5% fresh water, most of which lies deep and frozen in Antarctica and Greenland, only about 0.26% flows in rivers, lakes and in the soils and shallow aquifers which can be readily used.

The concept of sustainable development implies development that meets the needs of present without compromising the ability of the future generations to meet their own needs. This is all the more important for a resource like water. Sustainable development would ensure minimum adverse impacts on the quality of air, water and terrestrial environment. The long term impacts of global climatic change on various components of hydrologic cycle are also important.

River Basin Map of India


India has sizable resources of water and a large cultivable land but also a large and growing population to feed. Erratic distribution of rainfall in time and space leads to conditions of floods and droughts which may sometimes occur in the same region in the same year. India has about 16% of the world population as compared to only 4% of average annual runoff in the rivers.

With the present population of around 1000 million, the per capita water availability comes to about 1170 m3/person/year. Here, the average does not reflect the large disparities from region to region in different parts of the country. Against this background, the problems relating to water resources development and management have been receiving critical attention. With a view to have a systematic and scientific development of its water resources, the country has prepared and adopted a comprehensive National Water Policy in the year 1987.




Geographical Area
        Flood Prone Area
Ultimate Irrigation Potential
Total Cultivable Land Area
Net Irrigated Area
Natural Runoff (Surface Water and Ground Water)
Estimated Utilisable Surface Water Potential
Groundwater Resource
Available Groundwater resource for Irrigation
Net Utilisable Groundwater esource for irrigation
329 millon ha.
         40 millon ha.
140 millon ha.
184 millon ha.
50 millon ha.
1869 Cubic km.
690 Cubic km.
432 Cubic km.

361 Cubic  km.

325 Cubic km.


Hydrologic Cycle


Hydrology is the science that treats the waters of the Earth, their occurance, circulation, movement and distribution, their chemical and biological properties and their reaction with their environment, including their realtion to living things. The domain of hydrology embraces the full life history of water on the earth.

Hydrological Studies vis-a-vis Water Resources Problems

Many of the country's problems seem to circle around water. Water resource constitutes one vital natural resource that has not been utilised as efficiently as in some developed countries. There is a lack of awareness in public about optimal use of water as well as less emphasis is being given to hydrology at the time of planning, designing and operation of water resources projects. Hydrology touches every human activity in some manner. Incomplete information and lack of awareness of principles of hydrology often result in mis-management of water and wastage of money. Some of the common examples are: over irrigation of fields by farmers by cutting canals which may result in water logging of the field; in many places taps are left running or there are no taps at all etc. Apart from these, wastage of water by evaporation; erosion of fertile soil; losses due to droughts and floods; degradation of water quality; failure of hydraulic structures etc. are some of the areas which can be tackled effectively if sufficient knowledge about hydrology is available. More and more increasing demands for food grains and water due to increase in population, increase in per capita consumption of water due to rise in living standards, and increase in industrial development provide opportunities and challenges for hydrologists.

Why Water is Scarce?

Increase in water requirements due to increase in population
Easily available sources of water tapped already
Delay in project initiation time due to increasing social and environmental concern
Contamination of available water sources due to increase in human activities
Industrial development
Human needs and desire for higher standards of living


Population and Food Grain Requirement
Various studies by demographers in India and abroad suggest that world population will continue to rise atleast till 2050 AD. The United Nations has projected world population in "World Population Prospects" the 1992 revision upto 2050 AD. This has been further extrapolated to 2050 AD in the publication "Sustaining Water-An Update (1994)". This indicates India's 2050 AD population as 1349 million (low projection), 1640 million (medium projection) and 1980 million (high projection). In India the food grain availability is at present around 525 gms per capita per day whereas the corresponding figures in China & USA are 980 gms & 2850 gms respectively. Assuming the same level of consumption, which although is supposed to rise with improvement in economy and resultant higher standard of living, the annual food grain requirement will be about 315 MT. If small raise is made in per capita consumption to 650 gms, the food grain requirement will be about 390 MT. Taking the projection of about 1800 million by 2050 AD as reasonable, it would require about 430 MT of food grain annually at the present level of consumption. The present productivity of irrigated land is about 2.5 T/ha and less than 0.5 T/ha for rainfed lands. Assuming that these levels can go upto 3.5 and 1.0 T/ha respectively by 2050 AD, it is imperative that we create an irrigation potential of atleast 130 m.ha for food crop alone and 160 m.ha for all crops to be able to meet demands of the country by 2050 AD.

Thus the question which needs to be asked is : are we capable of producing these amounts of foodgrains for the consumption in the country on a sustainable basis. This will mean a much greater use of available inputs. First input is water, the second input would be fertilizers and third input would be much larger emphasis on research. But even if it is taken for granted that no "Wonder" foodgrain seed will be available, we will have to increase the area under irrigation from present 28% to roughly about 40 percent by the year 2050. The possible options available to meet the future irrigation and food needs may, therefore include drip and sprinkler irrigation, change of cropping pattern, evaporation control and reduction of conveyance losses, recycling of water, inter-basin transfer, de-salinisation of sea water and ground water in coastal areas, rainfall by cloud seeding, improved technology etc. Loss of top soil due to erosion is one of the forms of degradation which can be contained on a limited scale but problems of salinity, alkalinity, water logging etc. reduce the productivity. The future lies in considering and bringing additional area under cultivation and considering intensified production on existing good agricultural land which would require in depth studies by hydrologists and water resources researchers.

Land and Water Resources
The total geographical area of land in India is 329 (exactly 328.762) m.ha. which is 2.45% of the global land area. The total arable land ( as per Food and Agriculture Organization estimate) is 165.3 m.ha. which is about 50.2% of total geographical area against the corresponding global figure of 10.2%. India possesses 4% of the total average annual runoff in the rivers of the world. The per capita water availability of natural runoff is atleast 1,100 cu.m. per year (year 2000 estimates).

The utilizable surface water potential of the country has been estimated to be 1869 cubic km. But the amount of water that can be actually put to beneficial use is much less due to severe limitations imposed by physiography, topography, inter-state issues and the present state of technology to harness water resources economically. The recent estimates made by the Central Water Commission indicate that the water resources utilisable through surface structures is about 690 cubic km. only (about 36% of the total). Ground water is another important source of water. Quantum of water which can be extracted economically from the ground water aquifers every year is generally reckoned as ground water potential. The preliminary estimates made by the Central Ground Water Board indicate that the utilisable ground water is about 432 cubic km. Thus, total utilisable water resource is estimated to be 1122 cubic km.

Of the total 329 m.ha. of land, it is estimated that only 266 m.ha. posseses potential for production. Of this, 143 m.ha. is agricultural land. It is estimated that 85 m.ha. suffers from varying degrees of soil degradation. Of the remaining 123 m.ha., 40 m.ha. are completely unproductive. The balance 83 m.ha. is classified as forest lands, of which over half is denuded to various degrees.

India has a large cattle population. The 419 million heads of livestock (as per 1982 census report) have to be supported on 13 m.ha. i.e. less than 4% of the land which is classified as pasture lands, most of which is overgrazed. Thus, out of 266 m.ha., about 175 m.ha. (66%) is degraded to varying degrees. Water and wind erosion account for the degradation of almost 150 m.ha. out of this. Soil erosion has increased from 6,000 million tonnes in 1972 to 1,2000 million tonnes in 1985. Per capita availability of land is half of what it used to be some 35 years ago. The challenge of prevention of erosion and indeed of restoration of India's land resources is therefore intimately related to strategies for the management of land, water and vegetative cover. At present 141 m.ha. are used for cultivation purposes. Between 1970-71 and 1987-88 the average net sown area has been 140.4 m.ha. with a maximum of 143.21 m.ha. in 1983-84 and a minimum of 136.18 m.ha. in 1987-88. The need for production of food, fodder, fibre, fuel and urbanisation will put severe competing claims on the land. Moreover, water logging, salinity, alkalinity of soils on account of inadequate planning and inefficient management of water resource projects in conjunction with over adverse physical factors, will severely constrain the growth of net sown area in the future.

National Water Policy
The National Water Policy deals with establishing standardised national information system, data collection, establishment of basinwise organisations with multi-disciplinary approach to the planning. formulation, clearance and implementation of projects, rehabilitation, ground water development, water zoning, flood and drought management, research and development including training. The National Water Policy provides a framework for coordinated water development across States and alternative uses of water, and it emphasises the need for river basin planning. However, the National Water Policy has had little operational impact due to lack of institutional mechanism to plan, coordinate and implement water development across State boundaries and among users. Another problem is limited data and mechanisms for sharing data between States and between users within the States. Each State has to reaffirm that National Water Policy fitting within the framework of that policy and river basin plans built so far. Madhya Pradesh has prepared a draft State Water Policy. Bihar has taken initiative in setting up of a Second Irrigation Commission and Water Resources Commission. Apart from these, no other State has taken any initiative to draft a State Water Policy. The National Water Policy may require some updating on certain issues in near future.

The National Water Policy in its present form appears to be a statement of intentions as it is not supported by any legislation and does not have an action plan. It does not provide any authority or makes anybody responsible for its implementation. The Policy does not provide the economic cost of water and investment scenarios. The constitutional provisions and legal issues have also not been addressed in the Policy.

Hence there is a need for evolving and operating the Policy according to a feasible action plan.

Development Trends and Urbanization
As per the recent estimates presently half of the world population is living in urban areas. In India also, there has been a major shift of population from rural areas to urban areas with a view to have better livelihood and better standards of living. As a result of this large human concentration there are changes that are likely to occur in the urban environment, with in its physical and socio- economic aspects.

This would necessitate integration of urban drainage, water supply, solid wastes and sewage disposal in order to cope with the increasing demands for municipal and industrial water uses. Most urban centres in the developing countries like India still lack the facilities that are adequate for proper collection and disposal of domestic and industrial wastes. Also, urban runoff is typically highly polluted with pathogenic and organic substances that are health threats during high flood events.

In India, in 1901 there were 1827 urban agglomerations with a population of 25.85 million which was 10.84% of the then total population, whereas as per 1991 census there are 3768 urban agglomerations/towns covering a population of 217.8 million which works out to about 25.72% of the country's population. The class-I (population of one lakh and above) towns account for 65.2% of the total urban population of the country in 1991. There are now 23 metropolitan cities with a population of one million or more each as compared to 12 such cities in 1981. These 23 cities account for roughly one-third of country's urban population and one-twelfth of country's total population. There are 5 mega cities with a population of 5 million each and almost one fourth of the population living in class-I towns in the country lives in these mega cities. This clearly indicates towards a shift from rural areas to urban areas.

In India less than half of the urban population has access to sewage disposal system. Most of the existing collecting systems discharge directly to the receiving water without treatment. Garbage, domestic and otherwise, is directly dumped into water bodies or roadside which can often later be washed into streams and lakes. This vulnerable environment requires special attention and the solution of such complex and interdisciplinary problems call for an integrated water resources management approach.

In India, till now very little emphasis has been laid on research on hydrology of urban areas. Taking into account that the trends of urban population concentration increase will continue in the future, a programme for encompassing all hydrological, ecological and socio-economic aspects of future urban planning and management needs to be taken up in right earnest.

This would require improvement in the management of existing urban drainage systems, disseminate knowledge of integrated urban water management, identify the impact of urbanization on surface and ground water quality through point and non-point sources, to study impact of storm water (wastewater discharges) on ecosystem health of receiving water courses and to establish experimental urban catchments.

Demands and Availability
The average annual surface water flows in India has been estimated as 186.9 m.ha.m. of which only 69 m.ha.m. can be utilised if appropriate storages can be created. The reason for this vast difference between potential and the conditional availability has been well recognised - the monsoonic climate, besides topographical and geological limitations. What is important to note is that not only does the whole rainfall occur in about 4 months in a year but the spatial and temporal distribution of rainfall is so uneven that the annual average have very little significance for all practical purposes. In fact, one - third of the country is always under threat of drought not necessarily due to deficient rainfall but many times due to its uneven occurrence. This is the peculiar phenomenon of "scarcity amidst plenty", manifesting often in the form of droughts and floods.

In addition to surface water, there is a dynamic (rechargeable) ground water resource. Its potential has been estimated as 43.2 m.ha.m. including recharge due to canal irrigation. This means that the total water availability would be 230.1 m.ha.m. in 2050 or the per-capita availability of 1403 m3. The country will thus be water stressed even if the total availabile water is taken into account.

The 1640 million population of India in 2050, half of them urban and half of them rural, would need 9 m.ha.m. of water to meet their domestic needs based on conservative estimates of 200 litre per capita per day (lpcd) for urban areas and 100 lpcd for rural areas. The latter includes demands of live stock. It may be noted that the ground water makes marginal contribution to urban demands but, meets almost the entire rural demand.

Surface waters shall have to be harnessed to meet the urban requirement of nearly 6 m.ha.m. keeping in view the fierce competition and sometimes, the conflicting demands of irrigation and domestic sectors. Drinking water being given first priority in the National Water Policy (NWP), does not mean unlimited quantities being appropriated to this sector. Only 20% of urban demand is for consumptive use. A major concern will, therefore, be treatment of urban domestic effluents, which would make or break the system. This has been discussed in the following sections.

Major industrial thrust to steer the economy is only a matter of time. By 2050, India would be a major industrial power in the world. Industry needs water - fresh or recycled. Processing industries depend on abundance of water. It is estimated that 6.4 m.ha.m. of water will be needed by 2050 to sustain the industries. In fact, the pollution caused due to industrial effluents is a far more serious problem, than the one due to domestic effluents because of their higher potential to damage the natural land-water resource system. Again, the actual consumptive use of water by industries is only about 20% of their demand.

Notwithstanding the present impasse in respect of storage based hydro-power due to environmental concerns, future plans for energy can not ignore a major thrust in this direction. The country lacks quality fossil fuel to meet the long term energy needs, besides their being no more friendly to the environment. The country also can not afford to deplete the fossil fuel, without adversely affecting sustainable development.

However, from the point of view of water resource potential, hydropower does not involve consumptive use except evaporation losses and flow from tail race. Thermal power generation needs water including a small part being consumptive. Taking into account the electric power scenario in 2050, energy related water requirement (evaporation plus consumptive use) is estimated at 15 m.ha.m.