Water next to air is essential for all living beings on this planet. The need for water for human beings is increasing with the increase in their numbers and the development of various socio-economic activities. The amount of freshwater available for human consumption is only less than 1 per cent of the total available water on the earth. Again, out of this, because of various anthropogenic activities particularly due to urbanisation and industrialisation, a large portion of water available to human society is getting polluted.
At present, nearly 70 per cent of the water is being used in agriculture, 23 per cent in industry and the rest 7 per cent for drinking and other domestic purposes. It may be mentioned here that, we ‘eat’ much more water than we drink. For example, in a rich country like the USA, a person ‘eats’ about 3000 litres of water indirectly through various food items and drinks only 2 to 5 litres per day. This is because most of the food grains, vegetables, fish, meat etc require a lot of water to be produced. For example, 800-4000 litres of water is required to grow a kg of wheat, 2000-16,000 litres of water to grow a kg of beef and 2000-8700 litres of water to grow a kg of cotton, are required.
It is reported that global food demand may increase by 70 to 90 per cent of the present figure by 2040 without any increase in water productivity under the present situation. Therefore, the water for food requirements without any change in diet, from rain-fed and irrigated land has to be doubled. Further, besides the agricultural sector, the demand for water in industrial and domestic sectors is likely to grow appreciably in the years to come.
Many parts of the world including India, even at present, have started facing water scarcity. This situation is going to be worse in the next decades unless some remedial measures to improve the water resource are undertaken. At present, more than 1.2 billion people (nearly 20 per cent of the world population) are living in water-stressed regions. The United Nation Development Programme (UNDP) estimates that by 2025, the number of people in the water-stressed regions will be around 3 billion.
A recent report co-sponsored by the Consultative Group on International Agricultural Research (CGIAR), Food and Agriculture Organisation (FAO), CBD and the RAMSAR Convention (formally, the Convention on Wetlands of International Importance, especially as Water flow Habitat), has warned the human society that it would be very difficult to meet the global demand for food in the next few decades unless necessary reforms in the management of water and agriculture sectors are undertaken.
The following anthropogenic activities are responsible for the scarcity of water
1. Pollution of freshwater resources:
The rapid development of industries and growing urbanisation are responsible for polluting a large proportion of available freshwater due to the release of toxic solids and liquid effluents to water bodies without any treatment, making most of the available water unsuitable for drinking and sometimes even for agricultural purpose. For example, Lake Tie, the third-largest freshwater body in China, is completely polluted by industrial and agricultural wastes. As a result, over 2.3 million households are unable to meet their water requirements, forcing them to look for alternate water supply.
2. The disappearance of wetlands:
Nearly half of the wetlands on this planet have disappeared during the last century due to the establishment of industrial infrastructures, roads, development of urban settlements etc. and hence resulted in an increasing water crisis. At present, in the world, some rivers no longer reach the sea and nearly 20 per cent of the estimated 10,000 freshwater fish species are now endangered or extinct. The situation regarding the rapid disappearance of wetlands of India is worse.
3. Climate change and irregularity of rainfall:
Global warming and climate change have taken place mainly due to the polluted atmosphere on this earth. According to the Intergovernmental Panel on Climate Change (IPCC) report, freshwater availability for all human beings is highly alarming. If the global average temperature increases by 30C, another hundred million people will be in the water-stressed region. The IPCC report also predicted that, by 2020, between 75 – 200 million people were likely to be exposed to increased water stress. For example, it is apprehended that, in near future, the yield from rain-fed agriculture may be reduced by 50 per cent in Africa. Climate change is expected to bring appreciable changes in precipitation pattern and disappearance of glaciers resulting in a significant decrease in the availability of freshwater for human consumption.
4. Extravagance in use of water:
Agricultural sector alone consumes nearly 2/3rd of the water used by human society and very often, the water actually used is much more than what is required. The main reason is the colossal loss of water due to faulty transportation, leakage, accumulation of excess water in some farmlands and evaporation. Further, the present irrigation system particularly in a country like India actually consumes only 37 to 50 per cent of water used and the rest of the water gets evaporated. In the industrial sector, the water used instead of being recycled after proper treatment is let out to the nearby water bodies and pollute these. Further, a good amount of freshwater is used for purposes like dedusting of roads and washing the vehicles and equipment. In the domestic sector, particularly in the urban areas, a huge quantity of potable water is used for less important purposes like flushing the toilets, watering the plants in the garden, washing vehicles and dedusting the roads etc.
In view of these, during the years to come, besides meeting the water crisis, human beings would lead a very miserable life by using polluted water. Therefore, it is necessary to undertake certain major steps for mitigating the water crisis with a zero waste approach:
- Rain Water Harvesting projects at suitable sites both in rural and urban areas should be planned and implemented scientifically for increasing both the surface and groundwater resources.
- Existing wetlands should be developed and new ones should be created particularly in low lying areas to enhance both the surface and groundwater resources.
- Programmes to keep the rivers and other water bodies away from wastes and effluents from the point and non-point sources should be undertaken.
- It should be mandatory for all mines and major industries to harvest rainwater to meet most of their requirements particularly during summer and winter months and recycling the wastewater for various purposes. They should also be motivated to develop wetlands.
- The irrigation system should be modernised so as to utilise water resources judiciously.
- Pricing of water per volume and tariff should be fixed in proportion to the benefits derived by the consuming agencies.
- High priority should be given to provide drinking water to all, preferably extracted from deep aquifers.
- A network of water quality monitoring system should be developed both in rural and urban areas and
- Government agencies at different levels should have the resources and responsibility to implement these programmes involving all concerned and also to bring awareness amongst the public for proper management of water resources.